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Journal articles on the topic 'Pyrimidine ring'

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Published: 10 December 2022

Last updated: 19 February 2023

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1

Verma, Vishal, Chandra Prakash Joshi, Alka Agarwal, Sakshi Soni, and Udichi Kataria. "A Review on Pharmacological Aspects of Pyrimidine Derivatives." Journal of Drug Delivery and Therapeutics 10, no. 5 (September 15, 2020): 358–61. http://dx.doi.org/10.22270/jddt.v10i5.4295.

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Pyrimidine is an aromatic heterocyclic organic compound similar to pyridine. One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has the nitrogens at positions 1 and 3 in the ring. Pyrimidines are typically synthesized by the “Principal Synthesis” involving cyclization of beta-dicarbonyl compounds with N-C-N compounds. Reaction of the former with amidines to give 2-substituted pyrimidines, with urea to give 2-pyrimidiones, and guanidines to give 2-aminopyrimidines are typical. Pyrimidines can be prepared via the biginelli reaction. Many other methods rely on condensation of carbonyls with diamines for instance the synthesis of 2-Thio-6-methyluracil from thiouria and ethyl acetoacetate or the synthesis of 4-methylpyrimidine with 4, 4-dimethoxy-2-butanone and formamide. Pyrimidine derivatives show antimicrobial activity, anticancer activity, anti-inflammatory activity, antidiabetic, and analgesic activity.1. Keywords: Pyrimidine derivatives, Synthesis, derivatives and pharmacological activities.

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2

Wenska, Grazyna, Bohdan Skalski, Stefan Paszyc, and Zofia Gdaniec. "Photochemistry of N-(pyrimidin-2-one-4-yl)pyridinium derivatives. The ring contraction of pyrimidinone into imidazolinone." Canadian Journal of Chemistry 73, no. 12 (December 1, 1995): 2178–84. http://dx.doi.org/10.1139/v95-270.

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Photochemical reactions (λ > 300 nm) of N-(1-methylpyrimidin-2-one)-and N-(1,5-dimethyl-pyrimidin-2-one)pyridinium chlorides were studied in deoxygenated aqueous solution at various pH's. Only the former compound was found to be reactive under these conditions to give pyrimidine ring contraction photoproducts 1-methyl-4-imidazolin-2-one and 1-methyl-4-imidazolin-2-one-5-carboxyaldehyde, with pH-dependent chemical yields. The photochemical pyrimidine ring contraction reaction does not occur for other photochemically reactive pyrimidin-2-ones bearing 3-methylimidazolium-1,1,2,4-triazol-1-yl, or imidazol-1-yl as substituents at the C-4 position. The suggested mechanism of the reaction involves the addition of water to the pyrimidinone part of the N-(1-methylpyrimidin-2-one)pyridinium salt in the excited triplet state as the primary photochemical step. Addition of alcohol to the pyridinium ring was found to be the major reaction under irradiation of N-(1-methylpyrimidin-2-one-4-yl)pyridinium chloride in methanol. Keywords: photochemistry, N-(pyrimidin-2-one-4-yl)pyridinium compounds, pyrimidine ring contraction, 1-substituted-4-imidazolin-2-ones, 4-imidazolin-2-one-5-carboxyaldehydes.

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3

Mohammed, F. K., and M. G. Badrey. "Synthesis of Pyrimidines and Heteroannulated Pyrimidine Ring Systems." Journal of the Korean Chemical Society 55, no. 2 (April 20, 2011): 218–29. http://dx.doi.org/10.5012/jkcs.2011.55.2.218.

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4

Azam, Mohammed Afzal, Loganathan Dharanya, Charu Chandrakant Mehta, and Sumit Sachdeva. "Synthesis and biological evaluation of some novel pyrazolopyrimidines incorporating a benzothiazole ring system." Acta Pharmaceutica 63, no. 1 (March 1, 2013): 19–30. http://dx.doi.org/10.2478/acph-2013-0001.

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In the present study, a series of benzothiazol derivatives 3a-l containing pyrazolo[3,4-d]pyrimidine moiety at the second position were synthesized and characterized by analytical and spectral data. The compounds were tested for their in vitro antimicrobial activity. Compounds 1-(1,3-benzothiazol-2- yl)-3-methyl-4-phenyl-1H-pyrazolo[3,4-d]pyrimidine (3a), 1- (1,3-benzothiazol-2-yl)-4-(4-chlorophenyl)-3-methyl-1H-pyrazolo[ 3,4-d]pyrimidine (3d) and 1-(1,3-benzothiazol-2-yl)- 3-methyl-4-substituted phenyl-1H-pyrazolo[3,4-d]pyrimidines (3h-j) showed significant inhibitory activity against P. aeruginosa whereas compounds 1-(1,3-benzothiazol-2-yl)-4- (2-chlorophenyl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidine (3b), 2-[1-(1,3-benzothiazol-2-yl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidin- 4-yl]phenol (3e), 1-(1,3-benzothiazol-2-yl)-4-(3,4-dimethoxyphenyl)- 3-methyl-1H-pyrazolo[3,4-d]pyrimidine (3h), 4-[1-(1,3-benzothiazol-2-yl)-3-methyl-1H-pyrazolo[3,4-d]pyri midin-4-yl]-N,N-dimethylaniline (3j) and 1-(1,3-benzothiazol- 2-yl)-3-methyl-4-[2-phenylvinyl]-1H-pyrazolo[3,4-d]pyrimidine (3k) were found to be active against C. albicans. Some of these synthesized compounds were evaluated for their in vivo acute toxicity, analgesic, anti-inflammatory, and ulcerogenic actions. The tested compound 4-[1-(1,3-benzothiazol- 2-yl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl]-N, N-dimethylaniline (3j) exhibited maximum analgesic and anti-inflammatory activities. Compounds 1-(1,3-benzothiazol- -2-yl)-3-methyl-4-(3-nitrophenyl)-1H-pyrazolo[3,4-d]pyrimidine (3i) and 3j showed a significant gastrointestinal protection compared to the standard drug diclofenac sodium.

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5

Gallagher, P. E., and N. J. Duker. "Detection of UV purine photoproducts in a defined sequence of human DNA." Molecular and Cellular Biology 6, no. 2 (February 1986): 707–9. http://dx.doi.org/10.1128/mcb.6.2.707-709.1986.

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The UV-irradiated, 3'-end-labeled, 92-base-pair terminus of the human alphoid sequence was incubated with purified endonuclease v. Previously unreported photoproducts were incised at purine loci. These were not pyrimidine photodimers, 6-4'-(pyrimidin-2'-one)-pyrimidines, base loss sites, or ring-opened purines. Therefore, purine-containing photoproducts, possibly dimers, were incised by the enzyme preparation.

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6

Gallagher, P. E., and N. J. Duker. "Detection of UV purine photoproducts in a defined sequence of human DNA." Molecular and Cellular Biology 6, no. 2 (February 1986): 707–9. http://dx.doi.org/10.1128/mcb.6.2.707.

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The UV-irradiated, 3'-end-labeled, 92-base-pair terminus of the human alphoid sequence was incubated with purified endonuclease v. Previously unreported photoproducts were incised at purine loci. These were not pyrimidine photodimers, 6-4'-(pyrimidin-2'-one)-pyrimidines, base loss sites, or ring-opened purines. Therefore, purine-containing photoproducts, possibly dimers, were incised by the enzyme preparation.

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7

Yamuna, Thammarse S., Jerry P. Jasinski, Brian J. Anderson, H. S. Yathirajan, and Manpreet Kaur. "4-Hydroxy-5-(2-methoxyphenoxy)-2,2′-bipyrimidin-6(5H)-one dihydrate." Acta Crystallographica Section E Structure Reports Online 69, no. 11 (October 26, 2013): o1707—o1708. http://dx.doi.org/10.1107/s1600536813028900.

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The title compound, C15H12N4O4·2H2O, crystallizes with two independent water molecules in the asymmetric unit. The dihedral angles between the mean planes of the benzene and pyrimidine rings and that of the pyrimidin-4-one ring are 85.1 (9) and 82.1 (1)°, respectively. The mean plane of the pyrimidine ring is twisted by 12.8 (8)° from that of the pyrimidin-4-one ring. The dihedral angles between the benzene ring and the mean planes of the pyrimidine and pyrimidin-4-one rings are 85.1 (9) and 82.1 (1)°, respectively.In the crystal, N–H...O, O—H...N and O—H...O hydrogen bonds involving both water molecules are present; these link the molecules into a two-dimensional network parallel to (010). In addition, weak C—H...π and π–π [centroid–centroid distance = 3.6183 (8) Å] interactions occur.

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8

Ahmed Elkanzi, Nadia Ali. "Synthesis and Biological Activities of Some Pyrimidine Derivatives: A Review." Oriental Journal Of Chemistry 36, no. 6 (December 30, 2020): 1001–15. http://dx.doi.org/10.13005/ojc/360602.

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Nitrogen containing synthetically and biologically important heterocyclic ring system namely pyrimidine possess both biological and pharmacological activities, and defend as aromatic six heterocyclic with 1and 3 nitrogen atom in ring. Preparation of pyrimidine via different methods offer its importance in fields of medicinal chemistry and Chemistry. Pyrimidines and their derivatives act as anti-inflammatory, anti-malaria, anti-tumor, cardiovascular agents, anti-neoplastic, anti-tubercular, anti- HIV, diuretic ,anti-viral, anti-microbial, ,analgesic .This review give light up on biological and pharmacological activities of pyrimidine nucleus.

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9

Behera, Manoranjan, M. Sambaiah, Poosa Mallesham, K. Shiva Kumar, Yamini Bobde, Prasanta Hota, Satyanarayana Yennam, and Balaram Ghosh. "Tandem Schiff-Base Formation/Heterocyclization: An Approach to the Synthesis of Fused Pyrazolo–Pyrimidine/Isoxazolo-Pyrimidine Hybrids." Synlett 30, no. 05 (February 5, 2019): 586–92. http://dx.doi.org/10.1055/s-0037-1612081.

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A new synthesis of pyrazolo[4,3-d]pyrimidines and isoxazolo[4,5-d]pyrimidines is described. Key steps in the synthesis involve Stille coupling of 4,6-dichloro-2-phenyl-pyrimidine with tributyl(1-ethoxyvinyl)stannane and tandem Schiff-base formation/heterocyclization of 2,6-di-aryl-5-fluoro-4-acetylpyrimidine with hydrazines or hydroxylamine to give pyrazolo[4,3-d]pyrimidines and isoxazolo[4,5-d]pyrimidines, respectively. The position of the fluoro group in the pyrimidine ring is important for the success of heterocylization reaction.

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10

Huppatz, JL. "Systemic Fungicides. The Synthesis of Pyrazolo[1,5-a]pyrimidine Analogues of Carboxin." Australian Journal of Chemistry 38, no. 1 (1985): 221. http://dx.doi.org/10.1071/ch9850221.

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The synthesis of a series of pyrazolo [1,5-a] pyrimidine derivatives, structural analogues of the systemic fungicide carboxin, is described. A common intermediate incorporating structural features desirable for fungicidal activity, N-phenyl-3(5)-amino-5(3)-methylpyrazole-4- carboxamide (6), was used to prepare pyrazolo [1,5-a] pyrimidines variously substituted in positions 5 and 7 of the ring system. Bromination of N-phenyl-2-methylpyrazolo[1,5-a]pyrimidine-3-carboxamide (8) occurred preferentially in the phenyl ring and the 6-bromo derivative was prepared by bromination of the corresponding 3-ethoxycarbonyl derivative (24). Attempted nitration of the ester (24) resulted in displacement of the ethoxycarbonyl substituent by a nitro group. The simplest pyrazolo [1,5-a] pyrimidine (8) showed a high level of fungicidal acitvity in fungal growth assays of Basidiomycete species, but compounds substituted in the pyrimidine ring were inactive.

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11

Nerkar, A. G., S. A. Ghone, and A. K. Thaker. "In SilicoScreening of the Library of Pyrimidine Derivatives as Thymidylate Synthase Inhibitors for Anticancer Activity." E-Journal of Chemistry 6, no. 3 (2009): 665–72. http://dx.doi.org/10.1155/2009/352717.

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We here report the virtual screening of several series of pyrimidine derivatives forin silicoThymidylate Synthase (TS) inhibition to arrive at possible potential inhibitors of TS with acceptable pharmacokinetic or ADME (Absorption, Distribution, Metabolism and Excretion) properties. Library of the molecules was constructed based upon structural modifications of pyrimidines nucleus. Structural modifications in descending order were performed for the series of pyrimidines,vizfrom pyrimidines with five membered heterocyclic ring to pyrimidines with four membered heterocyclic ring to simple pyrimindine carboxylates in an order to arrive at pyrimidines with better inhibition scores (G-Scores) as compared with Raltitrexed (RTX) and active metabolite of 5-Fluorouracil (5-FUMP). The molecules with betterG-Scores were subjected to predict pharmacokinetic or ADME properties. The molecules with acceptable ADME properties and betterG-Scores were prioritized for synthesis and anticancer evaluation. Three molecules from pyrimidine carboxylate series PIC1-31were found acceptable withG-Scores and pharmacokinetic properties. Thus a library of pyrimidine derivatives was constructed based upon the feasibility of synthesis and in silico screened to prioritize the molecules and to obtain potential lead molecules as TS inhibitors.

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12

Maji, Pradip Kumar. "Synthesis of Pyrimidine-Annulated Five-Membered Heterocycles: An Overview." Current Organic Chemistry 23, no. 20 (December 24, 2019): 2204–69. http://dx.doi.org/10.2174/1385272823666191019111627.

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This review describes the non-exhaustive scenery of the synthesis of various biologically interesting pyrimidine annulated five-membered heterocyclic ring systems that have been appeared in the literature during the last two decades. During this period, different synthetic routes and various methodologies have been developed for the functionalization of pyrimidine ring towards the construction of five-membered heterocyclic rings. The aim of this review is to give an overview of the assorted methodologies that have been reported about the chemistry of construction of pyrimidines annulated nitrogen, oxygen and sulphur containing five-membered heterocycles.

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13

Mosaad Sayed Mohamed, Samir Mohamed Awad, Neama Abdallah Abd El-tawab, and Naglaa Mohamed Ahmed. "An overview on synthesis and biological activity of pyrimidines." World Journal of Advanced Research and Reviews 15, no. 1 (July 30, 2022): 272–96. http://dx.doi.org/10.30574/wjarr.2022.15.1.0689.

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Pyrimidines represent an important class of heterocycles containing two nitrogen atoms at position 1 and 3 of the six membered ring show wide range of biological activities. Numerous methods for the synthesis of pyrimidine and their diverse reactions offer enormous scope in the field of medicinal chemistry. Pyrimidine possesses wide spectrum of biological activities including antitubercular, antibacterial, antifungal, antiviral, anti-inflammatory, antimalarial, anticancer, and anti-HIV activity. The present review attempts to give brief information about the synthesis and various biological activities of pyrimidines and their derivatives.

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14

Jubete, Guillem, Raimon Puig de la Bellacasa, Roger Estrada-Tejedor, Jordi Teixidó, and José I. Borrell. "Pyrido[2,3-d]pyrimidin-7(8H)-ones: Synthesis and Biomedical Applications." Molecules 24, no. 22 (November 16, 2019): 4161. http://dx.doi.org/10.3390/molecules24224161.

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Pyrido[2,3-d]pyrimidines (1) are a type of privileged heterocyclic scaffolds capable of providing ligands for several receptors in the body. Among such structures, our group and others have been particularly interested in pyrido[2,3-d]pyrimidine-7(8H)-ones (2) due to the similitude with nitrogen bases present in DNA and RNA. Currently there are more than 20,000 structures 2 described which correspond to around 2900 references (half of them being patents). Furthermore, the number of references containing compounds of general structure 2 have increased almost exponentially in the last 10 years. The present review covers the synthetic methods used for the synthesis of pyrido[2,3-d]pyrimidine-7(8H)-ones (2), both starting from a preformed pyrimidine ring or a pyridine ring, and the biomedical applications of such compounds.

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15

Cawrse, Brian M., Nia’mani M. Robinson, Nina C. Lee, Gerald M. Wilson, and Katherine L. Seley-Radtke. "Structural and Biological Investigations for a Series of N-5 Substituted Pyrrolo[3,2-d]pyrimidines as Potential Anti-Cancer Therapeutics." Molecules 24, no. 14 (July 23, 2019): 2656. http://dx.doi.org/10.3390/molecules24142656.

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Pyrrolo[3,2-d]pyrimidines have been studied for many years as potential lead compounds for the development of antiproliferative agents. Much of the focus has been on modifications to the pyrimidine ring, with enzymatic recognition often modulated by C2 and C4 substituents. In contrast, this work focuses on the N5 of the pyrrole ring by means of a series of novel N5-substituted pyrrolo[3,2-d]pyrimidines. The compounds were screened against the NCI-60 Human Tumor Cell Line panel, and the results were analyzed using the COMPARE algorithm to elucidate potential mechanisms of action. COMPARE analysis returned strong correlation to known DNA alkylators and groove binders, corroborating the hypothesis that these pyrrolo[3,2-d]pyrimidines act as DNA or RNA alkylators. In addition, N5 substitution reduced the EC50 against CCRF-CEM leukemia cells by up to 7-fold, indicating that this position is of interest in the development of antiproliferative lead compounds based on the pyrrolo[3,2-d]pyrimidine scaffold.

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16

Bischoff, Kerstin, Ulrich Girreser, Dieter Heber, and Martin Schütt. "Two-Step Synthetic Approach to 6-Substituted Pyrido[2,3-d]pyrimidine(1H,3H)-2,4-diones from 6-Amino-, 6-Alkylamino-, and 6-Arylamino-1,3-dimethyluracils." Zeitschrift für Naturforschung B 61, no. 4 (April 1, 2006): 486–94. http://dx.doi.org/10.1515/znb-2006-0415.

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The Mannich reaction of 7-aryl-5,6-dihydropyrido[2,3-d]pyrimidines 3, easily accessible by condensation of 6-amino-1,3-dimethyluracil (1) with Mannich bases 2a - c, gives rise to a mixture of 7-aryl-6-(N,N-dimethylaminomethyl)pyrido[2,3-d]pyrimidines 6 and 7 as well as 1,2-bis- (7-arylpyrido[2,3-d]pyrimidin-6-yl)ethane 13 the ratio of which depends on the reaction conditions and the amine used. 6-Alkylamino-1,3-dimethyluracils 15 - 18 were converted to the corresponding 5-(3-oxo-3-phenylpropyl)uracils 19 - 22 by condensation with the Mannich base 2a. Ring closure of 19 - 22 was performed by Vilsmeier formylation to afford the 8-alkyl- and 7,8-diaryl-5,8- dihydropyrido[2,3-d]pyrimidine-6-carbaldehydes 9 - 12 via the corresponding iminium salts 27 - 30

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17

Kang, Gihaeng, Jineun Kim, Hyunjin Park, and Tae Ho Kim. "Crystal structure of nuarimol." Acta Crystallographica Section E Crystallographic Communications 71, no. 8 (July 22, 2015): o586—o587. http://dx.doi.org/10.1107/s2056989015013493.

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The title compound [systematic name: (RS)-(2-chlorophenyl)(4-fluorophenyl)(pyrimidin-5-yl)methanol], C17H12ClFN2O, is a pyrimidine fungicide. The asymmetric unit comprises two independent molecules,AandB, in which the dihedral angles between the plane of the pyrimidine ring and those of the chlorophenyl and fluorophenyl rings are 71.10 (6) and 70.04 (5)° in moleculeA, and 73.24 (5) and 89.30 (5)° in moleculeB. In the crystal, O—H...N hydrogen bonds link the components into [010] chains of alternatingAandBmolecules. The chains are cross-linked by C—H...F hydrogen bonds and weak C—H...π and C—Cl...π [Cl...ring centroid = 3.7630 (8) Å] interactions, generating a three-dimensional network.

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18

Bommagani, Shobanbabu, Narsimha R. Penthala, Sean Parkin, and Peter A. Crooks. "Crystal structure of (E)-13-(pyrimidin-5-yl)parthenolide." Acta Crystallographica Section E Crystallographic Communications 71, no. 12 (November 28, 2015): 1536–38. http://dx.doi.org/10.1107/s2056989015021507.

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The title compound, C19H22N2O3, {systematic name (1aR,4E,7aS,8E,10aS,10bR)-1a,5-dimethyl-8-[(pyrimidin-5-yl)methylidene]-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one} was obtained from the reaction of parthenolide [systematic name (1aR,7aS,10aS,10bR,E)-1a,5-dimethyl-8-methylene-2,3,6,7,7a,8,10a,10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one] with 5-bromopyrimidine under Heck reaction conditions, and was identified as anEisomer. The molecule possesses ten-, five- (lactone) and three-membered (epoxide) rings with a pyrimidine group as a substituent. The ten-membered ring displays an approximate chair–chair conformation, while the lactone ring shows a flattened envelope-type conformation. The dihedral angle between the pyrimidine moiety and the lactone ring system is 29.43 (7)°.

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19

Zhang, Zheng-Hong, Xiao-Ling Liu, and Long-Ju Chen. "2-(2-Hydroxyethylamino)-3-phenyl-1-benzofuro[3,2-d]pyrimidin-4(3H)-one dichloromethane hemisolvate." Acta Crystallographica Section E Structure Reports Online 65, no. 6 (May 20, 2009): o1330. http://dx.doi.org/10.1107/s1600536809017814.

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In the title compound, C18H15N3O3·0.5CH2Cl2, the fused ring benzofuro[2,3-d]pyrimidine system is essentially planar [maximum deviation 0.029 (1) Å]. The planes of the pyrimidinone and phenyl rings are nearly perpendicular [dihedral angle = 87.50 (14)°]. The packing of the molecules in the crystal structure is governed mainly by intermolecular O—H...O and N—H...O hydrogen-bonding interactions and intermolecular π–π interactions between benzofuro[3,2-d]pyrimidine units [the interplanar distances areca3.4 and 3.5 Å, and the distances between adjacent ring centroids are in the range 3.64 (1)–3.76 (1) Å]. The dichloromethane solvent molecule lies on a special position.

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20

Bernhardt, Paul V., and Curt Wentrup. "Structures of 4-Iminopyrido[1,2-a]pyrimidines, Pyrido[1,2-a]pyrimidin-4-ones, Pyridopyrimidinium Olates, and Thiazolo[3,2-a]pyrimidine Analogues." Australian Journal of Chemistry 65, no. 4 (2012): 371. http://dx.doi.org/10.1071/ch12040.

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The Structure-Correlation Principle of Bürgi and Dunitz is invoked in an analysis of the structures of 2-chloro-8-methyl-4-(2-(4-picolinyl)imino-4H-pyrido[1,2-a]pyrimidine 8, 7-chloro-5-(2-thiazolyl)imino-5H-thiazolo[3,2-a]pyrimidine 9, 2-methylamino-4H-pyrido[1,2-a]pyrimidin-4-one 10, 7-methylthio-5H-thiazolo[3,2-a]pyrimidin-5-one 11, 2,3-dihydro-7-methylthio-5H-thiazolo[3,2-a]pyrimidin-5-one 12, and 1-methyl-2-[(o-tert-butylphenyl)imino]-1,2-dihydropyrido[1,2-a]pyrimidin-1-ium-4-olate 13, which have been determined by X-ray crystallography. The most notable structural peculiarities are the long ‘amidine’ and ‘amide’ C–N bonds (1.40–1.50 Å) and the tilting of the ‘amidine’ C=N and ‘amide’ C=O groups towards a ring nitrogen atom (NCX = 114–118°). Also the ‘amidine’ C=N (1.28 Å) and ‘amide’ C=O bonds (1.22–1.24 Å) are long, i.e. in the normal range for resonance-stabilized amidines and amides in spite of the lack of such resonance in these compounds. These features mimic the transition states for ring opening to ketenes. The long amidine and amide C–N bonds and acute NCX angles are in accord with the observed thermal ring opening to ketenimines and ketenes, respectively.

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21

Maccabee, Margaret, Janet S. Evans, Mary P. Glackin, Zafer Hatahet, and Susan S. Wallace. "Pyrimidine Ring Fragmentation Products." Journal of Molecular Biology 236, no. 2 (February 1994): 514–30. http://dx.doi.org/10.1006/jmbi.1994.1162.

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22

Monier, Mohamed, Doaa Abdel-Latif, Ahmed El-Mekabaty, Başak D. Mert, and Khaled M. Elattar. "Advances in the Chemistry of 6-6 Bicyclic Systems: Chemistry of Pyrido[3,4- d]pyrimidines." Current Organic Synthesis 16, no. 6 (November 26, 2019): 812–54. http://dx.doi.org/10.2174/1570179416666190704113647.

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The aim of this work is to discuss the chemistry of pyrido[3,4-d]pyrimidines as one of the most important heterocyclic compounds with remarkable synthetic, biological and medical applications. In this overview, the chemistry of heterocyclic compounds incorporated the pyrido[3,4-d]pyrimidine scaffold as demonstrated by chemical reactions and different preparation processes. The anticipated compounds were synthesized from pyridine or pyrimidine compounds and a description of the reactivity of substituents attached to ring carbon and nitrogen atoms is discussed. On the other hand, the synthesis and reactions of fused heterocycles incorporated pyrido[3,4-d]pyrimidine scaffold is described. The diamine analogs included pyrido[3,4-d]pyrimidine core were reported as tyrosine kinase inhibitors. The chemical reactions of certain unexpected and chemically substantial compounds have been discussed.

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23

Sankar, T., S. Naveen, N. K. Lokanath, and K. Gunasekaran. "Crystal structure of ethyl 4-(2,4-dichlorophenyl)-2-methyl-4H-benzo[4,5]thiazolo[3,2-a]pyrimidine-3-carboxylate." Acta Crystallographica Section E Crystallographic Communications 71, no. 5 (April 15, 2015): o306—o307. http://dx.doi.org/10.1107/s2056989015007033.

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In the title compound, C20H16Cl2N2O2S, the pyrimidine ring has a screw-boat conformation. The attached dichlorophenyl ring is twisted at an angle of 89.29 (13)° with respect to the pyrimidine ring mean plane. The benzothiazole group is approximately planar (r.m.s. deviation = 0.008 Å) and inclined to the pyrimidine ring mean plane by 3.04 (10)°. The carboxylate group assumes an extended conformation with respect to the pyrimidine ring, which can be seen from the O=C—O—C torsion angle of 3.2 (4) °. In the crystal, molecules are linkedviaC—H...O and C—H...N hydrogen bonds, forming slabs lying parallel to (100).

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24

Chaudhary, Ankita. "Multicomponent Approach for the Sustainable Syntheses of Pyrido[2,3-d]pyrimidine Scaffold." Current Organic Chemistry 25, no. 23 (December 16, 2021): 2856–84. http://dx.doi.org/10.2174/1385272825666211117152900.

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Pyrido[2,3-d]pyrimidine is an N-fused heterocyclic compound formed by the ortho fusion of pyridine and pyrimidine ring. Pyrido[2,3-d]pyrimidines hold a prominent position in medicinal chemistry owing to their wide spectrum of biological activities like antiviral, antihistaminic, antibacterial, diuretic, anti-inflammatory, analgesic, anticonvulsive, antipyretic, etc. The extraordinary features of pyrido[2,3-d]pyrimidines make their synthesis a perpetual field of research. Moreover, the construction of elaborate biologically relevant moieties via a multicomponent approach has become a promising area of research, owing to the burgeoning ‘green chemistry drive’. Advances in the exploitation of proficient synthetic routes involving a multicomponent approach for the assembly of this scaffold are reported in this review.

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25

Hordiyenko, Olga V., Volodymyr A. Tkachuk, Vyacheslav O. Shishkanu, Tetiana M. Tkachuk, and Svitlana V. Shishkina. "2-Carbamimidoylbenzoic Acid as a New Effective and Available Precursor for the Synthesis of Substituted 2-(Pyrimidin-2-yl)benzoic Acids." Synthesis 53, no. 02 (November 16, 2020): 371–82. http://dx.doi.org/10.1055/s-0040-1705941.

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AbstractA new approach to the synthesis of 2-(pyrimidin-2-yl)benzoic acids based on the ring contraction of the 2-carbamimidoylbenzoic acid [(2-amidinobenzoic) acid] with 1,3-dicarbonyl compounds and their synthetic equivalents has been developed. The intramolecular condensation of the obtained acids with 1,3-dielectrophiles proceeds with the formation of the 4,6-dihydropyrimido[2,1-a]isoindole-4,6-dione system, the pyrrolidone ring of which is easily opened under the action of weak nucleophiles. The reaction of 2-amidinobenzoic acid with chromones, which have an aryloxy group at 3-position does not stop at the step of pyrimidine ring formation and undergoes further spontaneous cyclization into 2-(benzo[4,5]furo[3,2-d]pyrimidin-2-yl)benzoic acids.

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26

Kordian, Marcus, Holger Feist, and Klaus Peseke. "Anellation and Ring Transformations of Push-pull-functionalized Deoxypyranosiduloses." Zeitschrift für Naturforschung B 64, no. 6 (June 1, 2009): 676–82. http://dx.doi.org/10.1515/znb-2009-0613.

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Reaction of (E)-3-aminomethylene-α-D-erythro-hexopyranosid-2-ulose 5 with substituted 5- aminopyrazoles afforded the pyrano-anellated pyrazolo[1,5-a]pyrimidines 8. The treatment of the corresponding (E)-2-aminomethylene-α-D-erythro-hexopyranosid-3-ulose 6 with 5-aminopyrazoles and (benzimidazol-2-yl)acetonitrile yielded in a ring transformation process the D-erythronoyl-pyrazolo[ 1,5-a]pyrimidine-3-carbonic acid derivatives 10 and D-erythronoyl-pyrido[1,2-a]benzimidazole- 4-carbonitrile (12), respectively

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27

Kant, Rajni, Vivek K. Gupta, Kamini Kapoor, S. Samshuddin, and B. Narayana. "2-[3,5-Bis(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl]-4,6-bis(4-methoxyphenyl)pyrimidine." Acta Crystallographica Section E Structure Reports Online 68, no. 8 (July 10, 2012): o2398. http://dx.doi.org/10.1107/s1600536812030516.

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In the title compound, C35H32N4O4, the pyrazole ring forms a dihedral angle of 15.04 (8)° with the adjacent pyrimidine ring. The pyrimidine ring forms dihedral angles of 9.95 (8) and 1.86 (7)° with its adjacent methoxy-substituted benzene rings, whereas the equivalent angles are 80.24 (9) and 11.55 (9)° for the pyrazole ring and its adjacent benzene rings. The crystal packing features π–π interactions, the centroid–centroid distance between the pyrimidine and methoxyphenyl rings being 3.604 (1) Å. The pyrazole ring is nearly planar, with a maximum deviation of 0.020 (3) Å for the –CH2– carbon.

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28

Abdelhamid, Ismail A., Amr M. Abdelmoniem, Farid M. Sroor, Muhammed A. Ramadan, and Said A. S. Ghozlan. "Hantzsch-Like One-Pot Three-Component Synthesis of Heptaazadicyclopenta[a,j]anthracenes: A New Ring System." Synlett 31, no. 09 (March 17, 2020): 895–98. http://dx.doi.org/10.1055/s-0040-1708001.

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A concise and efficient approach to novel tetrahydroheptaazadicyclopenta[a,j]anthracene-5,7-diones, by the reaction of aldehydes with two moles of 7-amino-2-methyl-3-phenylpyrazolo[1,5-a]pyrimidin-5-one is reported. Also, pyrazolo[1,5-a]pyrido[3,2-e]pyrimidine-7-carbonitrile derivatives were prepared by a three-component reaction of aldehydes, 7-amino-2-methyl-3-phenylpyrazolo[1,5-a]pyrimidin-5-one, and 3-aminocrotononitrile.

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29

Sankar, T., S. Naveen, N. K. Lokanath, and K. Gunasekaran. "Crystal structure of (2-methyl-4-phenyl-4H-benzo[4,5]thiazolo[3,2-a]pyrimidin-3-yl)(phenyl)methanone." Acta Crystallographica Section E Crystallographic Communications 71, no. 5 (April 2, 2015): o276—o277. http://dx.doi.org/10.1107/s2056989015006428.

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In the title compound, C24H18N2OS, the pyrimidine ring has a flat envelope conformation with the methine C atom as the flap. The attached phenyl and benzoyl rings are inclined to the mean plane of the pyrimidine ring by 84.87 (8) and 75.33 (9)°, respectively. The benzothiazolo group is planar (r.m.s. deviation = 0.009 Å) and inclined to the mean plane of the pyrimidine ring by 3.27 (6)°. In the crystal, molecules are linked by pairs of C—H...N hydrogen bonds, forming inversion dimers.

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30

Sharma, Naresh, Goutam Brahmachari, Suvankar Das, Rajni Kant, and Vivek K. Gupta. "2-[4-(Piperidin-1-yl)-5H-chromeno[2,3-d]pyrimidin-2-yl]phenol." Acta Crystallographica Section E Structure Reports Online 70, no. 4 (March 15, 2014): o447—o448. http://dx.doi.org/10.1107/s1600536814005625.

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In the title compound, C22H21N3O2, the pyrimidine ring is essentially planar [maximum deviation = 0.018 (2) Å] and forms dihedral angles of 22.70 (8) and 0.97 (7)°, respectively, with the fused benzene ring and the hydroxy-substituted benzene ring. The piperidine ring has a chair conformation and the pyran ring has a flattened twist-boat conformation. The hydroxy group was refined as disordered over two sets of sites in a 0.702 (4):0.298 (4) ratio. The disorder corresponds to a rotation of approxomiately 180° about the C—C bond connecting the phenol group to the pyrimidine ring and hence, both the major and minor components of disorder form intramolecular O—H...N hydrogen bonds. In the crystal, pairs of weak C—H...π interactions form inversion dimers. In addition, π–π interactions are observed between the pyrimidine ring and the hydroxy-substituted benzene ring [centroid–centroid separation = 3.739 (2) Å].

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31

Jung, Eunkyung, Ruben Soto-Acosta, Robert J. Geraghty, and Liqiang Chen. "Zika Virus Inhibitors Based on a 1,3-Disubstituted 1H-Pyrazolo[3,4-d]pyrimidine-amine Scaffold." Molecules 27, no. 18 (September 19, 2022): 6109. http://dx.doi.org/10.3390/molecules27186109.

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To search for Zika virus (ZIKV) antivirals, we have further explored previously reported 7H-pyrrolo[2,3-d]pyrimidines by examining an alternative substitution pattern of their central scaffold, leading to compound 5 with low micromolar antiviral activity. To circumvent the synthetic difficulties associated with compound 5, we have exploited a 1H-pyrazolo[3,4-d]pyrimidine scaffold and performed structure-activity relationship studies on its peripheral rings A and B. While ring B is less sensitive to structural modifications, an electron-withdrawing group at the para position of ring A is preferred for enhanced antiviral activity. Overall, we have not only discovered an alternative substitution pattern centered on a 1H-pyrazolo[3,4-d]pyrimidine scaffold but also generated anti-ZIKV compounds including 6 and 13, which possess low micromolar antiviral activity and relatively low cytotoxicity. These compounds represent new chemotypes that will be further optimized in our continued efforts to discover anti-ZIKV agents.

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32

Soni, Hetal I., and Navin B. Patel. "PYRIMIDINE INCORPORATED SCHIFF BASE OF ISONIAZID WITH THEIR SYNTHESIS, CHARACTERIZATION AND IN VITRO BIOLOGICAL EVALUATION." Asian Journal of Pharmaceutical and Clinical Research 10, no. 10 (September 1, 2017): 209. http://dx.doi.org/10.22159/ajpcr.2017.v10i10.19302.

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Objective: Versatile biological activities of nitrogen containing heterocycles in medicinal chemistry, mainly pyrimidine and pyridine ring based heterocyclic moieties are very important. Pharmaceutical important of pyrimidine and isoniazid moiety prompted us to synthesize isoniazid clubbed pyrimidine derivatives and evaluated for antimicrobial and antituberculosis activity.Method: 2-(2-(3-bromo benzylidene)-1-isonicotinoyl hydrazinyl)-N-(4-(substituted phenyl)-6-(substituted aryl) pyrimidin-2-yl) acetamide 2(A-J) have been synthesized by condensation reaction of 2-chloro-N-[4-(substituted phenyl)-6-(substituted aryl) pyrimidin-2-yl] acetamide and N’-[(E)- (3-bromophenyl) methylidene]pyridine-4-carbohydrazide. All newly synthesized compounds were screened for in vitro antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus pyogenes, antifungal against Candida albicans, Aspergillus niger, and Aspergillus clavatus, and antituberculosis activity against Mycobacterium tuberculosis H37RV.Results: Majority of the compounds exhibited good antibacterial, antifungal, and antituberculosis activity. All titled compounds were characterized by spectral analyses (infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectroscopy).Conclusion: 2-(2-(3-bromo benzylidene)-1-isonicotinoyl hydrazinyl)-N-(4-(substituted phenyl)-6-(substituted aryl) pyrimidin-2-yl) acetamide 2(A-J) showed good antimicrobial activity and comparatively good antituberculosis activity. Hence, all the compounds of this series considered for future investigation mainly in area of antibacterial, antifungal study.

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33

Journal, Baghdad Science. "Synthesis of Some Heterocyclic Compounds derived from 2-mercapto pyrimidine." Baghdad Science Journal 7, no. 2 (June 6, 2010): 1014–22. http://dx.doi.org/10.21123/bsj.7.2.1014-1022.

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In this work 2-hydrazino pyrimidine (1) was prepared from 2-mercapto pyrimidine with hydrazine hydrate. Treatment of (1) with active methylene compounds gave 2-(3,5-dimethyl -1 H – Pyrazole-1-yl) pyrimidine , whereas the reaction of (1) with carboxylic anhydride namely maleic anhydride or 1,2,3,6-tetra hydro phthalic anhydride yielded 1-Pyrimidine-2-yl-1,2-dihydro pyridazine-3,6-dione (3) and 2 – Pyrimidin -2-yl -2,3,4 a ,5,8 a – hexahydro phthalazine 1,4 – dione (4) . Reaction of (1) with phenyl isothiocyanate and ethyl chloro acetate afforded 3-Phenyl-1,3-thiazolidine-2,4-dione-2( pyrimidine -2- yl hydrazone (6) Azomethine (7-10) were prepared through condensation of (1) with aromatic aldehydes or ketones, then compounds (7-9) are converted into a number of tetrazole derivatives (11-13). Treatment of (1) with acetic acid afforded the derivative (14) . The reaction of 2-mercapto pyrimidine with ethyl chloro acetate afforded (15),whereas the reaction of (15) with thiosemicarbazide and 4% sodum hydroxide leads to ring closure giving 1,2,4 triazole derivative (17). Moreover the reaction of 2-mercapto pyrimidine with chloro acetic acid gave (18) followed by refluxing (18) with o- amino aniline to give the benzimidazole derivative (19).the structure of these compounds were characterized by FR-IR, UV spectra and some of them were characterized by element analysis.

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34

Moyaert, Tristen E., Christina Paul, Weibin Chen, Amy A. Sarjeant, and Louise N. Dawe. "Aquachlorido(2-{[6-(dimethylamino)pyrimidin-4-yl]sulfanyl}pyrimidine-4,6-diamine)copper(II) chloride hydrate." Acta Crystallographica Section E Crystallographic Communications 73, no. 10 (September 25, 2017): 1534–38. http://dx.doi.org/10.1107/s205698901701338x.

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A copper(II) complex of the non-symmetric bidentate ligand 2-{[6-(dimethylamino)pyrimidin-4-yl]sulfanyl}pyrimidine-4,6-diamine (L1) is reported. The single-crystal X-ray structure of aqua[aqua/chlorido(0.49/0.51)](2-{[6-(dimethylamino)pyrimidin-4-yl]sulfanyl}pyrimidine-4,6-diamine)copper(II) 0.49-chloride 1.51-hydrate, [CuCl1.51(C10H13N7S)(H2O)1.49]Cl0.49·1.51H2O or [(L1)Cl1.51(H2O)1.49Cu]0.49Cl·1.51H2O, exhibits distorted square-pyramidal geometry around the metal centre, with disorder in the axial position, occupied by chloride or water. The six-membered metal–chelate ring is in a boat conformation, and short intermolecular S...S interactions are observed. In addition to its capacity for bidentate metal coordination, the ligand has the ability to engage in further supramolecular interactions as both a hydrogen-bond donor and acceptor, and multiple interactions with lattice solvent water molecules are present in the reported structure.

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35

Mahesha, Ninganayaka, Hemmige S. Yathirajan, Tetsundo Furuya, Takashiro Akitsu, and Christopher Glidewell. "The crystal structure of 1-(2-iodobenzoyl)-4-(pyrimidin-2-yl)piperazine: a three-dimensional hydrogen-bonded framework, augmented by π–π stacking interactions and I...N halogen bonds." Acta Crystallographica Section E Crystallographic Communications 75, no. 2 (January 4, 2019): 129–33. http://dx.doi.org/10.1107/s205698901801811x.

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In 1-(2-iodobenzoyl)-4-(pyrimidin-2-yl)piperazine, C15H15IN4O, the central piperazine ring adopts an almost perfect chair conformation with the pyrimidine substituent in an equatorial site. The planar amide unit makes a dihedral angle of 80.44 (7)° with the phenyl ring. A combination of C—H...O and C—H...π(arene) hydrogen bonds links the molecules into a complex three-dimensional network structure, augmented by a π–π stacking interaction and an I...N halogen bond, all involving different pairs of inversion-related molecules. Comparisons are made with the structures of a number of related compounds.

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36

Zeng, Qing, Demin Ren, Aiting Zheng, and Xiaofang Li. "Synthesis of Octahydropyrano[2,3-d]Pyrimidine Derivatives via Tetrahydropyrano[3,2-e][1,3]Thiazolo[3,2-a]Pyrimidine and 2,6-Dichlorobenzonitrile Oxide." Journal of Chemical Research 42, no. 6 (June 2018): 317–19. http://dx.doi.org/10.3184/174751918x15293130141511.

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N1-substituted octahydro-1 H-pyrano[2,3- d]pyrimidines derivatives were prepared in moderate yield by the reaction of methyl [(4a RS,5 SR,10a RS)-5-aryl-2-oxo-3,4,4 a,10 a-tetrahydro-2 H,5 H-pyrano[3,2- e][1,3]thiazolo[3,2- a]pyrimidin-8(9 H)-ylidene]acetate and 2,6-dichorobenzonitrile oxide via a domino 1,3-dipolar cycloaddition/ring-opening/dethionation process. The structures of the products were characterised by spectroscopic and X-ray crystallographic analysis.

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37

Li, Hong-Xia, Yu-Su Song, Yong-nian Qu, Jiang-Bing Lu, and Hong-Mei Wang. "Ethyl 2-methyl-6-(propan-2-ylamino)-4-sulfanylidene-3H,11H-pyrimido[1,6-c]quinazoline-1-carboxylate." Acta Crystallographica Section E Structure Reports Online 68, no. 6 (May 19, 2012): o1821. http://dx.doi.org/10.1107/s1600536812019952.

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The title compound, C18H22N4O2S, contains a substituted pyrimidine ring fused to both a benzene ring and a substituted thioxopyrimidine ring. The pyrimidine and thioxopyrimidine rings adopt distorted chair conformations. In the crystal, adjacent molecules are linked by pairs of N—H...S and N—H...O hydrogen bonds to generate centrosymmetric R 2 2(8) and R 2 2(16) loops, respectively. This combination leads to [100] chains of molecules.

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38

Wolska, Irena, and Franciszek Herold. "Crystal and Molecular Structure of 4-Arylhexahydro-1H,3H-pyrido[1,2-c]pyrimidine-1,3-dione Derivatives." Zeitschrift für Naturforschung B 57, no. 11 (November 1, 2002): 1315–19. http://dx.doi.org/10.1515/znb-2002-1118.

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The X-ray crystal structure determination of 4-(2-methylphenyl)hexahydro-1H,3H-pyrido[ 1,2-c]pyrimidine-1,3-dione (2) and 4-(3-methylphenyl)hexahydro-1H,3H-pyrido[1,2-c]- pyrimidine-1,3-dione (3) is reported. The crystal structures show the formation of centrosymmetric dimers via intermolecular N-H···O hydrogen bonds. The saturated ring adopts a slightly distorted halfchair conformation in both 2 and 3. In either compound the planar phenyl ring is twisted with respect to the pyrimidine-1,3-dione fragment.

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39

Wei, Xia, and Xieraili Maimaitiyiming. "Enrichment of highly pure large-diameter semiconducting SWCNTs by polyfluorene-containing pyrimidine ring." RSC Advances 9, no. 56 (2019): 32753–58. http://dx.doi.org/10.1039/c9ra06819h.

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40

Swinton Darious, Robert, Packianathan Thomas Muthiah, and Franc Perdih. "Supramolecular architectures in the salt trimethoprimium ferrocene-1-carboxylate and the cocrystal 4-amino-5-chloro-2,6-dimethylpyrimidine–ferrocene-1-carboxylic acid (1/1)." Acta Crystallographica Section C Structural Chemistry 73, no. 9 (August 18, 2017): 743–48. http://dx.doi.org/10.1107/s2053229617011913.

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In the salt trimethoprimium ferrocenecarboxylate [systematic name: 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidin-1-ium ferrocene-1-carboxylate], (C14H19N4O3)[Fe(C5H5)(C6H4O2)], (I), of the antibacterial compound trimethoprim, the carboxylate group interacts with the protonated aminopyrimidine group of trimethoprim via two N—H...O hydrogen bonds, generating a robust R 2 2(8) ring motif (heterosynthon). However, in the cocrystal 4-amino-5-chloro-2,6-dimethylpyrimidine–ferrocene-1-carboxylic acid (1/1), [Fe(C5H5)(C6H5O2)]·C6H8ClN3, (II), the carboxyl–aminopyrimidine interaction [R 2 2(8) motif] is absent. The carboxyl group interacts with the pyrimidine ring via a single O—H...N hydrogen bond. The pyrimidine rings, however, form base pairs via a pair of N—H...N hydrogen bonds, generating an R 2 2(8) supramolecular homosynthon. In salt (I), the unsubstituted cyclopentadienyl ring is disordered over two positions, with a refined site-occupation ratio of 0.573 (10):0.427 (10). In this study, the two five-membered cyclopentadienyl (Cp) rings of ferrocene are in a staggered conformation, as is evident from the C...Cg...Cg...C pseudo-torsion angles, which are in the range 36.13–37.53° for (I) and 22.58–23.46° for (II). Regarding the Cp ring of the minor component in salt (I), the geometry of the ferrocene ring is in an eclipsed conformation, as is evident from the C...Cg...Cg...C pseudo-torsion angles, which are in the range 79.26–80.94°. Both crystal structures are further stabilized by weak π–π interactions.

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41

Kokorekin, Vladimir A., Sergey V. Neverov, Vera N. Kuzina, and Vladimir A. Petrosyan. "A New Method for the Synthesis of 3-Thiocyanatopyrazolo[1,5-a]pyrimidines." Molecules 25, no. 18 (September 11, 2020): 4169. http://dx.doi.org/10.3390/molecules25184169.

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In this article, we demonstrate how an original effective “metal-free” and “chromatography-free” route for the synthesis of 3-thiocyanatopyrazolo[1,5-a]pyrimidines has been developed. It is based on electrooxidative (anodic) C–H thiocyanation of 5-aminopyrazoles by thiocyanate ion leading to 4-thiocyanato-5-aminopyrazoles (stage 1, yields up to 87%) following by their chemical condensation with 1,3-dicarbonyl compounds or their derivatives (stage 2, yields up to 96%). This method is equally effective for the synthesis of 3-thiocyanatopyrazolo[1,5-a]pyrimidines, both without substituents and with various donor (acceptor) substituents in the pyrimidine ring.

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42

Wolska, Irena, and Franciszek Herold. "Structural Investigation of Two 4-AryIhexahydro-1H,3H-pyrido[1,2-c]pyrimidine-1,3-diones." Zeitschrift für Naturforschung B 55, no. 11 (November 1, 2000): 1089–94. http://dx.doi.org/10.1515/znb-2000-1116.

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The X-ray crystal structure determination of 4-(4'-fluorophenyl)hexahydro-1H,3H-pyrido[ 1,2-c]pyrimidine-1,3-dione (5) and 4-(4'-chlorophenyl)hexahydro-1H,3H-pyrido [1,2-c]- pyrimidine-1,3-dione (8) is reported. The crystal structures show the formation of centrosymmetric dimers via intermolecular N-H···O hydrogen bonds. The saturated ring adopts a slightly distorted sofa conformation both in 5 and in 8. In either compound the planar phenyl ring is twisted with respect to the pyrimidine-1,3-dione fragment.

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43

Delia, Thomas J., and Robin J. Hood. "Bromination of Pyrimidines: A Simple Inexpensive Method." Australian Journal of Chemistry 68, no. 2 (2015): 254. http://dx.doi.org/10.1071/ch14416.

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Although the introduction of halogens into the pyrimidine ring has been accomplished numerous times, the methods usually involve either specialised reagents or very aggressive conditions. This communication paper describes the introduction of bromine into position 5 of the pyrimidine ring using common inorganic salts at room temperature. An evaluation of the substituents required for successful reaction is provided.

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44

Chmiel-Szukiewicz, Elżbieta. "Polyurethane foams with 1,3-pyrimidine ring." Journal of Applied Polymer Science 109, no. 3 (2008): 1708–13. http://dx.doi.org/10.1002/app.27159.

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45

Tomlinson, Patricia Tolson, and Carol J. Lovatt. "Nucleotide Metabolism in ‘Washington’ Navel Orange Fruit: I. Pathways of Synthesis and Catabolism." Journal of the American Society for Horticultural Science 112, no. 3 (May 1987): 529–35. http://dx.doi.org/10.21273/jashs.112.3.529.

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Abstract The capacity of ‘Washington’ navel orange fruit [Citrus sinensis (L.) Osbeck] to synthesize and catabolize purines and pyrimidines was assessed. De novo biosynthesis of purine nucleotide was demonstrated by [14C] bicarbonate incorporation into purine nucleotides, blockage of this process by four known inhibitors, and assimilation of radiolabeled carbon from formate, both carbons of glycine, and carbon-3 of serine into the adenine ring. De novo synthesis of pyrimidines via the orotate pathway in young fruit was demonstrated by incorporation of [14C] bicarbonate and [6-14C]orotic acid into uridine nucleotides, release of 14CO2 from [7-14C]orotic acid, and blockage of these processes by 6-azauridine. Synthesis of purine and pyrimidine nucleotides via salvage reactions was demonstrated by incorporation of radiolabeled bases and ribonucleosides into nucleotides and into nucleic acids. Release of 14CO2 from radiolabeled adenine, adenosine, hypoxanthine, and xanthine, uric acid, urea (purines), uracil, and uridine (pyrimidines) provided evidence the pathways for catabolism (degradation) of purines and pyrimidines in navel orange fruit are similar to those found in microorganisms and animal tissues. To the best of our knowledge, this report is the first to assess the capacity of anabolic and catabolic pathways of purine and pyrimidine nucleotide metabolism in fruit of any species. De novo synthetic activities in orange fruit permit increases in the pools of purine and pyrimidine nucleotides using simple precursors. Further, the patterns of salvage and catabolism suggest riboside pools are reused predominantly as nucleotides, while the majority of base pools are degraded to permit recycling of carbon and nitrogen into other metabolites.

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46

Farghaly, Ahmed M., Ola H. Rizk, Inas Darwish, Manal Hamza, Mezna Saleh Altowyan, Assem Barakat, and Mohamed Teleb. "Design, Synthesis, Pharmacodynamic and In Silico Pharmacokinetic Evaluation of Some Novel Biginelli-Derived Pyrimidines and Fused Pyrimidines as Calcium Channel Blockers." Molecules 27, no. 7 (March 30, 2022): 2240. http://dx.doi.org/10.3390/molecules27072240.

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Some new pyrimidine derivatives comprising arylsulfonylhydrazino, ethoxycarbonylhydrazino, thiocarbamoylhydrazino and substituted hydrazone and thiosemicarbazide functionalities were prepared from Biginelli-derived pyrimidine precursors. Heterocyclic ring systems such as pyrazole, pyrazolidinedione, thiazoline and thiazolidinone ring systems were also incorporated into the designed pyrimidine core. Furthermore, fused triazolopyrimidine and pyrimidotriazine ring systems were prepared. The synthesized compounds were evaluated for their calcium channel blocking activity as potential hypotensive agents. Compounds 2, 3a, 3b, 4, 11 and 13 showed the highest ex vivo calcium channel blocking activities compared with the reference drug nifedipine. Compounds 2 and 11 were selected for further biological evaluation. They revealed good hypotensive activities following intravenous administration in dogs. Furthermore, 2 and 11 displayed drug-like in silico ADME parameters. A ligand-based pharmacophore model was developed to provide adequate information about the binding mode of the newly synthesized active compounds 2, 3a, 3b, 4, 11 and 13. This may also serve as a reliable basis for designing new active pyrimidine-based calcium channel blockers.

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47

Yu, Wang, Jingbao Song, and Aijian Wang. "Crystal structure of 4,6-bis[(E)-4-bromostyryl]-2-(butylsulfanyl)pyrimidine." Acta Crystallographica Section E Structure Reports Online 70, no. 12 (November 21, 2014): o1282. http://dx.doi.org/10.1107/s1600536814024714.

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In the title compound, C24H22Br2N2S, the dihedral angles between the central pyrimidine ring and the pendant bromobenzene rings are 11.02 (11) and 13.20 (12)°. The butyl side chain adopts agaucheconformation [C—C—C—C = −67.4 (4)°]. In the crystal, weak aromatic π–π stacking is observed between the pyrimidine ring and one of the benzene rings [centroid–centroid separation = 3.6718 (17) Å].

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48

Acosta, Lina M., Andrés F. Yepes, Alirio Palma, Justo Cobo, and Christopher Glidewell. "Six closely related 4,6-disubstituted 2-amino-5-formylpyrimidines: different ring conformations, polarized electronic structures, and hydrogen-bonded assembly in zero, one, two and three dimensions." Acta Crystallographica Section C Crystal Structure Communications 69, no. 2 (January 8, 2013): 162–71. http://dx.doi.org/10.1107/s0108270112051049.

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Abstract:

In each of ethylN-{2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}glycinate, C16H19N5O3, (I),N-{2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}glycinamide, C14H16N6O2, (II), and ethyl 3-amino-N-{2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}propionate, C17H21N5O3, (III), the pyrimidine ring is effectively planar, but in each of methylN-{2-amino-6-[benzyl(methyl)amino]-5-formylpyrimidin-4-yl}glycinate, C16H19N5O3, (IV), ethyl 3-amino-N-{2-amino-6-[benzyl(methyl)amino]-5-formylpyrimidin-4-yl}propionate, C18H23N5O3, (V), and ethyl 3-amino-N-[2-amino-5-formyl-6-(piperidin-4-yl)pyrimidin-4-yl]propionate, C15H23N5O3, (VI), the pyrimidine ring is folded into a boat conformation. The bond lengths in each of (I)–(VI) provide evidence for significant polarization of the electronic structure. The molecules of (I) are linked by paired N—H...N hydrogen bonds to form isolated dimeric aggregates, and those of (III) are linked by a combination of N—H...N and N—H...O hydrogen bonds into a chain of edge-fused rings. In the structure of (IV), molecules are linked into sheets by means of two hydrogen bonds, both of N—H...O type, in the structure of (V) by three hydrogen bonds, two of N—H...N type and one of C—H...O type, and in the structure of (VI) by four hydrogen bonds, all of N—H...O type. Molecules of (II) are linked into a three-dimensional framework structure by a combination of three N—H...O hydrogen bonds and one C—H...O hydrogen bond.

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49

Krishnamurthy, M. S., and Noor Shahina Begum. "Crystal structure of methyl 4-(2-fluorophenyl)-6-methyl-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carboxylate." Acta Crystallographica Section E Crystallographic Communications 71, no. 11 (October 14, 2015): o838—o839. http://dx.doi.org/10.1107/s2056989015018873.

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In the title compound, C13H13FN2O2S, the pyrimidine ring adopts a twist-boat conformation with the MeCNand methine-Catoms displaced by 0.0938 (6) and 0.2739 (3) Å, respectively, from the mean plane through the other four atoms of the ring. The 2-fluorobenzene ring is positioned axially and forms a dihedral angle of 89.13 (4)° with the mean plane through the pyrimidine ring. The crystal structure features N—H...O, N—H...S and C—H...O hydrogen bonds that link molecules into supramolecular chains along thebaxis. These chains are linked into a layer parallel to (10-1) by C—H...π interactions; layers stack with no specific interactions between them.

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50

Devidas, Amrutkar Rakesh, Amrute Bhavesh Bharat, Ahire Ashishkumar Harishchndra, and Ziyaul Haque s. Ahmed. "IN SILICO ADMET PROFILING AND MOLECULAR DOCKING OF NOVEL SUBSTITUTED THIENO[3,2-d] PYRIMIDINES AGAINST LIGAND BINDING DOMAIN OF THE HUMAN PEROXISOME PROLIFERATOR ACTIVATED RECEPTOR GAMMA IN COMPLEX WITH SYNTHETIC AGONIST." International Research Journal of Pharmacy 11, no. 11 (November 30, 2020): 36–40. http://dx.doi.org/10.7897/2230-8407.111195.

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Pyrimidine ring system has wide range of pharmacological activities in the form of substituted and fused ring system and its derivatives. In this study we use some new computational tools for predicting ADMET, Pharmacological profile and Molecular docking of some novel substituted Thieno[3,2-d]pyrimidine. The side effect during the investigation is Carcinogenicity, Hepatotoxicity, etc., Molecular docking by using QSAR Software (Drug-receptor Interaction) it also focuses.

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