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Journal articles on the topic 'Organic synthesis problems'

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Author: Grafiati

Published: 10 December 2022

Last updated: 28 January 2023

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1

Wang, Yi, Han Ding, and Ge Ging Xu. "Computer Aided Organic Synthesis Based on Graph Grammars." Applied Mechanics and Materials 411-414 (September 2013): 227–30. http://dx.doi.org/10.4028/www.scientific.net/amm.411-414.227.

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Traditionally, computer aided organic synthesis is based on the one-dimensional string model that employs string grammars to tackle the structure of molecular; the processing of organic reactions, and the establishment of the knowledge bases and file systems. Because of the limitations of one-dimensional method for tackling two-dimensional issues like organic syntheses, this paper presents a method for computer aided organic synthesis based on two-dimensional graph grammars. The method could apply the basic principle of the graph grammars to effectively and efficiently solve organic synthesis problems.

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2

Amsad, L. N., S. Liliasari, A. Kadarohman, and R. E. Sardjono. "Revealing students’ problems in learning synthesis organic." Journal of Physics: Conference Series 1521 (March 2020): 042063. http://dx.doi.org/10.1088/1742-6596/1521/4/042063.

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3

Schaller, Chris P., Kate J. Graham, and T. Nicholas Jones. "Synthesis Road Map Problems in Organic Chemistry." Journal of Chemical Education 91, no. 12 (October 16, 2014): 2142–45. http://dx.doi.org/10.1021/ed400886k.

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4

Kurth, Laurie L., and Mark J. Kurth. "Synthesis–Spectroscopy Roadmap Problems: Discovering Organic Chemistry." Journal of Chemical Education 91, no. 12 (September 23, 2014): 2137–41. http://dx.doi.org/10.1021/ed500109a.

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5

Nakahara, Yoshiaki. "Problems and Progress in Glycopeptide Synthesis." Trends in Glycoscience and Glycotechnology 15, no. 85 (2003): 257–73. http://dx.doi.org/10.4052/tigg.15.257.

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6

Flynn, Alison B. "How do students work through organic synthesis learning activities?" Chem. Educ. Res. Pract. 15, no. 4 (2014): 747–62. http://dx.doi.org/10.1039/c4rp00143e.

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Organic chemistry has the long-standing reputation as a challenging course, and organic synthesis is an aspect of organic chemistry that requires students to make the most links between concepts and requires the highest order of thinking. One-on-one interviews were conducted with students from a second undergraduate organic chemistry course in which participants solved synthesis problems using a think aloud protocol. Those problems had been previously designed to scaffold students' acquisition of synthesis problem-solving skills. The research question for this study asked whether students worked through the synthesis learning activities as designed, toward the intended learning outcomes. The results show that in some questions, students used or tried to use desirable problem solving skills, such as using reaction mechanisms and chemical principles to explore possible solutions. However, with other question types, students (i) relied on familiarity with the reactions in question and lacked a problem-solving strategy when they could not recall the answer or (ii) avoided the purpose of the question and attempted to provide an answer that the professor “wanted.” Strategies for promoting desired synthesis skills and addressing other issues are discussed.

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Arslanov, Kh A., T. V. Tertychnaya, and S. B. Chernov. "Problems and Methods of Dating Low-Activity Samples by Liquid Scintillation Counting." Radiocarbon 35, no. 3 (1993): 393–98. http://dx.doi.org/10.1017/s0033822200060409.

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The important problem of contamination of old samples by younger 14C necessitates treatment of organic and carbonate samples to ensure more complete removal of contaminating carbon. Here we present studies of chemical procedures for the liquid scintillation method of 14C dating undertaken since 1960 in the former USSR. We discuss new procedures such as lithium carbide synthesis from charred organic samples and benzene synthesis on a V2O5·Al2O3·SiO2 catalyst, as well as memory effect in the carbide synthesis procedure and characteristics of two homemade counters.

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8

Amii, Hideki, Aiichiro Nagaki, and Jun-ichi Yoshida. "Flow microreactor synthesis in organo-fluorine chemistry." Beilstein Journal of Organic Chemistry 9 (December 5, 2013): 2793–802. http://dx.doi.org/10.3762/bjoc.9.314.

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Organo-fluorine compounds are the substances of considerable interest in various industrial fields due to their unique physical and chemical properties. Despite increased demand in wide fields of science, synthesis of fluoro-organic compounds is still often faced with problems such as the difficulties in handling of fluorinating reagents and in controlling of chemical reactions. Recently, flow microreactor synthesis has emerged as a new methodology for producing chemical substances with high efficiency. This review outlines the successful examples of synthesis and reactions of fluorine-containing molecules by the use of flow microreactor systems to overcome long-standing problems in fluorine chemistry.

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9

Hippe, Z. S., G. Fic, and M. Mazur. "A preliminary appraisal of selected problems in computer-assisted organic synthesis." Recueil des Travaux Chimiques des Pays-Bas 111, no. 6 (1992): 255–61. http://dx.doi.org/10.1002/recl.19921110603.

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10

Heifets, Abraham, and Igor Jurisica. "Construction of New Medicines via Game Proof Search." Proceedings of the AAAI Conference on Artificial Intelligence 26, no. 1 (September 20, 2021): 1564–70. http://dx.doi.org/10.1609/aaai.v26i1.8331.

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The production of any new medicine requires solutions to many planning problems. The most fundamental of these is determining the sequence of chemical reactions necessary to physically create the drug. Surprisingly, these organic syntheses can be modeled as branching paths in a discrete, fully-observable state space, making the construction of new medicines an application of heuristic search. We describe a model of organic chemistry that is amenable to traditional AI techniques from game tree search, regression, and automatic assembly sequencing. We demonstrate the applicability of AND/OR graph search by developing the first chemistry solver to use proof-number search. Finally, we construct a benchmark suite of organic synthesis problems collected from undergraduate organic chemistry exams, and we analyze our solvers performance both on this suite and in recreating the synthetic plan for a multibillion dollar drug.

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11

Dong, Yuxin, Yifan Ji, and Ziyan Lai. "Carbon Dioxide Capture in Metal-Organic Frameworks." Highlights in Science, Engineering and Technology 21 (December 4, 2022): 50–56. http://dx.doi.org/10.54097/hset.v21i.3137.

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Excessive carbon dioxide emissions have caused several environmental problems. This has an unpromising impact on the Earth's ecosystem. Metal-organic frameworks (MOFs) attracted more and more attention because of their extraordinary specific surface area, adjustable framework and excellent stability in the effective capture and conversion of carbon dioxide. This article introduced the main synthesis methods of MOF materials, including ionothermal synthesis, mechanochemical synthesis, sonochemical synthesis and ultrasound synthesis method. Each synthesis method of MOFs has its advantages such as shorter reaction times or faster screening rates, which contribute to the development of the synthesis of MOFs. The key evaluation metrics for carbon dioxide capture using MOFs including adsorption isotherm, adsorption ability, enthalpy and high selectivity also were discussed, which have a direct impact on the capture of carbon dioxide. Additionally, the main carbon capture by MOFs in power plants, such as post-combustion capture, capture before combustion and oxy-fuel combustion were also highlighted.

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12

Kurniawan, Yehezkiel Steven, Krisfian Tata Aneka Priyangga, Philip Anggo Krisbiantoro, and Arif Cahyo Imawan. "Green Chemistry Influences in Organic Synthesis : a Review." Journal of Multidisciplinary Applied Natural Science 1, no. 1 (January 7, 2021): 1–12. http://dx.doi.org/10.47352/jmans.v1i1.2.

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Environmental pollution and global warming cause serious problems in human life. Since the demand for our human daily appliances had been increased by years, the organic chemical-based industries response that demand increment by increasing their production process. Because of that, the environmental pollution becomes worse and worse. Green chemistry thus was introduced to influence the chemical industries to strive for better environmental sustainability. Over 20 years, green chemistry principles have to influence the organic chemistry field especially as many researchers have put their attention on that field of research. So far, synthesis process involving organic compounds has been considered on waste prevention, safer solvents, design for high energy efficiency, and usage of renewable feedstocks. This review comprehensively discusses in brief about the implementation of green chemistry principle and their applications in the synthesis process of organic compounds.

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13

Ma, Yuan Hui, Cheng Chun Tang, and Lei Zhang. "Property and Research Process of Metal-Organic Frameworks." Advanced Materials Research 427 (January 2012): 119–22. http://dx.doi.org/10.4028/www.scientific.net/amr.427.119.

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Metal-organic frameworks (MOFs) are new functional materials, which are developing quickly last years, especially as new hydrogen storage materials. This review introduces concept, characteristics, application, classification, and synthesis and development trend of metal-organic frameworks. Some new problems and difficulties in metal-organic frameworks study and next challenges are also discussed.

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14

Lima, Rafael C., Christian W. Lopes, Jhonny Villarroel-Rocha, Lindiane Bieseki, Karim Sapag, and Sibele B. C. Pergher. "Organic-Free Synthesis of Finned Mordenite Zeolite." Nanomaterials 12, no. 15 (July 29, 2022): 2623. http://dx.doi.org/10.3390/nano12152623.

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Mordenite is a well-known zeolite widely used for industrial processes. However, its pore architecture can be inconvenient due to diffusional issues. A study of the synthesis parameters from an organic-free dense gel was carried out to control the crystal morphology, which resulted in finned mordenite zeolite particles. The obtained materials were characterized by XRD, FTIR, 29Si and 27Al MAS-NMR, elemental analysis, nitrogen physisorption, SEM, and TEM. We found that careful manipulation of the hydrothermal parameters directly affected the sizes and morphologies of the crystallites and particles, as well as the textural properties of the final products. Additionally, it was found that mordenite could exhibit a fin morphology with additional mesoporosity, which is a promising means to reduce the diffusional problems of one-dimensional-channel zeolites.

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15

Dembitsky, V. M., G. A. Tolstikov, and M. Srebnik. "Boranes in Organic Chemistry 2. β-Aminoalkyl- and β-sulfanylalkylboranes in organic synthesis." Eurasian Chemico-Technological Journal 4, no. 3 (June 30, 2017): 153. http://dx.doi.org/10.18321/ectj528.

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<p>Problems on using of β-aminoalkyl- and β-sulfanylalkylboranes in organic synthesis are considered in this review. The synthesis of boron containing a-aminoacids by Curtius rearrangement draws attention. The use of β-aminoalkylboranes available by enamine hydroboration are described. Examples of enamine desamination with the formation of alkenes, aminoalcohols and their transformations into allylic alcohol are presented. These conversions have been carried out on steroids and nitrogen containing heterocyclic compounds. The dihydroboration of N-vinyl-carbamate and N-vinyl-urea have been described. Examples using nitrogen and oxygen containing boron derivatives for introduction of boron functions were presented. The route to borylhydrazones by hydroboration of enehydrazones was envisaged. The possibility of trialkylamine hydroboration was shown on indole alkaloids and 11-azatricyclo-[6.2.1<sup>1,8</sup>0<sup>2,7</sup>]2,4,6,9-undecatetraene examples. The synthesis of β-sulfanyl-alkylboranes by various routes was described. The synthesis of boronic thioaminoacids was carried out by free radical thiilation of dialkyl-vinylboronates. Ethoxyacetylene has been shown smoothly added 1-ethylthioboracyclopentane. Derivatives of 1,4-thiaborinane were readily obtained by divinylboronate hydroboration. Dialkylvinylboronates react with mercaptoethanol with the formation of 1,5,2-oxathioborepane derivatives. Stereochemistry of thiavinyl esters hydroboration leading to stereoisomeric β-sulfanylalkylboranes are discussed. Examples of radical thiilation of various structural types vinylboronates were presented. In particular, 1,3,2-dioxaborinanes and 1,3,2-dioxaborolanes, containing by boron atom vinyl-, propenyl-, isopropenylor isopropylidene substituents have been used. Thiilation has been achieved by use of alkylmercaptanes, as well as mercaptamine derivatives. Alkylmercaptanes were able to replace the bromine substituent in tris-(2-bromoctyl)-borane. Dialkylvinylborates have been added hydrosulfite with the formation of 2-boronoethane sulfuric acids. A lot of examples of radical thiilation of vinylboronic acid dialkyl esters with mercaptoacids are presented. Under the azaisobutyric acid dinitryle conditions thioglycolic, β-mercaptopropionic, 2-mercaptoamberic acids and their esters as well as cysteine were added. Vinyl-, propenyl- and isopropenyldioxaborolanes were also participated in the thiilation with the formation of acetic, propionic or amberic acid thioethanoboronates. The high reactivity of B,B,B-trivinyl-N,N,N-triphenylborazine in the reaction with thiophenol, leading to B-tris-(phenylmercaptoethyl)-N-phenylborazine was shown. The problems of asymmetric hydroboration leading to chiral β-sulfanylalkylboranes were discussed briefly. In particular, an example, including dihydro-thiophene hydroboration, leading to (+)-R-thiofan-3-yl-diisopinocamphenylborane, and the interaction with acetaldehyde with the formation of (+)-R-3-thiophanyl-diethoxyborane was implemented. The reaction with 3,4-dihydrothiapyrane proceeds analogously. A synthetic route to sulfono-norbornen-boronic acid esters by Diels-Alder reaction of cyclopentadiene with arylsulfanyl-vinylboronic acid esters has been discussed.</p>

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16

Salame, Issa I., Pauline Casino, and Natasha Hodges. "Examining Challenges that Students Face in Learning Organic Chemistry Synthesis." International Journal of Chemistry Education Research 3, no. 3 (May 22, 2020): 1–9. http://dx.doi.org/10.20885/ijcer.vol4.iss1.art1.

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Organic chemistry is the offered after general chemistry and is the course that many find it challenging and difficult. Synthesis is first introduced in organic chemistry I course and is widely considered as one of the topics in which students struggle with and is evident in their performance in the topic. Our method of data collection is a Likert-type and open-ended questionnaire that was distributed at the end organic chemistry I course in an anonymous fashion. The collected data enabled us to examine the challenges students face in learning organic chemistry synthesis. Our findings support the notion that students have many difficulties with multistep organic chemistry synthesis including challenges recalling all of the varied required reactions, the amount of content and topics covered in organic chemistry, conceptual understanding of needed important topics such as mechanisms, acids and bases, nucleophiles and electrophiles, and stereochemistry, and problem-solving competency. Students view organic chemistry synthesis as challenging because of their reliance on memorization of a large number of reactions, reagents, and rules, poor conceptual understanding of the topics, ineffective teaching methods which lacks active learning and student engagement, and the myriad number of possible pathways to solve synthesis problems. Our participants suggest that memorization and rote-learning plays an important role in the learning of multistep organic synthesis, which might cause a hindrance to process of learning and can impede students’ problem-solving ability.

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17

Nikolova, Marina. "PROBLEMS AND OPPORTUNITIES FOR REALIZATION OF BULGARIAN ORGANIC PRODUCTION." Trakia Journal of Sciences 17, Suppl.1 (2019): 259–67. http://dx.doi.org/10.15547/tjs.2019.s.01.042.

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The modern ecological crisis that the world is experiencing today is much more threatening than economic and threatens us all because of the increased exploitation of the Earth's natural resources. This is why there is a growing talk of organic production and more precisely organic farming. Organic farming is an important priority in agriculture development policy in the Republic of Bulgaria and one of the highlights of the common agricultural policy for the period 2014-2020. It is a fact that interest in organically produced food and drink is strengthened in Global scale. The purpose of our research is related to the study of the market environment in Bulgaria for the realization of organic production. The research methods used in the study include: general scientific research Methods, survey, generalization and synthesis, logical method, tabular, graphical and schematic representation of characteristics and trends. The results of the survey can be systematised in several directions: the growth of production and the number of farmers in the bio-production sector in recent years is mainly due to increased market demand, as well as to The increase in interest on the question "food quality with which we eat"; There is still an underdeveloped market for organic production in Bulgaria; The main problems are related to limited channels for distribution of production in the country, low market share of organic products, difficulties in the production process, presence of counterfeit organic products; High cost; Not sufficient consumer information, etc. The fact that the number of bio-based products is growing is an indicator that agro-entrepreneurs see potential for development in this direction, despite the general negative trends in economic development as a whole, and consumers remain interested. In conclusion, measures to improve the supply chain of organic products in Bulgaria should be directed towards a strong horizontal and vertical integration between the key figures in the sector. The effect of producer associations on a territorial/regional scope would be particularly pronounced.

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18

Roulland, Emmanuel. "Tiacumicin B: An Antibiotic of Prime Importance and a Natural Product with an Inspiring Complex Structure." Synthesis 50, no. 21 (September 6, 2018): 4189–200. http://dx.doi.org/10.1055/s-0037-1609933.

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This short review aims at decrypting and analyzing the various strategies used for the synthesis of tiacumicin B. Natural products synthesis is a way for organic chemists to express inventiveness, intellectual dexterity, and elegance in strategy of synthesis. Some molecular structures are more inspiring than others; and if like tiacumicin B, the architectural challenge meets high biological and medicinal interest, the molecule can then attract the attention of many groups of synthetic chemists.1 Introduction2 The Strategic Challenges of this Total Synthesis3 Construction of the C1–C5 Region4 Construction of the C14–C19 Region5 Construction of the C5–C12 Region6 Construction of the C12–C15 Diene Motif7 Macrocyclization8 Synthesis of the Rhamnosyl Donor9 Synthesis of the Noviosyl Donor and Glycosylation10 The Recurrent Problems Caused by Protective Groups11 Conclusion

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19

Pramanik, Amit, Manabendra Saha, and Sanjay Bhar. "“On-Water” Catalyst-Free Ecofriendly Synthesis of the Hantzsch Dihydropyridines." ISRN Organic Chemistry 2012 (August 12, 2012): 1–7. http://dx.doi.org/10.5402/2012/342738.

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An eco-friendly “on-water” protocol for efficient catalyst-free synthesis of the Hantzsch dihydropyridines from aryl, heteroaryl, alkyl, and vinylogous aldehydes has been developed with minimum auxiliary substances, toxic reagents, organic solvents, and disposal problems.

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20

HIPPE, Z. S., G. FIC, and M. MAZUR. "ChemInform Abstract: A Preliminary Appraisal of Selected Problems in Computer-Assisted Organic Synthesis." ChemInform 23, no. 44 (August 21, 2010): no. http://dx.doi.org/10.1002/chin.199244300.

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21

Wong, Chi-Huey, Randall L. Halcomb, Yoshitaka Ichikawa, and Tetsuya Kajimoto. "Enzymes in Organic Synthesis: Application to the Problems of Carbohydrate Recognition(Part 1)." Angewandte Chemie International Edition in English 34, no. 4 (March 7, 1995): 412–32. http://dx.doi.org/10.1002/anie.199504121.

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22

Wong, Chi-Huey, Randall L. Halcomb, Yoshitaka Ichikawa, and Tetsuya Kajimoto. "Enzymes in Organic Synthesis: Application to the Problems of Carbohydrate Recognition(Part 2)." Angewandte Chemie International Edition in English 34, no. 5 (March 20, 1995): 521–46. http://dx.doi.org/10.1002/anie.199505211.

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23

Dembitsky, V. M., G. A. Tolstikov, and M. Srebnik. "Boranes in Organic Chemistry 1. α-Carbonylalkyl- and β-Oxyalkylboranes in Organic Synthesis." Eurasian Chemico-Technological Journal 4, no. 2 (June 30, 2017): 87. http://dx.doi.org/10.18321/ectj522.

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<p>This review is devoted to the synthesis of a-carbonylalkyl- and β-hydroxy-alkyl boranes and their use in organic synthesis. a-Carbonyl-alkylboranes include several heteroatomic compounds, in particular, [1.2.3]-diazaborinines, uracyl boronic acids, and [1.2.3.4]-diaza-diboretes. The latter type has been obtained by the ketene aminoborations. The reactions of halogenboranes with diazoesters and sulfur ylides resulting in formation of a-carbonyl alkylborates containing diazofunction or ylide structural fragment are described. Amino and halogen boration of acetylenic acid esters was also used for the synthesis of a-carbonyl alkyl boranes. Reactions involving Cr-carbene complexes and acetylenic borone esters were presented for the synthesis of naphthoquinone boronic acids. The formation of amidoboranes by boration of dichloroacetanilides was remined. Boration of 4,8-dimethoxy-2-quinolone with trimethylborates leading to 2-quinolone-3-boronic acid was described. The common synthetic method to a-carbonyl alkyl boranes based on the hydroboration of acrylic acid derivatives was discussed. The results of enhydrazones hydroboration, leading to stable cyclic complexes have been mentioned. The interaction of a-bromoketones with trialkyl or dialkylboranes represents as a general synthetic method to a-carbonyl alkyl boranes. Synthetic approaches to â-hydroxy alkyl boranes are performed. The wide spread hydroboration of vinyl and allyl esters received a well-described attention. The hydroboration of cyclanone enol acetates, 3-keto- and 17-keto-steroids and cyclic allyl alcohol acetates was discussed. The results of aliphatic and alicyclic vinyl esters (including dihydrofuran derivatives) boralylation leading to β-hydroxy alkyl boranes have been envisaged. The synthesis of optically active β-hydroxy alkyl boranes using chiral borane hydrides was discussed. The heterocyclic boran dihydrides are obtained by the hydroboration of dihydropyranes, chromenes and flavenes. Borosilylation of allyl allenylic esters was also been envisaged. The synthetic scheme to optically active boranes and further optically active alcohols were presented. The problems of selectivity regularities in hydroboration reaction by intermolecular complex formations have been discussed.</p>

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24

Zhang, Mengzhao, Taohua Leng, Yongjia Shen, and Chengyun Wang. "Reaction-based fluorescent probe for the selective and sensitive detection of thiophenols with a large Stokes shift and its application in water samples." Analyst 143, no. 3 (2018): 756–60. http://dx.doi.org/10.1039/c7an01994g.

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25

Anelli, Pier Lucio, Fernando Montanari, and Silvio Quici. "Polymer-supported cryptands. Problems arising in the synthesis of highly loaded polymers." Journal of Organic Chemistry 51, no. 25 (December 1986): 4910–14. http://dx.doi.org/10.1021/jo00375a028.

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26

Shaik, Irfansha, and Jaco Van de Pol. "Classical Planning as QBF without Grounding." Proceedings of the International Conference on Automated Planning and Scheduling 32 (June 13, 2022): 329–37. http://dx.doi.org/10.1609/icaps.v32i1.19817.

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Most classical planners use grounding as a preprocessing step, essentially reducing planning to propositional logic. However, grounding involves instantiating all rules and actions with concrete object combinations, and results in large encodings for SAT/QBF-based planners. This severe cost in memory becomes a main bottleneck when actions have many parameters, such as in the Organic Synthesis problems from the IPC 2018 competition. We provide a compact QBF encoding that is logarithmic in the number of objects and avoids grounding completely by using universal quantification for object combinations. We show that we can solve some of the Organic Synthesis problems, which could not be handled before by any SAT/QBF based planners due to grounding.

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27

Moore, Max N., Mark Andrade, Anthony N. Scozzari, and Achim H. Krotz. "Overcoming Backpressure Problems during Solid-Phase Synthesis of Oligonucleotides." Organic Process Research & Development 8, no. 2 (March 2004): 271–74. http://dx.doi.org/10.1021/op030213j.

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28

Liang, Zhenye, Chen Tian, Xiaoxi Li, Liwei Cheng, Shanglei Feng, Lifeng Yang, Yingguo Yang, and Lina Li. "Organic–Inorganic Lead Halide Perovskite Single Crystal: From Synthesis to Applications." Nanomaterials 12, no. 23 (November 28, 2022): 4235. http://dx.doi.org/10.3390/nano12234235.

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Organic–inorganic lead halide perovskite is widely used in the photoelectric field due to its excellent photoelectric characteristics. Among them, perovskite single crystals have attracted much attention due to its lower trap density and better carrier transport capacity than their corresponding polycrystalline materials. Owing to these characteristics, perovskite single crystals have been widely used in solar cells, photodetectors, light-emitting diode (LED), and so on, which have greater potential than polycrystals in a series of optoelectronic applications. However, the fabrication of single-crystal devices is limited by size, thickness, and interface problems, which makes the development of single-crystal devices inferior to polycrystalline devices, which also limits their future development. Here, several representative optoelectronic applications of perovskite single crystals are introduced, and some existing problems and challenges are discussed. Finally, we outlook the growth mechanism of single crystals and further the prospects of perovskite single crystals in the further field of microelectronics.

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29

Sebati, Wilhemina, and Suprakas Ray. "Advances in Nanostructured Metal-Encapsulated Porous Organic-Polymer Composites for Catalyzed Organic Chemical Synthesis." Catalysts 8, no. 11 (October 24, 2018): 492. http://dx.doi.org/10.3390/catal8110492.

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Porous organic polymers (POPs) are of growing research interest owing to their high surface areas, stabilities, controllable chemical configurations, and tunable pore volumes. The molecular nanoarchitecture of POP provides metal or metal oxide binding sites, which is promising for the development of advanced heterogeneous catalysts. This article highlights the development of numerous kinds of POPs and key achievements to date, including their functionalization and incorporation of nanoparticles into their framework structures, characterization methods that are predominantly in use for POP-based materials, and their applications as catalysts in several reactions. Scientists today are capable of preparing POP-based materials that show good selectivity, activity, durability, and recoverability, which can help overcome many of the current environmental and industrial problems. These POP-based materials exhibit enhanced catalytic activities for diverse reactions, including coupling, hydrogenation, and acid catalysis.

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30

Yeon, Seung Ho, Bong Woo Lee, Sun Il Kim, and Il Nam Jung. "Problems and solutions involved in direct synthesis of allylchlorosilanes." Organometallics 12, no. 12 (December 1993): 4887–91. http://dx.doi.org/10.1021/om00036a031.

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31

Blatt, Celso. "Professor Remolo Ciola, a Master and a Genius." Brazilian Journal of Analytical Chemistry 8, no. 10Years (June 2021): 16–21. http://dx.doi.org/10.30744/brjac.2179-3425.letter-cblatt.

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Professor Remolo Ciola has always impressed me with his knowledge of basic chemistry, organic chemistry, synthesis, polymers and catalysis. In addition, he was very good at designing and creating technological solutions to solve problems.

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32

Dandapani, Sivaraman, Mario Jeske, and Dennis P. Curran. "Synthesis of All 16 Stereoisomers of Pinesaw Fly Sex Pheromones − Tools and Tactics for Solving Problems in Fluorous Mixture Synthesis." Journal of Organic Chemistry 70, no. 23 (November 2005): 9447–62. http://dx.doi.org/10.1021/jo051526a.

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33

Pechkovsky, V. V., and L. S. Eshchenko. "Porous Phosphates of Trivalent Metals: Problems of Their Synthesis and Application." Phosphorus, Sulfur, and Silicon and the Related Elements 51, no. 1-4 (September 1990): 430. http://dx.doi.org/10.1080/10426509008040954.

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34

Molinari, Raffaele, Cristina Lavorato, and Pietro Argurio. "Visible-Light Photocatalysts and Their Perspectives for Building Photocatalytic Membrane Reactors for Various Liquid Phase Chemical Conversions." Catalysts 10, no. 11 (November 17, 2020): 1334. http://dx.doi.org/10.3390/catal10111334.

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Photocatalytic organic synthesis/conversions and water treatment under visible light are a challenging task to use renewable energy in chemical transformations. In this review a brief overview on the mainly employed visible light photocatalysts and a discussion on the problems and advantages of Vis-light versus UV-light irradiation is reported. Visible light photocatalysts in the photocatalytic conversion of CO2, conversion of acetophenone to phenylethanol, hydrogenation of nitro compounds, oxidation of cyclohexane, synthesis of vanillin and phenol, as well as hydrogen production and water treatment are discussed. Some applications of these photocatalysts in photocatalytic membrane reactors (PMRs) for carrying out organic synthesis, conversion and/or degradation of organic pollutants are reported. The described cases show that PMRs represent a promising green technology that could shift on applications of industrial interest using visible light (from Sun) active photocatalysts.

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Gao, Xiang, Jiao Liu, Xin Zuo, Xinyue Feng, and Ying Gao. "Recent Advances in Synthesis of Benzothiazole Compounds Related to Green Chemistry." Molecules 25, no. 7 (April 5, 2020): 1675. http://dx.doi.org/10.3390/molecules25071675.

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Benzothiazoles have played an important role in the field of biochemistry and medicinal chemistry due to their highly pharmaceutical and biological activity. The development of synthetic processes is undoubtedly one of the most significant problems facing researchers. In this review paper, we provided recent advances in the synthesis of benzothiazole compounds related to green chemistry from condensation of 2-aminobenzenethiol with aldehydes/ketones/acids/acyl chlorides and the cyclization of thioamide or carbon dioxide (CO2) as raw materials, and the future development trend and prospect of the synthesis of benzothiazoles were anticipated.

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Futaki, Shiroh, Kiwada Tatsuto, Yasuhisa Shiraishi, and Yukio Sugiura. "Total synthesis of artificial zinc-finger proteins: Problems and perspectives." Biopolymers 76, no. 2 (2004): 98–109. http://dx.doi.org/10.1002/bip.10562.

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Bakayoko, Moussa, Loissi Kalakodio, Adiara Kalagodio, Bodjui Olivier Abo, Jean Pierre Muhoza, and El Moctar Ismaila. "Synthesis and characterization of the removal of organic pollutants in effluents." Reviews on Environmental Health 33, no. 2 (June 27, 2018): 135–46. http://dx.doi.org/10.1515/reveh-2018-0004.

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Abstract The use of a large number of organic pollutants results in the accumulation of effluents at the places of production and the environment. These substances are, therefore, dangerous for living organisms and can cause heavy environmental damage. Hence, to cure these problems certain methods were used for the elimination of organic effluents. Indeed, the methods of elimination through magnetic adsorption and/or separation prove to be effective in the treatment of certain wastes, but the effectiveness of each one of these methods depends on several characteristics and also present limitations according to the pollutants they adsorb. This review examines on the one hand the capacity of certain elements of these methods in the elimination of certain pollutants and on the other hand the advantages and limits of these methods. Elements like biochars, biosorbents and composite materials are used due to their very strong porosity which makes it possible for them to develop an important contact surface with the external medium, at low costs, and the possibility of producing them from renewable sources. The latter still run up however against the problems of formation of mud and regeneration. Depollution by magnetic separation is also used due to its capacity to mitigate the disadvantages of certain methods which generally lead to the formation of mud and overcoming also the difficulties like obtaining an active material and at the same time being able to fix the pollutants present in the effluents to treat and sensitize them to external magnetic fields.

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Milenkovic, Alexandra, Mathieu Macaud, Emmanuelle Schulz, Tamás Koltai, David Loffreda, Michel Vrinat, and Marc Lemaire. "How could organic synthesis help the understanding of the problems of deep hydrodesulfurization of gasoils?" Comptes Rendus de l'Académie des Sciences - Series IIC - Chemistry 3, no. 6 (November 2000): 459–63. http://dx.doi.org/10.1016/s1387-1609(00)00128-6.

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Cassells, John M., and Peter J. Halling. "Protease-Catalyzed peptide synthesis in low-water organic two-phase systems and problems affecting it." Biotechnology and Bioengineering 33, no. 11 (May 1989): 1489–94. http://dx.doi.org/10.1002/bit.260331117.

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WONG, C. H., R. L. HALCOMB, Y. ICHIKAWA, and T. KAJIMOTO. "ChemInform Abstract: Enzymes in Organic Synthesis: Application to the Problems of Carbohydrate Recognition. Part 1." ChemInform 26, no. 27 (August 17, 2010): no. http://dx.doi.org/10.1002/chin.199527323.

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WONG, C. H., R. L. HALCOMB, Y. ICHIKAWA, and T. KAJIMOTO. "ChemInform Abstract: Enzymes in Organic Synthesis: Application to the Problems of Carbohydrate Recognition. Part 2." ChemInform 26, no. 29 (August 17, 2010): no. http://dx.doi.org/10.1002/chin.199529335.

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Santos, Filipa, Luís C. Branco, and Ana Rita C. Duarte. "Organic Salts Based on Isoniazid Drug: Synthesis, Bioavailability and Cytotoxicity Studies." Pharmaceutics 12, no. 10 (October 10, 2020): 952. http://dx.doi.org/10.3390/pharmaceutics12100952.

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Tuberculosis is one of the ten causes of morbidity and mortality worldwide caused by Mycobacterium tuberculosis complex. Some of the anti-tuberculosis drugs used in clinic studies, despite being effective for the treatment of tuberculosis, present serious adverse effects as well as poor bioavailability, stability, and drug-resistance problems. Thus, it is important to develop approaches that could provide shorter drug regimens, preventing drug resistance, toxicity of the antibiotics, and improve their bioavailability. Herein, we reported the use of organic salts based on the isoniazid drug, which can act as an organic cation combined with suitable organic anions such as alkylsulfonate-based (mesylate, R or S-Camphorsulfonate), carboxylate-based (glycolate, vanylate) and sacharinate. The synthesis, characterization, and cytotoxicity studies comparing with the original isoniazid drug have been performed. The possibility to explore dicationic salts seems promising in order to improve original bioavailability, and promote the elimination of polymorphic forms as well as higher stability, which are relevant characteristics that the pharmaceutical industry pursues.

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Kostadinova, N. "THE BIOAGRICULTURE-ECOLOGY SYNERGY." Trakia Journal of Sciences 18, Suppl.1 (2020): 560–63. http://dx.doi.org/10.15547/tjs.2020.s.01.089.

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Agriculture affects nature and natural resources, changes the environment, and causes environmental problems. But as an economic activity it is directly related to natural conditions and dependent on natural forces. And nature management leads to environmental consequences. Organic farming has a lesser impact on the environment and contributes to its protection. The purpose of this study is to monitor the impact of organic farming on ecology and environmental protection. To achieve this goal the following tasks are solved: analyzing the state and development of organic farming in Bulgaria; studying the impact between organic farming and ecology; to substantiate the conclusions and recommendations of the study The methods and approaches used to achieve the goal and solve the problems are analysis and synthesis, systematic, synergetic and structural approach, induction and deduction, statistical methods, expert evaluations. The expectations of the study are to establish that there is a potential for the growth of organic farming which has an impact on environmental protection.

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Jones, David J., Eileen M. O’Leary, and Timothy P. O’Sullivan. "An improved synthesis of adefovir and related analogues." Beilstein Journal of Organic Chemistry 15 (March 29, 2019): 801–10. http://dx.doi.org/10.3762/bjoc.15.77.

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An improved synthesis of the antiviral drug adefovir is presented. Problems associated with current routes to adefovir include capricious yields and a reliance on problematic reagents and solvents, such as magnesium tert-butoxide and DMF, to achieve high conversions to the target. A systematic study within our laboratory led to the identification of an iodide reagent which affords higher yields than previous approaches and allows for reactions to be conducted up to 10 g in scale under milder conditions. The use of a novel tetrabutylammonium salt of adenine facilitates alkylations in solvents other than DMF. Additionally, we have investigated how regioselectivity is affected by the substitution pattern of the nucleobase. Finally, this chemistry was successfully applied to the synthesis of several new adefovir analogues, highlighting the versatility of our approach.

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Anderson, Shannon Y. C., Whitney S. Y. Ong, and Jennifer L. Momsen. "Support for instructional scaffolding with 1H NMR spectral features in organic chemistry textbook problems." Chemistry Education Research and Practice 21, no. 3 (2020): 749–64. http://dx.doi.org/10.1039/c9rp00252a.

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Nuclear magnetic resonance (NMR) spectroscopy is vital to synthesis and provides rich problem-solving opportunities to organic chemistry students. Using the theories of scaffolding, interleaving, and blocking, our research systematically explores how textbooks introduce and reinforce spectral features when teaching students to solve ¹H NMR spectroscopy problems. Specifically, we investigated the ¹H NMR spectral features presented in worked examples and practice problems across four undergraduate organic chemistry textbooks. We examined the frequency and ordering of spectral features to explore how the textbooks could support scaffolded instruction. Spectral features like the number of signals and chemical shift were covered by problems more frequently, while integration was covered least. Our findings suggest that textbooks do not provide sufficient practice with all ¹H NMR spectral features. We observed no discernible pattern in how textbooks ordered spectral features of ¹H NMR in problems, indicating that there is little systematic method to the design of textbook chapters. Implications for textbook authors and editors, instruction, and research are discussed.

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Dyudeeva, E. S., A. S. Pavlova, M. S. Kupryushkin, D. V. Pyshnyi, and I. A. Pyshnaya. "Problems of the Synthesis of Oligonucleotide Derivatives in the Realization of the Anchimeric Effect." Russian Journal of Bioorganic Chemistry 47, no. 2 (March 2021): 505–13. http://dx.doi.org/10.1134/s1068162021020096.

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Bagirov, Gyulyara, S. R. Rafiyeva, F. A. Nasirov, G. N. Hasanova, A. D. Kuliyev, A. M. Tagiyeva, and N. F. Janibayov. "DIRECT SYNTHESIS OF 1.4-CIS POLYBUTADIENE WITH APPLICATION OF HETEROGENIZED DITHIOSYSTEM." JOURNAL OF ADVANCES IN CHEMISTRY 11, no. 6 (September 16, 2015): 3678–84. http://dx.doi.org/10.24297/jac.v11i6.856.

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The problems of phosphorusulphurization of mordenite, preparation of metalcomplex dithiophosphates and results of their investigation as the heterogenized catalytic systems in combination with aluminum-organic compounds in the polymerization process of butadiene are considered. It has been established that Ni- and Co-containing dithiosystem are the high-active and high-selective catalysts of this pricess

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Kardooni, Rezvan, and Ali Reza Kiasat. "Polyethylene Glycol as a Green and Biocompatible Reaction Media for the Catalyst Free Synthesis of Organic Compounds." Current Organic Chemistry 24, no. 12 (September 22, 2020): 1275–314. http://dx.doi.org/10.2174/1385272824999200605161840.

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Replacing harmful organic solvents that caused environmental pollution with an alternative medium for the development of ideal synthetic strategies is one of the primary focal points of green chemistry. Utilizing polyethylene glycol (PEG) as a nonvolatile solvent and promotor for the evaluation of safe processes has made a considerable contribution to the reduction of pollution problems. The current review summarizes the recent well-known catalyst-free organic reaction performed in polyethylene glycol as a green and biocompatible reaction medium.

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Rubab, Laila, Ayesha Anum, Sami A. Al-Hussain, Ali Irfan, Sajjad Ahmad, Sami Ullah, Aamal A. Al-Mutairi, and Magdi E. A. Zaki. "Green Chemistry in Organic Synthesis: Recent Update on Green Catalytic Approaches in Synthesis of 1,2,4-Thiadiazoles." Catalysts 12, no. 11 (October 29, 2022): 1329. http://dx.doi.org/10.3390/catal12111329.

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Green (sustainable) chemistry provides a framework for chemists, pharmacists, medicinal chemists and chemical engineers to design processes, protocols and synthetic methodologies to make their contribution to the broad spectrum of global sustainability. Green synthetic conditions, especially catalysis, are the pillar of green chemistry. Green chemistry principles help synthetic chemists overcome the problems of conventional synthesis, such as slow reaction rates, unhealthy solvents and catalysts and the long duration of reaction completion time, and envision solutions by developing environmentally benign catalysts, green solvents, use of microwave and ultrasonic radiations, solvent-free, grinding and chemo-mechanical approaches. 1,2,4-thiadiazole is a privileged structural motif that belongs to the class of nitrogen–sulfur-containing heterocycles with diverse medicinal and pharmaceutical applications. This comprehensive review systemizes types of green solvents, green catalysts, ideal green organic synthesis characteristics and the green synthetic approaches, such as microwave irradiation, ultrasound, ionic liquids, solvent-free, metal-free conditions, green solvents and heterogeneous catalysis to construct different 1,2,4-thiadiazoles scaffolds.

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Yuliyanto, Eko, Yosef Wijoyo, Enade Perdana Istyastono, and Fitria Fatichatul Hidayah. "REFLEKSI PRAKTIKUM KIMIA ORGANIK CALON PENDIDIK KIMIA MENGGUNAKAN REKAMAN VIDEO." JURNAL PENDIDIKAN SAINS (JPS) 6, no. 2 (November 16, 2018): 76. http://dx.doi.org/10.26714/jps.6.2.2018.76-83.

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Organic chemistry is one of the courses that must be taken by a pre-service teacher. However, not all students like the subject, on the other hand they have to learn. Practicum of Organic chemistry has been carried out for some time by chemistry education students. Therefore to bridge the gap and problems. It needs to be an improvement to find out the problem. Therefore it is necessary to reflect on organic chemistry practicum using videos. This research was in the form of observation of learning organic chemistry which was participated by 29 semester 3 chemistry education students with acetic acid synthesis material, saponification and synthesis of butyl acetate. Based on the results of the study concluded that 1). It is important to prepare students' skills in using equipment 2). Practical topics getting closer to everyday products, will be more interesting, 3).Preliminary confirmation before practicum is important to ensure student readiness, 4). Reflection is very helpful in reminding lecturers of the results of learning objectives.

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