Concentrated Aqueous Sodium Tosylate as Green Medium for Alkene Oxidation and Nucleophilic Substitution Reactions

Sela, Tal; Lin, Xianfu; Vigalok, Arkadi

doi:10.1021/acs.joc.7b01679

Cited by 12 publications

(8 citation statements)

References 37 publications

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“…gave 9 in 65% yield (Scheme 2). The usual methods for removing the toluenesulfonate, such as NaOTs/ H 2 O, 19 CeCl 3 •7H 2 O/NaI, 20 and Mg/MeOH, 21 were examined for the transformation of 9 to the diol 1. Among these, Mg/MeOH effectively completed the transformation and gave 3β,25dihydroxy-5α-cholesta-7-ene 1 in 79%.…”

Section: Resultsmentioning

confidence: 99%

A Facile Synthesis of 3β,25-dihydroxy-5α-Cholest-7-ene, the Precursor to HMG-CoA Reductase Inhibitor

Jin

Liao

Sun

et al. 2018

Journal of Chemical Research

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An efficient four-step procedure is described for the synthesis of 3β,25-dihydroxy-5α-cholest-7-ene from 3β-hydroxy-5α-cholesta-7,24-diene in an overall yield of 34%. This product can serve as a precursor for the synthesis of an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase. The 3β-toluene- p-sulfonate ester of 5α-cholesta-7,24-diene was obtained from natural lanolin followed by treatment with toluene- p-sulfonyl chloride. The key step in the synthesis is a very mild method for the hydroxybromination of this ester with N-bromosuccinimide in water, followed by reduction with LiAlH4 to obtain the 3β-toluene- p-sulfonate ester of 25-hydroxy-5α-cholesta-7-ene. The final product was obtained after desulfonation of 3β-toluene- p-sulfonyoxy-25-hydroxy-5α-cholesta-7-ene to afford 3β,25-dihydroxy-5α-cholest-7-ene in excellent yield. The reagents are all relatively cheap, non-toxic and stable.

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Section: Resultsmentioning

confidence: 99%

A Facile Synthesis of 3β,25-dihydroxy-5α-Cholest-7-ene, the Precursor to HMG-CoA Reductase Inhibitor

Jin

Liao

Sun

et al. 2018

Journal of Chemical Research

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“…Hydrogen peroxide (H 2 O 2 ) with sodium hydroxide in THF [27], ceric foam (CeO 2 ) [124] and hydrotropic sodium tosylate (NaOTs) [125] are another type of catalysts used for the epoxidation of chalcones with an excellent yield (90-95%). In some conditions, H 2 O 2 could only produce cinnamic acid instead of epoxide in acetonitrile [126].…”

Section: Other Catalystmentioning

confidence: 99%

One Pot and Two Pot Synthetic Strategies and Biological Applications of Epoxy-Chalcones

Farooq

Ngaini

2020

Chemistry Africa

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Epoxy chalcone is a heterocyclic molecule and an important precursor for the synthesis of biologically active compounds. This mini-review is elucidating the synthetic strategies of chalcone epoxide via one pot and two pot routes including nature of reactants, nature of catalyst and variety of catalyst to improve yield of desired product, biological applications and advantages and drawbacks of these synthetic strategies. One pot route has wide variety of reactants and efficient one is the condensation of aldehyde and ketone. However, two pot route is consisted of chalcone synthesis preceding to epoxy chalcone. The synthetic routes for the preparation of epoxy chalcone and the usage as a precursor for the synthesis of various organic molecules with biological application is comprehensively discussed. This review is outstanding in organic chemistry and pharmaceutical industries to produce new molecules with various applications. Graphic AbstractO O

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“…57,58 There are fewer literature examples of using deactivated alkene derivatives, such as alkenes with multiple EWGs 59 (trans-stilbene) using metal-free green procedures. 60,61 This gap in knowledge in the literature allowed for the optimization of known green chemistry epoxidation conditions with deactivated alkenes in the format of a CURE course. Students could apply and further develop their understanding of alkene nucleophilicity by optimizing the reaction conditions in terms of conversion and then further optimizing in terms of greenness.…”

Section: ■ Introductionmentioning

confidence: 99%

“…An epoxidation reaction was chosen, as epoxides are universally studied in a wide array of chemistry applications, ranging from polymer and material chemistry − to biochemical reactions catalyzed by cytochrome P450s. − Epoxides also have applications as useful synthetic intermediates for preparing diverse carbon skeletons, , especially given their straightforward preparation from alkenes. However, alkene epoxidation has historically used conditions that are environmentally unfriendly or dangerous. , Efforts in the literature have addressed these environmental concerns, but green epoxidation procedures have been limited to more “activated” alkene substrates, such as alkenes that have few electron-withdrawing groups (EWGs) (e.g., styrene), have electron-donating groups (EDGs) (e.g., cyclohexene), and/or involve the use of metal catalysts. , There are fewer literature examples of using deactivated alkene derivatives, such as alkenes with multiple EWGs ( trans -stilbene) using metal-free green procedures. , …”

Section: Introductionmentioning

confidence: 99%

Catalyzing the Development of Self-Efficacy and Science Identity: A Green Organic Chemistry CURE

et al. 2022

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To remain globally competitive, education in the United States must focus on retaining students in science, technology, engineering, and mathematics (STEM). As laboratory courses have the potential to be powerful attractors or deterrents to a field, developing effective laboratory pedagogies is important to retain students in STEM. A course-based undergraduate research experience (CURE) is one model for laboratory instruction that has generated an increasing amount of attention. This has been driven by their success, especially in increasing students’ self-efficacy and science identity, two long-term indicators of persistence in STEM. Herein is reported a large introductory organic chemistry CURE course framework that focuses on green reaction optimization. Students were given an unoptimized alkene epoxidation procedure, split into small “research” groups, and tasked with improving conversion while minimizing reaction inputs. After three rounds of optimization, groups increased conversion 10–20-fold compared to baseline conditions. Then, students investigated the substrate scope of their conditions and analyzed trends in relative reactivities based on principles learned in lecture and from the literature. Lastly, students summarized their findings in a final slideshow presentation. Surveys were used to evaluate different aspects common to CURE courses and students’ sense of project ownership. The scores obtained were consistent with other reported CURE courses. Importantly, students saw large gains in self-efficacy and science identity. Students had an overwhelmingly positive response to the curriculum based on informal and written feedback. This approach is generalizable to a wide range of institutions with different equipment availability, reaction types, and course coverage schedules.

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Concentrated Aqueous Sodium Tosylate as Green Medium for Alkene Oxidation and Nucleophilic Substitution Reactions

Cited by 12 publications

References 37 publications

A Facile Synthesis of 3β,25-dihydroxy-5α-Cholest-7-ene, the Precursor to HMG-CoA Reductase Inhibitor

A Facile Synthesis of 3β,25-dihydroxy-5α-Cholest-7-ene, the Precursor to HMG-CoA Reductase Inhibitor

One Pot and Two Pot Synthetic Strategies and Biological Applications of Epoxy-Chalcones

Catalyzing the Development of Self-Efficacy and Science Identity: A Green Organic Chemistry CURE

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