Catalytic asymmetric S -oxidation of N -benzoyl-1,5-benzothiazepines

Makino, Kosho; Yoneda, Tetsuya; Ogawa, Risa; Kanase, Yuki; Tabata, Hidetsugu; Oshitari, Tetsuta; Natsugari, Hideaki; Takahashi, Hideyo

doi:10.1016/j.tetlet.2017.06.021

Cited by 9 publications

(6 citation statements)

References 13 publications

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“…These results prompted us to investigate the photoracemization reaction in the presence of a photosensitizer. We anticipated that quick racemization of sulfoxides should be applicable to technology, such as the dynamic kinetic resolution . Herein, we report the high-speed photoracemization of chiral alkyl aryl sulfoxides using a photosensitizer 2,4,6-triphenylpyrylium tetrafluoroborate (TPT + ).…”

Section: Introductionmentioning

confidence: 99%

“…We anticipated that quick racemization of sulfoxides should be applicable to technology, such as the dynamic kinetic resolution. 10 Herein, we report the high-speed photoracemization of chiral alkyl aryl sulfoxides using a photosensitizer 2,4,6-triphenylpyrylium tetrafluoroborate (TPT + ). Some sulfoxides with specific functional groups resist photoracemization, and this is appropriately assessed based on cyclic voltammograms.…”

Section: Introductionmentioning

confidence: 99%

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Rapid Photoracemization of Chiral Alkyl Aryl Sulfoxides

et al. 2021

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The photoracemization of chiral alkyl aryl sulfoxides with a photosensitizer has not been sufficiently investigated thus far. Therefore, in this study, a rapid photoracemization reaction of enantiopure alkyl aryl sulfoxides using 1 mol % 2,4,6-triphenylpyrylium tetrafluoroborate (TPT + ) was developed. Various substitution patterns were tolerated and every racemization reaction proceeded extremely fast ( k 2 = 1.77 × 10 4 –6.08 × 10 1 M –1 s –1 , t 1/2 = 0.4–114 s). Some chiral sulfoxides with easily oxidizable functional groups are not appropriate for this photoisomerization. The electrochemical potentials of the functional groups, determined via cyclic voltammetry, are useful for predicting the reactive or nonreactive groups in this photoracemization reaction. A theoretical study was conducted to clarify the sp 2 -like nature of S of the sulfoxide cation radical, which makes photoracemization easier.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rapid Photoracemization of Chiral Alkyl Aryl Sulfoxides

et al. 2021

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“…50 The 1,5-benzothiazepine derivatives also exhibited various important biological activities. [51][52][53][54][55] As shown in Scheme 7B, in the presence of Cu(OTf) 2 under air, dearomatized cycloadduct 3q was smoothly converted to 1,5-benzothiazepine derivative 10 in 93% yield and 95% ee. The structure of 1,5-benzothiazepine 10 was also confirmed by single-crystal X-ray diffraction analysis.…”

Section: Resultsmentioning

confidence: 99%

Cu-catalyzed Asymmetric Dearomative [3 + 2] Cycloaddition Reaction of Benzazoles with Aminocyclopropanes

Zhang

Wang

Xie

et al. 2019

Chem

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The enantioselective dearomative [3 + 2] cycloaddition reaction of benzazoles with aminocyclopropanes has been successfully developed. In the presence of a copper complex, derived from Cu(OTf) 2 and bisoxazoline, a series of hydropyrrolo-benzazole derivatives containing quaternary stereogenic centers were obtained in high yields with excellent enantioselectivity. This method could also provide 2-amino cyclopropanes with high enantiomeric purity by an efficient kinetic resolution. In addition, products could be transformed to pyrrolobenzothiazines and 1,5-benzothiazepines.

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“…The substrate scope of the reaction was also investigated for the preparation of diversly substituted 1,5-benzothiazepines. [51] Dandia heteroannulation protocol for the exclusive synthesis of medicinally important azeto[2,1-day] [1,5]benzothiazepines (77) involve condensation of 2-carboxy-2,3-dihydro-1,5-benzothiazepines (76) and chloroacetyl chloride (75, 2 mmol) in the presence of 10 mol% K 2 CO 3 under sonication (Scheme 17). In contrast to the conventional synthesis, where mixture of products were obtained after several hours of heating, the present method offered several advantages such as the exclusive formation of the desired products, simpler work-up procedure, higher yields in shorter reaction time, and green aspects through the avoidance of toxic catalysts and solvents.…”

Section: Enantioselective Synthesis Of 15-benzothiazepinesmentioning

confidence: 99%

Recent advances in the synthetic chemistry of 1,5‐benzothiazepines: A minireview

Devi

Singh

Monga

2020

Journal of Heterocyclic Chem

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Benzothiazepine, a prominent “drug prejudice core”, is a heterocyclic moiety of immense importance due to its presence in a wide range of bioactive compounds. They act as a primary “biolinker” in diverse synthetic routes to obtain bioactive molecules and serve as important templates in synthetic and medicinal chemistry. They are known to possess a plethora of pharmacological activities, which include Ca2+ channel blockers, CNS acting agents, anti‐HIV, ACE inhibitors, antimicrobial, antifungal, anticancer. Their promising behaviour as drug molecules led the scientific community to develop novel, mild, green, and highly efficient synthetic routes for their synthesis. The conventional synthesis generally involved the condensation of chalcones with 2‐aminothiophenol in the presence of acid/base with high‐temperature heating, mostly resulting in poor yields or mixtures. However, recent trends are replacing these conditions with mild and green conditions through organocatalysis or other methodologies. In this review, an attempt has been made by authors to summarize (a) Recent developments in the synthetic strategies of 1,5‐benzoathiazepines and its derivatives (b) Conventional methods for the synthesis of 1,5‐benzothiazepines including progress in the green chemistry routes (c) Applications of various metals and organocatalysts to achieve the enantioselective synthesis of title compounds.

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Catalytic asymmetric S -oxidation of N -benzoyl-1,5-benzothiazepines

Cited by 9 publications

References 13 publications

Rapid Photoracemization of Chiral Alkyl Aryl Sulfoxides

Rapid Photoracemization of Chiral Alkyl Aryl Sulfoxides

Cu-catalyzed Asymmetric Dearomative [3 + 2] Cycloaddition Reaction of Benzazoles with Aminocyclopropanes

Recent advances in the synthetic chemistry of 1,5‐benzothiazepines: A minireview

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