- Wittig–Horner mediated synthesis of 4-vinyl sulfide derivatives of pyrazoles
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The synthesis of a series of 4-vinyl sulfide derivatives of 1,3-diarylpyrazoles, including their corresponding sulfoxides and sulfones, is reported. Access to the target vinyl sulfides was stereoselectively achieved, in moderate to good yields, by the n-BuLi-mediated Wittig–Horner reaction of 4-formylpyrazoles with arylthiophosphonates and α-chloroarylthiophosphonates in dimethoxyethane. Their oxidation with H2O2in AcOH and mCPBA in CH2Cl2afforded satisfactory yields of the expected vinyl sulfoxides and vinyl sulfones, respectively. Enrichment in the more stable isomers during both oxidation processes was detected and a plausible general mechanistic explanation was given to these observations.
- Padilha, Gustavo,Kaufman, Teodoro S.,Silveira, Claudio C.
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- Catalyst-freegem-chlorosulfurization of difluoromethyl-substituted diazo compounds with disulfide and PhICl2
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A series ofgem-chlorosulfurization products bearing difluoromethyl substituents were synthesized in high to excellent yields directly fromp-toluenesulfonyl difluorodiazoethane (TsCF2CHN2), disulfides and PhICl2without any catalysts or additives. The mild reaction conditions and high functional group compatibility indicated the utility and sustainability of the method. In addition, thegem-chlorosulfurization products could be efficiently converted to sulfur-containing and aryl substituted difluoromethyl derivatives by a feasible multi-component operation.
- Li, Jiuling,Li, Bin,Chen, Juan,Jia, Xinyu,Wang, Min,Hao, Chengjun,Zheng, Xinhua,Dai, Hongmei,Hu, Wenhao
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supporting information
p. 8030 - 8034
(2021/10/04)
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- Free radical desulfenylation and deselenylation of α-sulfur and α-seleno substituted phosphonates with the n-Bu3SnH/AIBN reagents system.
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Selestive desulfenylation and deselenylation of α-sulfur- and α-seleno-substituted phosphonates under free radical condition are described.Chemoselectivity and scope of title reaction were studied using phosphonates additionaly functionalized in the α-position alkyl, phenyl,ethoxy,chloro,carbonyl and sulfenyl groups.It was found the reduction of a halogen tolerates the presence of the sulfenyl group and the latter could be reduced in the presence of the sulfinyl and sulfonyl moieties.Moreover,one sulfenyl group was selectively removed from α-phosphoryl dithioacetals and the phenylsulphenyl group was reduced preferentially in the presence of the methylsulfenyl one. Key words:Desulfenylation,deselenylation,α-phosphoryl sulfides,α-phosphoryl selenides, tri-n-butyltinhydride,α,α-azaisobutyronitrile.
- Balczewski,Piotr
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p. 113 - 122
(2007/10/03)
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- SYNTHESIS OF S,S-THIOACETALS OF FORMYLPHOSPHONATE FROM CHLORO(ARYLTHIO)METANEPHOSPHONATE
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Treatment of chloro(arylthio)methanephosphonate with thiols under mild conditions in the presence of stannic chloride affords S,S-thioacetals of formylphosphonate.
- Kim, Taek Hyeon,Oh, Dong Young
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p. 1611 - 1614
(2007/10/02)
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- NEW SYNTHETIC METHOD OF O,S-THIOACETALS OF FORMYLPHOSPHONATES
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The reaction of diethyl phosphonate with N-chlorosuccinimide (NCS) affords α-chloromethanephosphonate(5), which can be converted into a variety of O,S-thioacetals of formylphosphonates(2) by reaction with alcohols.
- Kim, Taek Hyeon,Oh, Dong Young
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p. 3479 - 3482
(2007/10/02)
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