- One-pot three-component heteroannulation of β-oxo dithioesters, amines and hydroxylamine: Regioselective, facile and straightforward entry to 5-substituted 3-aminoisoxazoles
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An efficient and highly regioselective one-pot three-component synthesis of previously inaccessible and synthetically demanding 3-(cycloalkyl/alkyl/ arylamino)-5-aryl/alkylisoxazoles has been achieved by the cyclocondensation of β-oxo dithioesters, amines and hydroxylamine in ethanol at reflux. This transformation proceeds via an in situ generated β-oxothioamide by the reaction of the β-oxo dithioester and amine, which undergoes nucleophilic attack by hydroxylamine followed by intramolecular cyclization with the oxo functionality and subsequent dehydration to give 5-substituted 3-aminoisoxazoles as a single regioisomer in good yields. Furthermore, the mechanism of the reaction has been established experimentally and shown to be in agreement with the hard and soft (Lewis) acid and base (HSAB) theory. A highly regioselective synthesis of 5-substituted 3-aminoisoxazoles has been achieved by a one-pot three-component coupling of β-oxo dithioesters, amines and hydroxylamine in ethanol at reflux via an in situ generated β-oxo thioamide intermediate. The mechanism of the reaction has been established experimentally and shown to be in agreement with the HSAB theory. Copyright
- Samai, Subhasis,Chanda, Tanmoy,Ila, Hiriyakkanavar,Singh, Maya Shankar
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supporting information
p. 4026 - 4031
(2013/07/19)
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- Highly regioselective one-pot, three-component synthesis of 1-aryl-3,4-substituted/annulated-5-(cycloamino)/(alkylamino)pyrazoles from β-oxodithioesters
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An efficient, highly regioselective protocol for the synthesis of the title compounds is reported. The reaction involves a one-pot, three-component cyclocondensation of β-oxodithioester, amine, and hydrazine in ethanol at reflux in the presence of a catal
- Nandi, Ganesh C.,Singh, Maya S.,Ila, Hiriyakkanavar,Junjappa, Hiriyakkanavar
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p. 967 - 974
(2012/03/27)
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- Cyclization Reactions of 2-Acyl-1-chloro-enamines with Thioamide Functional Compounds: Alternative Access to the 1,3-Thiazine and 1,3-Oxazine Series
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2-Acyl-1-chloro-enamines 2 react with thioureas to 2,6-diamino-1,3-thiazinium salts 3, following to usual transformation mode of 1-heterosubstituted acylvinylchlorides A.On the other hand the reaction of 2 with thiobenzamide preferably leads to 4-amino-1,
- Spitzner, Roland,Freitag, Sabine,Schroth, Werner
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p. 1383 - 1394
(2007/10/02)
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- Reactions of Polarized Keten S,N-Acetals with Guanidine: A Facile General Route to Novel 5,6-Substituted 2-Amino-4-N-alkyl/aryl/N-azacycloalkylaminopyrimidines
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The polarized keten S,N-acetals (1a-f), (8a-c), (10a-f), 12 and 14, which are derived from a variety of active methylene compounds like acetophenone, acetone, arylacetonitriles, malononitrile, phenyl acetate and ethyl cyanoacetate have been shown to be us
- Vishwakarma, J. N.,Apparao, S.,Ila, H.,Junjappa, H.
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p. 466 - 471
(2007/10/02)
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