Singh, Gurdeep ; Ila, Hiriyakkanavar ; Junjappa, Hiriyakkanavar (1987) Polarised ketene dithioacetals. Part 50. Reactions of α-aroyl-α-bromoketene dithioacetals with hydrazine hydrate: formation of rearranged pyrazoles Journal of the Chemical Society, Perkin Transactions 1 . pp. 1945-1949. ISSN 0300-922X
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Official URL: http://pubs.rsc.org/en/Content/ArticleLanding/1987...
Related URL: http://dx.doi.org/10.1039/P19870001945
Abstract
The reactions of α-aroyl-α-bromoketene dithioacetals (2a-c) with hydrazine hydrate yields unexpected pyrazoles, i.e. 3(5)-aryl-5(3)-4-bis(alkylthio)pyrazoles (7), 3(5)-arylpyrazoles (8), and 4-amino-5(3)alkylthiopyrazoles (9) in varying yields. The corresponding S-ethyl-α-bromoketene dithioacetal (2d) gave only the bis(ethylthio)pyrazole (7d) and 4-amino-4(3)-ethylthiopyrazole (9d) under similar conditions. The reactions of cyclic α-bromo ketene dithioacetals (2e-g) with hydrazine hydrate on the other hand afforded only the [1,4]dithiinopyrazole derivatives (7e-g) in high yields. The probable mechanisms for the formation of the pyrazoles (7)-(9) have been suggested.
Item Type: | Article |
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Source: | Copyright of this article belongs to Royal Society of Chemistry. |
ID Code: | 15480 |
Deposited On: | 13 Nov 2010 08:59 |
Last Modified: | 22 Feb 2011 09:06 |
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