- Alkylacylimidazoles in Claisen–Schmidt and Knoevenagel Condensations
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Abstract: Alkylacylimidazoles were shown to be good reagents for Claisen–Schmidt and Knoevenagel-like condensations. The Claisen–Schmidt condensation of N-acetylimidazole with benzaldehyde followed by acidification with HCl gave cinnamic acid. The Knoevenagel-like condensation of N-(acetoacetyl)imidazole with hydrated aldehydes resulted in a fast and efficient formation of β-hydroxyketones. The studied reactions provide a new and general synthetic approach to cinnamic acid derivatives and β-hydroxyketones, as well as a new application field of alkylacylimidazoles.
- Mei, X.,Ning, J.,Quan, H.,She, D.,Wang, L.,Wang, Zh.
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p. 1462 - 1467
(2020/10/02)
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- Direct aldol and tandem Mannich reactions in room temperature ammonia solutions
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An economical, simple, and efficient direct aldol reaction via the double activation of both aldehydes and ketones by ammonia has been developed. An unprecedented tandem Mannich reaction was observed when hydroxybenzaldehydes, pyrrole-2-carboxyaldehyde, a
- Feng, Lichun,Xu, Lijin,Lam, Kimhung,Zhou, Zhongyuan,Yip,Chan, Albert S.C.
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p. 8685 - 8689
(2007/10/03)
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- Lewis Acid Catalysis of Ene Addition of Chloral and Bromal to Olefins; Product Studies
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The addition of chloral and bromal to a variety of alkyl-substituted alkenes has been investigated.The effect of the reaction of varying the Lewis acid catalyst and the structure of substrate have been studied.Anhydrous AlCl3 was found to be most effective catalyst, and ene-type adducts were the major products in most cases.Side reactions were observed with the less reactive systems leading, variously, to the formation of trihalogenoketones, hydrohalogenated ene adducts, and cyclic ethers.Conditions for optimising the yield of ene adducts were established in some cases.The trihalogenoketone by-products can be conveniently removed by a Grignard-type reaction.
- Benner, Jill P.,Gill, G. Bryon,Parrott, Stephen J.,Wallace, Brian
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p. 291 - 313
(2007/10/02)
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