Nitroketene acetal chemistry: efficient synthesis of 2-amino-3-nitro-4H-chromenes
作者:H. Surya Prakash Rao、K. Geetha
DOI:10.1016/j.tetlet.2009.04.018
日期:2009.7
Base-catalyzed reaction of the nitroketene N,S-acetals and the ring substituted 2-hydroxybenzaldehydes afforded a combinatorial library of the 2-alkylamino-3-nitro-4-alkylsulfanyl 4H-chromenes in excellent yields. Nucleophilic displacement of the C4 alkylsulfanyl group with different thiols afforded 4H-chromenes with structural diversity. (c) 2009 Elsevier Ltd. All rights reserved.
Choline hydroxide: An efficient and biodegradable catalyst for the synthesis of 2-amino-3-nitro-4<i>H</i>-chromene derivatives in an aqueous medium
Abstract An expedient, eco-friendly and efficient procedure for the synthesis of novel 2-amino-3-nitro-4H-chromene derivatives has been developed through the reaction of various 2-hydroxybenzaldehydes and (E)-N-methyl-1-(methylthio)-2-nitroethenamine in the presence of the basic ionic liquid catalyst (choline hydroxide (ChOH)) at room temperature an aqueous medium. The advantageous of this method is