Three-Component Reaction between Alkyl Isocyanides, Dialkyl Acetylenedicarboxylates, and Carboxylic Acids

Abstract

Protonation of the reactive intermediates produced in the reaction between alkyl isocyanides and dialkyl acetylenedicarboxylates by carboxylic acids leads to vinylnitrilium cations which then undergo nucleophilic addition of the conjugate bases of the carboxylic acids. This intermediate rearranges to produce dialkyl (E)2-{[(aryl)acetyl(alkylamino)]carbonyl}-2-butenedioate derivatives.

Three-Component coupling of Alkyl/Aryl Isocyanides, Acetylene Dicarboxylates and (2,4-Dioxothiazolidin-3-Yl)Acetic Acids

“…Basing our procedure on one previously reported, 17 we found the reaction of alkyl or aryl isocyanides 1 with dialkyl acetylenecarboxylates 2 in the presence of carboxylic acids 3 proceeded at room temperature in dichloromethane to completion within 12 h and the corresponding dialkyl…”

“…6,7 In spite of extensive developments in the trapping of the 1 : 1 intermediate formed between dialkyl acetylenedicarboxylates and isocyanides with O-H, N-H, and C-H acids, [8][9][10][11][12][13][14][15] less attention has been paid to trapping of the initially formed 1 : 1 intermediate with a carboxylic acid. 16,17 We describe an efficient synthesis of (E)-2-{[N-alkyl/aryl-2-(2,4-dioxo-1,3-thiazolidin-3-yl)acetamido]carbonyl}but-2enedioate derivatives 4 via the reaction in CH 2 Cl 2 of dialkyl acetylenedicarboxylates 2 and alkyl or aryl isocyanides 1 with (2,4-dioxothiazolidin-3-yl)acetic acids 3 (Z=CH 2 ) or their 5-arylidene derivatives 3 (Z=aryl-CH=C) (Scheme 1).…”