An efficient one-pot multicomponent approach to 5-amino-7-aryl-8-nitrothiazolo[3,2-a]pyridines

Some reactions of 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido) acetic acids

“…Recently, we have reported some chemistry incorporating mesoionic 1,3-dipoles; namely sydnones, nitrile oxides, nitrile imines and electron-deficient alkenes, alkynes, [22] [21] [10,11] 2-nitromethylenethiazolidine and benzothiophene 1,1-dioxide. [23][24][25][26][27][28] Herein, we report a study of munchnones€ generated from 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido)acetic acids 3 and acetic anhydride, DCC and DIPC in the presence of 2nitromethylenethiazolidine 4 and diisopropylamine. In this regard, the products were one enol ester, five imides and seven benzoic acid derivatives obtained by the autoxidation reaction between munchnone€ precursors (amino acids) and acetic anhydride in the presence of 2-nitromethylenethiazolidine.…”

NitroketeneN,S-acetals: synergistic building blocks for the synthesis of heterocycles

“…The Et 3 N-catalyzed one-pot reaction was executed using active methylene compounds (i.e., malononitrile 90), ethyl cyanoacetate 126 and the aryl aldehydes 38 with 36 under mild conditions (Scheme 50). 82 When the ethyl cyanoacetate 126 was used, only 1,4-dihydropyridine 127 was formed via grinding using a mortar for 10 min under neat conditions (Scheme 51). Moreover, the ratios of the enamine and imine tautomers 129 and 130, respectively, were observed in an active methylene compound bearing a sulfoxide group, 2-phenyl sulfonylacetonitrile 128 (Scheme 52).…”

2.14 Other Condensation Reactions (Knoevenagel, Perkin, Darzens)

“…63 This situation allowed for a combination of the Suzuki-Miyaura coupling of aryl halides 61 and phenylboronic acid (62) A multicomponent reaction between aromatic aldehydes (64), 2-nitromethylenethiazolidine (65), and nitriles 66 in the presence of Et 3 N afforded a series of 5-amino-7-aryl-8-nitrothiazolo[3,2-a]pyridines (67) (Scheme 21, Table 4). 64 This one-pot multicomponent reaction was initiated by the Knoevenagel reaction of aldehyde with nitrile compound, followed by conjugated addition of enamine and cyclization.…”