Studies on isocyanides and related compounds: a facile synthesis of 1, 6-dihydro-6-oxopyrazine-2-carboxylic acid derivatives via Ugi four-component condensation

…, M García-Valverde, S Marcaccini, R Pepino…

Index: Faggi, Cristina; Garcia-Valverde, Maria; Marcaccini, Stefano; Pepino, Roberto; Pozo, Ma. Cruz Synthesis, 2003 , # 10 p. 1553 - 1558

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Citation Number: 10

Abstract

Abstract The Ugi four-component condensation (U-4CC) between arylglyoxals 7, amines 6, benzoylformic acid (4) and isocyanides 5 afforded the expected products 8 which were cyclized in a 5+ 1 fashion with ammonium acetate to give 1, N-disubstituted 4-aryl-1, 6- dihydro-6-oxo-5-phenylpyrazine-2-carboxamides 9 in good yields. Evidence for the assigned structures 9 was provided by 13 C NMR spectra and X-ray analysis of 9a.