Abstract The syntheses in good yields of a considerable number of moderately to severely sterically-crowded 1, 2, 5-trisubstituted pyrroles by means of modifications of the Knorr-Paal condensation are described. Notwithstanding reports to the contrary, the classical procedure; succeeded in moderately sterically-crowded cases, eg, R 2= R 5= Me, R 1= i-Pr, Me 2 CHMeCH-, Me 2 N-, Ph 2 N-, 9-carbazolo, subst. 4-morpholino, 1-piperazino, 1- ...
