The additions of pyrrole and indole upon N-acetyl- and N-alkylpyridinium, quinolinium or isoquinolinium salts are reported. The resulting dihydroazines are either isolated or oxidised to the more stable aromatic compounds. The use of a two-phase system was studied and slight enantiomeric excesses were observed when chiral catalysts were used. The separation of enantiomers of some 4-indolyl-1,4-dihydropyridines was achieved by HPLC using chiral stationary phases. (C) 1997 Elsevier Science Ltd.
The additions of pyrrole and indole upon N-acetyl- and N-alkylpyridinium, quinolinium or isoquinolinium salts are reported. The resulting dihydroazines are either isolated or oxidised to the more stable aromatic compounds. The use of a two-phase system was studied and slight enantiomeric excesses were observed when chiral catalysts were used. The separation of enantiomers of some 4-indolyl-1,4-dihydropyridines was achieved by HPLC using chiral stationary phases. (C) 1997 Elsevier Science Ltd.