NEW METHODOLOGY FOR THE PREPARATION OF PYRROLE AND INDOLE-DERIVATIVES VIA IMINOPHOSPHORANES - SYNTHESIS OF PYRROLO[1,2-A]QUINOXALINES, INDOLO[3,2-C]QUINOLINES AND INDOLO[1,2-C]QUINAZOLINES

The aza-Wittig reaction of iminophosphorane N-[o-(triphenylphosphoranylidene)amino]-phenyl pyrrole 4 with heterocumulenes leads to functionalized pyrrolo[l,2-a]quinoxalines. Iminophosphorane 19, derived from 2-(o-amino)phenyl indole, reacts under mild conditions with isocyanates to form 21 which are converted into 5-amino-11H-indolo[3,2-c]quinolines 22. Iminophosphorane 19 also reacts with carbon dioxide and carbon disulfide to give indolo[3,2-c]quinolines 23. Iminophosphorane 28. derived from 2-fo-azido)-phenyl-3-phenyl indole, reacts with isocyanates, carbon dioxide and carbon disulfide to form indolo[l,2-c]-quinazolines 29 and 30 respectively. © 1990.