Tetrahedron letters

One pot preparation of pyrido [2, 3, 4-de] quinazolines and benzo [de][1, 6] naphthyridines by a consecutive process involving an aza-Wittig/electrocyclic ring-closure/ …

P Molina, M Alajarín, A Vidal

Index: Molina, Pedro; Alajarin, Mateo; Vidal, Angel Tetrahedron Letters, 1991 , vol. 32, # 39 p. 5379 - 5382

Full Text: HTML

Citation Number: 19

Abstract

Abstract Aza Wittig-type reaction of bis (iminophosphorane) 1 with one mole of isocyanate leads to the iminophosphoranes 5 which by treatment with a second mole of isocyanate afforded pyrido [2, 3, 4-de] quinazolines 6. Similarly, reaction with ketenes leads to the formation of benzo [de][1, 6] naphthyridines 9. Direct conversion 1→ 6 and 1→ 9 were achieved using two moles of isocyanate or ketene respectively.