Synthetic applications of bis(iminophosphoranes) - Preparation of some derivatives of the 11H-quinazolino[2,3-b]- and quinazolino[4,3-b]quinazoline ring systems

Article abstract of DOI:10.1002/jlac.199719970116

Aza Wittig reaction of bis(iminophosphorane) 3 with two equivalents of aryl isocyanates directly provided the bicyclic guanidines 4. However, 3 undergoes intramolecular aza Wittig reaction on thermal treatment to give the iminophosphorane 6 derived from the 2-(o-azidophenyl)-4(3H)-quinazolinone. Compound 6 reacts with isocyanates, acyl chlorides and carbon disulfide to yield quinazolino[4,3-b]quinazoline derivatives 8a-c, 9a-c, 10, and 11. VCH Verlagsgesellschaft mbH, 1997.