NEW METHODOLOGY FOR THE PREPARATIONOF QUINAZOLINE DERIVATIVES VIA TANDEM AZA-WITTIG/HETEROCUMULENE-MEDIATED ANNULATION. SYNTHESIS OF 4(3H)QUINAZOLINONES, BENZIMIDAZOQUINAZOLINES, QUINAZOLINOQUINAZOLINES AND BENZOTHIAZOLOQUINAZOLINES.

Article abstract of DOI:10.1016/S0040-4020(01)81321-1

The aza-Wittig reaction of iminophosphoranes derived from N-substituted o-azidobenzamides, 2-(o-azidophenyl)-benzimidazole, -benzothiazole or -3,1-benzoxazin-4-one with heterocumulenes leads to functionalized quinazolines.Iminophosphoranes 9, derived from N-substituted o-azidobenzamides, react under mild conditions with isocyanates to form 4H-3,1-benzoxazine-4-imines 11 which are converted into 2-substituted-4(3H)-quinazolinones 12.Iminophosphoranes 9 also react with carbon disulfide and carbon dioxide to give the quinazolinones 13 and 14 respectively.Iminophosphorane 26, derived from 2-(o-azidophenyl)benzimidazole, reacts with isocyanates, carbon disulfide and carbon dioxide to form 6-substituted benzimidazo<1,2-c>quinazolines 27, 28, and 29 respectively.In benzene at room temperature, iminophosphorane 31, reacts with isocyanates yielding quinazolino<3,2-a>quinazolines 34.Compounds 34 can also be prepared from iminophosphorane 36 and isocyanates.Iminophosphorane 40 derived from 2-(o-azidophenyl)benzothiazole reacts with aliphatic and aromatic isocyanates or isothiocyanates to give 7H-benzothiazolo<3,2-c>quinazoline-7-imines 42.Iminophosphorane 40 also reacts with carbon dioxide or carbon disulfide to afford the corresponding isocyanate 43 or isothiocyanate 44, The molecular structures of 11d and 42a have been determined by X-ray diffraction methods.