(Chemical Equation Presented) The carbodiimides 5, obtained from reactions of iminophosphorane 4 with aromatic isocyanates, reacted with amines, phenols or ROH to give 2-substituted 5,6,7,8-tetrahydropyrido[4′,3′:4,5] thieno[2,3-d]-pyrimidin-4(3H)-one 7 in the presence of catalytic amount of sodium alkoxide or solid potas...