Efficient Synthesis of 7-benzyl-5,6,7,8-tetrahydropyrido[4',3':4,5]thieno [2,3-d]pyrimidin-4(3H)-Ones Via Aza-Wittig Reaction

7-benzyl-5,6,7,8-tetrahydropyrido[4',3':4,5]thieno[2,3-d]pyrimidin-4(3H)-ones were synthesized by base catalytic reactions of nucleophilic reagents (aliphatic amines, alcohols or phenols) with carbodiimides 4, which were obtained from the aza-Wittig reaction of iminophosphoranes 3 with aromatic isocyanates.