Benzofuro[3,2-d]pyrimidine derivatives are prepared using aza-Wittig reactions of iminophosphoranes with n-butyl isocyanate at 40–50 °C to give carbodiimide intermediates, which are reacted with nitrogen-oxygen-containing nucleophiles to give 3-alkyl-2-amino (aryloxy/alkoxy)-benzofuro[3,2-d]pyrimidin-4(3H)-ones in satisfactory yields in the presence of a catalytic amount of sodium ethoxide or K2CO3. The iminophosphorane also reacts directly with excess carbon disulfide, followed by n-propylamine; further reaction with alkyl halides or halogenated aliphatic esters in the presence of anhydrous K2CO3 produces the corresponding 2-alkylthio-3-n-propyl-benzofuro[3,2-d]pyrimidin-4(3H)-ones in good yields. Their structures of the products are confirmed by 1H NMR, 13C NMR, mass spectrometry, infrared and elemental analysis.

中文翻译：

---

3-烷基-2-多样性取代的苯并呋喃[3,2-d]嘧啶-4(3H)-one衍生物的有效合成

苯并呋喃[3,2-d]嘧啶衍生物使用亚氨基正膦与异氰酸正丁酯在40-50°C下的氮杂-Wittig反应得到碳二亚胺中间体，再与含氮氧亲核试剂反应得到3-烷基-2-氨基(芳氧基/烷氧基)-苯并呋喃[3,2-d]嘧啶-4(3H)-酮，在催化量的乙醇钠或K2CO3存在下，产率令人满意。亚氨基正膦也直接与过量的二硫化碳反应，然后是正丙胺；在无水 K2CO3 存在下与烷基卤化物或卤化脂肪族酯进一步反应，以良好的产率生成相应的 2-烷硫基-3-正丙基-苯并呋喃 [3,2-d]嘧啶-4(3H)-酮。产物的结构经1H NMR、13C NMR、质谱、红外和元素分析证实。