Study On Synthesis Of Thieno [2,3-d] Pyrimidinone Derivatives And Biological Activities

Many azole compounds have been found to show widespread biological activities. Some of them have been used as fungicide, herbicide, pesticide and medicine .In this paper, a new synthetic method to 2-substituted thieno[2,3-d]pyrimidin-4(3H)-one derivatives was proposed. This synthetic method has the advantage of easily accessible starting material, mild condition and good yields. The reactions of aza-Wittig were studied further.The spectral properties were also researched and some of them were found to show good fungicidal activities. Thirty-six unreported compounds were synthesized, it may be summarized as follows:1. Gewald reaction was utilized to obtain ethyl 2-aminothiophene-3-carboxylate.2. iminophosphorane was synthesized as an important intermediate.3. The iminophosphorane reacted with aryl isocyanates to give carbodimide as actived intermediate.4. The carbodimide reacted with second amines to give 2-alkylamino-3-aryl -4-ethyl-5-methyl thieno[2,3-d]pyrimidin-4(3H)-one derivatives via aza-Wittig reaction catalyzed by NaOR.5. The carbodimide reacted with alcohols to give 2-alkyloxyl-3-aryl -4-ethyl-5-methyl thieno[2,3-d]pyrimidin-4(J//)-one derivatives via aza-Wittig reaction catalyzed by NaOR.6. The carbodimide reacted with phenols to give 2-aryloxyl-3-aryl-4-ethyl-5-methylthieno [2,3-d]pyrimidin-4(3H)-one derivatives via aza-Wittig reaction catalyzed by solid K₂CO₃.7. The cyclization of carbodiimide with second amines and alcohols was carried out in presence of sodium alkoxide .But the cyclization of carbodiimide with phenols was completed in presence of solid potassium carbonate.8. The biological activities of partial compounds were studied. The results showed that some of compounds exhibit obviously fungicidal activity.