Starting from tetraacetylribofuranose (Ⅰ) and 6-chloropurine (Ⅲ), in the presence ofp-toluenesulfonic acid as catalyst, the intermediate 2',3',5'-tri-O-acetyl-6-chloropurine nucleoside (Ⅲ) was synthesized for the first time under microwave irradiation in the yield of 80.1%. The title compounds 6-chloro-9-β-D-purinenucleoside (Ⅳ) and 6-methoxy9-β-D-purinenucleoside (Ⅴ) were easily obtained by treatment the intermediate (Ⅲ) with NH3/CH3OH and Na2CO3/CH3OH in the yields of 78.8% and 76.9%, respectively. Structures of Ⅳ and Ⅴ have been identified by 1H NMRand elementary analysis. The optimal conditions for condensation were as follows: n(Ⅰ): n(Ⅱ)= 1: 1, m(TsOH):m(6-chloropurine)=3 × 10-2, microwave irradiation at 595 W for 4.5 min, at 462 W for 1 min, at 119 W for 0.5 min;aminolysis condition for Ⅳ: room temperature for 5 min; alkaline hydrolysis conditions for Ⅴ: reflux for 5 h.……
以硫脲和氯乙酸为原料,在无溶剂和350 W微波辐射4 m in条件下,缩合生成中间体2,4-噻唑烷二酮(Ⅰ)产率91.5%;随后在无溶剂和400 W微波辐射5 m in条件下,通过V ilsm e ier甲酰化反应,生成中间体4-氯-5-甲酰基噻唑-2(3H)-酮(Ⅱ),产率86.7%;最后以正丙醇为溶剂,450 W微波辐射7 m in条件下,成环得到5-氨基-噻唑[4,5-d]嘧啶-2(3H)-酮(Ⅲ),产率80.5%。反应总产率为63.9%。合成产物与中间体的结构经1HNMR,MS和元素分析确认。