A Convenient Approach to Dialkyl Heteroarylmethylphosphonates and [Alkylthio(heteroaryl)methyl]phosphonates: Synthesis of Imidazo[1,2-<i>a</i>]pyridine, Imidazo[1,2-<i>a</i>]pyrimidine, Indolizine and Thiazole Derivatives
作者:Martina Drescher、Elisabeth Öhler、Erich Zbiral
DOI:10.1055/s-1991-26466
日期:——
The [heteroaryl(hydroxy)methyl]phosphonates 2-5 (indolizines 2, imidazo[1,2-a]pyridines 3, imidazo[1,2-a]pyrimidines 4, and 2-phenylthiazoles 5, are converted readily to the corresponding O,O-thiocarbonates 6-8 and 18 on treatment with p-tolyloxythiocarbonyl chloride in acetonitrile/4-dimethylaminopyridine, while reaction in pyridine/dichloromethane affords the isomeric O,S-thiocarbonates 9-11 and 19, respectively. Homolytic cleavage of both series of compounds proceeds smoothly, using tributyltin hydride/azobisisobutyronitrile (AIBN) in warm toluene to give the new heteroarylmethylphosphonates 12-14 and 20. Conversion of the O,S-thiocarbonates 9-11 and 19 into the synthetically attractive α-methylthio-substituted derivatives 15-17 and 21 is effected efficiently upon saponification with sodium methoxide in methanol and subsequent alkylation with methyl iodide.
杂芳基(羟基)甲基]膦酸盐 2-5(吲哚利嗪 2、咪唑并[1,2-a]吡啶 3、咪唑并[1,2-a]嘧啶 4 和 2-苯基噻唑 5)在乙腈/4-二甲氨基吡啶中与对甲氧基硫代碳酰氯反应后,很容易转化为相应的 O. O-硫代碳酸盐 6-8 和 18、O-硫代碳酸酯 6-8 和 18,而在吡啶/二氯甲烷中反应则分别生成异构体 O,S-硫代碳酸酯 9-11 和 19。使用三丁基氢化锡/偶氮二异丁腈(AIBN)在温甲苯中顺利地对这两个系列的化合物进行同质裂解,得到新的杂芳基甲基膦酸盐 12-14 和 20。在甲醇中用甲醇钠进行皂化,然后用碘甲烷进行烷基化,可将 O、S-硫代碳酸盐 9-11 和 19 有效地转化为具有合成吸引力的δ-甲硫基取代衍生物 15-17 和 21。