4-(p-Chlorophenyl)-3-hydroxythiazole-2(3H)-thione (3) can be prepared in good yields and in useful quantities from p-chloro acetophenone (1). 0-Alkylation of the cyclic thiohydroxamic acid 3 via the respective potassium or the tetraethyl ammonium salts affords the esters 4. A slightly modified procedure allows the conversion of the acid 3 to the mixed anhydrides 5. The esters 4 and the anhydrides 5 are colorless to yellowish crystalline compounds which show a good shelf life. Visible light photolysis of the N-alkoxy derivatives 4e-g and reactive hydrogen donors affords substituted tetrahydrofurans 7 or tetrahydropyrans 8 via an alkoxyl radical pathway.
4-(对
氯苯基)-3-羟基
噻唑-2(3H)-
硫酮(3)可从对
氯乙酰苯(1)制备,产率高且产量足够。通过相应的
钾盐或
四乙基铵盐对环状
硫代羟
肟酸3进行O-烷基化,得到酯4。稍作修改的程序可将酸3转化为混合酸酐5。酯4和酸酐5是无色至淡黄色的晶体化合物,具有良好的储存稳定性。可见光光解N-烷氧基衍
生物4e-g与活性氢供体,通过烷氧自由基途径生成取代的
四氢呋喃7或
四氢吡喃8。