Azoles. Part 13. Synthesis and bromine ? lithium exchange reactions of some 1-substituted 4,5-dibromo-1H-1,2,3-triazoles and 2-substituted 4,5-dibromo-2H-1,2,3-triazoles
作者:Brian Iddon、Martin Nicholas
DOI:10.1039/p19960001341
日期:——
4,5-Dibromo-1H-1,2,3-triazole was synthesised by various routes and reacted with chloromethyl methyl ether (N-1/2), methyl chloroformate (N-1), benzyl chloride (N-1), 4-methoxybenzyl chloride (N-1), 4-nitrobenzyl chloride (N-1/2) or triphenylmethyl chloride (N-2) under various conditions, to give isolable products substituted at the N-atoms shown in parentheses.4,5-Dibromo-l-methoxymethyl-1H- and -2-methoxymethyl-2H 1,2,3-triazole reacted with butyllithium (in diethyl ether or tetrahydrofuran at low temperatures) at position-5 and the resulting lithiated derivatives were quenched with aqueous ammonium chloride, carbon dioxide, methyl chloroformate, benzophenone or dimethyl or diphenyl disulfide to give high yields (71â93%) of the corresponding 5-substituted 1,2,3-triazole. l-Benzyl-4,5-dibromo-1H-1,2,3-triazole was converted similarly into 1-benzyl-4-bromo-5-methylsulfanyl-1H-1,2,3-triazole (91.5%). In a âone potâ sequence and through two successive treatments with butyllithium and the appropriate quenching reagent (Ph2S2 and H2O), 4,5-dibromo-2-methoxymethyl-2H-1,2,3-triazole was converted similarly into 2-methoxymethyl-4-phenylsulfanyl-2H-1,2,3-triazole (47% yield).
4,5-二溴-1H-1,2,3-三氮唑通过多种路线合成,并在不同条件下与氯甲基甲醚(N-1/2)、甲基氯甲酸酯(N-1)、苄氯(N-1)、4-甲氧基苄氯(N-1)、4-硝基苄氯(N-1/2)或三苯甲基氯(N-2)反应,得到可在N原子上取代的可分离产物,如括号所示。4,5-二溴-1-甲氧甲基-1H-和-2-甲氧甲基-2H-1,2,3-三氮唑在位置-5与丁基锂(在低温下的乙醚或四氢呋喃中)反应,得到的锂代衍生物通过氨水、二氧化碳、甲基氯甲酸酯、二苯酮或二甲基或二苯基二硫化物淬灭,得到高产率(71–93%)的相应5-取代的1,2,3-三氮唑。1-苄基-4,5-二溴-1H-1,2,3-三氮唑同样被转化为1-苄基-4-溴-5-甲硫基-1H-1,2,3-三氮唑(91.5%)。在一个“一锅法”序列中,通过丁基锂的连续两次处理和适当的淬灭剂(Ph2S2和H2O),4,5-二溴-2-甲氧甲基-2H-1,2,3-三氮唑同样被转化为2-甲氧甲基-4-苯硫基-2H-1,2,3-三氮唑(47%产率)。