Tautomeric equilibria of 2(4)-monooxopyrimidines in the gas phase, in low-temperature matrices and in solution
作者:M.J. Nowak、K. Szczepaniak、A. Barski、D. Shugar
DOI:10.1016/0022-2860(80)85222-7
日期:1980.2
Abstract IR absorption spectra, including the NH, OH and CO stretching regions, have been recorded for 4-oxo-6-methyl- and 2-oxo-4,6-dimethyl pyrimidines and several related derivatives, in the gas phase, in low-temperature inert matrices, and in several liquid solvents. All the 4-oxopyrimidines in the gas phase, and 4-oxo-6-methylpyrimidine in low-temperature matrices, exhibit comparable populations
摘要 4-oxo-6-methyl-和2-oxo-4,6-二甲基嘧啶和几种相关衍生物在气相中的红外吸收光谱,包括NH、OH和CO伸缩区,已被记录,在低温惰性基质和几种液体溶剂中。气相中的所有 4-oxopyrimidine 和低温基质中的 4-oxo-6-methylpyrimidine 都表现出相当数量的酮和烯醇形式。相比之下,2-氧代嘧啶主要以烯醇形式存在。这两类化合物在液体溶剂系统中主要以酮形式存在。4-oxo-2,6-二甲基嘧啶在气相中的互变异构平衡常数 (KT) 约为 2,其他 4-oxopyrimidine 的互变异构平衡常数 (KT) 约为 1。对于 4-oxo-6-methylpyrimidine,惰性基质中的平衡常数随基质气体的活性而略有变化,活性更高的基质中更倾向于酮互变异构体。根据 KT 的温度依赖性,计算出气相中 4-oxo-6-methylpyrimidine