Unstable neutral radicals [ROCONHOU.] 2 and nitrosoformates 3 are formed by oxidation of N-hydroxycarbamates with lead dioxide. In the presence of alcohols or phenols and water they solvolyzed to mixtures of symmetrical 4 and asymmetrical 5 carbonates. The content of asymmetrical carbonates 5 increases with increasing reactivity of the nitrosoformates 3 formed, temperature, the content of water in the reaction mixture, and with decreasing reactivity of alcohol. The reactivities of individual alcohols have been evaluated with the help of competitive alcoholysis. The new method of alcohol or phenol alkoxylation has been verified experimentally by preparing six asymmetrical carbonates which were obtained in 34 to 47% yields.
不稳定的中性自由基[ROCONHOU.] 2 和亚硝基甲酸酯 3 通过氧化 N-羟基氨酸酯与二氧化铅形成。在醇或酚和水的存在下,它们溶解成对称 4 和不对称 5 碳酸酯的混合物。不对称碳酸酯 5 的含量随着形成的亚硝基甲酸酯 3 的反应性增加、温度升高、反应混合物中水的含量增加以及醇的反应性降低而增加。通过竞争性醇解评估了各种醇的反应性。通过制备六种不对称碳酸酯,实验证实了醇或酚烷氧基化的新方法,产率为 34% 到 47%。