A method of producing 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) by nitrosation of 1,3-bis(2-chloroethyl)-urea utilizing as a nitrosating agent dinitrogen trioxide (N.sub.2 O.sub.3) in molar excess of theoretical wherein the molar excess of N.sub.2 O.sub.3 ranges from 10-200% and preferably from 10-20%. The nitrosation reaction is conventionally carried out in the cold from 0.degree. C to -20.degree. C and a non-aqueous solvent is utilized. The preferred non-aqueous solvent is of the chlorinated variety; i.e., methylene dichloride. Other preferred solvents include related halogenated compounds such as ethylene dichloride, nitro-compounds such as nitromethane, acetonitrile, and simple ethers such as ethyl ether. Other less preferred but operable compounds include esters such as ethyl acetate, simple ketones such as acetones, and chloroform. Solvents to be avoided are olefins, unsaturated ethers and other unsaturated compounds, amines, malonate esters, acid anhydrides, and solvents which would interact with the reactant N.sub.2 O.sub.3 and the urea as well as the product nitrosourea.
通过使用
二氧化氮(N.sub.2 O.sub.3)作为亚硝化剂,以理论上的摩尔过量生产1,3-双(2-
氯乙基)-1-亚硝基
脲(
BCNU)的方法,其中N.sub.2 O.sub.3的摩尔过量范围为10-200%,最好为10-20%。亚硝化反应通常在0℃至-20℃的低温下进行,并使用非
水溶性溶剂。首选的非
水溶性溶剂是
氯化物种类,例如
二氯甲烷。其他首选溶剂包括相关的卤化化合物,如
乙烯二氯乙烷,
硝基化合物如
硝基甲烷,
乙腈和简单醚如
乙醚。其他较不理想但可操作的化合物包括
酯类如
乙酸乙酯,简单
酮类如
丙酮和
氯仿。应避免的溶剂包括烯烃,不饱和醚和其他不饱和化合物,胺,
马来酸酯,酸酐以及可能与反应物N.sub.2 O.sub.3和
脲以及产物亚硝基
脲发生相互作用的溶剂。