The Synthesis Of A Series Of O-Substituted Hydroxylamines

O-substituted hydroxylamines is an expensive intermediate in organic synthesis, which have wide applications and especially can be used as raw materials for preparing 3-hydroxycyclohex-2-enones herbicides , new medicine and pesticides.This research optimized the synthetical process on the basis of many documents, O-ethylhydroxylamine, O-allylhydroxylamine, O-benzylhydroxylamine and O-(3-chloro-2-propenyl)-hydroxylamine were synthesized starting from ethyl acetate and hydroxylamine hydrochloride via a facile, three-step procedure including acetylamination, etherification and hydrolysis.The improvements in this research for the synthetical process of O-substituted hydroxylamines mentioned in previous documents were listed as follows:(1) Hydroxylamine sulfate was replaced by hydroxylamine hydrochloride in the first step which simplified the procedure. The optimum molar ratio of ethyl acetate, sodium hydroxide and hydroxylamine hydrochloride was determined via a series of parallel experiments.(2) The effective separation of product and by-product was achieved with appropriate extraction solvents in the second step. The yields of both O-allylhydroxylamine and O-(3-chloro-2-propenyl)-hydroxylamine in this step reached more than 90%.(3) The target products were obtained with high purity and high yields by appropriate post treatment methods. The purity of O-(3-chloro-2-propenyl)-hydroxylamine reached more than 99%.In conclusion, many improvements were made with this synthetical process compared with the methods in documents, such as cheap and available raw materials, mild reaction conditions, simple operation, high yields. The main intermediate and target products were confirmed by GC/MS.