Facile One-Pot Synthesis of Substituted Hydantoins from Carbamates
作者:Manjinder Gill、Dinesh Tanwar、Anjali Ratan
DOI:10.1055/s-0036-1588468
日期:2017.10
A novel and simple approach for the preparation of 3-substituted, 5-substituted, or 3,5-disubstituted hydantoins is reported. It involves the reaction of α-amino methyl ester hydrochlorides with carbamates to yield the corresponding ureido derivatives, which subsequently cyclize under basic conditions to produce substituted hydantoins in good yields. By applying this method, the bioactive anticonvulsant
Compounds of general formula (I) are useful for treating mental disorders, wherein R.sub.1 and R.sub.2 are the same or different and selected from hydrogen or lower alkyl; Ar are the same or different and selected from pyridyl and phenyl groups, n is 1 or 2, X is nitrogen or methine. When X is nitrogen, Y is methylene. When X is methine, Y is selected from nitrogen or oxygen. A is selected from carboxylic derivatives. The pharmacologically active salts of formula (I) are also embraced. ##STR1##
An isocyanate production method according to the present invention is a method in which an isocyanate is produced by subjecting a carbamate to thermal decomposition, and includes: a step of preparing a mixture liquid containing the carbamate, an inactive solvent and a polyisocyanate compound; a step of conducting a thermal decomposition reaction of the carbamate by continuously introducing the mixture liquid into a thermal decomposition reactor; a step of collecting a low-boiling decomposition product by continuously extracting the low-boiling decomposition product in a gaseous state from the reactor, the low-boiling decomposition product having a boiling point lower than the polyisocyanate compound; and a step of collecting a high-boiling component by continuously extracting, from the reactor, a liquid phase component which is not collected in a gaseous state at the step of collecting the low-boiling decomposition product.