4,4-Pentamethylene-1,3-oxazolidine-5-one-2-thione is to be obtained from 1-amino cyclohexane carboxylic acid and thiophosgene, however, it was not isolated because of its unstability. When it was treated with $C_{6}H_{5}NH_{2},$ N-phenyl-(1-aminocyclohexane) carboxylic acid and N-(1-carboxycyclohexyl), N-phenyl thiourea were obtained. When refluxed in $H_{2}O$ at pH 2, pH 12 and neutral condition, the resulting carboxylic compound, being anticipated by us, was 1-aminocyclohexane carboxylic acid. From the above results, we have got the suggestion f the chemical behavior of 4,4-pentamethylene-1,3-oxazolidine-5-one-2-thione and also some informations of the reaction mechanism between 1-aminocyclohexane carboxylic acid and thiophosgene.