Manufacturing Process
A mixture of 24.1 g (0.10 mol) of 3-o-methoxyphenoxy-2-hydroxy-1-propyl carbamate and 6.0 g (0.10 mol) of urea was heated rapidly to the temperature range of 180°C to 200°C, and maintained there for five hours. The reaction melt was poured into 50% ethyl alcohol, from which the product crystallized as a white solid. The crude yield was 18.3 g (82%); melting point 131.5% to 137°C. Crystallization from water and 95% alcohol gave 9.0 g (40.3 %) of pure 5-o-methoxyphenoxymethyl-2-oxazolidone; melting point 141°C to 143°C. This melting point was not depressed when the material was mixed with an authentic sample. In additional runs acetone was used instead of ethyl alcohol with equivalent results.
It was found that when the heating time was reduced to three hours and a reaction temperature of 190°C to 200°C was maintained, equivalent yields (40 to 50%) were obtained, but that the yields were appreciably lowered when the heating time was further reduced to two hours. It was also found that when the temperature was lowered to the range of 170°C to 180°C the yield was significantly lowered.
When the material was isolated by extraction with chloroform and distillation,
the yield of pure material was 58.5%.
