PURPOSE: To inexpensively and advantageously obtain the subject compd. of an intermediate for synthesis of plant hygienic and medicinal agents with a smaller number of stages by using monoacylhydrazine and phosgene as starting raw materials, bringing these products into reaction with a specific compd. under prescribed conditions, then cyclizing the reaction product.
CONSTITUTION: The 1,3,4-oxadiazoline-2-one is obtd. by bringing the phosgene and the monoacylhydrazine of formula I into reaction at 0 to 130°C in a solvent. The compd. of formula R2NH2 and the compd. of formula II are then brought into reaction at 10 to 160°C under 20 atm. pressure of below to obtain the acylsemicarbazide of formula III in the solvent, such as aromatic solvent. In succession, the compd. of the formula III is cyclized by sodium hydroxide or potassium hydroxide in the presence of the solvent from the previous stage, by which the compd. of formula IV (R1 is H, 1 to 20C aliphat. group, etc.; R2 is H, 1 to 20C aliphat. group, etc.; R3 is H, 1 to 6C alkyl, etc.).
PATORIKU BORUFU
GEIRII UDOUN
