PURPOSE: To obtain a cyclized iminothiazole having an excellent herbicidal activity against monocotyledonous and dicotyledonous weeds through a novel intermediate from aniline under mild conditions without accompanying impurities which are difficult to separate.

CONSTITUTION: a) A compound of formula I (R2 is 1-6C alkyl or phenylmethyl) is reacted with thiophosgene in the presence of an acid coupling agent to yield a novel compound of formula II, b) which is then reacted with a compound of formula III (A is CH2 or CH2CH2) to yield another novel compound of formula IV. c) The obtained compound is cyclized with a mineral acid to yield still another novel compound of formula V, d) which is hydrolyzed under basic or acidic conditions to obtain a compound of formula VI. e) This compound is further reacted with a compound of formula R1-X (R1 is 1-6C alkyl, 2-6C alkenyl, 3-6C alkynyl, 1-6C alkoxycarbonyl-1-6C alkyl; and X is Cl, Br, I, etc.), to yield the target compound of formula VII. Among the steps described, those other than step d) can be carried out in an appropriate solvent, and steps from b) to d) preferably in a single reaction vessel.