2-Aminophenol → 2(3H)-Benzoxazolone

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Reaction Steps

According to the reaction scheme, o-aminophenol is reacted with ethyl chloroformate, the resulting 3H-benzoxazol-2-one obtained is nitrated with nitric acid, the nitro group of the resulting compound of formula (IX) is reduced with hydrogen in the presence of a hydrogenation catalyst, such as palladium-on-charcoal, the 6-amino-3H-benzoxazol-2-one thus obtained is reacted with 2-methylthioimidazoline, preferably in the form of an acid addition salt such as the hydroiodide, and the resulting compound of formula (XII) is acidified to give 2-(4-amino-3-hydroxyphenylimino)-imidazolidine, which is reacted with formic acid in the presence of acetic anhydride, or with methylsulphonyl chloride, or with a compound NaNCO or R'NCO (wherein R' represents an alkyl radical having from 1 to 4 carbon atoms) to obtain an imidazolidine derivative of general formula (IB).

Provenance & Evidence