PURPOSE: To prepare the titled compound useful as an intermediate of pharmaceuticals, etc., economically, in an industrial scale, by catalytically hydrogenating a furan compound having substituent group corresponding to the objective compound using a palladium catalyst in the presence of trifluoroacetic acid, and thermally decomposing the hydrogenation product.

CONSTITUTION: The compound of formula I (R1 and R2 is H, substituted or unsubstituted alkyl, alkoxy or carbonyl) is catalytically hydrogenated in the presence of preferably 1.5W3 equivalent, based on said compound, of trifluoroacetic acid using a palladium catalyst such as palladium, palladium oxide, palladium chloride, etc. supported by a carrier such as carbon, alumina, silica- alumina, etc. The resultant compound is thermally decomposed to obtain the compound of formula II easily from an abundantly available inexpensive raw material within a relatively short time. The trifluoroacetic acid produced as a by-product can be recovered and reused. The hydrogenation reaction and the thermal decomposition reaction can be carried out in one pot.