Patent ID: 7528169

Claim:
A compound represented by the following formula (I) or a salt thereof: wherein R 1 represents an alkyl group, an alkenyl group, or —CO—R 3 (wherein R 3 represents an alkyl group, an aryl group, or an alkylamino group); R 2 represents formyl group, —CH 2 —OCOR 4 (wherein R 4 represents an alkyl group, an aryl group, or an alkylamino group), —CH 2 —O—R 5 (wherein R 5 represents an alkyl group, or an alkenyl group), —CH 2 ═N—O—R 6 (wherein R 6 represents hydrogen atom or an alkyl group), or CH 2 ═CH—R 7 (wherein R 7 represents an alkyl group, an alkyloxycarbonyl group, formyl group, or an alkyloxycarbonylalkenyl group).