Patent ID: 8569276

Claim:
A compound of the general formula: wherein: R 1 is a member selected from the group consisting of —CHO, —CH(OH)CH 3 , and —C(O)CH 3 ; R 2 is a member selected from the group consisting of —SAc, alkoxy, vinyloxy, —SCN, and —OC(O)R 6 , wherein R 6 is a member selected from the group consisting of alkyl, substituted alkyl, alkoxyalkyl, alkoxy, vinyloxy and ethynyloxy; R 3 is a member selected from the group consisting of alkyl, substituted alkyl, alkoxy and acyloxy; R 4 is a member selected from the group consisting of hydrogen and alkyl; and X is a member selected from the group consisting of ═O and ═N—OR 5 , wherein R 5 is a member selected from the group consisting of hydrogen and alkyl; wherein the term “alkyl” refers to a saturated monovalent hydrocarbon radical of 1-12 carbon atoms; and with the proviso that if R 2 is —OC(O)R 6 , wherein R 6 is alkyl, and R 1 is —CHO or —C(O)CH 3 , then R 3 is other than C 1-4 alkyl or —OC(O)C 1-6 alkyl.