4-Hydroxycinnamic acid 12-Hydroxystearic acid Diethyl acetylenedicarboxylate Acetylenedicarboxylic acid Di-tert-butyl acetylenedicarboxylate Bis(trimethylsilyl)acetylenedicarboxylate Bis(tri-n-butyltin)acetylenedicarboxylate 3-(1-Hydroxycyclohexyl)-2-propynoic acid 4-Hydroxy-4-methyl-pent-2-ynoic acid