Tetrolic acid590-93-2100 % similar Acetylenedicarboxylic acid142-45-061 % similar 3-(Trimethylsilyl)propiolic acid5683-31-848 % similar 2-Hexynoic acid764-33-044 % similar 2-Octynoic acid5663-96-740 % similar Monopotassium acetylenedicarboxylate928-04-139 % similar Propiolic acid471-25-039 % similar Methyl 2-butynoate23326-27-438 % similar Phenylpropiolic acid637-44-538 % similar Ethyl 2-butynoate4341-76-834 % similar