CAS 671188-20-8 appears in our catalog under these names: 3-(N-Prop-2-ynylcarbamoyl)prop-2-enoic acid, 95%, FA-alkyne/ 99.53% (existing batch purity), 3-(N-Prop-2-ynylcarbamoyl)prop-2-enoic acid, 98%, 98%, 4-Oxo-4-(prop-2-yn-1-ylamino)but-2-enoic acid, 98%. Offered by: Combi-blocks, TargetMol, Chemat, Fluorochem. Available pack sizes: 250mg, 1g, 1mg, 2mg, 5mg, 10mg, 25mg, 50mg.