CAS 21622-00-4 appears in our catalog under these names: Cyclopent-3-ene-1,1-dicarboxylic acid diethyl ester, 95%, Diethyl 3–Cyclopentene–1，1–dicarboxylate, Diethyl 3-Cyclopentene-1,1-dicarboxylate, Diethyl 3-Cyclopentene-1,1-dicarboxylate 96%, Diethyl 3-Cyclopentene-1,1-dicarboxylate, >95%, >95%. Offered by: Combi-blocks, GLPBio, Biosynth, Ambeed, Chemat. Available pack sizes: 250mg, 5g, 1g, 100g, 10g, 25g, 100mg.