2-(7-Cyano-8,16-dihydroxy-9,11,13,15-tetramethyl-18-oxooxacyclooctadeca-4,6-dien-2-yl)-cyclopentanecar boxylic acid 5-18-09-00385 (Beilstein Handbook Reference) 7184-60-3 97328-74-0 BRN 0066270 Borrelidin NSC 216128 Treponemycin