(4R-(4R*,5S*,6S*,7R*,9R*,11E,13E,15S*,16R*))-16-Ethyl-4,6-dihydroxy-15-(hydroxymethyl)-5,9,13- trimethyl-2,10-dioxooxacyclohexadeca-11,13-diene-7- acetaldehyde, cyclic 5,20-hemiacetal 61219-81-6 Tylonolide hemiacetal