Synonyms: SirodesminB, (5'R,7a)-; Sirodesmin K;Spiro[furan-2(3H),9'(10'H)-[5,11a](iminomethano)[11aH]cyclopenta[4,5]pyrrolo[2,1-e][1,2,3,4,6]tetrathiazocine]-3,6',12'(5'H)-trione,10'-(acetyloxy)hexahydro-10'a-hydroxy-5'-(hydroxymethyl)-4,4,5,13'-tetramethyl-,[5'R-[5'a,7'aa,9'b(R*),10'a,10'aa,11aa]]-