Synonyms: Butanoicacid,1,1a,1b,4,4a,5,7a,7b,8,9-decahydro-4a,7b-dihydroxy-3-(hydroxymethyl)-1,1,6,8-tetramethyl-5-oxo-9aH-cyclopropa[3,4]benz[1,2-e]azulene-9,9a-diylester, [1aR-(1aa,1bb,4ab,7aa,7ba,8a,9b,9aa)]-; 9aH-Cyclopropa[3,4]benz[1,2-e]azulene,butanoic acid deriv.; 12,13-Di-O-butyrylphorbol; 4b-Phorbol 12,13-dibutyrate; PDBU; Phorbol12,13-dibutyrate; Phorbol dibutyrate