8H-[1,3]dioxolo[6,7][2]benzopyrano[3,4-c]indol-6a(3H)-ol, 4,4a,5,6-tetrahydro-3-methoxy-5-methyl- InChI=1/C18H21NO5/c1-19-9-18(20)17(4-3-12(21-2)6-16(17)19)13-7-15-14(22-10-23-15)5-11(13)8-24-18/h3-5,7,12,16,20H,6,8-10H2,1-2H tazettine