(6R,12aR)-2,3,6,7,12,12a-hexahydro-2-methyl-6-(3,4-methylenedioxyphenyl)-pyrazino[2',1':6,1]pyrido[3,4-b]indole-1,4-dione
(6R,12aR)-6-(3,4-dihydroxyphenyl)-2-methyl-2,3,6,7,12,12a-hexahydropyrazino[1',2'-1,6]-pyrido[3,4-b]indole-1,4-dione
(6S,12aR)-2-methyl-6-(3,4,5-trimethoxyphenyl)-2,3,12,12a-tetrahydropyrazino[1',2':1,6]pyrido[3,4-b]indole-1,4(6H,7H)-dione
(6S,12aR)-6-(2-bromophenyl)-2-methyl-2,3,12,12a-tetrahydropyrazino[1',2':1,6]pyrido[3,4-b]indole-1,4(6H,7H)-dione