(16E)-16,17,18,19-Tetradehydro-17-methoxycorynan-16-carboxylic acid methyl ester 18904-54-6 AIDS-002667 AIDS002667 Corynantheine Indole alkaloid Indolo[2,3-a]quinolizine-2-acetic acid, 3-ethenyl-1,2,3,4,6,7,12,12b-octahydro-.alpha.-(methoxymethylene)-, methyl ester, (.alpha.E,2S,3R,12bS)-