2-((5-Methoxy-2,5-dihydro-2-furanyl)carbonyl)-4,9-dihydro-3H-2.lambda.~5~-.beta.-carboline 5-(4,9-Dihydro-3H-2.lambda.~5~-.beta.-carbolin-2-ylcarbonyl)-2,5-dihydro-2-furanyl methyl ether AIDS-139126 AIDS139126 NSC647382