AIDS-051201 AIDS051201 NSC661831 Spiro[1H-2-benzopyran-1,4'-piperidine]-3-carboxylic acid, 3,4-dihydro-6,7-dihydroxy-1'-methyl-, methyl ester, (3R)-, compd. with benzenesulfonic acid, 4-methyl- (1:1)