Die Struktur des Antibioticums Roridin H. Verrucarine und Roridine, 20. Mitt. [1]

Structure 1 has been established for roridin H (C29H36O8), an antibiotic isolated from Myrothecium verrucaria and formerly namend verrucarin H [3]. Base catalysed hydrolysis of 1 gave the known terpene alcohol verrucarol (8; C15H22O4) and myrothecinic acid (3; C14H18O6), a previously undescribed dicarboxylic acid. The structure of 3 was determined by spectral methods and by chemical cleavage of the unusual acetal group of dimethyl hexahydromyrothecinoate (6) by hydrolysis with HCl in the presence of 2, 4‐dinitrophenylhydrazine, producing the 2, 4‐dinitrophenylhydrazone 13 of 3‐methylglutaric acid semialdehyde 10 and methyl 6, 7‐dihydroxy‐octanoate (11). 13 was transformed in to dimethyl 3‐methylglutarate (15). Cleavage of 11 with HIO4 gave acetaldehyde and adipic acid semialdehyde (17) which was oxidized to adipic acid (19). The 220 MHz NMR spectra of roridin H (1) and dimethyl hexahydromyrothecinoate (6) allowed unequivocal assignment of the signals to the majority of the protons in the antibiotic.