THERMOSPRAY MASS-SPECTRAL ANALYSES OF CORYNOMYCOLIC ACIDS AND THEIR DERIVATIVES

Thermospray mass spectral (TSP-MS) analyses were carried out on methyl corynomycolates, their 3-O-acetyl and 3-O-benzoyl derivatives, and on corynomycolic acids and their 3-O-acetyl derivatives, using an ion ge nerating solvent system consisting of water/isopropanol (99:1, v/v) co ntaining 0.1 M ammonium acetate. Methyl corynomycolates generated thre e groups of peaks corresponding to adducts M-18+H, M+H and M+NH4, whil e two groups of peaks representing adducts M-60+H and M+H+NH4 were see n in the spectra of 3-O-acetyl methyl corynomycolates. The 3-O-benzoyl methyl corynomycolates gave a series of peaks representing the adduct s M-122+H, M+2H and M+H+NH4. In the spectra of 3-O-acetyl corynomycoli c acids, a series of peaks which represented M-60+H and M+NH4 was obse rved, and in turn, mass spectra of corynomycolic acids revealed peaks that represented the adducts M-18+H and M+NH4. Therefore, methyl coryn omycolates, 3-O-acyl derivatives of methyl corynomycolates, 3-O-acetyl ated derivatives of corynomycolic acids and the underivatized corynomy colic acids all exhibited the formation of all adduct of the anhydro c ompounds. These anhydro forms were generated by a generalized process.