Smith A G, Brooks C J
Biomed Mass Spectrom. 1976 Apr;3(2):81-7. doi: 10.1002/bms.1200030208.
Thirty-six delta5- and 5'alpha-3beta-hydroxysteroids have been oxidized with cholesterol oxidase to give the corresponding delta4- and 5alpha-3-ketosteroids, respectively. The mass spectral characteristics of the products (or their trimethylsilyl ether derivatives, in the case of 3-keto-hydroxysteroids) varied considerably, depending especially on the nature of the C-17 sidechain. The ion of m/e 124 (or its equivalent) from cleavage of ring B was frequently a major fragment from delta4-3-ketosteroids, but in some instances was of insignificant abundance. Trimethylsilylation of the product of the oxidation of neoergosterol gave neoergosterone enol-trimethylsilyl ether. Fragmentations of the sidechain predominated in the mass spectra of the 5alpha-3-ketosteroids.
36种△5-和5'α-3β-羟基类固醇已用胆固醇氧化酶氧化，分别得到相应的△4-和5α-3-酮类固醇。产物（或3-酮羟基类固醇情况下的三甲基硅醚衍生物）的质谱特征有很大差异，尤其取决于C-17侧链的性质。环B裂解产生的m/e 124离子（或其等效物）常常是△4-3-酮类固醇的主要碎片，但在某些情况下丰度微不足道。新麦角固醇氧化产物的三甲基硅烷化得到新麦角甾酮烯醇-三甲基硅醚。5α-3-酮类固醇的质谱中侧链裂解占主导。
