Stigmasterol, degradation

Degradation of the sterol stigmasterol to progesterone is achieved by the sequence shown in Figure 5.120. The double bond in the side-chain allows cleavage by ozonolysis, and the resultant aldehyde is chain shortened via formation of an enamine with piperidine. This can be selectively oxidized to progesterone. In this sequence, the ring A transformations are carried out as the... 

SITOSTEROL Sitosterol is another phytosterol and is an analogue of stigmasterol with a saturated side chain. It is obtained from soy oil and com oil. The side chain cannot be degraded chemically, but microbiologically it is possible to produce intermediates of valne to the steroid industry. Sitosterol can therefore be used as a starting material for the synthesis of steroid hormones. 

Like the flatworms, insects cannot synthesize steroids and so they degrade the plant steroids, stigmasterol and sitosterol, to obtain their essential cholesterol. The special enzymes used for this purpose are suitable targets for selective attack, because most other forms of life synthesize their steroids de novo. 

Japanese Patent 30915 (1964) Derwent Abstr. 19, 293). Degradation of cholesterol, sitosterol, or stigmasterol by Corynebacterium simplex and other known 1-dehydrogenating species, in the presence of agents which chelate copper or iron, to give 4-androstene 3,17-dione, l,4-androstadiene-3,17-dione, and other products. 

Indyk [705] studied the tocopherols, stigmasterol, and cholesterol extracted from milk powder on a Cjs column (A = 295 run, ex 330 nm, em for tocopherols, or 212 nm UV detection for all other analytes). Elution was complete in 30 min when a 99.9/0.1 hexane/IPA mobile phase was used. Detection limits were given as 0.04 xg/injection and 4 mg/kg sample (cholesterol). The author noted that the use of isopropyl ether as the extraction solvent caused problems with the chromatography. Baseline disturbances were reported to occur early in the chromatogram, in the region where the tocopherols eluted, most likely due to the elution of diisopropyl ether and diisopropyl ether degradation components. 

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