Steroids stigmasterol

Progesterone is a hormone, secreted by the corpus luteum, that is involved in the control of pregnancy. Its structure was established, in part, by the following synthesis from the steroid stigmasterol, obtained from soybean oil. 

The plant steroid stigmasterol is readily available on a commercial scale from soybeans. Suggest a method for its conversion into the acid shown here, a compound that has been used as a starting material for the production of pharmaceutically valuable steroids. 

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. 

Stearic Acid StearinsSure Stearin Stearin Stearyl Alcohol Stearylalkohol Stearylamine Stearylamin Steroids Steroide Stigmasterol Stigmasterin Straw Stroh... 

Many selective epoxidations are possible with polyunsaturated steroids. In general, oc, -unsaturated ketones are not attacked by peracid, although linear dienones react slowly at the y,5-double bond. Aw-Chloroperbenzoic acid is the reagent of choice for this reaction.When two isolated double bonds are present in the steroid nucleus, e.g. (27) and (30), the most highly substituted double bond reacts preferentially with the peracid. Selective epoxidation of the nuclear double bond of stigmasterol can likewise be achieved.However, one exception to this general rule has been reported [See (33) (34)]. ... 

A. Molecular Ion Because of low volatility, most steriods are derivatized before analysis by GC/MS. Molecular ions are usually observed for steriods sufficiently volatile to be analyzed underivatized by GC/MS (see Figure 31.1) Some important steroids in urine include estrone, estradiol, estriol, pregnanediol, and 17-ketosteroids. which can be analyzed by GC/MS as the TMS or the MO-TMS derivatives. The plant steroids, such as camposterol, ergosterol. stigmasterol, cholestanol, and sitosterol, are generally analyzed as the TMS derivatives. 

Steric approach control, 67 Steric strains, 71 Steric strain control, 69 Steroid hydrogenation, 111 5/3-Stigmast-22-en-3-one, 130 Stigmasterol, 266 Sulfur dichloride, 459 Sulfur tetrafluoride, 459, 472 Sulfur tetrafluoride fluorination, 471 Surface catalysts, 157... 

Owing to periodic fluctuations in the price of diosgenin. alternative law materials such as solasodinc have been used for the synthesis of steroid drugs. In the U.S., the plant sterols stigmasterol and /3-sitosterol arc a significant raw material for the synthesis of antiinflammatory glucocorLicuids and other steroid hormones. 

Most steroids are alcohols, and accordingly are named as sterols. Important examples include cholesterol, ergosterol, estradiol, stigmasterol, and other representative sterols given in Table 30-2. As you can see from their structures, most possess the same ring skeleton but vary considerably in their peripheral structural features, stereochemistry, and in the degree of ring unsaturation. 

The sterols that were chosen as substrates contained two double bonds, one at various positions in the side chain and A5 in the steroid nucleus. Whereas the latter double bond was never touched in reactions with the Fe(III) porphyrin vesicle system 183 in the presence of PhIO, the side chain double bonds of desmosterol 186 and fucosterol 187 were epoxidized to 188 and 189 in 32% and 22% yield, respectively (Fig. 31). In contrast, stigmasterol 190 was not reactive, since the double bond cannot approach the reactive iron-oxo intermediate. 

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