Commercial Steroid Starting Materials

which will proceed to the plant steroid avenasterol. Shifting the side chain double bond to positions 23-24 finally leads to 6-3, an intermediate in the formation of stigmasterol, one of the important commercial steroid starting materials. 

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Processing Raw Materials. Along with the aforementioned chemical methods of processing steroid raw materials, microbial transformations have been and are used in a number of commercial degradation processes. The microbial degradation of the C17 side chain of the two most common sterols, cholesterol (2) and P-sitosterol (41), is a principal commercial method for the preparation of starting materials in Japan and the... 

The androstane nucleus is sufficiently complex so as to effectively mle out total synthesis as a commercial source for starting materials. The great preponderance of steroid natural products includes carbon side chains at the 17 position. Preparation of androstane starting compounds thus relies on schemes for degrading those side... 

Solasodine and related compounds may serve as useful starting materials for the commercial preparation of steroid hormones,17 and the search for suitable... 

Fabaceae and Plantaginaceae. When dissolved in water, saponins form soapy solutions and can therefore be used as detergents in the preparation of galenicals and cosmetics. Saponins can increase the permeability of biomembranes and may thus exhibit cytotoxic, haemolytic and antiviral properties most of them are highly toxic for fish. Moreover, steroid saponins are important starting materials for the commercial production of steroid hormones. 

In this chapter we introduce compounds which have been successfully applied in the construction of supramolecular assemblies. Only the amphiphiles which have been prepared in sufficient quantities have been admitted milligram quantities being considered unacceptable as starting materials for the preparation, analysis and application of assemblies. Experience proves that complicated dyes, pore builders, receptors etc. never reappear in the literature after their syntheses and spectroscopic properties have been reported. On the other hand, such easily attainable synkinons and surfactants around the ten gram scale need not, of course, be too simple. On the contrary, they may contain all the components of the chiral pool, i.e. amino acids, carbohydrates, steroids etc., as well as all commercial dyes of interest such as protoporphyrin, phthalo-cyanines, carotenes, viologen and quinones. 

The relative simplicity of the structure of estranes compared with those of other classes of steroids has made this structural class an attractive target for work aimed at total synthesis from so-called coal tar starting materials. About half a dozen syntheses have been developed, one of which, the Smith-Torgov synthesis, is probably stiU used commercially. 

Solasodine (1) and related Solanum alkaloids are useful starting materials for the commercial preparation of steroid hormones." In particular the pregnane derivative (6) was prepared from solasodine in 65% overall yield via the intermediates (2), (3), and (4). The oxidative cleavage of the 20(22) double bond of pseudosolasodine diacetate (3), which is the least efficient step in this synthesis, has been investigated in more detail With sodium dichromate in acetic acid compound (3) gave the hydroxyester (5) and the hydroxylactone (7), in addition to the ester (4). Results of a kinetic study of this reaction were interpreted in terms of formation of hydroxyester (5) via allylic oxidation of pseudosolasodine diacetate prior to cleavage of the 20(22) double bond. ... 

Table 3.3.1 lists a few commercial steroids, in particular those that can be used as inexpensive starting materials. Most industrial syntheses of steroids are based on these naturally occurring compounds. Only norgestrel is made by total synthesis and is therefore expensive. 

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. 

One example of a commercial application is the isolation of diosgenin, the most important starting material for partial synthesis of steroids. Drivsun, a Chinese company, is isolating this compound on a scale of 300 tpy by SCFE from tubers of... 

An example of a naturally occurring steroid is diosgenin, obtained from root extracts of the Mexican yam and used as a starting material for the synthesis of several commercial steroids. Most striking is the number of rings in the compound. 

The extent to which the immunoaffinity column can be reused depends mainly on the nature of the analyzed samples as well as the stability of the antibody and the support. The most important step is to remove any of the material physically adsorbed to the antibody so that the column may be reused with reproducibility. All that it is required for a column to be reequilibrated is the passage of several volumes of the starting buffer. Table 20.6 presents an outline of commercial column protocols used during analysis of steroid and -agonist residues in urine. Most columns have been shown to last at least 100 runs, provided that the sample is properly defatted and does not contain solid particles (169). 

This intramolecular aldol reaction has attracted attention from the beginning, for example, due to the easy access to steroid precursors octahydronaphthalenedi-one 60 and tetrahydroindanone 61, starting from readily available raw materials, and using commercially available L-proline catalyst (Figure 44.13) [121]. 

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