Derivatives of-, steroids

CH3)3SiO=CH—CH=CH2 (from the A ring inTMS derivatives of steroids)... 

Vitamin D is commonly found in two forms, both derivatives of steroids. These are known as cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2). Cholecalciferol is formed directly from the steroid known as 7-dehydrocholesterol by the action of sunlight, or other source of ultraviolet (UV) light, in the skin of humans and other animals. When parents encourage their children to go out and play in the sun, there is good reason for doing so (but avoid sunburn). ... 

Other methods of synthesizing estrone have been suggested using other available functionalized derivatives of steroids isolated from natural sources as starting material, which are then modified [3-22]. 

Peroxy derivatives of steroids have been isolated from both marine and terrestrial sources. They are most commonly 5a, 8a-endoperoxides with variations in the side-chains. The ergosterol peroxide 102 is the most ubiquitous endoperoxide-containing natural product and is isolated from a large number of sources. Ergosterol peroxide 102 was found to have antitumour activity against breast cancer and carcinosarcoma cell lines. A number of other steroidal endoperoxides have been reported which differ in the nature of the side-chain. Compound 103 was found to be an inhibitor of tumour promotion in mouse studies . 

Mass spectra of methoxime (MO)-TMS derivatives of steroids typically give the following fragments M-31 (loss of oxime), sequential 90 losses (trimethylsilanol), loss of the primary TMS group (M-103), and combinations thereof. Often the ion chosen for monitoring is one formed by the above fragmentations. A detailed de-... 

The synthesis of derivatives of steroids dihydrotestosterone 160 and epiandrosterone 161, containing indole and phosphoryl fragments, is described in the patent [156],... 

Hydrogen abstraction under conditions similar to those in Section 3.8.1 may occur also from nitrogen compounds, with formation of amidyl free radicals. The results vary, depending on the substrate for example, 6-amino derivatives of steroids were converted into TV-substituted pyrrolidines [127], Medium-sized lactams underwent transannular cyclization to bicyclic lactams [128], and bicyclic carbinolamides afforded mainly -fragmentation products (Table 3.7). 

Halomethyldimethylsilyl ethers of steroids possess longer retention times than TMS derivatives, which makes it possible to separate steroids with different numbers of hydroxyl groups. Thomas and co-workers [332,333] exploited chloromethyldimethylsilyl derivatives of steroids, the retention times of which are up to three times longer... 

Halogenated acyl derivatives of steroids have been applied in order to increase sensitivity of the analysis. It follows from a comparison of the ECD responses of haloacetates of steroids that the highest sensitivity can be obtained with the aid of monochloro-acetates [351]. Brownie et al. [352] applied them in the analysis of testosterone in blood. The method involves the extraction of blood plasma with diethyl ether, purification by TLC and derivatization. GC analysis is performed only after a preliminary separation on a thin layer. Preparation of the derivatives is carried out by treating a dried extract with... 

The preparation of nine 75Se derivatives of steroids has been described these labelled steroids have proved useful in assaying the comparative binding of proteins.77 Reaction of 75Se02 with dehydroepiandrosterone yields a selenium derivative (183) which upon reduction with dithiothreitol or HSCH2CH2OH and then methylation furnishes the corresponding methylseleno-steroid. 

The critical temperature for the thermal rearrangement of 3a under various conditions (in the melt,96 in quinoline20 or naphthalene17) appears to be in the vicinity of 180°. The 3-methoxy derivative (70) isomerizes readily with lithium iodide (in methyl ethyl ketone at 64°).17,96 When ethyl iodide is added to this reaction, i r-methylsaccharin (8) and iV-ethylsaccharin (22) are formed together.96 Lithium iodide catalysis is particularly useful in rearranging nucleoside derivatives, e.g., 71.17 The 3-benzyloxy derivative (73) reacts with debenzylation.17 Even more complex systems like derivatives of steroid alcohols17,20 are isomerized on heating in reasonable yields. When the optically active 3-(2-(cZ)octyloxy)benz[d]isothiazole-l, 1-dioxide was thermally re-... 

Eq. 13). The method proved to be particularly effective with C-3 and C-17 dithiolane derivatives of steroid ketones which are usually deblocked under more vigorous conditions. 

Enamine derivatives of steroidal ketones have found most use as protecting groups [220], but also undergo a few useful reactions. Enamine formation involves addition of a secondary amine to the carbonyl group to give a carbinolamine intermediate (5), which then loses a molecule of water. Both steps appear to be involved in determining the over-all rate of reaction [221]. Steroidal A -3-ketones react spontaneously... 

Analytical Methods.—Convenient new methods are described for the estimation of steroidal alcohols and ketones as fluorescent derivatives. 1-Dimethylamino-naphthalene-5-sulphonyl chloride [ dansyl chloride 550)] reacts with steroidal alcohols to provide fluorescent esters which are suitable for thin-layer chromatography.The corresponding sulphonyl hydrazine [ dansyl hydrazine (551)] provides similar fluorescent derivatives of steroidal ketones. A fluorescent... 

Figure 9 shows 2D H- Sn HMQC spectra [16] recorded with different delays of 3.8, 62, 102 and 260 ms on two organotin derivatives of steroids. As expected the longer delays give more noisy spectra but very small couplings become visible, with a delay of the order of 60 to 100 ms. These delays usually provide a good compromise, as illustrated here. 

Photolysis of nitramine derivatives of steroids has also been recently described (I6. ... 

Circular Dichroism. The salicylidene-imino chirality rule has been applied to cyclic steroidal amines. This rule was previously used to correlate the absolute configuration of cyclic terpenoid amines with the signs of the observed Cotton effects near 255 and 315 nm in their circular dichroism spectra. Similar considerations were used to interpret the c.d. spectra of fV-salicylidene derivatives of steroidal cyclic amines. These spectra were reported but no simple interpretation was possible. 

The synthesis of dimethylaminomethylene derivatives of steroidal ketones and lactones such as (127), (128), (129), and (130) has been described. Some compounds of this type possess high anabolic activity. 

Lanostan-3j8-yl azidoformate (248) and its A -unsaturated derivative are thermolysed or photolysed to give the oxazolidinones (249) and the products (250), functionalized in the 4a-methyl group. Other reactions leading to heterocyclic derivatives of steroids are described on p. 305. 

New derivatives of steroidal hormones, prepared for biological evaluation, include 17-dialkylaminoalkanoates and other novel esters of 17a-hy-droxyprogesterone," trimethylsilyl ethers of 17a-hydroxyprogesterone, testosterone, 19-nortestosterone, 17a-methyltestosterone, and other androstane... 

The classical syntheses of quinolines and isoquinolines such as the Skraup and Bischler Napieralski reactions have been extended to the naphthologues. These routes have been supplemented by syntheses based on rearrangements of derivatives of steroidal ketones The heteroatom is incorporated either at the position originally occupied by the carbonyl function or at a contiguous position. 

Sterols are derivatives of steroid. As discussed in chapter on saponins some chemical constituents present in plant flora resemble with steroids. Modem clinical studies have supported their role as anti-inflammatory and analgesic agents. P-sitosterol has significant hypolipidemic activity. 

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