Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Steroid nitrogen-containing

Various addition reactions to the C = C bond have been studied by Barton and co-workers in the steroid series. Although the yields of products generally depend on the substituent, they are usually higher with oxygen-containing substituents, e.g. 17 (Y = OAc. OMe)34 and 18, and lower with nitrogen-containing substituents, e.g. 17 (Y = pyrrolidino).34" 37... [Pg.272]

Generally, hypervalent iodine reagents are often better than traditional reagents of similar reactivity, with respect to efficiency and chemoselectivity - sometimes even stereoselectivity. Unusual reactivity is another interesting feature which has often resulted in unexpected transformation. Examples of such reactions may be found in the oxidation of nitrogen-containing compounds, the Hofmann rearrangement in acidic conditions, the acetalization of carbonyl compounds in alkali, the remote functionalization of steroids, etc. Some unique transformations were effected in the... [Pg.6]

Other Nitrogen-containing Derivatives of Ketones.—The Schmidt reaction of 6- and 7-oxo-steroids (with NaNj-polyphosphoric acid) gave the same lactams as the Beckmann rearrangements of the corresponding oximes. [Pg.281]

Substitution reactions using azide ion have become a popular route to nitrogen-containing steroids. The high nucleophilicity of NJ makes it effective even in some cases where Sn2 reactions are normally unfavourable. A notable example is... [Pg.278]

Powerful competitive steroid inhibitors of aromatase have been synthesized by replacing the C-19 methyl with sulfur- or nitrogen-containing functions that can coordinate to the heme iron (e.g.. Figure 7.31) The 19-methyl substituents include the following CHjSCH... [Pg.288]

The nitroxide (467), a free-radical species with potential value as a spin label, has been synthesized in three steps (Me2S04. CH2=CH—CH2MgBr, and m-chloroperbenzoic acid) from the lactam (468) The formation of some novel steroids with fused heterocyclic rings is described on pp. 326, 346,351,355, and 359 and a novel method for the introduction of thio- and nitrogen-containing substituents at C-5 on p. 357. [Pg.371]

Synthesis of natural products with polycychc systems 13CPB251. Synthesis of steroids with nitrogen-containing substituents in ring D 12KGS1536. [Pg.250]

The flame ionization detector (FID) is the detector most often used in steroid analyses. For very low concentrations of steroids, the application of ECD is needed. Thermal conductivity detectors (TCDs) cannot be used in the analysis of steroids because of their very low sensitivity. For steroidal alkaloids, a nitrogen-specific detector (NPD) has also been used. By the use of dual detector systems (e.g., FID and NPD), closely related nitrogen-containing and non-nitrogen-containing steroids can be easily differentiated. The application of MS as detector was already discussed in a previous entry in this encyclopedia." By using a GC/MS system, the identity of the peak(s) can be determined in an undisputed manner. ... [Pg.2253]

The C27-steroid alkaloids contain two heterocyclic rings attached to a steroid nucleus. Either one or both contain a nitrogen atom. The alkaloids are glycosides with the sugars attached to the hydroxy group in position 3. A well-known representative is oc-tomatine, which contains a branched sugar chain frequently found also with steroid saponins (D 6.4.2). [Pg.236]

A subgroup of the steroidal saponins are the glycoalkaloids, in which the aglycone is a steroidal alkaloid (contains a nitrogen atom). The most common source of these compounds is the Solanum genus, including the common potato Solanum tuberosum. [Pg.76]


See other pages where Steroid nitrogen-containing is mentioned: [Pg.394]    [Pg.394]    [Pg.132]    [Pg.421]    [Pg.40]    [Pg.41]    [Pg.246]    [Pg.351]    [Pg.150]    [Pg.44]    [Pg.229]    [Pg.29]    [Pg.132]    [Pg.292]    [Pg.916]    [Pg.42]    [Pg.340]    [Pg.421]    [Pg.962]    [Pg.265]    [Pg.46]    [Pg.34]    [Pg.404]    [Pg.123]    [Pg.32]    [Pg.421]    [Pg.1030]    [Pg.817]    [Pg.98]    [Pg.133]    [Pg.82]    [Pg.28]    [Pg.608]    [Pg.160]    [Pg.13]    [Pg.92]    [Pg.1055]    [Pg.639]    [Pg.1415]    [Pg.637]    [Pg.240]    [Pg.245]   
See also in sourсe #XX -- [ Pg.298 ]

See also in sourсe #XX -- [ Pg.298 ]




SEARCH



Contain Nitrogen

Containers nitrogen

Nitrogen-containing

© 2024 chempedia.info