Mercury acetate steroids

In a further study of routes to steroids with an aromatic ring C, 18-norandrost-13-enes (273) were found to give 7a-hydroxy-18-norandrosta-8,l 1,13-trienes (274) on reaction with selenium dioxide, while the 18-norandrosta-7,13-dienes reacted with mercury(n) acetate to give the 7a-acetate (276), as well as its 7j8-epimer. Mechanisms, including stepwise dehydrogenations, are discussed.226... 

In contrast to lead tetraacetate, simple addition to the double bond does not occur as a side re-action. While allylic rearrangement is common and mixtures of products are frequently obtained, the reaction often proceeds in very high yield and is simple to carry out the alkene is simply heated in an appropriate solvent with mercury(II) acetate until reaction is complete. Mercury(II) acetate has also been us for dehydrogenation, particularly in the steroid field. One interesting example incorporating simultaneous dehydrogenation and allylic oxidative rearrangement is seen in the reaction of abietic acid (37 equation 16). ... 

Alkyl hypochlorites and hypobromites are relatively stable molecules alkyl hypoiodites can only be prepared in situ, usually by the reaction of alcohols with metal acetates or oxides and iodine or by the reaction of alcohols with a hypervalent iodine compound and iodine.1319 Alkyl hypochlorites and hypoiodites can be utilized in reactions that parallel those of the organic nitrites (Barton reaction Section 6.4.2). For example, the photochemistry of the steroidal hypoiodite 497, prepared by the reaction of the corresponding alcohol with iodine oxide (I2O) generated from mercury(II) oxide and molecular iodine in situ, affords a new five-membered ring via an O I bond fission, 1,5-hydrogen abstraction and substitution (Scheme 6.244).1353... 

Mercuric acetate reacts with l,4,6-trien-3-ones to give, after treatment with sodium chloride, the 2-mercury steroid (590) which on reduction with sodium borohydride gave 3j8-hydroxy-4,6-diene. 

Essentially the same transformation can be conducted on a more highly substituted steroid. The required nitroso ester can in principle be prepared from reaction of DHEA 3-acetate (6-1) with bromine and nitrous acid (Scheme 3.6). The reaction sequence would start by addition of bromine from the open a-side of the steroid to form bromonium ion 6-2. Attack on that ion by the nitroso anion from the [3 side together with the rule of diaxial opening of a three-membered ring will the lead to formation of the nitrite 6-3. Irradiation of a toluene solution of the nitrite ester with a mercury vapor lamp walks the nitro group across the gap, in effect functionalizing C19. Heating the initially formed nitroso dimer in propan-... 

Allylic substitution of steroidal olefins by a modified Treibs reaction has been described." With mercury(ii) trifluoroacetate, allylic substitution of steroidal olefins (3/3-hydroxyandrost-5-en-17-one acetate, cholesterol derivatives) proceeded under milder conditions (even at 0°C) than with mercury(ii) acetate the 6jS-hydroxy-A -compounds were obtained. Similarly, paravallarine derivatives (46 R = H, Me, COMe, or COCF3) gave 6/8-hydroxy-compounds (47) (yields 18—46%). In this case it was possible to isolate, in neutral medium, the isomeric 4/8-hydroxy-A -compounds (48). 

Ally lie trifluoroacetoxylation. This salt is more reactive than mercury(II) acetate for allylic hydroxylation. Thus cholesterol esters are converted, after hydrolysis, into -3j3,6j3-dihydroxy steroids, even at 0°. Yields are about 50%. A -3/3-Aminosteroids are converted into mixtures of A -3 3-amino-4/3-hydroxy-... 

General Reactions - Studies on the addition of halocarbenes to unsaturated steroids continue. blfluorocarbene reacts with the 17-acetylenic side chain of the 17-acetate of ethinyl estradiol 3-methyl ether to yield a cyclopropene derivative which upon acid hydrolysis gives the eyelopropenone 5. The use of phenyl (trihalogeno) mercury precursors results in addition of halogenocarbenes to highly hindered double bonds of steroids.23 In a typical experiment cholest-7-en-3p-yl benzoate and the chloromercurial react to give a 7a,8a-adduct in 50% yield. 

Naproxen, [(S)-6-methoxy ex -methyl 2-naphthalene acetic acid] is a non steroidal anti-inflammatory (NSAID), indicated for the treatment of rheumatoid, osteo and juvenile arthritis, as well as ankylosing spondylitis [16]. It is very useful for the relief of mild and moderate pain. Naproxen has also caused kidney problems and has sometimes caused blood pressure increases, especially for older people [17]. In the amperometric method, mercury [18] and Pt [19] have been used as the electrode materials of choice. However, mercury electrodes have some limitations as they are toxic and there is rapid deterioration of the electrode response. Conversely, the use of Pt electrodes shows high background current in the CV resulting in low S/B ratio with the addition of analyte and the linear dynamic range of concentrations is also very narrow. During the course of the synthesis of naproxen, other conditions such as pH, light and temperature may favor the formation of impurities such as 2-acetyl-6-methoxy naphthalene (AMN) (Scheme 1) in addition to naproxen, and it is very important to detect this compound precisely in both raw materials and final products. 

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