5a-Androstan-ll-one

Zinc dust (35 mg) is added to a solution of 9a-bromo-5a-androstan-ll-one (225, 13 mg) in anhydrous ether (2 ml) and acetic acid-OD (0.5 ml, prepared by heating an equimolar mixture of acetic anhydride and deuterium oxide) and the resulting suspension is stirred at room temperature for 4 hr. (The progress of the reaction can be checked by thin layer chromatography.) The... 

Studies with 5a-androstan-ll-one, and other ketones, in CCI4 containing benzene up to 9M-concentration, are said to indicate formation ofa 1 1 complex between benzene and the ketone, although other workers, using camphor as the model ketone, favour a time-averaged cluster of benzene molecules rather than a discrete 1 1 complex. ... 

It has been widely assumed that the stoicheiometry of the benzene-solute collision complex is 1 1, and consistent with this assumption is the observation that the solvent shift at various concentrations of benzene in carbon tetrachloride is approximately proportional to the mole fraction of benzene. Dilution studies such as these do not exclude the co-occurrence to a small extent of other solute-solvent combinations, such as 2 1 or 1 2. Phase-independent 1 1 associations at isolated polar sites can account for the additivity of benzene-induced solvent shifts. For example, addition of the solvent shifts (d = CDci3 <5cgH6) of the H-18 and H-19 protons of 5a-androstan-ll-one (12) and 5a-androstan-2-one (13) gives A values which are in... 

Extensive studies have been carried out on the empirical use of benzene solvent-induced shifts in structural and stereochemical correlations. Saturated aliphatic ketones in particular have been the subject of many investigations, and an important generalization, the so-called carbonyl plane rule , has been proposed by Williams and Bhacca and independently by Connolly and McCrindle. This rule states that in the specific case of an isolated carbonyl group, as found in 5a-androstan-ll-one for example, the benzene-induced solvent shift (Ac He ) positive for protons... 

A pertinent example is the reduction of 5a-androst-8-en-l 1-one (154) which yields 8/7-d Sa-androstan-ll-one (155) in 93% isotopic purity.182 Saturation of A7-6-keto steroids gives equally good results for labeling the 8/ -position.153,169... 

Androsten-3,16,17-trione 3a-Hydroxy-5 aiidrt tane-ll, 17-rKone 3tt-Hydr xy-5a-aiidrostane-11,17-dione 3a, 1 lp-Dihydroxy-5 androstan-17-one 3 , 11 )S-1 )ihydro -5a-androstan-l 7-one 3-Oxo-A-aiidrosten-17 yl-sulfatc l7 -Hydioxy-5-androsten-3/3-yl-sulfate l7-Oxo-5a-androstan-3a-yl-sulfate... 

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