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The Reformatsky reaction between an ethyl a-halogenopropionate and dehydroepiandrosterone acetate (I) gives the esters of a mixture of isomeric acids (11-V).Two of these (I1 and 111), when dehydrated, give the esters of 3P-acetoxy-20P-pregna-5 : 16-dien-20-oic acid (VII) and 3P-acetoxypregna-5 : 17(20)-dien-( ? trans-)20-oic acid (VIII), both of which after hydrogenation yield methyl 3~-acetoxybisnoraZZocholanoate (X) . These results are considered to provide additional evidence for believing that this allocholane derivative and the natural steroids have the @-configuration a t &).THE ethyl esters of the four isomeric acids (II-V), differing in configuration at C(17) and C(zo), are the possible products of a Reformatsky reaction between an ethyl a-halogenopropionate and dehydroePiandrosterone acetate (I). Lardon and Reichstein (Helv. Chim. Acta, 1941, 24, 1127), using ethyl a-bromopropionate, obtained two of these esters, one in 20% and the other in 5% yield, together with a small quantity of an incompletely characterised third product, m. p. 124-126", corresponding to such an ester which had been dehydrated. Addition reactions at the CO group at position 17 involving, e g . , hydrogen, Grignard reagents, potassium acetylide, osmium tetroxide, or perbenzoic acid are known to proceed in such a way that the chief product results from the entering group's coming from behind the molecule (cf. Fieser and Fieser, " Natural Products related to Phenanthrene,"

Dehydration of 2-methyl-6-phenylheptan-3-01 with different reagents gave 2-rnethyl-&phenylhept-2-ene, with minor amounts of the hept-3-ene. Reaction of the alcohol with hydrobromic acid followed by dehydrobromination yielded the hept-2-ene.As a preliminary step in an investigation into the regulated degradation of sterol sidechains the preparation of 2-methyl-6-phenylheptan-3-01 (I) was undertaken. This compound has the same side-chain as 24-hydroxycholesterol. The alcohol was prepared from styrene, which was converted into 1-bromoethylbenzene and thence into l-phenylethylmalonic acid ; decarboxylation of the latter gave p-phenylbutyric acid which was reduced to 3-phenylbutan-1-01 and then converted successively into 1-bromo-3-phenylbutane and, by a Grignard reaction with isobutaldehyde, into 2-methyl-6-phenylheptan-3-01 (I). The various stages in this synthesis were accomplished by standard reactions. All the compounds are liquids and no crystalline derivative of the desired alcohol, which has two asymmetric carbon atoms, was obtained. However, oxidation gave 2-methyl-6-phenylheptan-3-one, which was characterised as the crystalline 2 : 4-dinitrophenylhydraone.Simonsen and his co-workers (J., 1939, 1504) showed that (-)-rx-curcumene consists of a mixture of 2-methyl-6-P-tolylhept-1-and -2-ene. This mixture was prepared in an optically inactive form by Carter, Simonsen, and Williams (J., 1940, 451) from 2-methyl-6p-tolylheptan-2-01, which was synthesised in a manner not unlike that used in the present work. This alcohol was dehydrated with potassium hydrogen sulphate to a mixture of the hept-1-ene and the hept-2-ene with the former predominating.The dehydration of 2-methyl-6-phenylheptan-3-01 has now been studied using a number of reagents. Comparatively few extensive studies on the dehydration of secondary alcohols of the type (CH,),CH*CH(OH)*CH,R are found in the literature. Tuot (Comfit. rend., 1940, 211, 561) dehydrated a number of secondary alcohols including 2-methylheptan-3-01 with anhydrous copper sulphate and concluded that where the hydroxyl 5 H

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