Barbier-Wieland, degradation of carboxylic acid by method

Bam mane ware, 25, 72, 97 Barbier Wieland, degradation of carboxylic acid by method of, 24,38,41 Barbituric acid, 21, 5 Barium carbonate, 22, 86 Barium chloride, 23, 17 Barium hydroxide, 22, 87, 91, 25, 75, 27, 1... 

Synthesis from Steroidal and Alkaloidal Intermediates Steroidal intermediates have been employed in the synthesis of certain alkaloids such as dihydroconessine (58)(ref.55), one of the 3-aminoconanine bases, from the bile acid compound 3-B-acetoxybisnorcholenic acid, a substance obtained from appropriately-protected coprostanol by oxidation and two Barbier-Wieland degradations. The method consisted in converting the carboxyl into a formylamino group, the acetoxy into a tosylate which was then substituted by a dimethylamino group, reduction of the formylamino to methylamino and formation of the five-membered ring E by... 

A fairly straightforward scheme, called the Barbier-Wieland degradation, was at that time used for determining the number of carbon atoms in an ahphatic acid fragment. This involves first converting the carboxylic acid 11-1 to the corresponding ester 11-2 (Scheme 1.11). Reaction of the ester with phenylmagnesium bromide leads to carbinol 11-3. Treatment with acid leads to dehydration and formation of the olefin 11-4. Oxidation by one of several methods cleaves... 

This procedure, coupled with the procedure described on p. 41, illustrates the Barbier-Wieland method for systematically degrading carboxylic acids. foxwor-Desoxycholic acid may be prepared from wor-desoxycholic acid by repetition of this procedure. If the chromic acid oxidation product is not sufficiently solid to filter after dilution with water, the mixture must be extracted with ether and washed with dilute hydrochloric acid before the alkaline extraction. Wxwor-Desoxycholic acid may be crystallized from ethyl alcohol. It melts at 239-241°. 

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