5-Acetyl-w-valeric acid

A liquid-liquid continuous extractor is convenient for extracting the crude acid from the aqueous solution. With such apparatus, it is possible to extract all the crude 5-acetyl-w-valeric acid from the aqueous acid in 6-8 hours. 

Acetyl-n-valeric acid has been prepared by the oxidation of 1-methylcyclohexene with potassium permanganate 5 by the oxidation of 2-methylcyclohexanone with chromic oxide and sulfuric acid 6 by the reaction of methylzinc iodide on the ethyl ester of adipic acid chloride and saponification of the ethyl ester of 5-acetyl-w-valeric acid so obtained 7 by the saponification of the ethyl ester of diacetylvaleric acid 2 and through the hydrolysis of ethyl a-acetyl-6-cyanovalerate with boiling 20% hydrochloric acid.3... 

The fore-run and the still residue contain some 5-acetyl- -valeric acid. These fractions may be combined and redistilled to yield an additional 5-10% of 5-acetyl-w-valeric acid, but the low cost of the starting materials and the ease of preparing the crude 5-acetyl-w-valeric acid scarcely justify the labor unless a considerable number of batches are being prepared. 

The first synthesis of rfZ-deoxynupharidine was reported by Kotake et al. (30). The starting material w as 2,5-lutidine which was made to react with formaldehyde to give the diol XXVII on dehydration, acetylation, and condensation with malonic ester XXVII afforded the diester XXVIII. On hydrogenation and acid hydrolysis XXVIII was decarboxylated to the valeric acid derivative XXIX. After esterification the acid was acylated with 3-furoyl chloride and distilled with soda lime to yield dehydrodeoxynupharidine (XXX), and this on hydrogenation gave dl-deoxynupharidine (II). 

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