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The reduction of trans-2-pentenoic acid (la), 4-pentynoic acid (5), and 2-bromopentanoic acid (6) with Ni-AI and Cu-AI alloys in 10 % NaOH solution afforded the expected pentanoic acid (4) in good yields. Under the above conditions, trans-3-and 4-pentenoic acids, (2) and (3), were not reduced. But, the reduction in the presence of 10 % Pd/C catalyst (43 weight % of the alloys) gave 4. In 10 % Na2C03 solution, the treatment of 5 with Cu-AI afforded pen-tenoic acid (3) as a major product. The reduction of 2,3-dibromopentanoic acid (8) gave 4 or a mixture of 4, la, and cis-2-pentenoic acid (lb) upon the conditions employed. Fumaric acid (10), maleic anhydride (11), and acety-lenedicarboxylic acid (12), and 2,3-dibromosuccinic acid (13) afforded the expected succinic acid (14) in 71-80 % yields in the reduction with the alloys in 10 % NaOH solution. It has been previously reported that the reduction of halogenated phenols, II benzoic acids, 2) acetophenones,3) and cyanobenzenes, 4) with Raney alloys in an alkaline solution afforded phenol, benzoic acid, I-phenylethanol, and benzylamine, respectively. In addition, deuteriated phenols, benzoic acids, and I-phenylethanols were prepared by the same reduction in NaOD-D20 solution. In the present paper, the reduction of aliphatic carboxylic acids with Raney alloys in an alkaline solution was investigated as a preliminary work for the preparation of deuteriated aliphatic acids, which are important for metabolic study. 5) Results and Discussion The reduction of trans-2-, trans-3-y, and 4-pentenoic acids, (la), (2), and (3), with Raney alloys in an alkaline solution was carried out under various conditions and the results ar