Hexahydronicotinic acid

Hexahydronicotinic acid (90%) is obtained by catalytic hydrogenation of nicotinic acid at 3 atm. pressure over colloidal platinum. Preparation of the catalyst is described. The 9,10 double bond in the acridine nucleus is reduced at 10° by sodium amalgam in dilute sodium carbonate solution to give 9,10-dihydroacridine-S>-carboxylic acid in 70% yield. 2-Phenyl-cyclohexanecarboxylic acid (96%) is prepared by the selective reduction, of 2-phenylbenzoic acid by a large excess of sodium in refluxing amyl alcohol. ... 

Hexahydronicotinic Acid (Piperidene-Z-earboxylic acid, nipecotic acid)... 

Rapala et al. J Am Chem Soc 79 3770 1957], nicotinic acid to hexahydronicotinic (nipecotinic) acid without decarboxylation [2 atmospheres, 25°, 4 hours Freifelder J Org Chem 27 4046 1962, Freifelder J Org Chem 28 602, 1135 1963], complete hydrogenation of quinoxaline [Broadbent at al. J Am Chem Soc 82 189 1960], reduetion of the 4,5-double bond of pyrimidine nucleosides and nucleotides [Cohn Doherty JAm Chem Soc 78 2863 1956], dehydrogenation e g. hydrogen transfer from hexahydrohexahelicene to benzene in order to provide hexahelieene and cyclohexane in 73% yield [Newman Lednicer J Am Chem Soc 78 4765 1956, cf also Anderson Anderson J Org Chem 22 1197 1957], and hydrogenation of anilines to cyclohexylamine with httle hydrogenolysis [Freifelder et al. J Org Chem 30 2485 1965],... 

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