TEREPHTHALIC 

ACID Sodium amalgam in faintly alkaline solution Sodium amalgam (hot) HEXAHYDRO Tropilene, C7H,oO, is obtained in small quantities by the distillation of a-methyltropine methyl hydroxide, and by the hydrolysis of 13-methyltropidine with dilute hydrochloric acid . It is an oily liquid, with an odour resembling that of benzaldehyde . It forms a benzal compound, and gives an oyxmethylene derivative and cannot be oxidized to an acid, reactions which point to it being a ketone containing the grouping -CH2•CO- . It is thus to be regarded as a cyclo-heptene-I-one-7 . Cyclo-heptane carboxylic acid (suberanic acid), C7H18CO2H, is obtained by the reduction of cyclo-heptene-i-carboxylic acid; from brom-cyclo-heptane by the Grignard reaction; and by the reduction of hydrotropilidine carboxylic acid by sodium in alcoholic solution (R . Willstatter, Ber., 1898, 31, p . 2504) . The corresponding oxyacid is obtained by the hydrolysis of the nitrite, which is formed by the addition of hydrocyanic acid to suberone (A . Spiegel, Ann., 1882, 2I1, p . 117) . Four cyclo-heptene carboxylic acids are known . Cyclo-heptene- (-carboxylic acid-i is prepared from oxysuberanic acid .

This acid when heated with concentrated hydrochloric acid to 120-130° C. yields a chlor-acid, which on warming with alcoholic potash is trans-formed into the cyclo-heptene compound . Cyclo-heptene-2-carboxylic acid-i is formed by the reduction of cyclo-heptatriene 2.4.6-carboxylic acid-I . On boiling with

caustic soda it isomerizes to the corresponding I-acid . Cyclo-heptatriene carboxylic acids, C7H7CO2H . All four are known . According to F . Buchner (Ber., 1898, 31, p . 2242) they may be represented as follows : cop coati A.1,3,5aot (11,3,corp . A1,4.6orr LI24,60rS The a-acid (a-isophenylacetic acid) is obtained by the hydrolysis of pseudophenylacetamide, formed by condensing diazoacetic ester with benzene, the resulting pseudophenyl acetic ester being then left in contact with strong ammonia for a long time . 13-Isophenylacetic acid is formed by strongly heating pseudophenylacetic ester in an air-free sealed tube and hydrolysing the resulting -isophenylacetic ester. y-Isophenylacetic acid is obtained by heating the 13 and S acids for a long time with alcoholic potash (A . Einhorn, Ber., 1894, 27, p . 2828; E .

Buchner, Ber., 1898, 31, p . 2249) . S-Isophenylacetic acid is obtained by heating the iodmethylate of anhydroecgonine ester with dilute caustic soda (A . Einhorn, Ber., 1893, 26, P . 329)- Numerous amino-derivatives of the cyclo-heptane

series have been prepared by R . Willstatter in the course of his investigations on the constitution of tropine (q.v.) . Amino-cyclo-heptane (suberylamine) is obtained by the reduction of suberone oxime or by the action of sodium hypobromite on the amide of cycloheptane carboxylic acid . Cyclo-octane Group . Few members of this group are known . By the distillation of the calcium salt of azelaic acid H . Mayer (Ann., 1893, 275, p . 363) obtained azelain ketone, C8H,4O, a liquid of peppermint odour .

It boils at 90-91° C . (23 mm.) and is readily oxidized by

potassium permanganate to oxysuberic acid . It is apparently cyclo-octanone (see also W . Miller and A . Tschitschkin, Centralblatt, 1899, 2., p . 181) . Pseudopelletierine (methyl granatonine), C9H16NO, an alkaloid of the pomegranate, is a derivative of cyclo-octane, and resembles tropine in that it contains a nitrogen bridge between two carbon atoms . It is an inactive base, and also has ketonic properties . On oxidation it yields methyl granatic ester, which, by the exhaustive methylation process, is converted into homopiperylene dicarboxylic ester, HO2C -CH :CH -CH2 .CH2 .CH :CH .CO2H, from which suberic acid may be obtained on reduction . When reduced in alcoholic solution by means of sodium amalgam it yields methyl granatoline, C8H,8OH.NCH3; this substance, on oxidation with cold potassium permanganate, is converted into granatoline, C8H16NO, which on distillation over zinc dust yields pyridine . Methyl granatoline on treatment with hydriodic acid and red phosphorus, followed by caustic potash, yields methyl granatinine, C9H,6N, which when heated with hydriodic acid and phosphorus to 24o° C. is converted into methyl granatanine, C8H,4.NCH3, and granatanine, CSH,4NH . The hydrochloride of the latter base when distilled over zinc dust yields a-propyl pyridine .

By the electrolytic reduction of pseudopelletierine, N-methyl granatanine is obtained, and this by exhaustive methylation is converted into .a '

des-drmethyl granatanine . This latter compound readily forms an iodmethylate, which on treatment with silver oxide yields the corresponding ammonium hydroxide . The ammonium hydroxide on distillation decomposes into trimethylamine, water and cyclo-octadiene•1.3 .