ALCOHOL AND KETONE  DERIVATIVES Borneol (Borneo camphor), C1oH17OH occurs in the pith cavities of Dryobalanops camphora, and in the oils of spike and rosemary; esters are found in many fir and pine oils . It may be prepared by heating camphor with alcoholic potash (M . Berthelot, Ann., 1859, 12, p . 363) ; or by reducing camphor in alcoholic solutionwith sodium (O . Wallach, Ann., 1885, 230, p . 225; J . Bertram and H . Walbaum, Jour. peak . Chem . 1894 (2), 49, p . 12) . L .

Tschugaeff (Chem . Centralbtatt . 1905 i , p 94) obtains pure d-borneol as follows.—Impure d-borneol (containing isoborneol) obtained in the reduction of camphor is dissolved in

xylene and converted into the sodium salt by metallic sodium . This salt is then turned into the xanthate, CIOH17OCS2Na, which with methyl sulphate yields the corresponding methyl ester . The unchanged isoborneol is removed by steam distillation, which also decomposes any methyl. xanthate of isoborneol that may have been formed . The residue is crystallized and hydrolysed, when pure borneol is obtained . It behaves as a secondary alcohol . Nitric acid oxidizes it to camphor and when heated with potassium bisulphate, it gives camphene . With phosphorus pentachloride it forms a bornyl chloride, identical with pinene hydrochloride . Isoborneol is a tertiary alcohol which may be obtained by dissolving camphene in glacial acetic acid, adding dilute sulphuric acid and heating to 50-6o° C. fcr a few minutes, the isobornyl acetate so formed being then hydrolysed (J . Bertram and H . Walbaum, loc. cit.) .

It crystallizes in leaflets, which readily

sublime . Chromic acid oxidizes it to camphor . Thujone (tanacetone), C10H18O, is found in many essential oils . Oil of thuja contains chiefly a-thujone, and oil of tansy chiefly ,B-thujone . Oil of artemisia and oil of sage contain a mixture of the two, whilst oil of absinthe contains principally the )3-variety . The two forms may be obtained by fractional distillation of the oils, followed by a fractional, crystallization of their semicarbazones from methyl alcohol. a-Thujone is laevo-rotatory and when warmed with alcoholic potash it is partially converted into /3-thujone . Sodium in the presence of alcohol reduces it to thujyl alcohol, which on re-oxidation is converted into l-thujone . The fl-form is dextro-rotatory and is partially converted into the a-variety by alcoholic potash . When heated to 28o° thujone is transformed into the isomeric carvotanacetone (A6-terpenone-2) . On boiling with ferric chloride it yields carvacrol . Hot dilute sulphuric acid converts it into isothujone (dimethyl-i . 2-isopropyl-3-cyclopentene-I-one-5) .

Thujone behaves as a saturated

compound and forms a characteristic tribromide . When heated with zinc chloride it yields hydropseudocumene . According to F . W . Semmler (Bee., 1900, 33, p . 275; 1903, 36, p . 4367) it is to be considered as a methyl-2-isopropyl-5-bicyclo-(o . I • 3)-hexanone-3 . Carone, C1oH160, is a trimethyl-3 . 7 • 7-bicyclo-(o . I • 4)-heptanone-2, obtained by acting with alcoholic potash on dihydrocarvone hydrobromide (A. v . Baeyer, Ber., 1896, 29, pp .

5, 2796; 1898, 31, pp . 1401, 2067) . It Is a colourless oil, having the odour of camphor and

peppermint, and boiling at 210° C . It is known in d-, l-, and i-forms . It does not combine with sodium bisulphite . When heated it is transformed into carvenone . It is stable to cold potassium permanganate solution, but on heating gives a dibasic acid, caronic acid, C5H8(CO2H)2, which Baeyer suggested was a gem-dimethyltrimethylene-r • 2-dicarboxylic acid . This was confirmed by W . H . Perkin, junr . (Jour . Chem .

Soc., 1899, 75, p . 48) who synthesized the acid from dimethylacylic ethyl ester . This ester with ethyl malonate yields ethyldimethylpropanetricarboxylic ester, which on hydrolysis and subsequent heating is converted into t913-dimethyl glutaric acid . The a-bromdirrethyl ester of this acid when heated with alcoholic potash yields cis-, and trans-caronic acids . Eucarvone, C1oH1,O, is a trimethyl-3.7.7-bicyclo-(0•I.4)-heptene-3-one-2 . O . Wallach (Ann., 1905, 339, p . 94) suggests that the ketone possesses the structure of a trimethyl-r .4 • 4-cycloheptadiene-5 . 7-one-2 . Phosphorus pentachloride converts it into 2-chlorcymene (A . Klages, Ber., 1899, 32, p . 2558) .

Camphor, C1oH16O, is a trimethyl-r . 7 . 7-bicyclo-(I • 2 • 2)-heptanone-2 . The d-variety is found in the camphor

tree (Laurus camphora), from which it may be obtained by distillation in steam . The l-variety is found in the oil of Matricaria parthenium . It crystallizes in transparent prisms which possess a characteristic odour, sublimes readily and is easily soluble in the usual organic solvents . It boils at 209° C. and melts at 176° C . (circa) . The d-form may also be obtained by the distillation of calcium homocamphorate (A . Haller, Bull . Soc . Chim., 1896 (3), 15, p .

324) . When heated with phosphorus pentoxide it yields cymene, and with

iodine, carvacrol . Nitric acid oxidizes it to camphoric acid, C8H14(CO2H)2, camphoronic acid, C9H1306, and other products . It forms an oxime with hydroxylamine which on dehydration yields a nitrile, from which by hydrolysis carnpholenic acid, C9HISCO2H, is obtained It combines with aldehydes to form alkylidene compounds, and yields oxymethylene compounds when subjected to the " Claisen " reaction . It does not combine with the alkaline bisulphites . It is readily substituted by chlorine and bromine; and with fuming sulphuric acid forms a camphor sulphonic acid . Sodium reduces it, in alcoholic solution, to borneol . When heated with sodium formate to 12o° C. it is converted into bornylamine . Caro's acid converts it into campholid, and a compound C10H1E0, (A. v . Baeyer and V . Villiger, Ber., 1899, 32, p . 3630) .

When heated with concentrated sulphuric acid to 105-110° C. it yields carvenone and 4-aceto-r • 2-xylol (J . Bredt, Ann., 1901, 314, P . 371) .