— 148 — 



The oxime boils between 122 and 128°, when the liquid is allowed to stand 

 for a long time, crystals (m. p. 95 to 96°) are precipitated. When subjected 

 to oxidation with permanganate of potassium it gives /-keto-«,/?,/3-t rim ethyl 

 valeric acid, CH 3 COC(CH 3 ) 2 CH(CH 3 )COOH, of which the ethyl ester 

 boiled between 105 and 107° (12 mm.). The semicarbazone of the ethyl 

 ester melts at 158 to 159°. When oxidised with sodium hypochlorite, /-keto- 

 «, ft, /?-tri methyl valeric acid yields trimethyl succinic acid, COOHCfCH^ 

 •CH(CH 3 )COOH (m. p. 152°). This shows the ketone C 9 H 14 to be 

 2, 3, 3, 4-tetramethyl cyclopentene-4,5-one-l : — 



CO COOH 



y-\ / 



HsC-CH CH H 2 CCH 



I II > I 



(H 3 C) 2 C CCH 3 |(H 3 C) 2 C— COCH 8 



2, 3, 3, 4-Tetram ethyl- /-Keto-a, #, #-trimethyl- 



cyclopentene-^S-one-l. valeric acid. 



CO 



V\ 



H 2 C CH 



I II 



(H 3 C) 2 C CCH, 



Laurenone. 



When the ketone is reduced with sodium in absolute alcohol there 

 results 2, 3, 3, 4-tetramethyl q/cfopentanol-1 (b. p. 87° at 10 mm.; m. p. of 

 the phenylurethane 113 to 114°). The corresponding ketone, 2,3,3,4- 

 tetram ethyl q/c/opentanone, boils at 178 to 180°. 



As Tiemann 1 ) has already given the name of laurenone to the ketone 

 of the structure given below, it is necessary to assign to tetramethyl 

 ci/dopentenone the name of a-methyl laurenone. 



On the specific rotation of camphor, see p. 123. 



On the determination of camphor as oxime, see p. 121. 



On the reduction of camphor and camphor oxime, see p. 141. 



Epicamphor. Two keto-derivatives are derivable from camphane, 

 viz., ordinary camphor (I), and a derivative (II) which F. R. Lankshear 

 and W. H. Perkin jun.-) propose to call ^camphor. For the purpose of 

 preparing this isomeride of camphor, camphor carboxylic acid (III) is con- 

 verted into bornylenecarboxylic acid (IV) by reduction and subsequent 

 elimination of water. When reduced with palladium and hydrogen, this 

 acid is converted quantitatively into camphane carboxylic acid (V). This 

 saturated acid is readily brominated by warming its chloride with bromine 



') Berl. Berichte 33 (1900), 2950. 



2 ) Proceed, chem. Soc. 27 (1911), 166. 



