176 — 



The nitrosochloride of d-l-methyl-3-ethylidenec?/cJohexene referred to 

 above, when heated with sodium acetate and glacial acetic acid to 65°, 

 yields the acetyl derivative of the oxime of 3-acetyl-l-methylc?/cZohexane-3-ol 

 (VII). When this alcohol is treated with methyl magnesium iodide, it gives 

 rise to d-l-methyl-3-isopropylc2/cZohexane-3,8-diol (VIII), the metaterpine 

 corresponding to J 2 ' 8C9) -m-menthadiene: m. p. 64°. 



HsC-CH CH 

 H«C 



H 3 C 



CO 



CH2 CH2 



I. d-1 -methyl cyclo- 

 hexane-3-one. 



,OH 

 CH(CH 3 )CO a C 2 H 6 



H S C 



CHCH 3 



II. l-methyl-3-hydroxyct/cZohexane- 

 3-a-ethylpropionate. 



III. D-l-l-methyI-3-ethyl- 

 idenecyctohexane. 



H S C 



H a C 



H 3 C 



C 



COCHs 



\ 



*CH« 



CH» 



JV. d-3-acetyl-l-methyl- 

 /} ' 2 -cyclohexene. 



H 2 C C (OH) COCHs 

 H 3 CHC<^ ScH 2 



^>C(OH)(CH 3 ) 2 Z^- 



V. d-d 2 -m-menthenol-8. VI. d-4 2 ' 8(9) -m-menthadiene. 



OH 



H 3 C 



H2 C CH2 



VII. 3-acetyl-l -methyl cyclo- 

 hexane-3-ol. 



C(OH)(CH 3 ) 2 



VIII. d-l-methyl-3-«sopropyI- 

 q/cZohexane-3, 8-diol. 



Four out of the six isomeric m-menthenols have thus far been prepared, 

 mz v z^-m-menthenol-S (dihydrocarvestrenol) 1 ), d 2 -m-menthenol-8 2 ), A s -m- 

 menthenol-8 2 ), and A 6 -m-menthenol-8 (dihydro-isocarvestrenol) 3 ). Recently, 

 Perkin 4 ) has succeeded in also preparing synthetically the two remaining 

 modifications of m-menthenol, viz., A*- and J 5 -m-menthenol-8. 



To attain this object, Perkin started from 5-hydroxy-m-toluic acid, which 

 he reduced with sodium and alcohol to l-methyl-q/cfohexane-5-ol-3-carboxylic 

 acid. By treating with hydrobromic acid this acid was converted into 

 5-bromo-l-methyl-c?/cfohexane-3-carboxylic acid, from which was prepared 

 the ethylester; the latter, when digested with diethylaniline, giving a mixture 

 of esters of 1 -methyl-^ 5 - and l-methyl-J 4 -q/cfohexene-3-carboxylic acid. The 

 reaction produced a far larger quantity of the first- than of the last-named 

 body. The free acids were removed by careful saponification and separated 

 by the fractionated crystallisation of their calcium salts. i-\-Methy\-A b -cyclo- 

 hexene-3-carboxylic acid constitutes a rather refractory oil of disagreeable 

 odour: b. p. 145° (20 mm.), 177 to 180° (100 mm.). The ethylester also 



*) Comp. Report April 1907, 145; October 1907, 146. 



2 ) Comp. Report October 1905, 94. 



s ) Comp. Report April 1909, 123. 



4 ) Journ. chem. Soc 97 (1910), 2129. 



