110 



Report of Schimmel § Co. 1921. 



The attempt to replace the hydroxyl group in hydroxycamphor by means of thionyl 

 chloride by chlorine yielded, instead of the expected hydroxycamphor chloride, the sulphite 

 ester of hydroxycamphor C20H30O5S (m.p. 187°). The oxidation of the acetyl hydroxy- 

 camphor with nitric acid did not yield the intended acetylated, dibasic hydroxy acid, but 

 the already-known p-diketocamphane. Saponification had taken place in spite of the acid 

 character of the solution, and there had been a secondary oxidation of the CHOH-group 

 into the carbonyl group. 



In order to prepare homocamphor (I), which differs from camphor only by another 

 CH 2 -group in the ketone ring, A. Lapworth and F. A. Royle 1 ) prepared first, by the Winzer 

 process 2 ), camphorylmalonic ester (II) from camphoric acid anhydride and reduced the 

 ester then by one of the following methods. They applied either sodium amalgam and 

 carbonic acid or they had recourse, with still better results, to electrolysis under definite 

 conditions. By hydrolysis of the reduction product they obtained the hydrocamphoryl- 

 malonic acid (III). From this body they obtained by distillation Winzer's hydrocamphoryl- 

 acetic acid (IV) (carbon dioxide being split off) which was finally converted into homo- 

 camphor, either by heating the lead salt of the acid in a current of carbon dioxide, or by 

 the prolonged action of acetic acid anhydride upon the acid and distillation in a vacuum. 



CH 2 



CH 



I 



CH 2 



I 

 CH 2 



I 



C(CH 3 ) 2 



I 

 CH 2 C(CH 3 )- CO 



(I) Homocamphor. 



CH, 



CH 



I 



C = C(COOC 2 H 5 ) 2 



C(CH 3 ) 2 O 

 I I 



CH 2 ^C(CH 3 )— CO 



CH 2 



CH, 



(II) Camphorylmalonic ester. 



— CH— — OVOVCOOH 

 C(CH 3 ) 2 



— C(CH 3 )~ COOH 



(IV) Hydrocamphorylacetic acid. 



CH S 



CH, 



CH 5 



CH 5 



CH— 



I 

 C(CH 3 ) 2 



I 

 -C(CHs)- 



CH 2 — CH(COOH) 2 



COOH 



(III) Hydrocamphorylmalonic acid. 



CH 



I 



CH 2 



I 



C(CH 3 ) 2 C = IS OH 



I I 



— C(CH 3 )— CO * 



(V) Jsonitrosohomocamphor. 



Homocamphor (m.p. 189 to 190°; [«] D — 112.9° [4 percent, solution of benzene]) 

 is a white, indistinctly crystalline mass which resembles camphor in smell and in its 

 behaviour towards the ordinary reagents. The body formed a semicarbazone (m. p. 250 

 to 252°) which crystallised in colourless needles, and an oxime (m.p. 167 to 168°) which 

 crystallised in long needles. When a small quantity of this oxime was heated with con- 

 centrated sulphuric acid the smell of campholenonitrile (raspberries) became noticeable. 

 From the isonitrosohomocamphor (V; m.p. 167 to 168°), pale-yellow crystals were ob- 

 tained in very small quantities by the action of formaldehyde and hydrochloric acid, 

 representing probably homocamphorquinone. 



The correctness of their constitutional formula for homocamphor was proved by 

 the authors by converting isonitrosohomocamphor with acetyl chloride and subsequent 



!) Joitrn. client. Soc. 117 (1920), 743. 



J ) LleiUfs Annalen 257 (1890), 298. 



