Notes on scientific research. 



109 



By the treatment ofpaeonol with nitric acid in glacial acetic acid A. Sonn 1 ) prepared 

 nitropaeonol and by reduction of this compound the corresponding aminopaeonol 

 (m. p. 115°, uncorr.). Sonn further prepared, by condensation of nitropaeonol with 

 anisaldehyde, 3-nitro-4-methoxy-6-hydroxyphenyl-4-methoxy-styryl ketone (m. p. 182° 

 uncorr.). The likewise prepared aminostyryl ketone melted at 203° ^uncorr.). 



Hydroxy camphor (Ketoborneol) . — By means of chromic acid in glacial acetic acid 

 H. Schrotter had in 1881 prepared, from a mixture of bornyl acetate and isobornyl acetate, 

 a body Ci 2 Hi80 3 which, saponified with caustic potash, gave a hydroxycamphor Ci Hi 6 O 2 . 

 J. Bredt and A. Goeb 2 ) nowshow that the so-far unexplained constitution of this body 

 (m. p. 238 to 246°; phenylurethane, m. p. 119°) probably corresponds to that of a 

 ^-ketoborneol (I). The hydroxyl and the carbonyl groups were proved to be present 

 by the acetylation of this body (acetate of the hydroxycamphor, m. p. 76 to 77°) and 

 by the formation of its semicarbazone (m. p. 222 to 224°). In the oxidation of the 

 hydroxycamphor by means of chromic acid the authors obtained a diketone (p-diketo- 

 camphane (III), m. p. 206.5 to 207°) which characterised it as a secondary keto-alcohol 

 (ketol). From the corresponding disemicarbazone they obtained, by reduction after 

 Kishner-Wolff (with sodium ethylate in a sealed tube at200°) 3 ), camphane (m. p. 156°) 

 and, similarly from the hydroxycamphor semicarbazone, pure borneol (m. p. 203 to 204°). 



OC 



H 2 C 



CH 



CH 3 -C-CH 3 



CH 



CH, 



CH 2 



H 2 C 







CH 2 







CH3 — C — CH3 





COH 

 H 



OC 



^C^l 



1 



COH 

 H 





CH 3 



Kycamphor 



)• 



(II) m-Ke 



toborneol 





OC 

 H 2 C 



CH 



CH3 — C — CH3 



CH 2 

 CO 



CH 3 



(III) p-Diketocamphane. 



It was thereby established that the camphor-skeleton was preserved, both in the diketone 

 and in the hydroxycamphor. Since the Schmiedeberg and Manasse hydroxy camphors 4 ) 

 differed essentially from the Schrotter hydroxycamphor mentioned, the position of the 

 carbonyl relative to the hydroxyl group could only conform to one of the two 

 formulae (I) and (II). The ketone obtained was, however, optically-active and should, 

 therefore, be asymmetrically-constituted and have the two CO-groups in ^-position (III). 

 The corresponding hydroxycamphor should, therefore, also be credited with the con- 

 stitution of a ^-ketoborneol (I). 



By the reduction of the hydroxycamphor by means of sodium and boiling alcohol 

 the corresponding glycol (p-dihydroxy camphane, m. p. 233 to 234°) and from this the 

 diacetate (b. p. 151.5° [15 mm.]) was obtained. 



Since the melting points of Schrotter's hydroxycamphor varied in the different 

 preparations between 238 and 246° and were never quite sharp, always indicating 

 a slight decomposition of the product, he had evidently been dealing with ,a mixture 

 of two stereo-isomerides, an exo- and an endo-form, corresponding to borneol and to 

 woborneol. The exo-form (m. p. 237.5 to 238°) was easily isolated by treatment with 

 zinc chloride according to the method applied by Bertram and Walbaum 5 ) in the 

 dehydration of isoborneol. 



x ) Berl. Berichte 54 (1921), 358. — 2 ) Journ. f. prakt. Chem. N. F. 101 (1920), 273. — 3 ) Liebig's Annalen 

 394 (1912), 86. — *) Berl. Berichte 30 (1897), 659; 35 (1902), 3811. — 6 ) Journ. f. prakt. Chem. N. F. 49 (1894), 8. 



