116 Report of Schimmel § Co. 1921. 



acid showed not the slightest inclination to pass into the corresponding coumarine. Why 

 this ring formation was x not possible has not yet been ascertained. The authors presume, 

 however, that there is a steric hindrance to ring-formation of the atoms in this reaction. 

 In order to build up coumarone-coumarine derivatives without the methyl group 

 the authors prepared the 5-hydroxycoumarone C 8 H 6 2 , so far unknown (m. p. 56°), from 

 7-acetoxycoumarine by means of the bromine compound and, further, the 5-hydroxy- 

 coumarone-4-aldehyde C 9 H 6 3 (partly decomposed at 260°). The Perkin reaction did 

 not convert this aldehyde either into the corresponding coumarine. 



OCH 3 



H I 



HC 

 OC 



C C CH CH 



Cx yyC 



CH HC 



CH OC 



iCH 



\/ C \y C \/ CU 

 O CH O O C O 



I 

 OCH 3 



(I) Bergaptene. (II) Xanthotoxin. 



All attempts to prepare the lactone a-campholide (I) having so far given little satis- 

 factory results, H. Rupe and A. Jaggi 1 ) have worked out a method which is based upon 

 the reduction of camphoric anhydride according to Sabatier and Senderens and which 

 yielded 98 per cent, of the theoretically-possible a-campholide. Attention had to be 

 paid in the reduction to the suppression of disturbing secondary reactions which took 

 place when the temperature of the electric furnace was not kept within 220 to 240°. 



The lactone crystallised from ligroin in stout needles and had the m. p. 210 to 211°. 



The vapours escaping especially at too high temperatures of the furnace were 

 conducted from the reduction tube through a wash bottle, cooled in ice, condensed 

 and separated into the following fractions by means of repeated fractionations over 

 metallic sodium: — (1) 108 to 115°; (2) 115 to 120°; (3) 120 to 125°; (4) 125 to 132°; 

 (5) 132 to 230°. The first four fractions were mobile colourless liquids, the last fraction 

 was yellow and rather viscous; whilst fractions 3 and 4 contained oxygen, the first 

 two fractions consisted of probably unsaturated hydrocarbons of the formula C 9 H 16 . 



By the method of v. Baeyer and Villiger 2 ) the authors prepared from the a-campho- 

 lide (by means of a solution of hydrogen bromide in glacial acetic acid) bromocampholic 

 acid (II), melting at 177° with decomposition); by modifying the method to a slight 

 extent (passing the hydrogen bromide into the solution of a-campholide in glacial acetic 

 acid) they were able to raise the yield from 60 to 80 per cent, of the theoretical. 



Starting from bromocampholic acid they prepared: — the chloride (m. p. 57.5°), the 

 amide (m. p. 207°), the anilide (m. p. 142°), the phenylhydrazide (m. p. 150 to 151°), 

 the methylester (b. p. 139° [15 mm.]), the ethylester (b. p. 142 to 143°, m. p. 9 to 10°), 

 the phenylester (m. p. 46 to 47°). Attempts to prepare an additive compound of the 

 bromocampholate with magnesium failed. On the other hand the methyl bromocampholate 

 reacted with benzylmagnesium chloride and yielded a body which probably had the con- 

 stitution of a 1 :2:2-trimethyl-3-phenylethyl-c2/c/opentane-l-benzylketone (III, m. p. 119°).* 



From the behaviour of the bromocampholate towards reagents which would split 

 off halogen hydrides, it could be demonstrated that the q/c/opentane ring was not 



!) Helvet. chim. acta 3 (1920), 654. — 2 ) Berl. Berichte 32 (1899), 3631. 



