Notes on scientific research. 115 



sodium in 6 cc. of xylene on the oil bath) yielded the camphorcarboxylate easily; by 

 boiling with concentrated hydrochloric acid the latter was converted into camphor with 

 a yield of 68 per cent. 



C — CH 3 C — CH 3 



CU 2 ^ ^-COO-C 2 H 5 CH 2 ^^ ^-CO 



I ! I 



C(CH 3 ) 2 C(CH 3 ) 2 



CH 2 ^ ^CH 2 COOC 2 H 5 CH 2 ^_ ^-C 



CH CH 



(I) Diethyl homocamphorate. (II) Ethyl camphocarboxylate. 



E. Spath 1 ) has realised the synthesis of sinapin, which is contained in black mustard 



and which Gadamer 2 ) considers as an ester of the sinapic acid (3 : 5-dimethoxy-4-hydroxy- 



cinnamic acid) and of choline, in the following way: — From trimethylgallic acid he 



prepared the carbethoxysyringic acid and from this, by means of hydrogen and pal- 



lidinised barium sulphate by the method of Rosenmund 8 ) carbethoxysyringinaldehyde 



C 6 H 2 CHO cl] (OCH 3 ) 2 [3 ' 5] OCOOC 2 H5 C4] (m.p. 100 to 101°) which, saponified with caustic 



soda in a vacuum, yielded quantitatively syringinaldehyde C 6 H 2 CHO [ % 1] (OCH 3 ) 2 [3, 5] OH [4] 



(m.p. 112 to 113°). Carbethoxysyringinaldehyde gave, heated with malonic acids and 



glacial acetic acid, a good yield of benzylidene malonic acid, from which he obtained 



carbethoxysinapic acid and sinapic acid C 6 H 2 • CH = CH • COOH [1] (OCH 3 ) 2 [3 ' 5] OH [41 



(m.p. 190 to 191°); this last acid was identical with the acid prepared from natural 



sinapin. By decomposition of acetylsinapin hydrochloride with hydroxy-ethyldimethyl- 



amine Spath prepared the /?-dimethylamino-ethylester of acetylsinapic acid, the acetyl 



group of which was removed by shaking the ethereal solution with 5 per cent, caustic 



soda in an ice-cooler. From the hydroxy-ethyldimethylamine ester of the sinapic acid a 



quaternary iodide (m.p. 185 to 187°) was prepared by means of methyl iodide; this 



product, as well as the rhodanide (m. p. 180 to 181°) and the acid sulphate (m.p. 190 to 



191°) prepared from it, agreed in all their properties with the corresponding salts of the 



natural sinapin. 



XH=CH— COOCH 2 — CH 2 — N(CH 3 ) 3 1 



6 2 ^\~OH Sinapin iodide. 



X OCH 3 



P. Karrer, A. Glattf elder and Fr. Widmer 4 ) report on the synthetic preparation of 

 bergaptene and xanthotoxin. Both these compounds occur in the oil of Fagara xanth- 

 oxyloides, Lam., and bergaptene alone in bergamot oil; they are coumarone-coumarine 

 derivatives and have according to Pomeranz, Thorns, and Thorns and Baetcke the 

 formula? I and II 5 ). 



Wishing first to prepare the simplest possible coumarone-coumarine derivatives, 

 they attempted to convert the 2-methyl-5-hydroxycoumarone-4-aldehyde (m. p. 181°) in 

 analagy to the coumarine-synthesis of Perkin, by means of acetic acid anhydride and 

 sodium acetate into the corresponding coumarine. Instead of the intended body they 

 obtained a well-crystallised compound which, boiled with water, soon formed the 

 2-methyl-5-hydroxycoumarone-4-acrylic acid Ci 2 H 8 3 (m. p. 114°). It is strange that this 



: ) Monateh. f. Chem. 41 (1920), 271. — 2 ) Arch, der Pharm. 235 (1897), 95. — 3 ) Berl. Berichte 51 (1918), 

 - *) Helvet. ddm. acta 3 (1920), 541. — 5 ) Cf. Gildemeister and Hoffmann, The Volatile Oils, 2 nd ed., 

 vol. II, p. 632 and vol. Ill, p. 64. 



8* 



