— 189 — 



Pulegenic alcohol. Some time ago E. Rupe 1 ) undertook a series of 

 experiments on the influence of the constitution of optically active bodies 

 upon their optical rotatory power, in the course of which he tried to 

 prepare a primary alcohol of the strongest possible rotatory activity. Among 

 other alcohols, he obtained one from the pulegenic acid discovered by 

 Wallach, but this only possessed a low rotatory power. Rupe, in con- 

 junction with J. Burgess 2 ), now describes the preparation and properties 

 of the last-named body. They started from pulegenic acid methyl ester, 

 which they reduced with sodium and alcohol. The resulting alcohol, for 

 which the authors propose the name of pulegenic or primary pulegyl 

 alcohol, consists of a rather viscous, colourless oil: b. p. 105 to 105,5° 

 (10,5 mm.), d 20 o 0,9296, « D20 o — 1,59°, n D20 o 1,48074. For purposes of iden- 

 tification they prepared the acetate (b. p. 110,5 to 111,5° at 9,5 mm.) and 

 the benzoate (b. p. 186,5 to 187,5° [9,5 mm.]). 



CHCH 3 CHCH 3 



H 2 C 

 H 2 C 



CHCOOCH 3 H 2 C 



+ 4H — 

 C:C(CH 3 ) 2 H 2 C 



CH.CH 2 -OH 



CHoOH 



C:C(CH 3 ) 2 

 Pulegenic ester Pulegenic alcohol 



Terpineol. Some years ago we mentioned briefly that Haller and 

 Martine 3 ) had reduced terpineol to hexahydrocymene in a hydrogen current 

 in the presence of reduced nickel. Under different experimental conditions, 

 A. Behal 4 ) has recently obtained from terpineol (m. p. 35°), no matter whether 

 optically active or not, a tertiary menthol (hydroterpineol) possessing the 

 following properties: b. p. 99 to 100° (17 mm.), 206 to 208° (atmospheric 

 pressure), d 20 o 0,912, a D -J- 0, n D180 1,46874, mol. refr. calc. for Ci H 2 oO 

 47,53, found 47,6. Theoretically, terpineol can give rise to two al- 

 cohols according to whether the methyl- and the isopropyl- groups are 

 in the cis- or trans-position. The reduction-product obtained by Behal, 

 however, only consisted of a single alcohol, as was evident from the uni- 

 formity of the phenylurethane. This was prepared from 15,6 g hydro- 

 terpineol and 11,9 g phenyl-isocyanate, the only resulting product being 

 a urethane melting at 94 to 95°, from which the alcohol possessing the 

 properties above described was regenerated. The acetic ester of the hydro- 

 terpineol boils at 104° (16 mm.). When the free alcohol is treated with 

 a mixture of glacial acetic acid and sulphuric acid it gives rise to a 

 menthene possessing the following constants: b. p. 172 to 174°, d 2 io 0,819, 

 n D2l0 1 ,45862, mol. refr. 46,00, calc. 45,63. When oxidised with a cold 



») Liebigs Annalen 369 (1910), 313. 

 3 Berl. Berichte 43 (1910), 1228. 



3 ) Compt. rend. 140 (1905), 1298; Report October 1905, 102. 

 I Comot. rend. 150 (1910), 1762. 



