— 129 — 



b. p. 109 to 110° (10 mm.), d 20 o 0,9845, « D + 13°30', n D 1,48519. On 

 boiling eksantalal with double its quantity of acetic acid anhydride in 

 a reflux-condenser the result is eksantalal -enolic acetate (b. p. 130 to 

 132° at 10 mm.; d 20 o 1,018) from which by oxidation with permanganate 

 of potassium in acetone, nor-eksantalic acid CiiHi 6 2 (m.p. 93°, b.p. 143 

 to 145° at 10 mm.) results. The methyl ester of nor-eksantalic acid has 

 the following constants: b. p. 102 to 104°, d 22 o 1,013, « D — 25,5°, n D 1,47348. 



It appears from this publication that Semmler has replaced the 

 whole of his previous formulas 1 ) for eksantalal, dihydroeksantalic acid, 8jc. 

 by others containing one more CH 2 - group. 



When the methyl ester of noreksantalic acid is treated with sodium in 

 absolute alcohol 2 ) the result is noreksantalol CnHi 8 0, a body possessing 

 the following properties: b. p. 1 14 to 1 17° (10 mm.), d 20 o 0,9958, [«] D — 0,7°, 

 n D 1,49049. When noreksantalol is oxidised with bichromate of potassium 

 and concentrated sulphuric acid it yields noreksantalal, CnHi 6 0, which 

 has the following constants : b. p. 92 to 94° (1 1 mm.), d 20 o 0,9964, [«] D — 30,8°, 

 n D 1,48301, m. p. of the semicarbazone 224°. By boiling this aldehyde 

 with acetic anhydride in a reflux condenser, enolic noreksantalal acetate, 

 CiiH 15 OCOCH 3 , results, a body possessing the following properties: 

 b. p. 110 to 113° (10 mm.), d 20 o 1,0270, W D — 25,6°, n D 1,48374. From 

 this it may be inferred that noreksantalal must contain, in juxtaposition to the 

 aldehyde-group, a CH 2 - or CH-group. The problem as to the nature of this 

 group was solved by the oxidation of noreksantalal acetate with perman- 

 ganate of potassium, when teresantalic acid, Ci Hi 4 O 2 , was formed, proving 

 that the aldehyde group is proximate to CH 2 - group, as otherwise an 

 acid C10H14O would have resulted. The teresantalic acid melted at 156°; 

 its methyl ester had d 1,031 and, when reduced, yielded teresantalol 

 (m. p. 114°). 



Finally, Semmler 3 ) reviews his researches into santalol as follows: — 



1. Santalol is not a uniform body, but consists of a mixture of two 

 alcohols, «- and /^-santalol. The b. p. of «-santalol is lower than that of 

 ^-santalol, the former being a simply unsaturated tricyclical, the latter a 

 doubly unsaturated bicyclical body. Whether a- and /^-santalol are really 

 uniform bodies remains to be confirmed by further experiment. 



2. Eksantalic acid, Ci 2 Hi 8 2 , is a derivative of teresantalic acid, hence 

 ^-santalol is also a derivative of the same acid. 



3. If santalene, or «-santalol, is a derivative of teresantalic acid, the 

 structure of which resembles somewhat that of camphor, it follows that 

 sesquiterpenes or sesquiterpene alcohols are partly derived from the 

 camphor-type. 



!) Comp. Berl. Berichte 40 (1907), 1120, 1124; 41 (1908), 1488; 42 (1909), 584; Report 

 November 1908, 182; April 1909, 128. 



2 ) Semmler and Zaar, Berl. Berichte 43 (1910), 1890. 



3 ) IUdem 1893. 



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