— 95 — 
was generally to be expected with racemic bodies. Analogous occur- 
rences were observed in the case of the acid phthalates of different 
bomeols; the molecular compounds from chloral, or bromal, and the 
isomeric bomeols, are also isomorphous. 
Menthol. On the strength of numerous tests made with the 
benzoate, oxalate, carbonate, succinate, and acetate, of menthyl, and 
also with menthyl benzyl ether and diphenyl menthyl urethane, 
Tschugaeff considers it an established fact, that these derivatives 
of menthol with an ester-like character are extremely difficult to 
decompose by distillation, and further that, when decomposition actually 
takes place, occurrences of isomerisation are then not at all excluded. 
On the other hand, the xanthogenates of terpene alcohols are dis- 
tinguished by a ^^ery peculiar and characteristic behaviour, and in this 
respect they appear to have no analogy whatever with any other com- 
pound. The dixanthogenides of the general formula C^Hgin + iOCS 
• SS CSOCnHgin + i decompose as readily as the corresponding xan- 
thogenates. The xanthogenic amides and thiourethanes , which only 
contain the group ROCS as residue of xanthogenic acid ROCS • S, 
rank in every respect with the xanthogenic compounds mentioned above 
(as Tschugaeff has recently found^); in their case, however, the de- 
composition occurs at a somew^hat higher temperature. Tschugaeff, 
following the method indicated by Debus, produced by means of the 
action of alcoholic ammonia on the methyl esters of the corresponding 
xanthogenic acids, a number of these xanthogenic amides, viz., menthyl 
xanthogenic amide, the two optically active bornyl xanthogenic amides, 
and the racemic isomers, fenchyl xanthogenic amide, and dihydrocarvyl 
xanthogenic amide. The reaction takes place according to the equation: 
ROCSSCH3-f-2NH3 ^ROCSNHg + NH^SCHg. 
Only the behaviour of menthyl xanthogenic amide was, however, 
examined more in detail. If this body is heated in a fractionating 
flask, decomposition with evolution of gas commences already a few 
degrees over 200°; at about 220^ it becomes very brisk, and it is 
then soon completed. Ammonia and carbon oxysulphide thereby 
occur as gaseous reaction - products , wMst in the receiver menthene 
can be condensed, v/hich, after one distillation over metallic sodium, 
shows the following properties: Boiling point 167 — 168; specific 
gravity \ 0,8121; np 1,45202, and [a]D -|- 1 13° 28'. It is therefore 
very similar to the distillate from menthyl xanthogenate. 
^) Berliner Berichte 35 (1902), iot6. 
