an as an gasses jeompaute (VIH, see p. 138 of this Report). 
the reason why it is so easily attacked by potassium permanganate. 
Dene fies & 
its on acid content ee to Welachs directions. 
ae ‘ 
2 aqueous solution of SOs, a sulphonic acid which is very easily soluble in water. Wallach ay 
has made a thorough examination of this pulegone sulphonic acid. Whilst the acid is 
_ obtained as an almost colourless syrup, which: decomposes over concentrated sulphuric — 
ies acid with darkening and the splitting off of sulphurous acid and pulegone, the well __ 
P - crystallised salts of pulegane sulphonic acid are remarkable for their great stability. If 
"the aqueous ‘solution of the barium salt of the sulphonic acid be warmed with bromine, — 
iy no precipitation of barium sulphate takes place. This fact speaks for a firm linking | es 
> 
a =o of the sulphurous acid tadicle. Also all the salts behave as saturated compounds in 
| the | ‘permanganate test. From this, the salts of pulegone sulphonic acid correspond by 
a means: with. the salts obtained by the addition of sodium bisulphite to saturated 
ketones, so that. ats is rather to be assumed that the sulphurous acid adds on to the 
oe -semicyclic linking. As the salts do not correspond to the simple formula C,oH1,0: -SO;M, 
~ and since they all contain water firmly bound, it may almost be assumed that ca 
__ carbonyl group takes part in the taking up of the water. 
fF ‘sulphurous acid to pulegone, and to the similarly behaving camphor phorone (ID. 
; the tertiary semicyclic carbon linking alone decisive for the additive power; are 
~~ semicyclic linkings completely endowed with this property, or, in the cases named, 
the: juxtaposition of the carbonyl group or of other acid-containing groups to Re 
_ double linking of the carbon atoms the cause? 
_ From the behaviour of sabinol (lll) it could be shown that the first question can 
- i, Of great interest was the question — which conditions favour the additive power ¥ 
ol | 
E 
iy 
4 ~~ 
- in all probability be answered in the affirmative. The chief reaction product between | 
is _ sabinol and sulphurous acid—apart from a neutral compound of m. p. 147 to 1489 =3 
Was a light and well crystallising sulphonic acid of the formula CioHi;SO3H (m. p. 98 to 
acid behaved as a strongly unsaturated compound both with permanganate and bromine. 
The question now arose whether this easy additive power was decided by the presence 
So of the menthene bond, or by the ease with which the 3-ring may be broken. From 
- thé” behaviour of the reduced sabinol, . thujyl alcohol (IV), it appeared that after 
ee ‘the breaking up of the semicyclic au bie ‘onal the additive power for sulphurous acid 
te completely disappeared. On the other hand the 3-ring remained intact in the sulphonic 
ee acid, for on being treated with caustic potash solution thujone (V) could be obtained. 
: pbreaking up of as nee ring resulted on oe cena of an ethylene linkage, 
ee 
a 
Zz : ) A f 
& as | Pulegone sdiipiiwis acid. — It has bese long known that pulesone (1) Fone with an 
The facts observed may be employed i in testing old stocks of essential oils for thujone- | 
The preparations are shaken up with caustic soda solution, the acid is then tested for 
999), whose formation took place with the elimination of one molecule of water. This 38 
Gaps 
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