112 
constantly shaken for 12 to 15 hours. The product is a colourless, 
mobile oil, with a faint odour reminding of the aldehyde. It boils 
at 142^ to 144.5° (14 mm pressure); d^° = 0,8737; «d = — 2,36°; 
Md = — 2,70°. 
With this ketone now the authors have made the interesting ob- 
servation that it unites under certain conditions with two molecules 
semicarbazide. H. Rupe and P. Schlochoff^) have subsequently 
followed this reaction further, applied to other a-^-unsaturated ketones, 
when they found that, within certain limits, the above-named ketones 
have a general capacity of adding, in addition to the semicarbazide 
rest chained to the carbonyl-group, a second molecule semicarbazide 
to the double - linking situated in the a -/3- position. These "semi- 
carbazide-semicarbazones" are well - characterised bodies, which can 
throughout be recrystallised from water. The derivative of citronellal 
acetone melts at 167^; the following formula may illustrate its 
constitution: 
)C . CH2 . CHj . CHg . CH(CH3) . CH2 . CH • CH^ • C • CH^ 
NH2 . NH . CO . NH N . NH . CO • NH^. 
Concentrated hydrochloric acid dissolves the compound instant- 
aneously; dilute hydrochloric acid splits it up on boiling into ketone 
and semicarbazide. Attempts to produce the corresponding compounds 
of benzal acetone, cinnamoyl acetone, and pulegone, led to no result. 
From this the authors conclude that the addition of a second mole- 
cule semicarbazide to the double -linking of a -/?- unsaturated ketones 
only occurs when there is neither a phenyl-group nor another double- 
linking in their proximity. The examination of the above reaction 
is being continued. 
Ketones. 
C. Harries 2) has now occupied himself for many years with the 
study of the reactions of unsaturated ketones, and in a recent number 
of Lie big's Annalen he has arranged the voluminous material, for 
the purpose of more readily finding the way in the matters relating 
to this subject. Harries distinguishes two large principal groups of 
unsaturated ketones: i^*- ketones with double -linking in a-^ff-position; 
2"^- ketones with double-linking not situated in a-^-position. Whereas 
the behaviour of the bodies belonging to the second category as a rule 
behave like saturated ketones, the bodies of the first group differ from 
^) Berliner Berichte 36 (1903), 4377. 
2) Liebig's Annalen 330 (1904), 185. 
