’ a Be A ge gi ha it 
+h & el bs , F 
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he Fe. 3s! Aid s ee A Be CL ' ‘ 
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Chemical Notes. 
Pr 
Bee emical research has at different times already dealt with the nomenclature of 
and polycyclic compounds, a satisfactory solution, however, has not been found 
herto?). In the opinion of J. Bredt and M. Savelsberg’), the principal drawback of 
‘h of the denominations was that they were too general, 7. ¢., that they comprised 
too large a number of different classes of chemical bodies under a uniform point of — 
view. Above all, the authors believe that the term “bridge linking” must be defined 
more e preciselly, and for this reason have worked out a new nomenclature for the deri- 
vatives of camphane, fenchane, pinane, carane, for compounds of. the cyclene type 
& such with bridged rings with a trimethylene ring attached thereto. In their 
10mination, they take into consideration, besides the fundamental ring, only the 
ntermediate groups effecting the division of the rings, but take not in account the 
number of new rings thereby formed. In counting the carbon atoms they start, with 
rega rd to the symmetrical structure of the molecule, and if possible, from the carbon 
without a symmetrical counterpart. In contradiction to v. Baeyer, Buchner, 
d Grignard, the authors differentiate between condensed ‘rings and rings with “bridge 
fn ings”. Furthermore, they endeavour to express the structure even of complicated 
rin s-formations, as much as possible, by means of names and not of numbers. In 
th eir terminology, all numbers are unmistakeable notations for the pestien of sub- 
tit ting groups in cyclohexanes - with “bridge linkings”’. | 
We discuss in the following, e. g., the new nomenclature of he Bydeceaitian 
unde lying the derivatives of the camphane and the fenchane series. | 
7 This hydrocarbon possesses two planes 
of symmetry, one given by the line A—B : : ne are 
a J the other given by C—D. Where these  —=§ 39’ Toe ig i 38 
two planes intersect, there is situated the ’* Hs C=. —CH 4 CH, 
o-mesomethylene rest, which in consequence — i 
0! f its ‘special position, being without any C< | Fit ee ale ae 
symn etrical counterpart, is naturally the start- 7) 
Sapoint for counting the carbon atoms. Meri etn, -CHe 
Both the tertiary carbon atoms which occupy Pa lance oat, ay 
1é same position with regard. to the p-meso- Ping at : 
me hylene, are denominated “2”, the other 
: he atoms are designed “3”. Numbering begins: therefore, with the “bridge” 
on atom, which is termed N° 1, and is continued in either direction up to N° 3. 
se a substituting group enters. this p- mesomethylene cyclohexane, there are 
e Be oc abilities of substitution: either with carbon atom N° 1, with N° 2, or with 
f0 3. With two or more substitutions, a different position may result, with regard 
oo as well as to C—D. For this reason, a further characterization of the 
a 
bet yy ‘Comp. inter alia Grignard, Bull. ‘soc. ih. IV. 11°(1912), 124; Report October 1912; 143. -See also 
Sr ed t Journ. tf. prakt. Chem. \l. 87° oT A apes April .1913,:146. —°?) Journ. Mea prakt. Chem. ll. 97 (1918),-1 
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