ON DYNAMIC ISOMERISM. ols 
indication of the minute proportion of enol in the mixture. It is of 
interest to note that the complete equilibrium may include no less than 
ten isomeric sugars. 
/ CHOH CHO CHOH CH,OH CH,OH 
| | | | 
$e CHOH CHOH COH CO COH 
0) | | | 
\. CHOH CHOH CHOH CHOH / CHOH 
Pe ge ie | SF Oya 
\CH CHOH * CHOH CHOH CHIH 
| | | | | 
CHOH CHOH CHOH CHOH ‘CH 
| | | 
CH,0H CH,OH CH,OH CH,OH CHOH 
a and B glucoside aldo-glucose enolic form keto-fructose a and f fructoside (?) 
a and 6 mannoside (?) aldo-mannose of glucose, 
mannose, and 
fructose 
The inversion of tetrahydro-B-naphthylamine, C,H re 
CH,.CH, 
involves the interchange of H and NH., and the readiness with which 
it takes place at ordinary temperatures is in marked contrast with the 
great stability of compounds containing the CHOH group. Itcanscarcely 
be supposed that the replacement of OH by NH, destroys the fixity of the 
four carbon valencies, and the isomeric change may perhaps depend on 
the dissociation of an ammonium hydroxide base in the sense of the 
equation 
>CH.NH,+H,02>CH.NH,;.0H 2 H,0+ >C:NH, (inactive). 
3 ) 
The salts do not appear to undergo optical inversion. Another case in 
which the optical isomerides are in equilibrium at ordinary temperatures 
is that of the d and / methylethylpropylstannic iodides,” in which isomeric 
change probably depends on dissociation. 
CH, I 
Op eames ee cs rey ay 4: 
These cases are of importance as indicating that the ‘spontaneous’ 
racemisation, frequently postulated in the so-called ‘chaotic’ molecules, 
may actually exist as a limiting case of dynamic isomerism. 
The optical inversion of camphor during sulphonation * necessitates 
the rupture of one of the three chains which connect the asymmetric 
carbon atoms, and occurs under conditions very similar to those which 
actually lead to the production of carvenone.! The inactive dynamic 
isomeride through which inversion is accomplished is perhaps the enolic 
form of dihydroeucarvone, which, like dihydrocarvone and camphor itself, 
1 Pope and Harvey, Jans. 1901, 79, 74. 2 Pope and Peachey, Proc. 1900, 16, 116. 
3 Kipping and Pope, Trans. 1897,'71, 958. +4 Bredt, Annalen, 1901, 314, 369, 
