The chemistry of synthetic drugs / by Percy May.

  • May, Percy, 1886-
Date:
1911
Catalogue details

Licence: In copyright

Credit: The chemistry of synthetic drugs / by Percy May. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    marked influence in causing the hypnotic character to appear, whereas methyl groups are entirely without this influence. In fact, there appears to be a marked difference between the ethyl and methyl groups with respect to their action on the central nervous system, for which the former seem to have a special affinity. Other groups of compounds show similar relation- ships. An interesting experimental result points to the same conclusion, as it has been shown that certain dyes containing the diethyl-amino group, N(C2H5)2, possess the property of dyeing the nerve fibres, but the corresponding dyes containing the dimethyl-amino group, N(CH3)2, do not have this property (Ehrlich and Michaelis). Another example of the difference between methyl and ethyl groups is furnished by para - phenetol - carbamide, C2H50 . C6H4. NH. CO . NH2 (Dulcin), which is two hundred times sweeter than sugar, whilst the corresponding methyl derivative, CH30 . C6H4—NH—CO—NH2, is tasteless. The entrance of a phenyl group often produces a marked change in the physiological action of a compound, but the effect varies greatly in different cases, and no general rule can be given. Effect of Hydroxyl Groups.—The entrance of an hydroxyl group into aliphatic compounds usually produces a weakening of their physiological activity, and this weakening effect is roughly proportional to the number of the hydroxyl groups. For example, the narcotic and poisonous alcohols give rise to the inactive glycols, glycerol, mannitol, etc., and from the very active aldehydes are obtained the less active aldols, such as /OH CH8— CH\ XCH2. CHO, and by the entry of more hydroxyl groups, the totally inactive aldoses (glucose, etc., CH2. OH(CH . OH)4. CHO). A similar effect is often produced in many other compounds, for example, caffeine, the physiological effect being lost in hydroxy-caffeine. In the aromatic compounds, the entrance of an hydroxyl group usually causes an increase in both the physiological effect and the toxicity. The entrance of an hydroxyl group in benzene