The structure of strychnine hydrobromide, CalHzaNaO,.HBr.2H,O, has been fully determined. The crystals are orthorhombic with space group P212121, and cell dimensions a=7.64, b=7.70, c = 33.20 A. The positions of the bromine atoms were found from Patterson projections. The general intensities were determined and a three-dimensional Fourier synthesis was calculated in which the F values were given the phases of the bromine atoms alone. Also the vector convergence diagram, lining the bromine positions, was obtained from the three-dimensional Patterson summation, and this was also employed to deduce the parameters of the complete structure. The structure possesses sheets of bromine atoms approximately at levels z = [ and ~ which axe linl~ed together by water molecules. Each bromine atom is bonded to a strychnine molecule through the basic nitrogen atom of each molecule. The strychnine molecule found has a configuration identical with that found by Bokhoven, Schoone & Bijvoet, and has the same structure as that now favoured by the organic chemists.
BOOK REVIEW oxygen indicated by red circles. Each compound occupies one page and data on over 250 compounds are contained in the atlas. Besides the crystallographic representation, each page contains the compound name, the molecular formula, a structural formula, and brief notes on the structural features and the pharmacological properties of the compound. Leading references to both the crystallographic and pharmacological literature are also cited. The range of compounds represented in this atlas include cholinergic agents, phenethylamines and catecholamines, H~-and Hz-receptor agonists and antagonists, opiates, antidiarrhoeals, hallucinogenics, anticonvulsants and hypnotics, anti-inflammatory agents and various miscellaneous medicinal chemicals. It excludes such drugs as steroids and antibiotics. On perusing this atlas-one does not read it-I was impressed by the beauty and simplicity of the drawings since many of the compounds represent a basic challenge to the synthetic organic chemist: what other ways can one combine atoms to hold the key functionalities in the correct orientation in space? Of course, such thoughts lead quickly to the realization that the biologically active conformation of a molecule need not be that found in the crystalline state. Nevertheless, this atlas will help the medicinal chemist to visualize more easily the three-dimensional character of the substances he deals with. The selection of compounds, which the authors declare was done very subjectively, contains examples of most of the more familiar compounds. This atlas will probably only reach the shelves of institutional libraries as a reference work. That it is necessary is a tribute to the advances made in the area of both medicinal chemistry and crystallography. It is hoped that the time will soon come when such information as is contained in this book is made available on visual computer-graphics systems !
A dry-heat oven with automatic, multiple-sample introduction and withdrawal has been constructed to achieve instantaneous heating and cooling of samples. The oven temperature fluctuation at set points of 170 to 2500C was ±0.10C, with temperature variation between the replicate samples of ±0.20C. Correction required for a sample come-up time was miniimal, i.e., less than 0.25 min of the dryheat destruction time.
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