Preliminary Crystallographic Investigations of 5,6-Dimethylbenzimidazolylcobamide Coenzyme

摘要: After the isolation of crystalline, 5,6-dimethylbenzimidazolylcobamide coenzyme by Barker et al. (l), a comparison its crystallographic properties with those vitamin Blz appeared desirable. This communication gives brief description so far determined. Crystals were obtained from Dr. H. A. Barker. They prepared crystalli5ation 87.5% (volume per volume) aqueous acetone at 4”. The crystals washed successively 90 7’ acetone, 100% and ethyl ether. Residual ether was removed stream dry air stored in tightly stoppered vial - 10” until used. contained 8% solvent, presumably water, that could be drying 56” for 2 hours vacuum over silica gel. Part this solvent may have been lost during manipulation individual crystals. used these studies showed forms characteristic orthorhombic system. occurred as flattened diamond-shaped six faces; largest dimension about 0.5 mm (Fig. 1). Two large pinacoid faces had developed normal to axis1 four prism parallel axis. It noted numerous cracks on crystal which resulted mosaic appearance reflected light rendered goniometric measurements uncertain. two interfacial angles, calculated x-ray data, 75”24’ 104”36’.