Bismuth iodide

A method for the estimation of the total alkaloids and of non-phenolic alkaloids (emetine fraction) is given in the British Pharmacopoeia, 1932, Addendum VI, which requires the drug to contain not less than 2 per cent, of alkaloids, of which at least 55 per cent, must be non-phenolic bases, calculated as emetine. The British Pharmacopoeia also gives an assay process for emetine in emetine bismuth iodide, the form in which the drug is chiefly used in medicine it is required to contain not less than 25 and not more than 28 per cent, of emetine. In the United States Pharmacopoeia, XIII, both Cephcelis Ipecacuanha and C. acuminata are recognised and must contain not less than 2 per cent, of ether-soluble alkaloids. 

HaO). Quinine salicylate, 2[B. CgH4(OH)(COOH)]. HaO, forms colourless needles, m.p. 187° (dec.), which slowly become pink in air. It is soluble in water (1 in 77 at 25°), alcohol (1 in 11 at 25°), or chloroform (1 in 37 at 25°). The foregoing are the most important quinine salts used in medicine, but many other salts have been used, e.g., the tannate, formate, valerate, ethylcarbonate, lactate, cacodylate, etc., as well as double salts such as quinine bismuth iodide. Descriptions of many of these salts will be found in the British Pharmaceutical Codex for 1934. 

Kurchi bark is principally used in India as a remedy for amoebic dysentery, and in recent years there has been a revival of medical interest in the drug in this eonneetion. It is generally used in the form of a bark extract but, in imitation of emetine bismuth iodide, kurchi bismuth iodide, consisting of the bismuth iodides of the mixed alkaloids of the bark, has also been used. On the pharmaceutical side Datta and Bal have studied the pharmacognosy of the bark and a method of alkaloidal assay has been devised by Schroff and Dhir, who have also described a process for the preparation of kurchi bismuth iodide, a product for which they, and also Mukherjee and Dutta, have provided methods of assay. 

Sandri (15) reported the formation of characteristic crystals with cadmium bromide-hydrobromic acid, bismuth iodide-potassium iodide, and bismuth bromide-hydrobromic acid, with compositions CdBr2 HBr CgHgN 4H 0, HBiI CgHoN, and HBiBr CgHgN, respectively. 

A technical process was developed by Lonza for the Ir-catalyzed hydrogenation of an intermediate of dextromethorphan (Fig. 34.9) which was carried out on a > 100-kg scale [70]. Important success factors were ligand fine tuning and the use of a biphasic system chemoselectivity with respect to C=C hydrogenation was high, but catalyst productivity rather low for an economical technical application. Satoh et al. reported up to 90% ee for the hydrogenation of an intermediate of the antibiotic levofloxacin using Ir-diphosphine complexes. Best results were obtained with bppm and a modified diop in the presence of bismuth iodide at low temperature [71]. 

MXj 6 2 One-third octahedral Bismuth iodide Bilj, FeClj, TiCls,... 

Ammino-bismuth Iodides.—Bismuth triodide absorbs ammonia gas on heating, forming a red crystalline mass of triammino-bismuth tri-iodide, [Bi(NH3)3]I3.6 From this, water abstracts ammonium iodide without change of colour of the substance. 

Pyridino-bismuth Iodide, [Bi(CsHsN)]I3, is formed by treating a eold mixture of bismuth trichloride in pyridine with potassium iodide, when the pyridino-iodide separates as a dark red powder.1 The substance is soluble in alcohol and in aqueous potassium iodide, and separates from a saturated solution in red needle-shaped crystals which decompose on heating. The corresponding quinoline derivative, [Bi(C9H7N)]I3, is also a red crystalline substance, and is produced by boiling quinolino-. bismuth chloride with an aqueous solution of potassium iodide. 

Ammino-derivatives of Arsenic Salts, Antimony Salts, Bismuth Salts—Pyridino-bismuth Iodide. 

Additional Exercises Copper oxide from copper (for combustion) bismuth iodide. 

In the determination of cesium, the coal sample and cesium carrier are digested, and the perchlorate separation and ferric hydroxide scavenging precipitation are made as in the procedure for rubidium. Cesium is then separated from the remaining solution by precipitation of cesium bismuth iodide. The final separation is made by precipitation of cesium chloroplatinate, which is counted with a Geiger counter for the 0.66 MeV /T decay of 134Cs (U = 2.1 yr), or counted for the 0.13 MeV y-ray associated with the isomeric transition of 134mCs (t% = 2.9 hr). 

Bismuth iodide prepared by precipitation with iodide from solutions of acidified bismuth salts (No. 76, II) must be purified by sublimation, preferably in C02 or N2. 

When diluted with water, the above reaction is reversed and black bismuth iodide is reprecipitated. Heating the precipitate with water, it turns orange, owing to the formation of bismuthyl iodide ... 

Indications. An orange, red-orange, or brown-orange precipitate suggests the presence of an alkaloidal base (precipitated as the alkaloidal bismuth iodide). Positive for primary, secondary, tertiary, and quaternary amines. This reagent is commonly used as a spray for detecting alkaloids on thin-layer chromatographic plates. 

Toxicity issues of hydrochloride, bismuth iodide complex,... 

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