Hydrogen iodide, anhydrous

Gaseous anhydrous hydrogen iodide can be prepared by the catalytic union of the elements and by the reaction of solid iodine with boiling tetrahydronaphthalene. The apparatus required for the direct combination of the elements requires considerable time to fabricate and, although 

The exit gas from the generator ice trap is dissolved directly in water. The hydrogen-ion concentration of the resulting solution is determined by titration with standard base, and the iodide-ion concentration by the precipitation of silver iodide. Only traces of tetrahydronaphthalene are detected by the very slight carbon-hydrogen bond-infrared absorption in the samples of the anhydrous gas prepared by this procedure. 

See also Cyclopentadienyl metal carbonyls and some derivatives, synthesis 31 

Sodium salts of carbonyl hydrides prepared in ethereal media, synthesis 53 

MnCCsHvOj) + 2NaCl + 2HC2H3O2 4Mn(C6H702)2 + KM11O4 + 7HC5H,02 + HC2Hs02-  

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Chervin, S M, Abada, P, Koreeda, M, Convenient, in situ generation of anhydrous hydrogen iodide for the preparation of a-glycosyl iodides and vicinal iodohydrins and for the catalysis of Ferrier... 

For the determination of the absolute configuration of the major diastereomer of silane (5,S)-3, the hydrogen iodide adduct (5,5)-3 HI was formed by reaction of the compound with anhydrous hydrogen iodide (solution in diethyl ether) at 0 °C. Colorless needles of (5,5)-3-HI were obtained as single crystals from CH2Cl2/n-pentane. 

Alkoxy and ester groups have been determined in polymers and co-polymers by the Ziesel procedure involving reaction with anhydrous hydrogen iodide at 100 C. 

Fluoropyridine. This isomer can be prepared in 54—81% yield by dia2oti2ation of 4-aminopyridine in anhydrous hydrogen fluoride (370,371,400). Eree 4-fluoropyridine readily undergoes self-quaterni2ation to give pyridyl pyridinium salts (401) stabili2ation can be effected as the hydrochloride salt (371,400). Numerous 4-fluoropyridinium salts, eg, 4-fluoro-l-methylpyridinium iodide, have been converted to novel penicillins (387,402). 

Hydrogen iodide (anhydrous) [10034-85-2] M 127.9, b -35.5°. After removal of free iodine from aqueous HI, the solution is frozen, then covered with P2O5 and allowed to melt under vacuum. The gas evolved is dried by passage through P2O5 on glass wool. It can be freed from iodine contamination by repeated fractional distillation at low temperatures. Fumes in moist air. HARMFUL VAPOURS. 

Impact causes a mixture of potassium and anhydrous hydrogen chloride to explode very violently [1], Molten potassium ignites in contact with hydrogen chloride, hydrogen bromide or hydrogen iodide [2],... 

The phosphonyl adduct 300 reacted with a dilute solution of anhydrous hydrogen chloride in ethanol or with sodium ethoxide to afford an essentially quantitative yield of the P-N cleaved product 304 with inversion of configuration. Addition of sodium ethoxide to a solution of 304 in methanol resulted in the formation of enantiomerically pure (+)-(.V)-ethyl methyl phenylphosphonate (305). It also reacted quantitatively with methylmagnesium iodide at room temperature to give the product of P-S bond cleavage 306, which upon acid catalyzed methanolysis afforded enantiomerically pure (+)-(R)- methyl methylphenylphosphinate (307) (Scheme 72) [108],... 

Silicon combines with halogens at elevated temperatures forming silicon tetrahalides. With chlorine, reaction occurs at 450°C forming silicon tetrachloride, SiCh. The tetrahalides also are obtained when sdicon is heated with anhydrous hydrogen chloride, bromide and iodide ... 

Orthophosphoric acid of 95% concentration is most efficient for effecting cleavage of tetrahydrofuran. Commercial orthophosphoric acid (85%) may be used however, the yield drops to 82% and approximately 10% of the tetrahydrofuran is recovered. Anhydrous orthophosphoric acid and tetraphosphoric acid cannot be employed conveniently because of the limited solubility of hydrogen iodide in these reagents. 

A synthetic study has revealed that the combination of anhydrous hydrogen chloride and zinc(II) chloride in the presence of a nucleophile, e.g. benzenethiol, promotes the ring cleavage of cyclobutanones such as bicyclo[3.2.0]heptan-6-one (28) to provide / -sulfanyl ketones such as 3-phenylsulfanylcycloheptanone (27).63 Alternatively, iodotrimethylsilane in the presence of either mercury/water or zinc(II) iodide also converts cyclobutanones to /i-iodo ketones 29.64 The synthetic applications of these transformations are summarized in Table 5. 

Phenylethyl Iodide. Use 146 g. (142 ml.) of (J-phenylethyl alcohol (b.p. 216 5-217°), 16 54 g. of purified red phosphorus and 154 g. of iodine. Lag the arm C (Fig.///, 40, 1) with asbestos cloth. Heat the alcohol - phosphorus mixture to boiling until sufficient alcohol (usually one-third to one-half of the total volume) passes into the reservoir B to dissolve all the iodine. Remove the flame and add the iodine solution at such a rate that the mixture boils gently. A little hydrogen iodide is evolved towards the end of the reaction. Allow the mixture to cool, add water and filter off the excess of phosphorus. Decolourise the filtrate with a little sodium bisulphite and add ether to assist in the separation of the water layer. Wash the ethereal solution with water, dry with anhydrous potassium carbonate, and distil under diminished pressure. B.p. 114 116°/12 mm. Yield 215 g. 

Rubber stoppers, as well as direct light, should be avoided in all operations with iodine and hydrogen iodide. This procedure and the one following may be used for the preparation of the anhydrous halogen acid using some modifications (see references). 

We wish to report that on treatment with a solution of sodium hydroxide in aqueous dioxan, (A) was converted by endocyclic P-0 cleavage into (C). Alkylation of (C) with methyl iodide followed by acetylation with acetic anhydride/pyridine resulted in (D), which reacted with a dilute solution of anhydrous hydrogen chloride in methanol to give R-(+)-ethyl 0,S-dimethyl phosphoro-thioate (E). Since both S-alkylation and O-acetylation involve no reaction at phosphorus, and available evidence suggests that under the conditions used acid catalysed P-N cleavage in N,N-dialkyl phosphoramidothioates occurs with inversion (6), the observed sequence (Scheme 2) implies that endocyclic P-0 cleavage occurs with retention of configuration at phosphorus. 

The preparation of pyridine compounds from a,o>-dinitrile systems has been studied by several workers. Johnson et al.101 found that 3-hydroxyglutaronitriles (128) or glutacononitriles (129) react readily with anhydrous hydrogen bromide or iodide to yield the 2-amino-6-halopyridines (130) as their salts, although in no case does hydrogen chloride cause cyclization to the expected 2-amino-6-chloropyridine. 

Ohle118 obtained 1-methyl-D-fructose by methylating 2,3 4,5-diiso-propylidene-D-fructopyranose and then hydrolyzing the resulting crystalline 1-methyl derivative. Brigl and Widmaier m have prepared 1-methyl-D-fructose from dibenzylidene-D-fructose. An alternative method is described by Brauns and Frush142 who hydrolyzed crystalline 1-methyl-D-fructosyl fluoride 3,4,5-triacetate, obtained by methylation with methyl iodide-silver oxide of crystalline D-fructosyl fluoride 3,4,5-triacetate, which results from the action of anhydrous hydrogen fluoride on D-fructose 1,3,4,5-tetraacetate. 

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