Hydrogen Chloride in Chloroform

The reaction of 1,2-dibenzoylethane with hydrogen sulfide and hydrogen chloride in chloroform, with zinc chloride as a catalyst, gives 2,5-diphenylthiophene in high yield and is claimed to be better than the classic P2S5 method. ... 

Normally, the hydrogenation of a readily hydrogenated double bond occurs over palladium-on-charcoal in ethanol at room temperature and atmospheric pressure. The more difficultly reduced olefins require elevated reaction temperatures and/or pressures for the reaction to proceed at a reasonable rate. The saturation of an 8(14)-double bond is virtually impossible under normal hydrogenation conditions. In order to remove unsaturation at this position it is necessary to first isomerize the double bond to the readily hydrogenated 14 position by treatment with dry hydrogen chloride in chloroform.30,135... 

The isomeric di-O-tritylcytidines 17b and 19b have been successfully oxidized by the Me2SO-DCC method to give, respectively, 1 -(2,5-di-0-trityl-/ -D-en/t/iro-pentofuranosyl-3-ulose)cytosine (18c) and l-(3,5-di-0-trityl-/ -D-erythro-pentofuranosyl-2-ulose)cytosine (20c). Treatment of 18a and 20a with anhydrous hydrogen chloride in chloroform at 0° afforded free N4-acetyl-3 - and -2 -ketocytidines, 18b and 20b, in good yields.25... 

It was also found that the phenyl-antimony bonds of (CH3) (C6H5)2Sb were cleaved selectively by dry hydrogen chloride in chloroform to give CH3SbCl2 (40). This cleavage reaction was successfully applied to the preparation of new ligands,11 bis(diorganostibino) methanes (41), as follows ... 

Dimethyl-J>arabinose (XXXVI) has been isolated from the products of hydrolysis of methylated araban94 and of methylated damson gum.97 It has been synthesized49 from methyl 5-trityl-L-arabofurano-sides (afi mixture) (XXXV) by methylation with methyl iodide and silver oxide followed by removal of the trityl group by means of hydrogen chloride in chloroform and hydrolysis of the methyl glycosides. ... 

The by-products which arose in the course of the Hilbert-Johnson reaction and were isolated either directly from the reaction mixture or after the usual work-up with alcoholic hydrogen chloride, hydrogen chloride in chloroform, or alcoholic ammonia might be divided into... 

As mentioned above, (7-aza-3-indolyl)acetonitrile (129) was reduced catalytically to give 7-azatr3rptamine (131). Other 7-azatryptamines prepared similarly are 1-methyl, 1-benzyl, 2-methyl, and l-(2-aminoethyl). This patent also describes several other 1-, 2-, and 3-(aminoalkyl) derivatives of the four azaindole isomers. The several 4-, 5-, 6-, and 7-azaindolylalkanonitriles were also treated with hydrolylamine to give amidoximes and with hydrogen chloride in chloroform, followed by ammonia to give amidines. ... 

Treatment of 9,ii dehydroergosterol (57) with hydrogen chloride in chloroform at room temperature leads to dehydration and rearrangement to give the so-called anthrasteroid (61) [iSs]. The reaction begins by acid-catalysed loss of the... 

Quantitative analysis is carried out in one of several ways depending on the solubility of the detritylated compound. If the latter is insoluble in an organic solvent which dissolves the trityl ether, a weighed sample of the ether (tritylcellulose, for example) is dissolved in a solvent such as chloroform, and a saturated solution of hydrogen chloride in chloroform is added. The solvent must be anhydrous and free of alcohol. The detritylated compoimd separates rapidly and is removed by filtration, washed with chloroform, dried and weighed. The combined chloroform solutions are then evaporated to dryness, and the weight of the trityl chloride residue is determined. 

Evans this behavior indicated the presence of acetylribosyl chloride. Since the isomeric n-arabinosyl-dihydroxyacetone tetraacetate of Kreider and Evans, which does not possess an orthoester structure, showed no reaction with hydrogen chloride in chloroform solution, it was concluded by Klingensmith and Evans that the behavior of the ribose derivatives is to be attributed to an orthoester structure. 

When heated with 0.1 hydrogen chloride in chloroform, the compound reacted rapidly in a manner characteristic of orthoesters. After... 

The acetylated neolactose methyl 1,2-orthoacetate was isolated in crystalline form when the original methanol solution was evaporated in air to a sirup and triturated with ethanol. After several recrystallizations the compound (XIV) had m. p. 121-122 and [a]n -t-25.3 . It showed the reactions and properties which characterize the sugar methyl orthoacetates, including stability of the orthoacetate group toward alkaline hydrolysis. When the new compound was treated with an anhydrous 0.1 V solution of hydrogen chloride in chloroform, it was converted into the crystalline heptaacetyl-a-neolactosyl chloride. Alkaline hydrolysis also indicated the presence of six acetyl groups, whereas dilute acid removed seven. 

In a second route4 to this ring system the a-diazoketone (7) was cyclized to the cyclopropane derivative (8). Cleavage of (8) with dry hydrogen chloride in chloroform gave the bridged-ring compound (9). Note that the bond in conjunction with... 

V solution of hydrogen chloride in chloroform, it was converted into the crystalline heptaacetyl-a-neolactosyl chloride. Alkaline hydrolysis also indicated the presence of six acetyl groups, whereas dilute acid removed seven. 

The proton NMR of the hydrogen dichloride ion has been studied in chloroform solution, and a limiting t value of -2,7 observed, relative to tetramethyl silane as 10,0. A similar value has been obtained in nitromethane solution. The concenuation dependence of the shift, in chloroform, is shown in fig. 2. The chemical shift for the dichloride ion is fat to low field of the values for hydrogen chloride in chloroform, and for liquid hydrogen chloride. We therefore conclude that the shielding of the proton is much reduced in the dichloride ion. 

An interesting reaction useful in testing for the orthoester structure is that which takes place with hydrogen chloride in chloroform. Under these conditions, the orthoester derivatives are converted to the normal 0-acetyl-glycosyl chlorides. 

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