Methanolic hydrogen chloride

The reaction of N-methyl-(p-dimethylamino)thiobenzamide (99) with a number of a-haloketones and a-bromoheptaldehyde gave stable 4-hydroxythiazolinium salts (100), which could be subsequently dehydrated by methanolic hydrogen chloride to the thiazolium salts (101), (Scheme 44) (622). 

There is a scattered body of data in the literature on ordinary photochemical reactions in the pyrimidine and quinazoline series in most cases the mechanisms are unclear. For example, UV irradiation of 4-aminopyrimidine-5-carbonitrile (109 R=H) in methanolic hydrogen chloride gives the 2,6-dimethyl derivative (109 R = Me) in good yield the 5-aminomethyl analogue is made similarly (68T5861). Another random example is the irradiation of 4,6-diphenylpyrimidine 1-oxide in methanol to give 2-methoxy-4,6-diphenyl-pyrimidine, probably by addition of methanol to an intermediate oxaziridine (110) followed by dehydration (76JCS(P1)1202). 

Although it is seldom used, esterification of pyrimidinecarboxylic acids proceeds normally. Conditions are illustrated by the conversion of pyrimidine-4-carboxylic acid (181 R = H) into its methyl ester (181 R = Me) by methanol/sulfuric acid (47%), methanol/hydrogen chloride (80%), or by diazomethane (ca. 100%) (60MI21300). The isomeric methyl pyrimidine-2-carboxylate is formed by treatment of the silver salt of the acid with methyl iodide. Higher esters, e.g. (182 R = Bu), are usually made by warming the acid (182 R = H) with the appropriate alcohol and sulfuric acid (60JOC1950). 

The chemical consequences of /3-protonation are illustrated further by the ring-opening reactions of furans with methanolic hydrogen chloride and of (V-substituted pyrroles with hydroxylamine hydrochloride (Scheme 11) (82CC800). 

The 2,4,6-trimethylbenzyl ester has been prepared from an amino acid and the benzyl chloride (Et3N, DMF, 25°, 12 h, 60-80% yield) it is cleaved by acidic hydrolysis (CF COOH, 25°, 60 min, 60-90% yield 2 N HBr/HOAc, 25°, 60 min, 80-95% yield) and by hydrogenolysis. It is stable to methanolic hydrogen chloride used to remove A-o-nitrophenylsulfenyl groups or triphenylmethyl esters. ... 

The Mattox Rearrangement Cortisone acetate (10 g) is suspended in dry methanolic hydrogen chloride (400 ml, 0.52 N). After 10 min of agitation the material dissolves completely to give a yellow solution which is then kept at 25° for 48 hr. Sodium acetate (22 g) in water (60 ml) is added and the solvent removed in vacuo to a volume of 75 ml. Water (100 ml) is added, and... 

In the first of these, the key step in the synthetic sequence involves an oxidative phenol coupling reaction patterned after the biosynthesis of the natural product. Preparation of the moiety that is to become the aromatic ring starts by methyla-tion of phloroglucinol (5) with methanolic hydrogen chloride to give the dimethyl ether (6). Treatment of that intermediate with sulfuryl chloride introduces the chlorine atom needed in the final product (7). 

The pharmacological versatility of this general substitution strategy is further illustrated by diazonium coupling of 14 with 2-nitrobenzenediazonium chloride to produce biarylal-dehyde 18. Formation of the oxime with hydroxylamine is followed by dehydration to the nitrile. Reaction with anhydrous methanolic hydrogen chloride leads to imino ether and addition-elimination of ammonia leads to the antidepressant amid-ine, nitrafudam (20). ... 

The treatment of kasugamycin hydrochloride with saturated methanolic hydrogen chloride gave a C9-amine (3) and d-inositol. The C9-amine (3) has a molecular formula of C9H1704N3. 

Oxidation of berberine (15) with potassium ferricyanide followed by treatment with sodium hydroxide afforded oxybisberberine (130) (30%), the structure of which is still unknown (Scheme 27). The product was treated with 10% methanolic hydrogen chloride to give 8-methoxyberberinephenolbetaine (131) (93%) and 15 (77%) (88,89). Alternatively, irradiation of 15 in methanol in the presence of sodium hydroxide and Rose Bengal in a stream of oxygen gave the tetramethoxyketone 132 (59%), which was aromatized to 131 (99%) by removal of methanol on heating in methanol (90,91). 

Cleavage of a hydroxyl group of 139 occurred in methanolic hydrogen chloride to give the imminium salt 140 (Scheme 28). Evaporation of the solvent generated O-methylprechilenine (117) in 96% yield. The imminium salt... 

The diketo acids were transformed to their methyl esters under the action of diazomethane (5), SOCl2/CH3OH (102), or methanolic hydrogen chloride (117). Like other benzils, JV-methyloxohydrasteine (109) when... 

Harle and Lyons isolated a mixture of dl and meso hydrodimers from the electrochemical reduction of coumarin (146) at pH 6.8 14t Archer and Grim-shaw, on the other hand, isolated a single diastereomer in high yield upon electrolytic reduction of 3-phenylcoumarin (147) in methanolic hydrogen chloride 141), Interpretation of the difference between the behavior of 146 and 147... 

Levi, Hawkins and Hibbert6 have recently confirmed the structure for L. mesenteroides dextran proposed by Fowler, Buckland, Brauns and Hibbert.34 Completely methylated dextran in an over-all yield of 71% was obtained by three methylations with dimethyl sulfate and sodium hydroxide, followed by six modified Muskat methylations. The methylated dextran was hydrolyzed at 140° with methanolic hydrogen chloride, and the mixture of methylated glucosides, obtained in 95% yield, was quantitatively separated by fractional distillation. 2,3-Di-methyl-D-glucose was identified by means of the phenylhydrazide of the corresponding D-gluconic acid. 

De Stevens and Nord (111) have reacted bagasse native lignin with diazomethane and with methanolic hydrogen chloride and have obtained similar results (Table 9). 

In about 1936, sialic acid was discovered by Blix, who found it to be a component of submaxillary-gland proteins, and who described many of its properties. However, little notice was taken of this work at the time it was published. In 1941, Klenk, who was working on glycolipids of the brain, described a compound, later shown to be a methyl glycoside of sialic acid, that had been obtained by treatment of a lipid fraction with 5% methanolic hydrogen chloride at 105°. In 1954, Klenk and Faillard reported the first isolation of pure N-acetyl-neuraminic acid from animal sources. 

Methanol-hydrogen chloride reaction, 16 320, 321, 322-323 Methanol-methyl ethyl ketone azeotrope, 8 818... 

C]gulono- 1,4-lactone. The hydroxyl groups at C-2 and -3 were protected by isopropylidenation, and the 5,6-glycol was oxidized by sodium periodate. Treatment of the resulting syrupy product with methanolic hydrogen chloride, followed by borohydride reduction and hydrolysis, afforded L-[5-,4C]arabinose. 

The composition of lipopolysaccharides (LPS) of bacterial origin have been investigated in two studies. Both studies used 2 M methanolic hydrogen chloride for 16-24 hours at 85°. The method allows analysis of... 

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