Sulfur methyl bromide solutions

A solution of 95 parts of methyl bromide in 356 parts of ether was added portionwise to a refluxing suspension of 24 parts of magnesium in 214 parts of ether. The mixture was refluxed for 2 hours, and 92 parts of 4-methylacetophenone were added in the course of 90 minutes. The refluxing was continued for 3 hours, and the mixture was stirred for 24 hours at room temperature. The Grignard complex was destroyed by the addition of ammonium chloride and 10% hydrochloric acid. The mixture was extracted with ether and the ether extracts were washed with 10% sulfuric acid and then with water. Then extracts were dried over anhydrous calcium chloride, filtered, and concentrated in vacuum to remove the solvent. About 0.5 part of hydroquinone was added to the residue, which was then heated to a temperature of 100-110°C at 50 mm. The distillate was extracted with ether and the ether extracts were dried over anhydrous calcium chloride and filtered. A small quantity of hydroquinone was added to the ether. The solution was fractionated by distillation to yield 4-methyl-a-methylstyrene boiling at about 72-74°C at 80 mm. 

To a solution of 105.6 g of 2-phenylbutanone-3 in 110 ml ether was added dropwise a solution of methylmagnesium bromide (prepared from 19.4 g magnesium and 94.7 g methyl bromide in 400 ml of ether) for 60-90 min. Then the mixture was refluxed for 1 hour. After cooling to the mixture was added diluted sulfuric acid and then extracted with ether. Organic layer was dries with sodium sulfate. After evaporation of ether the 2-phenyl-3-methylbutanol was distilled, B.P. 116-118°C/20 mm, yield 105 g, nd22 1.5152. 

The manufacture of methyl bromide generally involves the reaction of hydrobromic acid with methanol. The acid is generated by adding sulfuric acid to a strong solution of sodium bromide and methanol in a reactor. The methyl bromide generated is distilled in a reflux column, which returns methanol and hydrobromic acid to the reactor for further reaction. The product is then dried by passing it through sulfuric acid before condensation, then further fractionated to remove impurities. [4]... 

A slow stream of purified and dried acetylene is passed for 3 hr through a solution containing 25 ml (75 mmoles) of a 3 TV solution of methyl magnesium bromide and 100 ml of anhydrous tetrahydrofuran. A solution consisting of 5 g (17 mmoles) of 3)5-hydroxyandrost-5-en-17-one and 50 ml of anhydrous tetrahydrofuran is then added and the mixture is boiled at reflux for 15 min, during which time a heavy precipitate forms. The reaction mixture is cooled and poured into 1 liter of water containing 20 ml of concentrated sulfuric acid. The crude product is obtained as a precipitate, which is filtered, washed with water and dried to yield 5.2 g of 17a-ethynylandrost-5-ene-3, 17 -diol mp 228-232°. One crystallization from chloroform-hexane yields 4.5 g (83%) mp 238-240° [[Pg.73]

Nitration of indolizines is seldom attempted in view of accompanying oxidation reactions. Thus the synthesis of 6- and 8-nitro-2-phenyl-indolizine has been achieved by the cyclization of appropriately substituted 2-methyl-1-phenacylpyridinium bromide.179 However, 1-nitro and 1,3-dinitro compounds have been prepared.4 From the behavior of the indolizine nucleus toward other electrophiles, 3-nitroindolizine might be expected to be the primary product. This compound has been synthesized using a dilute solution of nitric acid in acetic acid at - 70°C where the substrate could well be the base and not the 3-protonated cation as in a nitric acid-sulfuric acid mixture.180... 

Pyridinium salts can be reduced with the mildly nucleophilic dithionite ion to produce mixtures of di-hydropyridines. Much work has been carried out since the early observation that NADPH could be obtained from NADP with this reagent. Reduction produces mainly the 1,4-dihydro isomer with minor amounts of the 1,2- or 1,6-dihydro adducts. The reduction is believed to proceed via a stable and sometimes isolable sulfinate intermediate (91). In acid solution this decomposes with loss of sulfur dioxide to form the dihydropyridine (92 Scheme 19). Various substituted pyridinium species undergo this reaction and the Isomer ratio obtained is dependent upon the nature of the solvent, temperature and pH. With l-methyl-4-carbamoylpyridinium bromide (93) and dithionite in aqueous sodium carbonate at 0-5 C for 10 min the only isolated product was the 1,2,5,6-tetrahydropyridine (94) obtained in 16% yield, but the 3-carbamoyl salt gave the 1,4-dihydronicotinamlde (95) in 90% yield, free of the 1,6-isomer. The 3-chloropyridlnium ion (96) gave a moderate yield of the 1,4-dlhydropyridlne (97). 

Whereas interaction between 2-thienyllithium and 2-furyllithium and carbon disulfide in THF affords the corresponding dithioates RCSSLi as the predominant products, aryllithium compounds seem to attack mainly on sulfur with formation of arenethiolates and tarry products [9]. If during the addition of carbon disulfide copper bromide is present in the solution, however, the desired formation of Ar—CSSLi does take place and subsequent addition of methyl iodide affords the dithioesters in good yields. Good results are also obtained when using less than stoichiometric amounts of CuBr. We therefore presume that carbon disulfide reacts more easily with the arylcopper intermediate than with aryllithium copper is subsequently transmitted from the copper dithioate to aryllithium. 

Naphthoic acid Methyl 1-naphthyl ketone is dissolved in glacial acetic acid (5-10 parts) and treated with the calculated amount of bromine in the cold. The mixture is warmed gently on a water-bath and then poured into water containing a little sulfur dioxide the precipitated crystals of bromomethyl 1-naphthyl ketone are filtered off and pressed on porous plate they are then treated with an excess of pyridine and, when reaction has set in, the mixture is heated for a short time on the water-bath, after which the whole is dissolved in alcohol and the l-(l-naphthoylmethyl)pyridinium bromide is precipitated by ether. If recrystallized from water (10 parts), this salt melts at 170°. For hydrolysis, the bromide (0.5 g) is dissolved in water (40 g) and ethanol (12 ml), 10% sodium hydroxide solution (2 ml) is added, and the whole is heated for 12 min on a water-bath. Acidification then precipitates the 1-naphthoic acid. 

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