Dimethyl ester of sulfuric acid

With phenols, NaOH is a strong enough base and dimethyl sulfate, the dimethyl ester of sulfuric acid, is often used as the electrophile. These variations do not affect the mechanism. As long as we have a good nucleophile (here reactive RO-), a methyl electrophile, and a good leaving group (here an iodide or a sulfate anion), the S>j2 mechanism will work well. 

DIMETHYL ESTER of SULFURIC ACID (77-78-1) Combustible liquid (flash point 182°F/83°C). Violent reaction with strong oxidizers, strong acids, strong alkalis, ammonia, ammonium hydroxide, barium chlorite, sodium azide. Incompatible with strong ammonia solutions. Attacks some plastics, rubber, and coatings. 

SYNONYMS dimethyl ester of sulfuric acid, dimethyl monosulfate, DMS, methyl sul-... 

Synonyms/Trade Names Dimethyl ester of sulfuric acid. Dimethylsulfate, Methyl sulfate... 

Definition Dimethyl ester of sulfuric acid Empirical C2H6O4S Formula (CH3)2S04... 

Similar results are obtained when benzoyl chloride and pyridine are used. When P-d-mannopyranose (38) reacts with dimethyl sulfate (Me2S04), the product is the pentaether, 84 (methyl tetra-O-methyl-p-d-mannopyranoside). Dimethyl sulfate is the dimethyl ester of sulfuric acid (see Chapter 20, Section 20.12), and it is a common reagent for converting an OH unit to an OMe unit. The suffix ide is used rather than ose for the ether. If 38 is treated with methanol and an acidic catalyst, the product is the monoether, methyl P-d-glucopyranoside (84). 

Scheme 8.30. One possible pathway for the formation of dimethyl sulfate (the dimethyl ester of sulfuric acid) by the reaction of sulfuryl chloride (SO2CI2) with methanol (CH3OH) in the...

Selected properties of dimethyl and diethyl esters of sulfuric acid are listed in Table 2. 

Reaction of carboxylate ion with nitrophenyl sulfites gives the carboxylate -nitrophenyl esters. If the -nitrophenyl sulfite is unsymmethcal (02NCgH40S(0)0R, where R is ethyl or phenyl), carboxylate attacks the -nitrophenyl side (69). Some amino acids react with methyl and benzyl sulfites in the presence of -toluenesulfonic acid to give methyl and benzyl esters of the amino acids as -toluenesulfonate salts (70). With alcohols, the conversion of henzil to a monoacetal upon addition of sulfuric acid to the henzil in methanol and dimethyl sulfite proceeds in high yield (71). 

To a mixture of 360 g 50% KOH and 138 ml methanol, add with stirring at -5° 70.5 g dimethyl ester of acetone dicarboxylic acid (dimethyl-beta-ketoglutarate — see method 3 for preparation) and let temperature rise to about 25° over V2 hour. Let stand ten minutes, cool to 0° and add 65 ml ether. Filter, wash precipitate with 65 ml ethanol and 150 ml ether at 0C to get 75 g (III). To 322 ml 1N HCI at 80c, add 41.1 g (I I) and stir twenty minutes cool to 10°, add 211 ml IN HCI, 98.2 g (Ml). 26.4 g Na acetate and 28.2 g methylamine HCI. Stir four hours at room temperature, cool to 10°, and saturate with 410 g KOH. Extract four times with methyl-Cl or benzene (75 ml each, fifteen minutes stirring) and evaporate in vacuum to get the methyl ester of tropan-3-one-2-COOH (IV), which precipitates from the oil (can distill 85/0,2). Test for activity. Dissolve 28.3 g (IV) in 170 ml 10% sulfuric acid cool to -5° and treat with 3.63 kg 1.5% Na-Hg amalgam with vigorous stirring at 0°. See below for easier methods of reducing (IV),... 

A stereocontrolled synthesis of the side-chain acid 186 of isoharringtonine from (R,R)-(-l-)-tartaric acid was reported by Zhang etal. (63) (Scheme 30). Dimethyl (2R, 3i )-tartrate acetonide (182) was allylated in the presence of lithium diisopropylamide to give 183, which underwent base-catalyzed epimerization to 184. Catalytic hydrogenation, followed by hydrolysis and by treatment with methanol in the presence of sulfuric acid, yielded the half ester 185, which was treated with aqueous trifluoroacetic acid to provide the side-chain acid of isoharringtonine (186) with the appropriate stereochemistry. 

An obvious question is how could such a group participate in electron-transfer or coupling reactions A few experimental observations for the terminal i.e., C12--C13) double bonds may be relevant to this question. This terminal bond undergoes certain addition reactions much more readily than do either of the two inner double bonds. For example, in dilute solutions of sulfuric acid in methanol, a dimethyl ester, dimethyl ether derivative (Figure 18) can be prepared without evidence of other products with methoxy groups at C5 or C9. We were surprised to find that as a consequence of this addition reaction at C13, a shift of 3 nm... 

When malonate 9 is treated with polyphosphoric acid at room temperature, formation of lactone 11 is observed, similar to the Darzens procedure with the use of sulfuric acid. The structure of lactone is being retained during subsequent hydrolysis and decarboxylation of the exocyclic ester group followed up treatment with anhydrous hydrogen fluoride gives dimethyl tetrahydronaphthalene carboxylic acid 12. Hydrolysis and decarboxylation of 10 under standard conditions gives the same product 12. ... 

Mercaptans add to olefins in good yields according to Markovnikoff s rule in the presence of sulfuric acid, boron trifluoride, or sulfur and also in an anti-Markovnikoff fashion in the presence of peroxides or via photochemical means. Vinyl chloride and allyl alcohol give lower yields than conjugated olehnic ketones, aldehydes, esters, and cyanides. Cupric acetate or triethylamine can be used as a catalyst for the reaction of methyl mercaptan with acrolein to give p-mercaptopropionaldehyde in 84% yield. Allene reacts homolytically with methanethiol to give allyl sulfide and the 1,3- and 1,2-dimethyl-thiopropanes. 

The most convenient laboratory method for the preparation of 2,4-dimethyl-5-carbethoxypyrrole is that given above. A cheaper method of obtaining large quantities consists in the partial hydrolysis of 2,4-dimethyl-3,5-dicarbethoxypyrrole with sulfuric acid, followed by decarboxylation. The ester has been obtained also by the alcoholysis of 5-trichloroaceto-2,4-dimethyl-pyrrole in the presence of sodium ethylate. The free acid has been obtained fronii-[2,4-dimethylpyrrole-5]-2,4-dimethylpyrrole-5-carboxylic acid and from 2,4-dimethylpyrrole-5-aldehyde. ... 

Meerwein s Ester (9) Dimethyl malonate (13.2 g, 0.4 mole) and 6 g of 40 % aqueous formaldehyde solution are mixed in an Erlenmeyer flask and cooled to 0° in an ice bath. To the mixture is added 0.3 g of piperidine and enough ethanol to produce a homogeneous solution. The solution is allowed to stand at 0° for 12 hours, at room temperature for 24 hours, and at 35 0° for 48 hours. The reaction product is washed with water (50 ml) followed by dilute sulfuric acid, then dried (sodium sulfate). Unreacted malonic ester is distilled off under vacuum leaving a residue of about 12.5 g, which contains methylenemalonic ester, methylenebismalonic ester, and hexacarbomethoxypentane. 

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