Ethyl acetate, acetylation with

Sodium hydroxyalkanesulfonates may be determined in the presence of an unsaturated hydrocarbon, including sodium alkenesulfonate. The sulfonates are converted to the free sulfonic acids using a slight excess of 2,4-dinitrobenzene-sulfonic acid. The hydroxyl group of the sulfonic acid liberated is acetylated in ethyl acetate solution by a known excess of acetic anhydride. The unconsumed anhydride is hydrolyzed by a pyridine-water mixture and the acids titrated potentiometrically with standard sodium hydroxide solution. The hydroxy-alkanesulfonate content is calculated after correction for any traces of acidity or alkalinity in the original sample. 

Synthetic Method 1 6-(dimethylamino)-3-(N-acetyl-N-methylamino)-10-acetylphenothiazine 8a (procedure from US. Patent 4,652,643).5 A mixture of 9.0g of 6-(dimethylamino)-3-(methylamino)phenothiazin-5-ium chloride (Azure B), 150.0ml of acetic anhydride, and lO.Og of zinc dust was maintained at reflux temperature for approximately 4 hs. After the reaction mixture was cooled to ambient temperature, it was poured into ice water with stirring and 300ml of toluene was added. After stirring for approximately 30 min the toluene layer was separated and washed twice, once with tap water and once with saturated aqueous sodium chloride solution. The toluene was then distilled off at reduced pressure. The residue which remained was dissolved in ethyl acetate and separated into various components by subjecting the solution to column chromatography using silica gel as substrate. Elution with ethyl acetate yielded a white-colored solid. 

Selective de-esterification of octa-O-acetylsucrose with alumina has been reported.43,44 A solution of octa-O-acetylsucrose in chloroform was placed on a column of silica gel (Laporte Type H) and allowed to stay in contact therewith for 44 h. The column was then eluted with ethyl acetate, to afford 2,3,4,6,l, 3, 4 -hepta-0-acetyl-sucrose18 (22), 2,3,6,l, 3, 4, 6 -hepta-0-acetylsucrose45 (21), and 2,3,4,6,l, 3, 6 -hepta-0-acetylsucrose in yields of 9, 2.7, and 6%, respectively.44... 

Acetylacetone has been prepared by the reaction of acetyl chloride with aluminum chloride followed by hydrolysis,3 and by the condensation of acetone with ethyl acetate under the influence of sodium,4 sodamide,5 and sodium ethoxide,5-6-7 and by the reaction of acetone and acetic anhydride in the presence of boron trifluoride.8... 

The dibasic side chain at position 7 can be alternatively provided by a substituted amino alkyl pyrrolidine. Preparation of that diamine in chiral form starts with the extension of the ester function in pyrrolidone (46-1) by aldol condensation with ethyl acetate (46-2). Acid hydrolysis of the (3-ketoester leads to the free acid that then decarboxylates to form an acetyl group (46-3). The carbonyl group is next converted to an amine by sequential reaction with hydroxylamine to form the oxime, followed by catalytic hydrogenation. The desired isomer (46-4) is then separated... 

The step 3 product (1.81 mmol) was dissolved in 20 ml tetrahydrofuran (THF) and then treated with triethylamine (2.17 mmol) and acetyl chloride (2.17 mmol) at 10°C and then stirred at ambient temperature and poured into water. The mixture was extracted with ethyl acetate, and then washed with saturated NaHCO and brine and then dried with MgS04 and concentrated. The residue was washed with CH2CI2 and then methyl-f-butylether and 0.70 g of product isolated. 

A solution of 4 (110 mg, 0.26 mmol) in a mixture of dichloromethane (25 mL) and methanol (8 mL), cooled to —78°C, was ozonized until the solution turned blue (about 4 min). Excess ozone was removed by a stream of nitrogen, the solution was allowed to attain room temperature and was concentrated to dryness. The crude product was dissolved in THF (10 mL) and a borane-THF complex (1.04 mL of a -M solution) was added at room temperature under nitrogen. After 24 h the reaction mixture was treated with diluted hydrochloric acid (5 mL) and the solution was extracted with ethyl acetate (4x15 mL). The combined extracts were dried (MgS04) and concentrated to dryness. The residue was dissolved in dichloromethane (20 mL) and acetylated with acetic anhydride (62 p,L, 0.66 mmol), triethylamine (200 p,L, 1.50 mmol), and a crystal of DMAP, under nitrogen atmosphere. After 12 h the reaction mixture was concentrated under diminished pressure, and the crude product was purified on a silica gel column with hexane-ethyl acetate (3 1) to give 5 (73 mg, 65%) mp 103°-105°C (after crystallization from hexane), [a]D — 26.6° (c 0.7, CHC13). 

To a solution of the a-anomer 4 (0.76 g, 3.3 mmol) in THF ( 5 mL), cooled to 0°C, a solution of sodium borohydride (60 mg) in water (1.5 mL) was added. After 40 min the product was extracted with ethyl acetate (3 X 10 mL), and the same volume of benzene was added to the combined extracts. The solution was filtered, and the filtrate was concentrated to dryness. The residue was chromatographed on a silica gel column with light petroleum-ether-methanol (6 4 0.5). The first eluted product was the ribo-stereoisomer 6 (383 mg, 50%) 4-0-acetyl derivative 7 (Ac20, C5H3N, DMAP) [a]D + 107° (c 1.1, MeOH). 

Acetylation. Primary alcohols are converted into acetates when stirred efficiently with ethyl acetate at 25-75° in the presence of Woelm-200-N alumina. Yields are generally high, even for unsaturated alcohols or chlorohydrins. This reaction is possible even in the presence of secondary alcohols.3,4... 

The filtrate was brought to pH = 1.8 with 10% hydrochloric acid. The ether layer was separated and the aqueous layer washed with ethyl acetate (3x2 L). The combined organic layers were washed with 5% KHS04 (3x1 L), water (3 x 1 L) and brine (1 L), dried over magnesium sulfate and concentrated in vacuo to yield 398.9 g of crude [R,lS,4S]-4-Cyclohexyl-l-[[[2-methyl-l-(l-oxopropoxy)propoxy](4-phenylbutyl)phosphinyl]acetyl]-L-proline, monosodium salt (isomer B). The crude product was dissolved in acetone (4393 ml), treated with a solution of 2-ethyl hexanoic acid, sodium salt (117.3 g) in acetone (1468 ml), then stirred at room temperature overnight. The resultant precipitate was collected by filtration, washed with acetone (3 x 400 ml) and hexane (1 L) then dried in vacuo. Yield 277 g, m.p. 195-196°C, [a]D= -5.1° (MeOH, c = 2), HI = 99.8%. Isomer "A" was not detectable. 

A solution of 6-acetylcodeine (10.0 g, 29.3 mmol), 1-chloroethyl chloroformate (5.51 g, 37.8 mmol), and proton sponge (1.0 g) in methylene chloride (80 ml) was heated at reflux for 80 min. The reaction mixture was evaporated in vacuo to dryness. The residue was chromatographed on silica gel with ethyl acetate to give 6-acetyl-17-(l-chloroethoxycarbonyl)norcodeine as an oil (12.13 g), which was dissolved in methanol with a few drops of cone. HCI. The solution was heated at reflux for 1 hr and evaporated in vacuo to almost dryness. The residue was added hexane and filtered to give 6-acetylnorcodeine hydrochloride (10.7 g, 100% yield). 

To a suspension of the 3-[(dimethylamino)acetyl]-N-methyl-lH-indole-5-methanesulphonamide (46.5 mg) in 1-propanol (5 ml) was added sodium borohydride (62 mg). The reaction mixture was brought to reflux for a period of 3 h, then an additional quantity of borohydride (60 mg) was added. After refluxing for a further 1 h, the mixture was allowed to cool to room temperature and quenched with 2 N HCI (10 ml). The aqueous solution was washed with ethyl acetate (5 ml) then neutralized (NaHC03 solution) and extracted with ethyl acetate (3 x 15 ml). The combined extracts were concentrated in vacuo and the residue chromatographed to give the 3-[2-(dimethylamino)ethyl]-N-methyl lH-indole-5-methanesulphonamide as a gum (2 mg) which was shown by TLC. 

The method described is that of Hampton, Harris, and Hauser2 and is an improvement over the earlier procedures 4 of Hauser and co-workers, which employed potassium amide. 2,4-Nonanedione has been prepared by the condensation of ethyl caproate with acetone in the presence of sodium hydride (54-80%), 5,6 and by the acylation of ethyl acetoacetate followed by cleavage and decarboxylation (51%).7 Other preparations include the acetylation of 2-heptanone with ethyl acetate and... 

The reaction mixture contained enzyme, 0.20 M Tris-HCl (pH 7.8) to give a final volume of 180 /xL, 9.5 /xL of 1.0 mM chloramphenicol, and 10 /xL of 10 mAf acetyl-CoA. After incubation for an hour at 37°C, 300 /xL of cold ethyl acetate was added to stop the reaction. The aqueous and ethyl acetate phases were separated by centrifugation. The aqueous phase was extracted two more times with ethyl acetate, and the combined ethyl acetate fractions were dried in a fume hood for 16 hours. The residues were redissolved in... 

The above vinylogous ester (46.7 g, 0.24 mol) is combined with acetamidine acetate (28.6 g, 0.24 mol) and anhydrous sodium acetate (19.8g, 0.24 mol) in 1,4-dioxane (11), and heated at reflux (60 h). After cooling, the solid is removed by filtration, and the dioxane solution is concentrated in vacuo to an oily solid which is dissolved in water (200 ml), and adjusted to pH 10 with concentrated sodium bicarbonate solution. The solution is decolorized with activated charcoal and concentrated under reduced pressure to give a solid. This is slurried in chloroform, and the solid is removed by filtration. The organic solution is concentrated to produce a heavy oil. Trituration with ethyl acetate gives (10) (R =Me) (12.44 g, 42%) as a yellow solid, m.p. 127-128°C. Similarly prepared are 4-acetyl-2-hydroxymethyl- (12%) and 4-acetyl-2-(4 -pyridyl)imidazoles (39%). 

A mixture of 3-chloro-4,4-dimethoxy-2-butanone (3.33 g, 20 mmol), benzami-dine hydrochloride (4.70 g, 30 mmol) and sodium acetate (4.10g, 50 mmol) is refluxed (42h) in dioxane (100 ml). After cooling, the salts are removed by filtration and the filtrate concentrated to an oil under reduced pressure. This oil is taken up in ethyl acetate (100 ml) and extracted with IM HQ (3 X 20 ml). The combined aqueous extracts are washed with ethyl acetate, and carefully basified with solid sodium carbonate. The aqueous solution is extracted with chloroform (3 x 20 ml), and the combined extracts are dried (MgS04), filtered and concentrated, to give the cmde product (3.23 g), which can be recrystallized from cyclohexane/toluene as fine yellow needles (2.33 g, 60%), m.p. 155-157°C. Similarly prepared are 4-acetyl-2-methyl- (46%) and 4-acetyl-2-hexylimidazoles (26%). 

To start our investigations, we examined the conversion of 2,3-dimethyl-2-butene (1) into 3,3,4-trimethyl-4-penten-2-one (2) as a model reaction (eq. 1). The choice of acetic anhydride as the acetylating agent was made in the light of related studies on the acylation of aryl ethers. Our work in this field had shown that acetic anhydride was the most effective reagent for the Friedel-Crafts acylation of anisole in the presence of Hp zeolite. A lower degree of conversion was achieved with acetyl chloride, while hardly any reaction occurred with ethyl acetate or acetic acid [6]. 

For the synthesis of sulfobacin A (158) and flavocristamide A (160), TBS ether of (f )-3-hydroxy-15-methylhexadecanoic acid was necessary, which was synthesized from 10-bromo-l -decanol (A) as shown in Figure 6.20. Chain elongation of A under the Schlosser conditions gave B, which was oxidized with PCC to give aldehyde C. ( )- 3-Hydroxy ester D was prepared from C by treatment with ethyl acetate and LDA. The corresponding ( )-acid was acetylated with vinyl acetate in the presence of lipase PS to give enantiomerically pure (R)-hydroxy acid and the acetylated (S )-acid. The former was converted to its TBS ether E. 

The susceptibility of the allylic ester group in tri-O-acetyl-D-glucal to hydrogenolysis in the presence of various catalysts has been carefully studied. Platinum catalysts (with ethyl acetate as the solvent) mainly caused direct additions (85%) to the double bond, whereas the incorporation of small proportions of dimethylamine promoted hydrogenolysis, so that 4,6-di-0-acetyl-l,5-anhydro-2,3-dideoxy-D-en/fJiro-hexitol was obtained in 95% yield. In the absence of added base, palladium catalysts would be expected to afford uncomplicated addition.38... 

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