2-acetyl-5-chlorophenyl

Acetyl-5-chlorophenyl Methyl Tellurium1 To a well-stirred solution of 9.17 g (50 mmol) of 4-chloro-/V,/V-dimethylbenzamide in 50 ml dry tetrahydrofuran at 0° is added dropwise a solution containing 55 mmol methyl lithium. The stirred mixture is kept at 0° for 2h. Then a solution of 8.7 g (11.3 m/, 75 mmol) of 1,2-bis[JV,JV-dimethylamino]ethane in 20 ml dry tetrahydrofuran is added. 47 ml of a 1.6 molar solution of butyl lithium (75 mmol) in hexane are added dropwise. The mixture is kept at 0° overnight and then a solution of 14.3 g (50 mmol) of dimethyl ditcllurium in 20 ml of dry tetrahydrofuran is added. The mixture is stirred for 6 h and then hydrolyzed and worked up in the usual way yield 30% m.p. 117 (hexane). 

Also obtained (by-product) by nitration of 2-acetyl-5-chlorophenyl acetate in sulfuric add solution at -10° (24%) [1784]. 

The nucleophilic reactivity of the oxygen has been observed in acetylation by acetic anhydride of 2-aryl- and 2-heteroaryl-A-2-thiazoline-4-ones (181) (388, 397, 410, 414, 416, 419, 422, 426. 427) and methylation of 5-(4 -chlorophenyl)-A-2-thiazoline-4-one (416) (Scheme 94). 

The research group of Backvall employed the Shvo s ruthenium complex (1) [21] for the racemization. This complex is activated by heat. For the KR they used p-chlorophenyl acetate as the acyl donor in combination with thermostable enzymes, such as CALB [20] (Figure 4.7). This was the first practical chemoenzymatic DKR affording acetylated sec-alcohols in high yields and excellent enantioselectivities. In the best case 100% conversion (92% isolated yield) with 99% ee was obtained. This method was subsequently applied to a variety of different substrates and it is employed (with a different ruthenium complex) by the Dutch company DSM for the large-scale production of (R)-phenylethanol [22]. 

Absolute configurations were ascribed on the basis of an empirical model by analogy to l-hydroxyaUcanephosphonates. They are opposite to those obtained from the NMR spectra of the Mosher s esters of 2-hydroxyalkanephosphonates (entries 4-6) and whose absolute configuration is known. / -Chlorophenyl acetate was used as the acetylating agent. 

The Helferich-Wedemeyer procedure may give mixtures of the anomers, depending on the nature of the aglycon. For example, condensation of bromide 128 with N-(benzyloxycarbonyl)-L-threonine penta-chlorophenyl ester (171) gave both N-(benzyloxycarbonyl)-3-0-(2,3,4,6-tetra-O-acetyl-a- and -/J-D-glucopyranosyl)-L-threonine pen-tachlorophenyl ester135 (172 and 173, respectively), but only the fi-D... 

Ru complex 46 [333b,334]. 4-Chlorophenyl acetate is a suitable acetyl donor because the produced 4-chlorophenol does not interfere with the catalytic racemization. 

Preparation of intermediate 4-(4-chlorophenyl)cyclohexane-l-carboxylic acid was needed at first. It was made as follows acetyl chloride (30 g), aluminium chloride (60 g) in carbon disulfide (120 ml) were stirred at -50°C. Cyclohexen (30 g) previously cooled to -50°C was added dropwise during 10 minutes and the mixture was stirred for 60 minutes at -50°C. The solvent was decanted and 300 ml chlorobenzene was added, the so-obtained solution heated at 40°C for 3 hours with stirring, poured onto a mixture of ice and concentrated hydrochloric acid and the organic layer washed with 2 M HCI, 2 M NaOH and water, dried over anhydrous Na2S04. The product was distilled in vacuo, the fraction boiling at 140°-154°C (0.1 mm Hg) collected, diluted with an equal volume of petroleum ether, cooled to -6°C and a stream of nitrogen gas bubbled through. 

To 9.5 g of 3-acetyl-2,5-hexanedione in 50 ml of benzene, 7.7 g of p-chloroaniline are added and the mixture is refluxed for 5 h with azeotropic removal of the water formed. The excess solvent is evaporated and residue is vacuum stripped 12.0 g (yield 80%) of l-p-chlorophenyl-2,5-dimethyl-3-acetylpyrrole as an orange oil which rapidly crystallizes are thus obtained, boiling point 144°-146°C. Melting point of it 80°-81°C (recrystallization from hexane). 

Into a 3-necked spherical flask of 1 L provided with a dropping funnel, a condenser surmounted by a calcium chloride tube and a mechanical stirrer, is introduced a suspension of 17.6 g (0.2 mol) of ethyl urea in 150 ml of anhydrous benzene. There is added through the dropping funnel in 20 minutes a solution of 18.9 g (0.1 mol) a-chlorophenyl-acetyl chloride in 300 ml of benzene. The mixture is left at ambient temperature for 15 minutes and is then heated under reflux on the water bath with stirring for 5 hours. The benzene solution is decanted at elevated temperature in order to separate it from an oil deposited on the bottom of the flask, the benzene is driven off on the water bath, the last traces removed in vacuum, the crystalline residue is triturated in a mortar in about 200 ml of water, and the crystalline solid is separated off and is with water and dried in vacuum over phosphorus pentoxide. There are thus recovered 19.6 g (yield 82%) of l-(2-chloro-2-phenyl-acetyl)-3-ethyl-urea, which when recrystallized from 80 ml of benzene, takes the form of white crystals soluble in benzene but insoluble in water. The product has melting point 146°C. 

C2,)H42ClN,0(,SSi2 1496)81-75-4) see Cladribine 2-[(4 chlorophenyl)acetyl]bcnzoic acid (C 5H, CI07 53242-76-5) see Azelastine a-chiorophenylacetyl chloride... 

Another Step 5 analogue, 9-[(4-chlorophenyl)acetyl]-1,4,7,8,9,lO-hexahydro-6-nitropyrido[(3,4-f]quinoxaline-2,3-dione, (II), has also been prepared and is discussed (3). 

CHLOROPHENYL)AMINO)-4,5-DIHYDRO-2H-BENZ(G)INDAZOL-2-YL)ACETYL)MORPHOLINE... 

N-(((4-CHLOROPHENYL)AMINO)CARBON iT)-2,fi-DIFLUOROBENZAMIDE see CJV250 4-((3-((4-CHLOROPHENYL)ANnNO)-4,5-DIHYDRO-2H-BENZ(G)INDAZOL-2-YL)ACETYL)MORPHOLINE see CJR210... 

C- or C-labelled pyridazine drugs or active compounds were prepared. Syntheses of 4-acetyl-5,6-bis(4-chlorophenyl)-2-(2-hydroxy-ethyl)-3(2// )-py ridazinone (81MI4), N-(2,5-dimethyl-1 //-pyrrol-1 -yl)-... 

C9H803 2-acetyl benzoic acid 577-56-0 500.48 43.931 2 16303 C9H9CI02 3-(2-chlorophenyl)propanoic acid 1643-28-3 491.59 43.076 2... 

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