2-acetylphenyl ethyl

Rivastigmine co-TA Paracoccus denitrificans) 3-Acetylphenyl ethyl(methyl)carbamate+L-alanine AS [39]... 

At = Ph) or ethyl 3-(4-acetylphenyl)prop-2-ynoate 150 (Ar = 4-MeCOCeH4) in ethanol (81PHA471) (Scheme 40). The synthesis of derivatives 156c,d from ethyl 3-phenylprop-2-ynoate 150 (R = Ph)and l-hydrazino-4-phenylphthalazine 155 (R = Bz) or 1 -hydrazino-4-benzyl Aithalazine 155 (R = Bz) woriced equally well in methanol at room temperature for 72 h or in refluxing methanol for 1 h (91PHA105). 

An important feature of the present reaction is the chemoselective addition of activated nitriles to the CN triple bonds of nitriles in the presence of carbonyl groups, because of the strong coordination ability of nitriles toward metals. The iridium-catalyzed addition of ethyl cyanoacetate to 4-acetylbenzonitrile (30) gives ethyl (Z)-3-(4-acetylphenyl)-3-amino-2-cyano-2-propenoate (31, 59%) chemoselec-tively, while the same reaction promoted by a conventional base such as AcONH4 and NaOH gives ethyl 2-cyano-3-(4-cyanophenyl)-2-butenoate (32) ( Z= 55 45) [20]. 

To a suspension of KF (0.19 g,2.0 mmol) in DMI (10 ml) was added difluoro(ethyl) (4-methylphenyl)silane (0.56 g, 3.0 mmol) under 1 atm of carbon monoxide (balloon). After stirring at room temperature for 10 min, the reaction mixture was heated at 100 °C for 3 h. Bulk of the solvent and the catalyst were removed by passing the mixture through a silica gel column with ethyl acetate-hexane = 1 10 as an eluent solvent. Evaporation of the solvent under reduced pressure afforded 4-acetylphenyl 4-methylphenyl ketone (0.43 g, 91% yield) as a colorless solid. 

Acetylphenyl trifluoromethanesulfonate (308.4 mg, 1.15 mmol), tripheny-larsine (28.2 mg, 0.0920 mmol), Pd2(dba)3 (10.5 mg, 0.0230 mmol Pd), and lithium chloride (146 mg, 3.44 mmol) were placed in a dry flask and stirred in anhydrous degassed NMP (5 cm ) for 10 min. Phenyltributyltin (0.450 cm, 1.38 mmol) was then added neat by syringe, and the solution was stirred at rt for 70 h. Addition of aqueous potassium fluoride solution (1 mol dm , 2 cm ), with stirring for 30 min, and dilution with ethyl acetate was followed by filtration. The filtrate was extensively washed with water, dried, and evaporated. Flash chromatography (silica, 10% ethyl acetate in hexane) gave 4-phenylacetophenone as a white solid (185 mg, 82%). 

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