Methyl phenyl ketone Acetophenone

Methyl phenyl ketone (acetophenone) 3,5,5-Trimethyl)-2-cyclohexen-l-one (isophorone) O S-CH3... 

Scheme 9.9. A representation of the pathway for the reaction of methyl phenyl ketone (acetophenone) with sodium hypochlorite (NaOCl) in aqueous base to produce chloroform (CHCI3) and benzenecarboxylic acid (benzoic acid). An example of the halofonn reaction.

Methyl phenyl ketone (acetophenone, C6H5COCH3) can be reduced to 1-phenylethanol [C6HsCH(OH)CH3], Equation 9.14, under the same conditions (in ethanol, CH3CH2OH, solvent) in 2.5 h. However, with a platinum (Pt) catalyst in ethanoic acid (acetic acid, CH3CO2H), the reduction of methyl phenyl ketone (acetophenone, C6H5COCH3) is very fast and most of the product is phenylethane, hydrogenolysis having occured (Equation 9.15). 

Interestingly, laboratory results that also occur with high enantioselectivity can be achieved by using a chiral catalyst. As shown in Scheme 9.21, phenylethanone (methyl phenyl ketone, acetophenone, C6H5COCH3) on treatment with borane... 

Scheme 9.21. A representation of the reduction of phenylethanone (methyl phenyl ketone, acetophenone, CeHsCOCHa) to (f j-l-phenylethanol with borane (BH3) in oxacyclopentane (tetrahydrofuran, THF) with an (.S j-oxazaborohdine. (See Corey, E. J. Bakshi, R. K. Tetrahedron Lett., 1990, 611, and Rao, A. V. R. Guijar, M. K. Shamma, P. A. Kaiwar, V.

Interestingly, if ammonium chloride (NH4" Cr) is used in the presence of methanal (formaldehyde, H2CO), the iminium ion thus formed (H2C=NH2" C1 ), lacking a-protons and thus incapable of forming an enamine, is nonetheless capable of condensing a- to the carbonyl of ketones that do have a-protons. The two-step process apparently occurs via the enol of the a-proton-bearing carbonyl component adding to the carbon of the iminium ion to eventually produce a primary amine. This is the Mannich reaction. The process is sketched in Scheme 9.89 for methyl phenyl ketone (acetophenone, CeHsCOCHs). 

Scheme 9.89. The Mannich reaction. The reaction between methanal (formaldehyde, H2CO) and ammonium chloride (NH4 Cr) prodnces the corresponding iminium ion (H2C=NH2 CT), which cannot form an enamine (it is lacking a-protons). The iminium ion is capable of condensing a- to the carbonyl (shown occnrring via the enol) of methyl phenyl ketone (acetophenone, C6H5COCH3). (See Mannich, C Schnmann, P. Chem. Ben, 1936, 69, 2299, and Schreiber, 1 Maag, H. Hashimoto, N. Eschenmoser, A. Angew. Chem. Int. Ed., 1971,10,330.)...

TTie true ketones, in which the >CO group is in the side chain, the most common examples being acetophenone or methyl phenyl ketone, C HjCOCH, and benzophenone or diphenyl ketone, C HjCOC(Hj. These ketones are usually prepared by a modification of the Friedel-Crafts reaction, an aromatic hydrocarbon being treated with an acyl chloride (either aliphatic or aromatic) in the presence of aluminium chloride. Thus benzene reacts with acetyl chloride... 

Acetophenone. Acetophenone [98-86-2] (methyl phenyl ketone) is a colorless Hquid that forms laminar crystals at low temperature (mp 20°C). It has a characteristic sweet orange blossom odor, and is soluble in alcohols and ethers. It is found in nature in oil of casatoreum, obtained from beavers oil of labdanum, recovered from plants and in buds of balsam poplar. It can be prepared by the Friedel-Crafts reaction (qv) of acetyl chloride with benzene in the presence of aluminum chloride however, this route is of Htde commercial significance. 

Acetophenone Methyl phenyl ketone 1.34 CgHgO Hydrogen bromide 226 HBr... 

Acetophenone FEMA No. 2009 Acetylbenzene Methyl Phenyl Ketone 120.15/C8H8O/ O II U practically colorless liq above 20°/ very sweet, pungent vs—most fixed oils, prop glycol s—ale, chloroform, ether ss—water ins—gly/ 202° 1 mL in 5 ml - 50% ale... 

Chemical Name acetophenone, methyl phenyl ketone... 

Acetophenone benzoyl hydride methyl-phenyl ketone ch3coc6h5 120.15 If. 1.03315415 20.5 202.3 i. s. S. 

D.89) (D.89) 1 -Ethanone, 1 -phenyl-, acetophenone, methyl phenyl ketone, acetylbenzene, hypnone... 

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