L- -3-phenyl-2 propanone

Compare electrostatic potential maps of enolates derived from 2-butanone, 4,4-dimethyl-2-pentanone, 4,4,4-trifluoro-2-butanone and l-phenyl-2-propanone with those of acetone. Which substituents cause significant changes in the electronic structure of these enolates and what are the nature of these changes Justify your answers by making drawings of any important resonance contributors. 

For preparative purposes fermenting baker s yeast (Saccharomyces cerevisiae) is commonly used instead of a purified enzyme preparation. However, isolated pyruvate decarboxylates can also be used30. In this context, the most important substrate is benzaldehyde31 which is converted by n-glucosc fermenting yeast to (7 )-l-hydroxy-l-phenyl-2-propanone. This conversion has gained considerable industrial importance because ( )-l-hydroxy-1-phenyl-2-propanonc is an important precursor for the synthesis of (-)-cphedrin. 

The acidifying effect of an adjacent phenyl group outweighs steric effects in the case of l-phenyl-2-propanone, and as a result the conjugated enolate is favored by both kinetic and thermodynamic conditions (Entry 5). 

Figure 4.2 Enzyme-hi-membrane-reactor synthesis of 1-pheny 1-2-propanol from l-phenyl-2-propanone applying a stirred-tank reactor, ultrafiltration module, extraction module and distillation...

With regard to other key chemicals used in the illicit manufacture of amphetamine-type stimulants, such as 3,4-methylenedioxyphenyl-2-propanone (3,4-MDP-2-P), l-phenyl-2-propanone (P-2-P) and safrole, it has been noted that no country reported any exports of 3,4-MDP-2-P for 2003. Several European countries, including Belgium, France and Germany,... 

Japan A -acetylanthranilic acid, ephedrine, ergometrine, ergotamine, isosafrole, lysergic acid, 3,4-methylenedioxyphenyl-2-propanone, l-phenyl-2-propanone, piperonal, pseudoephedrine and safrole 17 December 1999... 

A series of five-membered heterocycles with two and three heteroatoms were synthesized. 4-Hydroxyisothiazoles 57 were prepared from a-amino ketones with sulfur monochloride (1968BCJ959). Polar solvents, especially N,Af-dimethylfor-mamide, were preferable (Scheme 28). In a similar reaction of 1-amino-l-phenyl-2-propanone with sulfur monochloride 5-chlorinated isothiazole 58 was obtained in high yield. 

The second example was the pyruvate decarboxylase catalyzed formation of (ll )-l-hydroxy-l-phenyl-2-propanone (PAC) with benzaldehyde as substrate (Fig. 5 a) [64]. This second reaction shows one potential limitation of this method. Some compounds are too volatile for direct measurement by MALDl mass spectrometry or they do not ionize directly due to their nonpolar character. In this case, these compounds have to be derivatized prior to their measurement in order to reduce their volatihty and to introduce ionizable functions. This is, however, often very easy using well estabhshed quantitative reactions, e.g., formation of oximes from aldehydes and sugars (Fig. 5b). 

P-2-P or l-phenyl-2-propanone, also known as BMK, is typically used for the manufacture of amphetamine, but can be also used for methamphetamine phenyl acetic acid is a precursor for the production of P-2-P and thus a pre-precursor for the manufacture of amphetamine. 

The rearrangement of light and deuterium-labelled cis- and trans-2-methyl-3-phenyloxiranes (1, 2 and 1, 2 ) was studied on ZnO, Al-O-j and WO, and in the presence of BF,. Both in the gas phase (473-673 K) and in the liquid phase (298-413 K), l-phenyl-2-propanone (3) and 2-phenylpropanal (4) were formed with high selectivities (0-90% and 11-80%, respectively). Ring-opening was found to occur by selective fission of the benzyl C-0 bond. Mechanistic studies revealed the formation of an open carbenium ion or a double-bonded surface intermediate. The acidic (electrophilic) and basic characters of the oxides determine the product distributions by affecting the relative importance of the competing mechanisms. 

Fig. 2. Mechanism of BF-,-catalysed rearrangement of isomeric 2-methyl-3-phenyl-oxiranes to l-phenyl-2-propanone (3).

The BINAP-Ru complex effectively differentiates enantiomers of 1-hydroxy-l-phenyl-2-propanone. Hydrogenation of the racemic compounds catalyzed by an (R)-BINAP-Ru complex gives the corresponding IS,2R diol with a 92% optical purity and unreacted R substrate with 92% ee at 50.5% conversion (Scheme 1.45) [lc]. The relative hydrogenation rate of the enantiomers, k /kR, is calculated to be 64 1. 

Arylcarbonyl Compounds as Initiators for Unsaturated Polyester/ Styrene Copolymerization Systems. Gel Time Determination and Reaction Curves. Ten blanks (gel time of 20 grams Vestopal A without initiator) gave a mean deviation from the average of 3.3% and a maximum deviation of 7.2%. Five measurements with l-phenyl-2-propanone as initiator gave a mean deviation from the average of 3.3% and a maximum deviation of 7.7%. An experimental error of 10% was therefore assumed and proved correct by spot checks. The exceptions (not used in the discussions) are most probably caused by the insolubility of the initiators in the reaction medium. 

Phenylacetic acid is an immediate precursor of l-phenyl-2-propanone (P-2-P), a substance in Table I of the 1988 Convention that is used in the manufacture of amphetamine and methamphetamine. Concerned by the increase in seizures of phenylacetic acid and illicitly manufactured P-2-P, the Board instructed its advisory expert group2 to review the situation. The review, conducted in October 2006, found that the illicit manufacture of both amphetamine and methamphetamine appeared to be on the rise, posing a threat to public health and lying at the root of other social problems. The Board concluded that the controls required for the substances in Table II of the Convention were insufficient to prevent diversions of phenylacetic acid. On that basis and having assessed the relevant comments and supplementary information provided by Governments pursuant to article 12 of the Convention, the Board submitted a communication to the Secretary-General in January 2007 to formally initiate the procedures for the transfer of phenylacetic acid from Table II to Table I of the Convention. 

Reported quantities of less than 1 kg have been rounded up and are reflected as 1 kg. a 3,4-Methylenedioxyphenyl-2-propanone. b l-Phenyl-2-propanone. 

Acetic anhydride TV-Acetylanthranilic acid Ephedrine Ergometrine Ergotamine Isosafrole Lysergic acid 3,4-Methylenedioxyphenyl-2-propanone Norephedrine l-Phenyl-2-propanone Piperonal Potassium permanganate Pseudoephedrine Safrole Acetone Anthranilic acid Ethyl ether Eiydrochloric acid3 Methyl ethyl ketone Phenylacetic acid Piperidine Sulphuric acid3 Toluene... 

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