1- Hydroxy*2-propanone

D.39) 2-Propanone, 1-hydroxy-, l-hydroxypropan-2-one, hydroxyacetone, acetyl carbinol,... 

F.19) 2-Propanone, l-(acetyloxy)-, 2-oxopropyl acetate, l-acetoxy-2-propanone, 1-hydroxy-2-propanone acetate, acetylmethyl acetate, acetol acetate, O-acetylacetol, acetoxyacetone 1592-20-1]... 

In this thiamine pyrophosphate-mediated process, ben2aldehyde (29), added to fermenting yeast, reacts with acetaldehyde (qv) (30), generated from glucose by the biocatalyst, to yield (R)-l-phen5l-l-hydroxy-2-propanone (31). The en2ymatically induced chiral center of (31) helps in the asymmetric reductive (chemical) condensation with methylamine to yield (lR,23)-ephedrine [299-42-3] (32). Substituted ben2aldehyde derivatives react in the same manner (80). 

Chemically, wood tar is a complex mixture that contains at least 200 individual compounds, among which the foUowing have been isolated (1) 2-methoxyphenol, 2-methoxy-4-ethylphenol, 5-meth5i-2-methoxyphenol, 2,6-x5ienol, butyric acid, crotonic acid, 1-hydroxy-2-propanone, butyrolactone, 2-methyl-3-hydroxy-4JT-pyran-4-one, 2-methyl-2-propenal, methyl ethyl ketone, methyl isopropyl ketone, methyl furyl ketone, and 2-hydroxy-3-methyl-2-cyclopenten-l-one. 

These extracts are then combined with the organic solvent layer and the combined organic phase is extracted four times with 100 ml portions of water. It Is then stirred for an hour with 230 ml of 10% sodium bisulfite solution. The organic solvent phase is then separated, washed seven times with 100 ml portions of water and dried over magnesium sulfate. Evaporation of the solvent gives 1-(4-hydroxy-3-methoxyphenyl)-2-propanone in the form of an oil. 

Chemical Name (R)-3-[(2-hydroxy-1-methyl-2-phenylethyl)amino] -1-(3-methoxyphenyl)-1-propanone... 

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. 

CN 1 -[4-(3-hydroxy phenyl)-1 -methyl-4-piperidinyl]-l -propanone hydrochloride... 

CN l-[2-[2-hydroxy-3-(propylamino)propoxy]phenyl]-3-phenyl-l-propanone hydrochloride... 

The scope of the reaction was considerably enlarged in 1935, when Clutterbuck and Reuter6 observed that the compound tetrahydroterrein, derived from the mold metabolite terrein, consumes more than the calculated amount of periodate per mole. They found that 1,2-diketones and a-hydroxy ketones are also oxidized under the conditions used by Malaprade. Although this type of oxidation had been earlier noted [in a study7 of the action of periodate on 1,3-dihydroxy-2-propanone (dihydroxyace-tone)], Clutterbuck and Reuter made a more thorough exploration of the reaction.6 In a series of model compounds, Ri and R2 were varied from... 

The reaction of ethyl acetoacetate with simple hydroxy ketones has been compared with the corresponding reactions of the ketoses. The results obtained with l-hydroxy-2-propanone and 3-hydroxy-2-butanone, under the same experimental conditions as with D-fructose, establish a parallel between these reactions. However, as in the case of the aldoses, the yield is greater for these simpler hydroxy ketones than for the ketoses.9 The resultant esters, (XV and XVI), were obtained in the form of sirups, but the free acids, (XVII and XVIII), and their phenacyl esters are crystalline. The acids were shown to be identical with those of known structure described in the literature.9... 

A mixture of 4.5 g. of 1-hydroxy-2-propanone, 80 ml. of ethyl acetoacetate, 60 ml of 96% ethyl alcohol, and 4 g. of anhydrous zinc chloride is heated under reflux on a steam bath for half an hour. After cooling, it is poured into water and extracted with benzene. The extract is washed successively with a bisulfite solution (twice), dilute aqueous sodium hydroxide, and dilute hydrochloric acid, and is dried over anhydrous sodium sulfate. The benzene is evaporated, giving 4 g. of an almost colorless oil which is saponified by heating with 5 g. of sodium hydroxide in 20 ml. of 96% alcohol for half an hour on a steam bath. Part of the alcohol is evaporated, water is added, and the solution is extracted twice with ether. The aqueous layer is acidified (to Congo Red) with hydrochloric acid (1 1). The resulting solid is removed by filtration and recrystallized from 180 ml. of water yield, about 3 g. It may be purified by steam distillation, affording colorless crystals m. p., 120-122°. 

Later, Patterson and Hibbert (S3) stated that ultraviolet absorption of lignin corresponded with the absorptions of hydroxy derivatives of 4-(4,hydroxy-3,methoxyphenyl)-l-propanone and l-(4,hydroxy-3, 5,dimethoxyphenyl)-4-propanone. These authors, therefore, assumed the presence in lignin of a carbonyl group, or of an ethylenic double bond conjugated with an aromatic nucleus. They ascribed the 280 mp band to m-position freedom in the benzene ring and the 310 mp baud to a masked carbonyl group in conjugation with a benzene nucleus. 

Photoinitiators. Photoinitiators used include Darocur 1173 and Darocur 4265 which are 2-hydroxy-2-methyl-1-phenyl-1-propanone Irgacure 907, which is 2-methyl-1-... 

Both D-[l- C]xylose and D-[5- C]arabinose were exposed to a concentrated phosphate buffer solution (pH 6.7). 1-Hydroxy-2-propanone (ace-tol) was distilled from the heated solution. Radioassay indicated that similar labeling [3- C] occurred in the acetol from both pentoses, with loss of the configurational difference thus, a 3-ketopentose or its enediol was suggested as an intermediate. Further work with 3-0- and 6-0-methyl-D-glucose and with 1-0-methyl-D-fructose indicated that /3-elimination from a 3-ketose or, in the case of a hexose, from a 3-ketose or a 4-ketose, or both, tautomerization of the resulting a-diketone to a /3-diketone, and hydrolytic cleavage are essential steps in the formation of acetol. 

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). 

One method for the preparation of isoxsuprine is given in Scheme 1 [5]. A mixture of l-(4-hydroxyphenyl)-l,2-propandione (1), l-methyl-2-phenoxyethylamine (2), and elemental Pt catalyst in ethanol was hydrogenated to give the Schiff base intermediate (3). This was further reduced to afford a racemic mixture of 1-(4-hydroxyphenyl)-2-(l-methyl-2-phenoxyethylamino)propanol (6), m.p. 102.5-103.5°C. Compound (6) could also be obtained using an alternate route, where 1-(4-hydroxy-phenyl)- 1 -hydroxy-2-propanone (4) is reacted with compound (2), to yield... 

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