3- Oxohexanoic acid

It is well known that bakers yeast is capable of reducing a wide range of ketones to optically active secondary alcohols. A recent example involves the preparation of the (R)-alcohol (7) (97 % ee) (a key intermediate to ( norephedrine) from the corresponding ketone in 79 % yield1281. Other less well-known organisms are capable of performing similar tasks for instance, reduction of 5-oxohexanoic acid with Yamadazyma farinosa furnishes (R)-5-hydroxyhexanoic acid in 98 % yield and 97 % ee[29]. 

A stirred solution of 13.0 g (100 mmol) of 5-oxohexanoic acid and 17.5 g of (1, S. 2.S )-2-amino-1-phcnyl-1,3-propanediol is heated under reflux in benzene for 16 h with azeotropic removal of water. The solution is concentrated and the residue is dissolved in 600 mL of diethyl ether. The solution is washed with sat. aq NH4C1, water, sat. aq Na2C03 and brine before drying over MgS04 and concentration in vacuo to give a colorless oil yield 24 g (96%) 84 14 2 mixture of isomers (the major isomers are diastereomers while the minor isomer is a regioisomer). Rccrystallization from ethyl acetate/hexane furnishes colorless needles yield 15.7g(60%) mp98-99°C [ ]D +13.3 (c = 1.1, ethanol). 

The synthesis of all four optical isomers of 4,6-dimethyltetrahydropyranone has been achieved from 3-methyl-5-oxohexanoic acid (74JOC3890). 

Oxohexanoic acid was purchased from Aldrich Chemical Company, Inc. and was used without further purification. 

To reach chiral cyclohexanones, we have found that the bicyclic lactam 10, derived from 5-oxohexanoic acid and the commercially available amino diol, gave excellent results. A number of examples were obtained (Table I).8... 

The (S)-enzyme (relative molecular mass 48000 -50000) reduced 3-oxoacid esters, 4-oxo and 5-oxoacids and esters enantioselectively to (S)-hydroxy compounds. The K -values for ethyl 3-oxobutanoate, ethyl 3-oxohexanoate, 4-oxopentanoic acid and 5-oxohexanoic acid were determined as 0.9 mM, 5.3 mM, 17.1 mM and 13.1 mM, respectively. 

C7H1203 4-methyl-5-oxohexanoic acid 6818-07-1 462.84 40.325 2 11602 C7H13CI02 ethyl 3-chloropentanoate 6513-13-9 462.15 40.260 1,2... 

In some cases intermediates could also be isolated. - Wolf and Dufiy treated 2-amino-5-chloro-A -morpholinobenzamide with 5-oxohexanoic acid in toluene and isolated the tetrahydroquinazolinone 80, which then was cyclized in a mixture of o-dichlorobenzene and xylene to the pyrido[l,2-a]quinazoline 81. 

Eukuzumi, T., H. Kaneko, and H. Takahara Isolation of a (-)-2-isopropyl-5-oxohexanoic acid from Turkish tobacco leaves and absolute configuration of solanone Agr. Biol. Chem. 31 (1967) 607. 

Michael addition of (149) to the activated double bond of an arylidenemalonitrile gave (150) <88PHA533, 90JCR(S)148>. When 5-oxohexanoic acid was treated with (151) in ethanol at room temperature the expected thiadiazole was not formed, but instead spontaneous cyclization occurred to yield (152) <86JCS(P1)1499, 89H(29)133>. 

Diazo compounds (natural). Various types of D. c. occur in nature. Thus, derivatives of diazoacetic acid ( azaserine) and diazoketones ( 2-amino-6-diazo-5-oxohexanoic acid) are known as metabolic products of streptomycetes with anti-tumor activity. Quinonedi-azide ( 4-diazo-2,5-cyclohexadien-1 -one) and phenyl-diazonium salts [ 4-(hydroxymethyl)benzenediazo-nium ion] have been detected in the ffuitbodies of the mushroom genus Agaricus. Further biologically active... 

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