4- Oxopentanoic acid

For example, 3-isopropyl-7a-methyl-5-oxo-perhydropyrrolo[2,l-A]oxazole 244 formed by condensation of (A)-vali-nol 243 and 2-(2,3-dimethoxy-5-methylphenyl)-4-oxopentanoic acid 242 in toluene was the key intermediate in the total synthesis of (-)-mastigophorene B 245 (Scheme 35) <1999JA2762>. 

Chemical/Physical. Gaseous products formed from the reaction of cyclohexene with ozone were (% yield) formic acid (12), carbon monoxide (18), carbon dioxide (42), ethylene (1), and valeraldehyde (17) (Hatakeyama et al., 1987). In a smog chamber experiment conducted in the dark at 25 °C, cyclohexane reacted with ozone. The following products and their respective molar yields were oxalic acid (6.16%), malonic acid (6.88%), succinic acid (0.63%), glutaric acid (5.89%), adipic acid (2.20%), 4-hydroxybutanal (2.60%), hydroxypentanoic acid (1.02%), hydroxyglutaric acid (2.33%), hydroxyadipic acid (1.19%), 4-oxobutanoic acid (6.90%), 4-oxopentanoic acid (4.52%), 6-oxohexanoic acid (4.16%), 1,4-butandial (0.53%), 1,5-pentanedial (0.44%), 1,6-hexanedial (1.64%), and pentanal (17.05%). 

Two of the more unusual bromoacids include the bromo-oxoacids 3,3-dibromo-4-oxopentanoic acid and 3-bromo-3-chloro-4-oxopentanoic acid. So far, there are no quantitative data on these other brominated acids, but preliminary toxicity data indicate that they may be toxicologically important. 

Similarly, with the same type of photocatalyst (Pt/TiC>2 or Fe2C>3) the decomposition of levulinic (4-oxopentanoic) acid in oxygen-free aqueous solution has been investigated in detail (60). In addition to the decarboxylation reaction, oxidative C-C scissions led to propionic and acetic acids (further converted into methane and ethane) and reductive cleavages to acetone and ethanal. The formation of acetone was apparently favoured by higher Pt contents (however product distributions referred to equal illumination durations and not to equal conversions). It was suggested that the variety of products resulted from the presence of two functional groups in levulinic acid. The quantum yield was probably of the order of 5 x IQ-3. 

An interesting aspect of the Bi-mediated Barbier-type allylation is that the reaction can be conducted in aqueous media. When the reaction is carried out using metallic bismuth powder in water, addition of an equimolar amount of potassium fluoride improves the yield of homoallyl alcohol (Equation (40)).74 The reaction is also compatible with hydroxyl and carboxyl groups of the carbonyl substrates. When succinaldehydic acid, 4-oxopentanoic acid,... 

Fructose, or a fructose-containing polysaccharide, can be transformed into HMF by aqueous sulfuric acid at 150 °C via a number of isomerization and dehydration steps [185]. Presumably, such a procedure was at the basis of the pi-lot-scale production of HMF by Siidzucker (Germany) [186]. Major problems are the competing rehydration of HMF into levulinic acid (4-oxopentanoic acid, LA, see Fig. 8.35) and the formation of polymeric side-products, which necessitate chromatographic purification. Yields have stayed modest (approx. 60%), in consequence. 

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. 

No loss of carbon monoxide occurs in the reaction of 3- and 4-oxocarboxylic acids. By variation of the reaction conditions, 4-oxopentanoic acid (24) can provide different products.116... 

The cerium(IV) oxidation of lactyllactic acid" and of 4-oxopentanoic acid in aqueous nitric acid solutions shows first-order dependence of the reaction on both cerium(IV) and substrate. A 1 1 complex formation between manganese(III) and amine, which later decomposes in the rate-limiting step, best explains the kinetics of oxidation of aliphatic amines by cerium(IV) in nitric acid medium in the presence of manganese(II). The kinetics of oxidation of naphthalene, 2-methylnaphthalene, and a-naphthol with cerium(IV) in perchloric acid solutions have been studied. Use of a 50-fold molar excess of cerium(IV) perchlorate results in complete oxidation of fiuorophenols to CO2, HCO2H, and HF in 48h at 50 °C. ... 

C6H10O3 3-methyl-4-oxopentanoic acid 6628-79-1 17.00 1.0932 1 8174 C6H11N04 L-glutamic acid 5-methyl ester 1499-55-4 25.00 1.1410 2... 

C7H10N2O3 2,2-dimethyl-4-methoxycarbonyi-2H-imidazole- 38000-94- 25.00 1.2276 2 11505 C7H1203 2,2-dimethyl-4-oxopentanoic acid 470-49-5 22.00 1.0239 2... 

C6H10O3 2-methyl-4-oxopentanoic acid 6641-83-4 459.55 40.012 2 7993 C6H11Br02 ethyl 2-bromobutanoate 533-68-6 450.15 39.116 ... 

Ethyl levulinate (4-oxopentanoic acid ethyl ester)... 

The reaction of 2-(benzylamino)benzamide and 4-oxopentanoic acid at 160°C gave the hexahydropyrrolo[2,l-i>]quinazoline-l,9-dione 226. ... 

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