Hydroxy aldehydes malonic acid

Higher-molecular-weight normal 2-alkenoic acids have been prepared in poor yields by the Doebner condensation of aldehydes with malonic acid,5-7 and by the Reformatsky reaction of aldehydes with ethyl bromoacetate followed by dehydration.8 The a-iodo acid, prepared from the bromo acid, has been dehydrohalogenated with potassium hydroxide in ethanol,9 but large quantities of the a-hydroxy acid are formed as a by-product which is difficult to separate in some instances. The present procedure is an adaptation of a published method.6... 

Benzo[6]thiophene aldehydes have been condensed with a variety of active methylene compounds, including cyclic511, 644 and open-chain645-647 ketones, aliphatic aldehydes,90 benzyl cyanides,93-436 malononitrile,487 rhodanine,144,648 hippuric acid,477 barbituric acid,487 diethyl malonate,487 and malonic acid (Section VI,M). Aliphatic nitro compounds condense smoothly with most benzo[6]-thiophene aldehydes03,141,337,343, 556,640,650 (except 5-hydroxy- and... 

Since oxazolidines and oxazolidinones are fiindamental structural classes in organic chemistry (chiral auxiliaries) and in medicinal chemistry (e.g., Linezolid) and since they mask P-hydroxy-a-amino acids, which are widespread in various biologically active compounds and in natural products, the enantioselective synthesis of oxazolidinones is a challenging topic. Indeed, a new method for the direct synthesis of chiral 4-carboxyl oxazolidinones 168 by the catalytic asymmetric aldol reaction of isocyanato-malonate diesters 166 with aldehydes 167 in the presence of a thiourea catalyst (TUC) was developed. Since the resulting chiral 4-carboxy oxazolidinones are the equivalent of P-hydroxy-a-amino acids, this procedure... 

When an ester enolate reacts with an aldehyde or a ketone, the product is a hydroxy-ester. This disconnection is shown for both partners. If the reaction is turned around, the reaction of an enolate derived from an aldehyde or a ketone and then with an ester gives a keto-aldehyde or a diketone. Both disconnections are shown. The enolate alkylation reaction involves disconnection of an alkyl halide fragment from an aldehyde, ketone, or ester. In addition, the malonic acid and acetoacetic acid syntheses have unique disconnections. 

The acid moiety of an amino acid can be activated for acyl substitution rather than converted to an aldehyde for acyl addition. Boc-alanine was converted to an acyl imidazole by reaction with carbonyl diimidazole (CDI see chapter two, section 2.4), and then condensed with the magnesium enolate of the mono ethyl ester of malonic acid to give keto-ester 5.9. Subsequent catalytic hydrogenation of the ketone moiety gave ethyl 3-hydroxy-5-(N-Boc amino)penlanoate, 5.10 Once the o... 

The a>bromo carboxylic acid required for preparation of the a>alkoxy acid is often obtained by a malonic ester synthesis the malonic ester is treated with an alkyl halide, the alkylmalonic acid obtained by hydrolysis of the product is brominated by elemental bromine at a low temperature, and the resulting a>bromo dicarboxylic acid is decarboxylated.54 This has led to a particularly important synthesis of aldehydes which utilizes the decarbonylation of -hydroxy or a-alkoxy acids for conversion of an alkyl halide RX into the aldehyde RCHO containing one more carbon atom ... 

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