Acylaminocarboxylic acids

Acylaminocarboxylic acids 288 are converted into 5(4//)-oxazolinones 289 by acid anhydrides (Scheme 140). In an extension of this reaction, A-acyl derivatives of glycine 290 react with aldehydes with concomitant cyclization to give azlactones 291 (Scheme 141) this is the basis of the Erlenmeyer synthesis of amino acids. Treatment of amino acid derivatives 292 with PBr3 affords the thiazolidine-2,5-dione 293 (Scheme 142) <1971CB3146>. 

The four component condensation (Ugi reaction) " converts a mixture of substituted amine, isonitrile, aldehyde (or ketone) and carboxylic acid (Scheme 6) to a-acylaminocarboxylic acid amides (pathway a), to diacylamines (pathway b) and to a-aminocarboxylic acid amides (pathway... 

Certain carboxylic acids, such as a-acylaminocarboxylic acids, or ketals of polyhydroxycarboxylic acids e.g. 1,2-3,4-diisopropylidene-D-galacturonic acid, can be esterified conveniently by simply heating their soln. in the respective alcohol under pressure at 180°, without use of a catalyst.—E A soln. of hippuric acid in methanol heated 10 hrs. at 180-185 under an initial pressure of 1000 lbs./sq.in./25° —y methyl hippurate. Y 82.5%. (F. e. s. H. Rinderknecht and C. Niemann, Am. Soc. 70, 2605 (1948) at atmospheric pressure s. W. J. Brehm and H. G. Lindwall, J. Org. Chem. 15, 685 (1950).)... 

Via intermediates Acetylenedicarhoxylic acid ester syntheses s. 3, 704 jd-Keto-o-acylaminocarboxylic acid esters and a-acylaminoketones from a-acylaminocarboxylic acids via oxazolones s. 4, 804 v.L -f- <—... 

Potassium carbonate o-Acylaminocarboxylic acid amides from quinazol-4(3H)-onium salts... 

Hydrogen iodide Qumazol-4(3H)-onium salts from o-acylaminocarboxylic acid amides and reverse reaction... 

A -oxazoline-4-carboxylic acid esters 26, 32 Acylaminocarboxylic acids... 

Reductive zj -oxazoline ring opening a-Acylaminocarboxylic acid esters... 

Transesterification Acylaminocarboxylic acid esters from acylaminocarboxylic acids... 

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