Acylglycines

Formation of 5-oxazolones (or azlactones ) (2) by intramolecular condensation of acylglycines (1) in the presence of acetic anhydride is known as the Erlenmeyer-Plochl azlactone synthesis. ... 

Acridine orange, pH-dependent change of fluorescence color 91 Activation of the layer 124ff. N-Acylglycine conjugates 176 ADB = 2-amino-2, 5-dichlorobenzophe-none 227... 

Thiazines, a heterocyclic system which is found, for example, in antibiotics of the cephalosporin type, were synthesized using a solvent-free domino procedure by Yadav and coworkers [24]. Hence, reaction of N-acylglycines 10-64, an aromatic... 

Formation of 5-oxazolones (or azlactones ) by intramolecular condensation of acylglycines in the presence of acetic anhydride. 

Another interesting synthesis started from A-acylglycine esters which generated A-acylimino esters in situ following bromination and base treatment. When these A-acylamino esters were alkylated with 1,3-dicarbonyl compounds and hydrazines, the corresponding pyrazoles were formed (Scheme 18) (88T5403). 

Glycine A -acyltransferase [EC 2.3.1.13] catalyzes the reaction of an acyl-CoA derivative with glycine to produce coenzyme A and an A-acylglycine. The acyl-CoA derivative can be one of a number of aliphatic and aromatic acids. However, neither phenylacetyl-CoA nor indole-3-acetyl-CoA can act as substrates. 

Diagnosis of medium chain acyl-CoA dehydrogenase deficiency by stable isotope dilution analysis of urinary acylglycines retrospective and prospective studies, and comparison of its accuracy to acylcamitine identification by FAB/mass spectrometry. 

Ring opening of 2-aryl-5(477)-oxazolones 230, obtained from A-acylglycines, with A,A-dimethyl-2-aminoethanol provides choline esters of A-substituted amino... 

A-Acyl peptides 277 containing an a,a-di(isopropylthio)glycine residue have also been described. These compounds were prepared as shown in Scheme 7.89. Thus, a 4,4-di(isopropylthio)-2-substituted-5(4//)-oxazolone 276 was prepared from a 2-substituted-5(4//)-oxazolone 275 by reaction with A-(isopropylsulfenyl)-succinimide. The starting 2-substituted-5(4//)-oxazolone was prepared by cychza-tion of an A-acylglycine. °... 

TABLE 7.30. SYNTHESIS OE UNSATURATED 5(4i7)-OXAZOLONES EROM iV-ACYLGLYCINES AND CARBONYL COMPOUNDS... 

One of the fundamental cleavage reactions of the heterocyclic ring in unsaturated oxazolones is the conversion to acids or esters. This process leads to dehydroamino acid derivatives from which a wide variety of amino acids are prepared by hydrogenation. The side chain of the final amino acid is determined by the aldehyde used to prepare the unsaturated oxazolone. For example, benzalde-hyde and an A -acylglycine afford 2-acylaminocinnamic acids 434 after hydrolysis of the oxazolone 433. In turn, 434 are excellent precursors to phenylalanine. 

Both stereoisomers of a 4-(a-arylethylidene)-5(477)-oxazolone 441 and 443, undergo stereospecihc hydrolysis-methanolysis to furnish the corresponding (Z) and (E) isomers of 2-acetylamino(or benzoylamino)-3-aryl-2-butenoic acid or methyl ester, 442 and 444, respectively (Scheme 7.146). ° The requisite starting oxazolones were prepared by condensation of an acetophenone with an acylglycine or by methylene insertion into the vinyl C—H bond of a 4-arylidene-5(4//)-oxazolone. 

Nitrosation of methyl 2-acylamino-3-(dimethylamino)propenoates 494 obtained from the corresponding oxazolones 493 effects the conversion of A -acylglycines to 5-substituted-l,2,4-oxadiazole-3-carboxylates 496 as shown in Scheme 7.157. ... 

A number of recent papers have appeared in the literature related to the synthesis of saturated 5(477)-oxazolones that were not yet covered in our contribution. 4-Acyl-2,4-dialkyl-5(477)-oxazolones 776 have been obtained from A-acylglycines. Thus, cyclization of an A-acylglycine in the presence of thionyl chloride affords a monosubstituted 5(477)-oxazolone 775. Acylation of 775 with an aroyl chloride in the presence of magnesium chloride occurred at C-4 to produce 776. Hydrolysis and decarboxylation of 776 gave the A-acylamino ketones 777 that are valuable intermediates to prepare oxazoles 778 (Scheme 7.236). 

Condensation of A -acylglycines with carbonyl compounds, the Erlenmeyer synthesis, continues to be exploited to prepare of a wide variety of unsaturated-5(47/)-oxazolones. The reaction is performed in the presence of a cyclodehydrating agent and recently bismuth(lll) acetate has been evaluated in this capacity. Alternatively, unsaturated 5(47/)-oxazolones can be obtained from hippuric acid and a carbonyl compound or from the appropriate dehydroamino acid derivative using 3-(aIkoxycarbonyl)benzotriazole-l-oxides as the cyclodehydrating agent. 

TABLE 7.30 SYNTHESIS OF UNSATURATED 5(4//)-OXAZOLONES FROM N-ACYLGLYCINES AND CARBONYL COMPOUNDS, 212... 

Table 3.1.3 Pathologic acylglycine species detected by organic acid analysis. CoA coenzyme A, FAO fatty acid oxidation, ILE isoleucine, LEU Leucine, MCAD medium-chain acyl-CoA dehydrogenase, MET methionine,...

Table 3.1.10 Reference ranges of organic acids and acylglycines in urine in children of different ages. Values are presented as mmol/mol creatinine. TIC average detection limit. 0.1 mmol/mol creatinine ...

Bartlett K, Gompertz D (1974) The specificity of glycine-N-acylase and acylglycine excretion in the organic acidaemias. Biochem Med 10 15-23... 

The first synthesis of acylglycine dithioester derivatives was described by Storer et al.[86l Their synthesis begins with the Pinner reaction 86 88 89 of the corresponding aminoacyl nitrile 39 in the presence of ethanethiol and HC1 gas to produce a thioimidoester hydrochloride 40. Use of an alcohol instead of a thiol gives the thionoesterJ90 The thioimidoester 40 was then treated with H2S gas in the presence of pyridine to yield the dithioester 41 (Scheme 18).[861... 

Attempts to synthesize ATrp derivatives by the well-known Erlenmeyer-Plochl method using an azlactone result in very poor yields.However, using an altogether different strategy Moriya et alJ143l synthesized ATrp derivatives with Z configuration in much better yields. In this method condensation of 3-(aminomethylene)-3//-indole 53 with A-acylglycine esters 54 was used to synthesize A-acyl-substituted ATrp derivatives 55 (Scheme 18). 

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