Phenyl-5-oxazolone

Griffiths, G.M., Berek, C., Kaartinen, M., Milstein, C. (1984). Somatic mutation and the maturation of immune response to 2-phenyl oxazolone. Nature 312, 271-275. 

Diazoalkanes add to the carbon-carbon double bonds of 2,3-diphenylthiirene 1-oxide and 1,1-dioxide. The adducts lose SO or SO2 to give pyrazoles and related compounds (Scheme 103) (80CB1632). Mesoionic oxazolones (75CLH53), 4-methyl-5-phenyl-l,2-dithiolene-3-thione (80JOU395) and pyrylium betaines (72JOC3838) react similarly via intermediate adducts (Scheme 104). Enamines (Scheme 96) and ynamines add to the double bond of 2,3-diarylthiirene 1,1-dioxides to give acyclic and cyclic sulfones by a thermal. 

Oxazol-5(2H)-one, 2-benzylidene-4-methyl-tautomerism, 6, 186 Oxazol-5(2ff)-one, 2-methylene-isomerization, 6, 226 Oxazol-5(2H)-one, 2-trifluoromethyl-acylation, 6, 201 Oxazol-5(4ff)-one, 4-allyl-thermal rearrangements, 6, 199 Oxazol-5(4H)-one, 4(arylmethylene)-Friedel-Crafts reactions, 6, 205 geometrical isomerism, 6, 185 Oxazol-5(4ff)-one, 4-benzylidene-2-phenyl-configuration, 6, 185 photorearrangement, 6, 201 Oxazol-5(4ff)-one, 4-benzyl-2-methyl-Friedel-Crafts reactions, 6, 205 Oxazol-5(4ff)-one, 4-methylene-in amino acid synthesis, 6, 203 Oxazol-5(4ff) -one. 2-trifluoromethyl-hydrolysis, 6, 206 Oxazolones... 

Modification of the Erlenmeyer reaction has been developed using imines of the carbonyl compounds, obtained with aniline," benzylamine or n-butylamine. Ivanova has also shown that an A-methylketimine is an effective reagent in the Erlenmeyer azlactone synthesis. Quantitative yield of 19 is generated by treatment of 3 equivalents of 2-phenyl-5(4ff)-oxazolone (2) (freshly prepared in benzene) with 1 equivalent of iV-methyl-diphenylmethanimine (18) in benzene. Products resulting from aminolysis (20), alkali-catalyzed hydrolysis (21), and alcoholysis (22) were also described. 

Several improved methods for the preparation of known unsaturated azlactones as well as some interesting new compounds of this type have been reported. Crawford and Little observed that the direct use of 2-phenyl-5-oxazolone (1) in the Erlenmeyer reaction gave much improved yields (35-74%) of unsaturated azlactones with aliphatic aldehydes and with ketones such as acetone and cyclohexanone [Eq, (1)], The usual procedure of mixing a carbonyl compound, hippuric acid, acetic anhydride, and sodium (or lead) acetate affords poor yields in the aliphatic series. 

The reaction of hippuric acid with a three-fold excess of trifluoro-acetic anhydride gives a 90% yield of 2-phenyl-4-(2, 2, 2 -trifluoro-l -hydroxyethylidene)-5-oxazolone (2). This compound is also obtained... 

A number of unusual aliphatic trifluoromethyl compounds have been obtained from 4-hexafluoroisopropylidene-2-phenyl-5-oxazolone (4) 10 The latter was prepared as shown in Eq. (2). The ease of formation... 

A new synthesis of unsaturated azlactones, which is especially useful in cases where the aldehyde is not readily available, has been developed. The reaction involves the nucleophilic displacement of chlorine in 4-chloromethylene-2-phenyl-5(4Z )-oxazolone (6) by a... 

Methyl-2-phenyl-5-oxazolone (22) reacts with excess phenyl-magnesiuin bromide to give 2-benzainido-1,1-diphenyl-1-propanoP (23). With excess ethylmagnesium bromide, 22 forms a dimer, N,N -... 

Arylazo-2-phenyl-5-oxazolone (30) is converted into the 1,2,4-triazole 31 by the action of phenylmagnesium bromide [Eq. (20)]. 

This procedure offers a reproducible method for the preparation of 2-phenyl-5-oxazolone, which is not commercially available It illustrates that strict attention to detail often smooths out an erratic procedure 2-Phenyl-5-oxazolone is, of course, an important intermediate in the synthesis of a-amino acids and related materials6... 

Acetic anhydride, condensation with and acetylation of glycine, 46, 1 in cyclization of c-formylphenoxy-acetic acid to coumarone, 46, 28 in cyclization of hippuric acid to 2-phenyl-5-oxazolone, 47, 101 reaction with N-nitroso-N-phenyl-glycine to yield 3-phenylsydnone, 46,96... 

Hippuric acid, cyclization to 2 phenyl-5 oxazolone with acetic anhydride, 47,101 Holarrhimine, 46, 61 Hydrazine, reaction with cinnamalde-hyde, 47, 99... 

Compounds of special interest whose preparation is described include 1,2,3-benzothiadiazole 1,1-dioxide (a benzyne precursor under exceptionally mild conditions), bis(l,3-diphenylimida-zolidinylidene-2) (whose chemistry is quite remarkable), 6- di-melhylamino)julvene (a useful intermediate for fused-ring non-benzenoid aromatic compounds), dipkenylcyclopropenone (the synthesis of which is a milestone in theoretical organic chemistry), ketene di(2-melhoxyethyl) acetal (the easiest ketene acetal to prepare), 2-methylcyclopenlane-l,3-dione (a useful intermediate in steroid synthesis), and 2-phenyl-5-oxazolone (an important intermediate in amino acid chemistry). 

The scientific group from Turkey62 studied photophysical and photochemical properties and behaviour of an azlactone derivative, 4-(p-N,N - dimethylaminophenylmethylene)-2-phenyl-5-oxazolone in sol-gel... 

Barbituric acid, 32, 7 Barium D-gulonate, 36, 39 Behenic acid, 37, 69 Beilstein test, 34, 38 Benzaldehyde, 30, 100 33, 70 34, 65 Benzaldehyde, p-AMINO, 31, 6 />-DIMETHYLAMINO-, 33, 27 Benzaldehyde, purification of, 33, 71 Benzalmalonic acid, ethyl ester, 37, S 4-Benzal-2-phenyl-5-oxazolone, 37, S Benzamidine, N,N -diphenyl-, 31, 48 N-phenyl-, 36, 64 Benzanilide, 31, 48... 

IZ Siemion, K Nowak. New method of synthesis of 2-phenyl-4-alkyl-oxazolones-5. Rocz Chem 43, 1479, 1960. 

Phenylmercuric chloride, conversion to phenyltrichloromethylmercury by reaction with sodium tri-chloroacetate, 46, 98 2-Phenyl-2-oxazolin-5-one, 47, 101 2-Phenyl-5-oxazolone, 47,101... 

The reaction of 5(4H)-oxazolones (32) and miinchnones with triphenylvinylphos-phonium bromide (33) provides a mild synthesis of substituted pyrroles (34) (Scheme 11). The cycloaddition-elimination reactions of 5-imino-l,2,4-thiadiazolidin-3-ones with enamines and ester enolates produce 2-iminothiazolidines. " Chiral isomtinchnone dipoles show jr-facial diastereoselectivity with IV-phenyl- or A -methyl-maleimide in refluxing benzene. ... 

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