4-Methyl-5-phenyl-3- -2-oxazolidone

Synthesis of 4-amino-2-pyrazolin-5-ones is usually achieved by treatment of an a-amido-/3-aldehydo- or /9-ketoester with hydrazines according to the classical method for preparation of 2-pyrazolin-5-ones. Variants on this procedure consist of using an a-amidoester which has /9-substituents whose reaction is equivalent to that of a /9-carbonyl substituent. Such compounds are D-benzylpenicilloic acid a-methyl ester,1027 ethyl phenylpenaldate243 and the acetal of an a-amido-/9-formyl ester.59,243 Cornforth has isomerized 2-phenyl-4-hydrazino-methylidyneoxazolidone to 4-benzamido-2-pyrazolin-5-one. The same compound was obtained by treatment of 1-ethoxyvinyl-2-phenyl-oxazolidone with phenylhydrazine.319... 

Methyl-5-phenyl-3-(3-phenylpro-pionyl)-2-oxazolidone, 24 (S)-l-[l-Methyl-2-pyrrolidinyl]-methylpiperidine, 116, 302 Methyl p-tolyl sulfoxide, 115 Norephedrine, 200 2-Oxazolidones, chiral, 24, 225, 267 (2R,4R)-Pentanediol, 205, 237 /r[Pg.403]

CARBENES, GENERATION Chloral. Dibromofluoromethane. Dimethoxy-methyl)trimethoxysilane. Dimethyl diazomethylphosphonate. S -Dimethyl-N-nitroso-2-oxazolidone. Ethylidene iodide-Diethylzinc. Ethyl trichloroacetate. Phenyl(dibromochloro methyl) mercury. Phenyl(dihalocarbomethoxymethyl)mer-cury. Phenyl(trifluoromethyl)mercury. Phenyl(trihalomethyl)mercury. Sodium chlorodiiluoroacetate. Zinc powder. 

Rings with Nitrogen and Oxygen.—The n.m.r. spectra of cis- and trans-A,5-diphenyl-, -4-methyl-5-phenyl-, and -3,4-dimethyl-5-phenyl-2-oxazolidones (34) have been interpreted in terms of ring conformations. ... 

Typical procedure. (4R,5R)-5-[(R)-(1-BenzYloxy-1-isopropoxYcarbonYl)ntethYl]-4-phenYl-2-oxazolidone, 595, and its enantiomer [421] At 0 °C, pyridine (200 pL, 2.5 mmol) and diphosgene (72 pL, 0.60 mmol) were successively added to a solution of 594 (207 mg, 0.60 mmol) in dichloromethane (2 mL). After stirring at the same temperature for 10 min, the mixture was diluted with water and ethyl acetate. The upper ethyl acetate layer was separated, washed successively with saturated NaHC03 solution and saturated brine, dried over anhydrous MgS04, and then concentrated in vacuo. The residue was purified by column chromatography (hexanes/EtOAc, 4 1—> 3 1) to afford (4R,5R)-5-[(R)-(l-ben2cyloxY-l-isopropoxYcar-bonyl) methyl]-4-phenyl-2-oxazolidone 595 as a colorless oil (199 mg, 90%). 

At 200 °C, the reaction of methyl isothiocyanate and alkylene oxide gives trimethyl isocyanurate. This reaction involves the trimerization of methyl isothiocyanate followed by stepwise replacement of the sulfur by oxygen via spiro compounds. Phenyl isothiocyanate reacts with ethylene oxide to give a mixture of triphenyl isocyanurate and 3-phenyloxazolidine-2-one 90 °. The formation of the oxazolidone is caused by the reaction of the initially formed 2-phenylimino oxathiolene 89 with ethylene oxide in the presence of the catalysts... 

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