Oxazole, 2-methyl-4,5-diphenyl

The reaction of 78 with phosphorus pentasulfide in xylene gives the corresponding 2-oxazolethione, which also forms the iV -methyl product with dimethyl sulfate and 4,5-diphenyl-2-methyhnercapto-oxazole in 98% yield on treatment with silver oxide-methyl iodide. 

Anhydro-acylation of l,2-dihydro-2-oxo-l-pyridylacetic acid with acid anhydrides yields bicyclic meso-ionic 4-acyl-l,3-oxazol-5-ones (67). Huisgen and his co-workers have reported extensive studies of the monocyclic meso-ionic l,3-oxazol-5-ones (66), which they have lightheartedly named munchnones. Cyclodehydration of N-benzoyl-A -methyl-C-phenylglycine using acetic anhydride at 55° gives the 3-methyl-2,4-diphenyl derivative (66, R = = Ph R = Me) as... 

The crude product was purifled by silica gel column chromatography using pentane/diethyl ether (6 1) as eluent to yield 3.43 g (9.23 mmol, 81%) of (45,55)-2-(5-methyl-2-phenyl-4,5-dihydro-oxazol-4-yl)-l,3-diphenyl-propan-2-ol as a white foam. 

SYNTHESIS OF (45, 55)-[(f -l,5-CYCLOOCTADIENE)- 2-(2-PHEN YL-5-METHYL, 5-DIHYDRO-OXAZOL-4-YL)-1,3-DIPHENYL-2-DIPHENYLPHOSPHINITE-PROPANE IRIDIUM(I)]-TETRAKIS[3,5-BIS(TRIFLUOROMETHYL)PHENYL]BORATE... 

Cyclooctadiene)- 2-(2-phenyl-5-methyl-4,5-dihydro-oxazol-4-yl)-l,3-diphenyl-2-diphenylphosphimte-propane mdium(l)]-tetrakis[3,5-bis(tri-fluoromethyl)phenyl]borate (1.72mg, l.Opmol). The catalyst is available from Strem Chemicals, Inc. (catalogue no. 77-5020). 

S)-Tetrahydro-l -methyl-3,3-diphenyl-1 H,3H-pyrrolo[l, 2-e][1,3,2]oxazaborole-boran complex Boron, trihydro(tetrahydro-1 -methyl-3,3-diphenyl-1H,3H-pyrrolo[1,2-c][1,3,2]oxazaborole-N7)-, [l-4-(3aS-cis)]- (12) (112022-90-9) (S)-Proline-N-carboxyanhydride lH,3H-Pyrrolo[1,2-c]oxazole-1,3-dione, tetrahydro-, (S)- (9) (45736-33-2)... 

Diphenyl-3-methyl-3-(4-melhyl-5-oxo-2-phenyl-4,5-dihydro-l,3-oxazol-4-yl)- 2846, 3149... 

Infrared spectra of 4-methyloxazole and 2,4-dimethyloxazole for the gaseous and liquid states, and of liquid 2-n-hexy 1-5-methyl oxazole, have been measured at room temperature between 4000 and 600 cm-1. A comparison with the spectra of oxazole and considerations of the rotational envelopes has allowed a plausible assignment of the absorption bands with reasonable success.261 Examination of the infrared spectra in the solid state of 2,4-dimethyl-, 2-methyl-4-phenyl-, and 2-methyl-4,5-diphenyl-oxazolcs, and various benzoxazoles shows regularities in the 1660-1500 cm-1 region. Absorption bands at 1660-1600 cm-1 and 1585-1500 cm-1 have been assigned to the vibrations arising from the heterocyclic ring system.262... 

Reactions of Oxazoles. The reaction of 4-phenyloxazole with di(acetoxy-methyl)acetylene gives the furan (531 R = CH2OAC) by extrusion of benzo-nitrile from the intermediate Diels-Alder adduct (530 R = CH20Ac). Similarly, 5-cyano-4-methyloxazole and hept-l-yne yield mainly the furan (532) and methyl cyanide a minor product, the 4-substituted isomer (533), arises from the alternative mode of addition of the acetylene. The sensitized photooxidation of 2,4-diphenyl-2-oxazolin-5-one (534) affords, inter alia, the coupled product (535). ... 

Irradiation of a methanolic solution of an oxazole at —78°C in the presence of O2 and rose bengal produced a 2,5-disubstituted 5-hydroperoxy-4-methoxy-4,5-dihydrooxazole 709 (Scheme 1.197). Here again, the oxazole substitution pattern determined the product distribution. For example, 4,5-diphenyl-2-methyloxazole 231a produced only N, iV-dibenzoyl acetamide 706 (Ri = CH3, R2 = R3 = CeHs). On the other hand, 4-methyl-2-phenyloxazole 701a gave 709 (Ri = CgHs, R2 = CH3, R3 = H), which decomposed on warming to room temperature to yield... 

A mixture of desyl chloride and acetonitrile liquefied by brief warming treated gradually with SnGl4 with water-cooling and occasional shaking, allowed to stand overnight, and heated 3 hrs. on a water bath -> 2-methyl-4,5-diphenyl-oxazole. Y 75%. F. e. and limitations s. M. Lora-Tamayo, R. Madronero, and H. Leipprand, B. 97, 2230 (1964). 

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