5-ethyl-2-phenyl-4- oxazole

A series of 2-aryloxazoloquinolones 32 having high affinity for the GABA receptor were prepared via a Pd-catalyzed intramolecular diaryl coupling of ethyl 5-bromo-2-phenyl-oxazole-4-carboxylate with 2-aminophenylboronic acid followed by cyclization [37]. This one-pot intramolecular Suzuki reaction was followed by cyclization to afford a tricyclic compound 32. 

The condensation of furo[3,2- ]pyrrole-type aldehydes 8g and 265-267 with hippuric acid was carried out in dry acetic anhydride catalyzed by potassium acetate as is shown in Scheme 26. The product methyl and ethyl 2-[( )-(5-oxo-2-phenyl-l,3-oxazol-5(4//)-ylidene)methyl]furo[3,2- ]pyrrol-5-carboxylates 268a-d were obtained. The course of the reaction was compared with the reaction of 5-arylated furan-2-carbaldehydes with hippuric acid. It was found that the carbonyl group attached at G-2 of the fused system 8 is less reactive than the carbonyl group in 5-arylated furan-2-carbaldehydes in this reaction <2004MOL11>. The configuration of the carbon-carbon double bond was determined using two-dimensional (2-D) NMR spectroscopic measurements and confirmed the (E) configuration of the products. 

Als Nebenprodukte entstehen oft 1,3-Oxazole (vgl. Bd. E8a, S. 903, 911). a-Hydroxy- und a-Acetoxy-ketone liefern die entsprechenden 1,3-Oxazole sogar als Hauptprodukte42,43. Aus 3-Brom-l-oxo-l-phenyl-butan erhalt man mit Ammoniumformiat in Ameisensaure 4-Ethyl-5-phenyl-imidazolin 75% Ausbeute. Dagegen entsteht aus dem isomeren l-Brom-2-oxo-l-phenyl-butan unter analogen Reaktionsbedingungen das entsprechende 1,3-Oxazol in iiber 70% Aus-... 

Dimethyl-3-(2-oxo-2-phenyl-ethyl--bromid lagert sich beim Kochen mit Triethylamin in Acetonitril in 2-(2-Imino-5-phenyl-2,3-dihydro-oxazol-3-yl)-4,6-dimethyl-pyrimidin um. Aus diesem werden durch Kochen in Alkoholen mit 4-Methyl-benzolsulfonsaure als Katalysator 2-Alkoxy-l-(4,6-dimethyl-2-pyrimidyl)-4-phenyl-imidazole oder durch Erhitzen mit primaren oder sekundaren Aminen ebenfalls in Gegenwart von 4-Methyl-benzolsulfonsaure 2-Alkylamino-l-(4,6-dimcthyl-2-pyrimidyl)-4-phe-nyl-imidazole erhalten374 ... 

Bei der Behandlung von 4-(2-Oxo-2-phenyl-ethyl)-3-phcnyl-furazancn mit cthanolischcr Salz-saure entstehen 3-Benzoyl-5-phenyl-l,2-oxazole auf folgendem Wege327,328 ... 

Dibenzoyl-furazan-2-oxid liefert mit Alkenen bzw. Alkinen 3-(l-Benzoyloxyimino-2-oxo-2-phenyl-ethyl)-4,5-dihydro-l, 2-oxazole bzw. 3-(l-Benzoyloxyimino-2-oxo-2-phenyl-ethyl)-l,2-oxazole auf folgendem Weg450,451 ... 

The Schlenk flask was charged with [Ir(COD)Cl]2 (83 mg) and 2mL of dry dichloromethane. (45,55)-(9- [ 1 -Benzyl-1 -(5-methyl-2-phenyl-4,5-dihydro-oxazol-4-yl)-2-phenyl-ethyl]-diphenylphosphinite (125 mg) was dissolved in anhydrous dichloromethane (5mL) under an argon atmosphere, and added to the metal precursor. The so-formed orange/yellow solution was heated at reflux for 1 h. 

Olefins react with benzenetellurinyl trifluoroacetate in acetonitrile in the presense of boron trifluoride etherate to give 2-acetaminoalkyl phenyl tellurium oxides that are converted, upon treatment with triethylamine in tetrahydrofuran at 30° for 4 h, to 4,5-dihydro-l,3-oxazoles4. These highly regio- and stereoselective reactions allow the one-pot, high-yield conversion of olefins to 1,3-oxazoles. Ethyl cyanide and phenyl cyanide can be used instead of acetonitrile. 

Preparation of 2-[l-[4-[4-[[2-[(E)-2-[4-(trifluoromethyl)phenyl]ethenyl]-l,3-oxazol-4-yl]methoxy]phenyl]butyl]-lH-imidazol-2-yl]ethyl isopropylcarbamate... 

Pyrimidin 6-Amino-4-hydroxy-5-(2-hydroxy-ethyl)-2-phenyl- E9b/2, 158 (2-NH2 —3-COOR —4,5-H2 —furan + Benzamidin) lH-l,2,4-Triazol 1-(4-Methoxy-phenyl)-3-(2-oxo-propyl)- E8d, 492 [5-CH3 - 3-(NH -CH = N -Ar)—1,2-oxazol + NaOR]... 

Oxazol (+ )-trans-(4R,5R)-2-Ethyl-4,5-dihydro-4-methyl-5-phenyl- E21a, 1020... 

Cyclopropan 1-Formylamino-l-(1 -hydroxy-1 -phenyl-ethyl)-E17e, 279 (4,5-H2 — 1,3-oxazol-Spalt.)... 

Oxazolidin 2-Phenyl-2,4,4-trimethyl- E14a/2, 666 (4,5-H2 — 1,3-oxazol/R-MgBr) Pentafulven 6-Ethyl-6-morpholino-V/2c, 561 Pentansaure... 

Oxazol, 2-[2-(4-Chlor-phenyl)-2-hydroxy-ethyl]-4-methoxycarbonyl- E8a, 949 [H3C-CN/H3C-OH +... 

Ethyl 2-phenyl-5>(1-azlrldlnyl)oxazole-4-carboxylate (3). A solution of 2-phenyl-5-ethoxyoxazole-4-carboxyiic acid chionde (1 257 g, 5 mmol) in PhH (20 mL) was stirred with azindine (0 215 g, 5 mmol) and tnelhytamme (0 5 g, 5 mmol) in PhH (40 mi.) (or 3 h at 20-°C. After washing with water, the solvent was removed and the residue crystallized (rom petroleum ether to give 1.032 g of 1 (80%)... 

Other C4-chiral oxazolidine-2-thiones. (45)- (2) and (4i )-ethyl-l,3-oxazolidine-2-thione (3) [(45)- and (4/ )-EOT], (45)-isopropyI-l,3-oxazol-idine-2-thione (4), and (4/ )-methyl-(55)-phenyl-l,3-oxazolidine-2-thione [(4/ ,55)-MPOT] (5) were likewise synthesized. Typical preparations of C4-chiral l,3-oxazolidine-2-thiones (2-5) from )3-amino alcohols (6-9) are as follows. 

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