5-methoxy-2- oxazoles

Oxazol 5-Methoxy-2-methoxy-carbonyl-4-methyl- 8a, 928 [ROOC -CH(CH3)-NH-CO — COOR + COCl2]... 

Oxazole, 2,5-dihydro-4-methoxy-synthesis, 6, 228 Oxazole, dihydro-2-methylene-reactions, 6, 215... 

They found that deuterium labeled 2-phenyl-5-methoxy-4-[(methoxy-d3)-carbonyl]oxazole (7) scrambled on heating to give a 1 1 equilibrium mixture of 7 and the corresponding rearranged ester 9 ... 

The development of the key intermediate, 5-(2-methoxy-4-nitrophenyl)oxazole (25), in the preparation of the hepatitis C drug candidate, VX-497, utilizes a van Leusen reaction of aldehyde 24 with TosMIC. ... 

Bis-[ ( benzo-1,3-oxazol) -yl-(2)-thio]- 343 Bis-[1,4- (bzw. 3,4]-dihydro-naphthy[-(2)-oxy]- 588 Bis-[dimethylamino]- 345 Bis-[4-dimethyIamino-phenyl]- 346 Bis-[4-hydroxy-phenyl]-(2-carboxy-phenyl)- 167 Bis-[4-methoxy-phenyl]-dideutero- 346 Bis-[4-methyl-phenyl]-Bis-f 2-methyl-thiiranyl-(2)]- 570 Bis-[naphthyl-(2)-oxy]- 588 Bis-[naphthyl-(2)-thio]-... 

The boron trifluoride etherate catalysed formation of oxazoles has been used in synthesis. Doyle has successfully employed the reaction in the synthesis of annuloline 20, a disubstituted oxazole isolated from the roots of the annual rye grass. Thus, l-diazo-4 -methoxy-acetophenone 19 was reacted with 3,4-dimethoxycinnamonitrile in the presence of boron trifluoride etherate to yield the natural product 20 in 48% yield (Scheme 11).<80JOC3657>... 

The facile proton abstraction of activated oxazolines offers a convenient method to convert cis oxazolines to the thermodynamically more stable trans isomer. Suga, Ibata, and co-workers took advantage of this property to correctly determine the stereochemistry for the oxazoline obtained from the [3 + 2] cycloaddition of 5-methoxy-2-(p-methoxyphenyl)oxazole with benzaldehyde (Scheme 8.122). 

Substituted binaphthyl compounds can be synthesized in high optical yields using nucleophilic aromatic substitution reactions in which the chiral leaving groups are alkoxy moieties derived from naturally occurring alcohols28-29. For example, the condensation of 2-(l-alkoxynaphth-2-yl)-4.5-dihydro-4,4-dimethyl-l,3-oxazole with 1-naphthyllithium or 2-methoxy-l-naphthyl 2-magnesium bromide leads to (ft)- or (.S)-(l,T-binaphthyl-2-yl)-4,5-dihydro-4,4-dimethyl-l,3-oxazole derivatives. 

R2 = OCH3 4.5-dihydro-4,4-dimethyl-2-(2-methoxy-l J-hinaphthyl-2-yl)-l, 3-oxazole 1 (ft)-isomer, 2 (5)-isomer... 

Methoxy carbonyl-3-(1-methyl-l-trimethylsilyloxy-ethyl)-l,2-oxazol 58%... 

Umsetzung mit 1-(4-Methoxy-pheny])-propen zu 3-Methoxycarbonyl-5-(4-methoxy-phenyl)-4-me-thyl-4,5-dihydro-l, 2-oxazol. 

Intramolekularer Ersatz einer Methoxy-Gruppe durch eine Amino-Gruppe erfolgt bei der Einwirkung von Lithium-diisopropylamid auf 2-[3-(co-Amino-alkyl)-2-methoxy-phe-nyl]-4,4-dimethyl-4,5-dihydro-l,3-oxazol in Tetrahydrofuran. Auf diese Weise lassen sich erhalten4 ... 

Methyl-4-[3-iodo-5-nitro-(4-methoxy-phenoxy)-benzylidene]-4-H-oxazol-5-one... 

Methoxy-2-phenyl-3a,6,7,7a-tetrahydro-5H-pyrano[3,2-d]oxazole (105a) [22]... 

In addition to the oxazoles O-isopentenylhalfordinol (19) (72), 0-geranylhal-fordinol (21) (75), and 2-pyridyl-5-(3-methoxy-4,5-methylenedioxy)phenyl ox-azole (24) (13), Amyris plumieri produces a number of novel chromenylated tyramides 41-43 and the (3-styrylamide 44 (12-14, 18). The only other iso-lable metabolites from this plant were nicotinamide (45) and 4-(3,3-dimethyl) allyloxybenzoic acid (46) (12, 18). These two latter compounds are thought to... 

Preparation of A -(3-methoxy-4-(oxazol-4-yl)phenyl-A -4-nitrophenyl urea... 

Preparation of 2-[l-[4-[4-[2-(E)-2-(4-trifluoromethylphenyl)ethenyl]oxazol-4-yl]methoxy-phenyl]butyl-lH-imidazol-2-yl]-l-ethanol... 

The particular reaction described in Scheme 2 using dimethyl diazomalonate produces oxazoles 5 that bear a methoxy group at C-5. If desired, this substituent may be removed in some cases by reductive cleavage using LiB(Et)3H to give the 5-unsubstituted oxazoles 6.3.15 Alternatively, the 5-unsubstituted derivatives 6 may be obtained directly through the use of diazo formylacetate (2) in place of dimethyl diazomalonate (1).3 15 Some additional, representative examples of the use of 1 and 2 are shown below in the Table. 

Carbomethoxy-5-methoxy-2-phenyl-1,3-oxazole 4-Oxazolecarboxylic acid, 5-methoxy-2-phenyl-, methyl ester (9) (53872-19-8)... 

Nitro-3-semicarbazido- -nitril E15/1, 781 (1,2-Oxazol + H2N-CO-NH-NH2) Pyrimidin 4-Hydrazino-6-methoxy-... 

Oxazol 2-(2-Hydroxy-ethyl)-5-methoxy-4-methoxycarbonyl-E8a, 905 [(ROOC)2C = N2 +... 

Oxazol 2-(4-Chlor-2-nitro-phenylthio)-5-methoxy- E8a, 950 (CN-CH2-COOR +... 

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