3-Phenyl-2 -quinoxalinone 4-oxide

A similar reaction resulting in the formation of compound 185 is observed when 3-phenyl-2-quinoxalinone 4-oxide (184) is treated with... 

Only one procedure has been reported recently within this category. Thus 7-chloro-l-methyl-5-phenyl-2,3-dihydro-lH-benzodiazepin-2-one 4-oxide (437) with dimethyl acetylenedicarboxylate in methylene chloride at 20° C for 3 days gave a separable mixmre of the primary tricyclic adduct, dimethyl lO-chloro-6-oxo-llb-phenyl-5,6,7, 1 lb-tetrahydroisoxazolo[2,3-t/] [ l,4]benzodiazepine-1,2-dicarboxylate (438), and its rearrangement product, 6-chloro-4-(2-methoxalyl-2-methoxycarbonyl-l-phenylvinyl)-l-methyl-3,4-dihydro-2(lT0-quinoxalinone (439) each product afforded 6-chloro-l-methyl-2(l//)-quinoxalinone (440) on refluxing in ethanol (see also Section 1.7.13). However, the final quinoxaline (440) was best obtained in 75% yield) by simply heating the initial substrate (437) and dimethyl... 

Phenyl-2(177)-quinoxalinone 4-oxide (57, R = H) gave l-benzyl-3-phenyl-2(177)-quinoxalinone 4-oxide (57, R = CH2Ph) (PhCH2Br, Na2C03, AcEt, reflux, 24 h 45%). ... 

Methoxy-5-nitro-3-phenylquinoxaline gave only 6-methoxy-5-nitro-3-phenyl-quinoxaline 1-oxide (232) (AcOH, 30% H2O2, 80°C, 3 h 81%) 1,3-dimethyl-2(17/)-quinoxalinone 4-oxide (233) was made similarly but in only... 

Ethyl-3-phenylquinoxaline 1,4-dioxide 2-Ethyl-3-phenylquinoxaline 1-oxide 2-Ethyl-3-phenylquinoxaline 4-oxide 1 -Ethyl2-phenyl-2( l//)-quinoxalinone 2-Ethyl-3-propylquinoxaline... 

Phenyl-2(l //)-quinoxalinone 4-oxide (164) gave the isomeric 3-o-hydroxy-phenyl-2(l//)-quinoxalinone (164a) hv (sunlight), MeOH, H20, 9 days 20%].340... 

Benzyl-3-phenyl-2(l//)-quinoxalinone 4-oxide 3-Benzyl-2-quinoxalinamine... 

Chloro-2/3-pheny lquinoxaline 1,4-dioxide 2-Chloro-3-phenylquinoxaline 4-oxide 6-Chloro-2-phenylquinoxaline 4-oxide 6-Chloro-3-phenylquinoxaline 1 -oxide 6-Chloro-3-phenyl-2( 17/)-quinoxalinone 6-Chloro-3-phenyl-2(17/)-quinoxalinone 4-oxide 2-Chloro-3-piperidinoquinoxaline... 

Hydroxy-3-oxo-3,4-dihydro-2-quinoxalinecarbonitrile 4-Hydroxy-3-oxo-3,4-dihydro-2-quinoxalinecarbonitrile 1-oxide 4-Hydroxy-3-oxo-3,4-dihydro-2-quinoxalinecarboxylic acid 1 -Hydroxy-3-phenyl-2( l/f)-quinoxalinone... 

Ethyl-cr-chlorophenylacetate and o-phenylenediamine in the presence of triethylamine give 3-phenyl-1,2,3,4-tetrahydro-2-quinoxalinone (16), which is oxidized to 3-phenyl-2-quinoxalinone (17) with potassium... 

Peracetic acid oxidation of 2-carbamoylquinoxaline (94) at 20°-25° gives the monoxides 95 and 96, and at higher temperatures the 1,4-dioxide (97) is isolated in 50% yield, together with a small amount of the 1,4-dioxide of 2-amino-3-quinoxalinone.m However, Hayashi and co-workers report the isolation of only 96 from 94 using monoperphthalic acid in ether <10°.109 In their attempt to correlate the nature of 2-substitution with the formation of 1- versus 4-oxides, they examined the behavior of some 2-alkyl substituted quinoxalines 113,114 2-ethylquin-oxaline gives the 1- and 4-oxides and the 1,4-dioxide, 2-isopropylquin-oxaline yields the 4-oxide and the 1,4-dioxide however, 2-f-butylquin-oxaline only furnishes the 4-oxide because of steric hindrance.114 The N-oxidation of 2-phenyl- and 2-alkyl-3-phenyl-quinoxalines with monoperphthalic acid furnishes the products shown in Table 1.114... 

Quinoxaline 1-oxide (209) reacts with phenyl isocyanate to give 2-anilinoquinoxaline (210) together with 1,3-diphenyl-l-(2-quinoxalinyl)-urea (211) and cyclized oxidation product of the urea 212.215 2-Quinoxalinone 4-oxide (205) and its 1-methyl derivative undergo addition reactions, e.g., with phenyl isocyanate and benzyne to give compounds 214 and 216, respectively.216 These reactions are formulated as proceeding via the intermediate cycloadducts 213 and 215. Compound 216 has also been obtained by photolysis of 3-(o-hydroxy-phenyl)quinoxaline 1-oxide.51 1,3-Dipolar cycloaddition of quinoxaline... 

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