3-Phenyl-2 -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... [Pg.371]

A similar reaction resulting in the formation of compound 185 is observed when 3-phenyl-2-quinoxalinone 4-oxide (184) is treated with... [Pg.410]

Dimethyl-1,2-benzenediamine with phenylglyoxylic acid (PhCOC02H) gave 6,7-dimethyl-3-phenyl-2(17/)-quinoxalinone (212, R = Ph) (EtOH, reflux. [Pg.30]

Benzenediamine (228) and diethyl dibromomalonate (229) gave ethyl 3-oxo-3,4-dihydro-2-quinoxalinecarboxylate (230) (MeOH, 20°C, 24 h 40%)." The same substrate (228) with ethyl a-bromoisobutyrate gave 3,3-dimethyl-3,4-dihydro-2(17i)-qumoxalinone (231) (Me2NCHO, NEtPr j, 110°C, 7 h 76%) or with methyl 2-bromo-2-phenylacetate gave 3-phenyl-3,4-dihydro-2(l//)-quinoxalinone (232) (KI, K2CO2, AcMe, reflux, 12 h then oily product, MeONa, PhH, reflux, 7 h 89%). ... [Pg.33]

Only one procedure in this category emerged from the present survey. Thus treatment of 1,2-benzenediamine (372) with 3,3-bis(trifluoromethyl)-5-oxazolinone (373, R = H) in ethyl acetate containing a trace of acetic acid at room temperature for a short time afforded 2(l//)-quinoxalinone (374, R = H) in 92% yield 3-methyl- (374, R = Me), 3-isopropyl- (374, R = Pr"), 3-phenyl- (374, R = Ph), and 3-benzyl-2(l//)-quinoxalinone (374, R = CH2Ph) were made similarly in 60-80% yield. ... [Pg.51]

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... [Pg.59]

Ethyl 10-chloro-7-methyl-6-oxo-l lb-phenyl-5,6,7,1 lb-tetrahydroisoxazolo[2, 3- /][l,4]benzodiazepine-l-carboxylate (563) gave a separable mixture of 6-chloro-4-(2-ethoxycarbonyl-2-formyl-l-phenylvinyl)-l-methyl-3,4-dihy-dro-2(17/)-quinoxalinone (564), 4-(2-benzoyl-2-ethoxycarbonylvinyl)-6-chloro-1-methyl-3,4-dihydro-2(l//)-quinoxalinone (565), and 6-chloro-l-methyl-3,4-dihydro-2(l//)-quinoxalinone (567) (EtOH, reflux, 21 h 2%, 8%, and 20%, respectively, after separation structures 564 and 565 were... [Pg.77]

An analogous substrate, dimethyl 10-chloro-7-methyl-6-oxo-l lb-phenyl-5,6,7,1 lb-tetrahydroisoxazolo[2,3-d][l,4]benzodiazepine-l,2-dicarboxylate (566), gave not 567 but 6-chloro-l-methyl-2(l/7)-quinoxalinone (EtOH, reflux, 30 h -40%). ... [Pg.77]

As in the preceding subsection, l,2-bis(benzenesulfonylimino)-4,5-dimethyl-benzene (598) and 2-phenylthiazolo[3,2-fl]quinolinium-l-olate (599) in dichloromethane at 20°C during 15 min afforded l,4-bis(benzenesulfonyl)-6,7-dimethyl-3-phenyl-3-(quinolin-2-ylthio)-3,4-dihydro-2(l//)-quinoxalinone (600) in almost quantitative yield. " ... [Pg.82]

Dimethoxy-3-phenyl-2(l/7)-quinoxalinone gave 2-chloro-5,7-dimethoxy-3-phenylquinoxaline (4) (POCI3, reflux, 30 min 94%) " 6,7-dimethoxy-2,3(1//,4//)-quinoxalinedione gave 2,3-dichloro-6,7-dimethoxyquinoxaline (5) (POCI3, 100°C, 4h 83%)J ... [Pg.134]

Dunethoxy-3-phenyl-2(l/7)-quinoxalinone gave 2-bromo-5,7-dimethoxy-3-phenylquinoxaline (19) (PBr3, 135°C, 75 min 50%)." ... [Pg.137]

The kinetics for alkaline hydrolysis of 2-(o-, m-, or -nitrophenoxy)quinoxaline to 2(171)-quinoxalinone have been measured in some detail. 6,7-Dimethoxy-2-phenylquinoxaline (17) gave 2-phenyl-6,7(l//,4//)-quinoxaline-dione (18) (48% HBr, reflux, 23 h 53% as hydrobromide). [Pg.191]

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%). ... [Pg.198]

Note Such deoxygenation is usually accompanied by partial nuclear reduction. 3-phenyl-2(177)-quinoxalinone (90) gave 2-phenyl-3,4-dihydroquinoxaline (91) (LiAlH4, THF, N2, 0°C reflux, 24 h 65%). ... [Pg.203]

Amino-5,7-dimethoxy-3-phenyl-2(17/)-quinoxalinone (127) gave 6-methoxy-3-oxo-2-phenyl-3,4-dihydro-5,8-quinoxalinequinone (128) (NaI04, H2SO4, MeOH, H2O, 20°C, 3 min 87%). ... [Pg.208]

Methyl-l-phenyl-2(17/)-quinoxalinone (226) and methyl methacrylate (227) gave the photoadduct, methyl l,2a-dimethyl-3-oxo-4-phenyl-2,2a,3,4-tetra-hydro-l//-azeto[l,2-fl]quinoxaline-l-carboxylate (228) as a separable mixture of two stereoisomers (CH2CI2, MeOH, hv, N2, <15 h 40% each) analogs likewise. " ... [Pg.225]

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... [Pg.226]

Amino-3-phenyl-3,4-dihydro-2(177)-quinoxalinone (181) and triphosgene gave 4-phenyl-47/-imidazo[l,5,4-< e]quinoxaline-2,5(l//, 6//)-dione (182) (EtsN, THF, 20°C, N2, until substrate gone by tic 65%) analogs Ukewise. ... [Pg.293]

Amino-3-phenyl-3,4-dihydro-2(l//)-quinoxalinone (194) gave 5-phenyl-2,3-dihydro-17/, 5//-pyrazino[l,2,3-tie]quinoxaline-2,3,6(77/)-trione (195) [(COCl)2,... [Pg.294]

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... [Pg.407]

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