6-Methyl-2 -quinoxalinone

Alkylation of pyrazinones and quinoxalinones may be carried out under a variety of conditions and it is usually observed that while O-alkylation may occur under conditions of kinetic control, to yield the corresponding alkoxypyrazines or alkoxyquinoxalines, under thermodynamic control the A-alkylated products are formed. Alkylation using trialkyl-oxonium fluoroborate results in exclusive O-alkylation, and silylation under a variety of conditions (75MI21400) yields specifically the O-silylated products. Alkylation with methyl iodide or dimethyl sulfate invariably leads to A-methylation. [Pg.173]

Chloro-l-methyl-2-quinoxalinone (215), which cannot anionize, reacts readUy with iV -methylaniline. 6-Bromo-as-triazine-3,5-dione (216) is largely anionized by dimethylamine but not by thiourea... [Pg.248]

A,A-Dibenzyl-2-(ethoxycarbonylmethyl)amino-4-(trifluoromethyl)aniline (27) underwent reductive debenzylation and spontaneous cyclization to 6-trifluoro-methyl-3,4-dihydro-2(17/)-quinoxalinone (28) [Pd(OH)2/C, EtOH, H2 (3 atm), 3 days 97%]. " °... [Pg.5]

Methyl-1,2-benzenediamine (215, R = Me) with the hydrate of 3,3,3-trifluoro-pyruvic acid gave a mixture of isomers (216, R = Me) and (217, R = Me) (dioxane, reflux, 30 min 98%) from which neither appears to have been isolated in a pure state in contrast, 4-nitro-1,2-benzenediamine (215, R = NO2) and the same synthon gave a mixture of 6-nitro- (216, R = NO2) and 7-nitro-3-trifluoromethyl-2(l//)-quinoxalinone (217, R = NO2) (dioxane, reflux, 4 h 95%), from which both isomers were isolable, albeit with... [Pg.31]

The same substrate (218) and ethyl ethoxalylacetate (Et02CC0CH2C02Et) gave 3-ethoxycarbonylmethyl-2(l//)-quinoxalinone (221, R = H) (EtOH, reflux, 3 h 80% ° likewise but 15 min 64%) the homologous substrate, 3,6-dimetyl-l,2-benzenediamine, and the same synthon gave 3-ethoxycarbonyl-methyl-5,8-dimethyl-2(l//)-quinoxalinone (221, R = Me) (AcOH, reflux, briefly 61%). ... [Pg.32]

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]

In contrast, 4-methyl-1,2-benzenediamine (263) and the same synthon (261) gave an inseparable 70 30 mixture of 3-amino-7-methyl- (264) and 3-amino-6-methyl-2(177)-quinoxalinone (265) [EtOH, 25°C, >8 h 77% (mixture)] likewise analogous mixtures. [Pg.38]

Benzenediamine (355) and 3-bromomethyl-4-methyl-2,5-dihydro-2,5-furan-dione (2-bromomethyl-3-methylmaleic anhydride 356) gave 3-(l-carboxy-vmyl)-3-methyl-3,4-dihydro-2(17/)-quinoxalinone (357) with loss of hydrogen bromide (CHCI3, — 15°C 20°C, 4 h 86%) a rational mechanism was... [Pg.48]

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]

Although useful, this synthesis of reduced quinoxalines has not been fully developed yet. 7-Azabicyclo[4.1.0]heptane (423, R = H) and glycine (424, Q = H) in refluxing aqueous ammonium chloride for 90 min gave octahydro-2(l//)-quinoxalinone (425, Q = R = H) in 40% yield." Similar treatment of 7-methyl-7-azabicyclo[4.1.0]heptane (423, R = Me) gave l-methyloctahydro-2(l//)-quinox-alinone (425, Q = H, R = Me) in 62% yield and 7-methyl-7-azabicyclo[4.1.0] heptane (423, R = Me) with L-alanine (424, R = Me) in refluxing aqueous ammonium chloride for 16 h gave two separable diastereoisomers of 1,3-dimethylocta-hydro-2(l//)-quinoxalinone (425, Q = R = Me), isolated as hydrochlorides in 26%... [Pg.57]

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]

Azido-3-methyl-2-indolinone (508) gave 3-methyl-2(l//)-quinoxalinone (509)... [Pg.68]

A/,//-Dunethylfuro[2,3-/>]qumoxalme-3-carboxamide (556) (as hydrochloride) in hot acidic or alkaline media for 1 h gave 3-methyl-2(l//)-quinoxalinone (555) in 60% or 95% yield, respectively " In contrast, the same amidic substrate (556) in hot alcoholic aUcoxide afforded 3-ethoxycarbonylmethyl- (557, R = Et) or... [Pg.75]

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]

Dimethoxy-1 -methyl-3-p-nitrostyryl-2( l//)-quinoxalinone gave 3-p-amino-phenethyl-6,7-dimethoxy-l-methyl-2(l//)-quinoxalinone (102) (H2, Pt02, AcOEt, 20°C 72% note incidental reduction of the nitro group). [Pg.111]

Ethoxalylmethyl-l-methyl-2(177)-quinoxalinone (118) underwent deacylation to give l,3-dimethyl-2(177)-quinoxalinone (119) (80% H2NNH2-H20, reflux,... [Pg.114]

Methyl-2(l//)-quinoxalinone (138) gave 3-(3-benzoylacetonyl)-2(17/)-quinox-alinone (139) [LiNPr 2 (made in situ), THF, reflux—>20°C, 90 min then BzCH2C02Et, 20°C, 2h 91%] several analogs like 3-nicotinoylmethyl-... [Pg.117]

Methoxycarbonylmethyl-1 -methyl-2( 177)-quinoxalinone gave 3-[a-methoxy-carbonyl-a-(p-tolylhydrazono)methyl]-l-methyl-2(177)-quinoxalinone (171) [ i-MeCcH4N20Ac (prepared in situ), ACOH-H2O, 20°C 95°C, 1 h 36%] " analogous esters likewise." " ... [Pg.123]

Chloro-l-methyl-2,3(l//,4/i)-quinoxalmedione (6) gave 3,6-dichloro-l-methyl-2(l//)-quinoxalinone (7) (POCI3, reflux, 90 min 74% note immunity of... [Pg.134]

Methyl-6-nitro-2(l//)-quinoxalinone gave the 2-chloro-3-methyl-6-nitroqui-noxaline (12) (POCI3, PhNMe2, reflux, 2h 86%). ... [Pg.135]

Chloro-l-methyl-2(l//)-quinoxalinone (120) gave 3-(// -ethoxycarbonylhy-drazino)-l-methyl-2(l//)-quinoxalinone (121) (EtOaCNHNHa, MeCN, 120°C, sealed , 2h %) analogs likewise. ... [Pg.156]

Dichloro-l-methyl-2(lf/)-quinoxalinone (173, R = C1) gave 3-azido-6-chloro-l-methyl-2(l//)-quinoxalinone (173, R = N3) (NaNs, Mc2NCHO, 120°C, 90 min 96%) analogs Ukewise. ... [Pg.165]

Bromomethyl-l-methyl-2(l//)-quinoxalinone (268, R = Br) gave l-methyl-3-phenoxymethyl-2(17/)-quinoxalinone (268, R = OPh) (PhOH, NaOH, Me3PhCH2NCl, CHCI3-H2O, 50°C, tic monitored 41% analogs like-wise). 5... [Pg.181]

Bromomethyl-6,7-dimethoxy-l-methyl-2(l//)-quinoxalinone reacts with many fatty and other acids (K2CO3, 18-crown-6, MeCN, 80°C, 20 min) to afford analytically useful fluorescent esters. " ... [Pg.183]

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