Quinoxalinones oxidation

In contrast, the reaction of dimethyl acetylenedicarboxylate with the benzodiazepinone 4-oxide 21 gives the quinoxalinone 24 by way of the isolable intermediates 22 and 23.249... [Pg.416]

Dimethyl-1,4-benzoquinone (328) and ethylenediamine (329) gave 7,8-dimethyl-6(4//)-quinoxalinone (330) (EtOH-CH2Cl2, 20°C, light exclusion 35% the required oxidation was probably provided by an excess of the quinone). ... [Pg.44]

Benzenediamine (358) and 5-(l,2-dihydroxyethyl)tetrahydro-2,3,4-furane-trione (359) (prepared in situ by oxidation of ascorbic acid with p-benzoqui-none) gave either 3-(2,3,4-trihydroxybutyryl)-2(17i)-quinoxalinone (360)... [Pg.49]

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-6-chloroquinoxaline 4-oxide (22, R = N3) gave 3-azido-7-chloro-2(lT0-quinoxalinone (23, R = N3) (AC2O, AcOH, reflux, 4 h 46%) " ° 6-chloro-2-piperidinoquinoxaline 4-oxide [22, R = N(CH2)s] gave 7-chloro-3-piperidino-2(177)-quinoxalinone [23, R = N(CH2)5](likewise 58%)." °... [Pg.192]

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]

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]

Fluoro-2(17/)-quinoxalinone 4-oxide (273) gave 6-fluoro-3-methyl-2(l//)-quinoxalinone (275), probably by degradation of the adduct (274) (ACCH2-COjEt, PhH, H2O, NaOH, 65°C, 1 h % several analogs likewise). ... [Pg.236]

The A-oxide tautomer, l-hydroxy-5,6,7,8-tetrahydro-2(l//)-quinoxalinone (284) gave l-benzyloxy-5,6,7,8-tetrahydro-2(l//)-quinoxalinone (285) (PhCH2Cl,... [Pg.237]

Benzenesulfonyl-l-ethoxycarbonylmethyl-3,4-dihydro-2(l//)-quinoxalinone (8) gave either l-carboxymethyl-2(l//)-quinoxalinone (9) (1.25M NaOH, reflux, 6 h 92% note additional nuclear oxidation by loss of PhS02H) or 4-benzenesulfonyl-1 -carboxymethyl-3,4-dihydro-2(lfl)-quinoxalinone (10) (H2 SO4, AcOH, H2O, 80°C, 15 min then 60°C, 5 h then 20°C, 16 h 27%). Methyl 3-methyl-2-quinoxalinecarboxylate 1,4-dioxide (11, R = Me) gave 3-methyl-2-quinoxalinecarboxyhc acid 1,4-dioxide (11, R = H) (Et3N, CaCl2,... [Pg.319]

Ethyl-l-methyl-2(17T)-quinoxalinone 4-oxide Ethyl 3-morpholino-2-quinoxalinecarboxylate Ethyl 6-nitro-2-quinoxalinecarboxylate... [Pg.407]

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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