5-Methyl-3,4-dihydro-2 quinoxalinone

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]

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]

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 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]

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]

Hydrazinocarbonylmethyl-2(l//)-quinoxalinone (112) gave 3-azidoformyl-methyl-2(l//)-quinoxalinone (113) (crude material uncharacterized) and thence 3-oxo-3,4-dihydro-2-quinoxalinecarbonitrile (114) [NaN02, H2O, 5°C solid azide, which redissolved on prolonged stirring then 95°C, 2 h product (114) (27% after separation from a major tricyclic product) a mechanism for this one-pot reaction is suggested]... [Pg.338]

At least two derivatives of pyran have been used for the primary synthesis of quinoxalines. Thus o-phenylenediamine (390) and 6-(p-methoxyphenyl)-6-methyl-5,6-dihydro-2//-pyran-2,5-dione (391) in methylene chloride at 20°C open to the air for 48 h gave 3-[2-hydroxy-2-(p-methoxyphenyl)propionyl]methyl-3,4-dihydro-2(1 //)-quinoxalinone (392) (as a mixture of two stereoisomers) in 92% yield 488 the 3,4,4a,5,6,7,8,8a-octahydro analog was made similarly from 1,2-diaminocyclohex-ane (91% of two separable stereoisomers).488... [Pg.53]

This category is represented in the facile reaction of o-phenylenediamine (408) with 4-benzoyl-5-phenyl-2,3-dihydro-2,3-thiophenedione (409) (in toluene at 20°C for 30 min) to afford 3-(a-benzoyl-p-mercaptostyryl)-2(l//)-quinoxalinone (410) in 98% yield 744 also in the complicated reaction of 3-methyl-2,2,4-trinitro-2,5-dihydrothiophene 1,1-dioxide (411) with 2 equiv of ethyl 4-aminobenzoate (412) (in acetonitrile but no further details) to give ethyl 2-(p-ethoxycarbonylphenyl)-3-(l-methyl-2-nitrovinyl)-6-quinoxalinecarboxylate (413) in 51% yield.831 Several... [Pg.55]

Methyl-2( 1 //)-quinoxalinone gave 3-(o-chlorophenylhydrazono)methyl-2( 1H)-quinoxalinone [i.e., 3-oxo-3,4-dihydro-2-quinoxalinecarbaldehyde o-chloro-phenylhydrazone (170)] [0-CIC6H4N2CI (made in situ), HCI-ACOH-H2O, 5°C, 30 min then 95°C, 1 h 98% 20l,210,cf 220 likewise the m- and p-isomers201,210 and analogous products.476,479,485... [Pg.123]

Methyl-3-oxo-3,4-dihydro-2-quinoxalinecarbonitrile 1-oxide (149) gave 6-methyl-2(lfl)-quinoxalinone (150) (Na2S204, H20, EtOH, °C, h %).98... [Pg.344]

Methoxy-4-methyl-3-oxo-2-phenyl-3,4-dihydro-5,8-quinoxalinequinone 6-Methoxy-1 -methyl-3-phcnyl-2(l //)-quinoxalinone... [Pg.415]

Methylamino-2-quinoxalinecarboxylic acid 3-Methylamino-2( I //)-quinoxalinethione 3-Methylamino-2( I //)-quinoxalinone Methyl 5-anilino-8-oxo-4,8-dihydro-6-... [Pg.418]

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