Quinoxalin-2-ones methyl

Synonyms Bay 36205 Bayer 4964 Bayer 36205 Chinomethionat Chinomethionate Cyclic 5, 5 -(6-methyl-2,3-quinoxalinediyl) dithiocarbonate ENT 25606 Erade Erazidon Forstan 6-Methyl-l,3-dithioIo[4,5- ]quinoxalin-2-one 6-Methyl-2-oxo-l,3-dithi-olo[4,5-Z ]quinoxaline 6-Methyl-2,3-quinoxaline dithiocarbonate 6-Methyl-2,3-quinoxa-linedithiol cyclic carbonate 6-Methyl-2,3-quinoxalinedithiol cyclic dithiocarbonate 6-Methyl-2,3-quinoxalinedithiol cyclic 5, 5 -dithiocarbonate 6-Methylquinoxaline-2,3-dithi-olcyclocarbonate S, S -(6-Methylquinoxaline-2,3-diyl) dithiocarbonate Morestan Mores-tane Oxythioquinox Quinomethoate SS 2074. 

Quinoxalin-4-ones, methylation of, 255 Quinoxalin-3-one 1-oxides, 218, 238-239 Quinoxalin-3-one-2-carboxylic acid, 205, 207... 

Poly(phenylquinoxaline—arnide—imides) are thermally stable up to 430°C and are soluble in polar organic solvents (17). Transparent films of these materials exhibit electrical insulating properties. Quinoxaline—imide copolymer films prepared by polycondensation of 6,6 -meth5lene bis(2-methyl-3,l-benzoxazine-4-one) and 3,3, 4,4 -benzophenone tetracarboxyUc dianhydride and 4,4 -oxydianiline exhibit good chemical etching properties (18). The polymers are soluble, but stable only up to 200—300°C. 

The predominance of the oxo forms of quinoxalin-2-one (125) and its 3-methyl derivative in aqueous solution was established by Cheese-man using the pK method, only a lower limit beii obtained for Kt (log Kt> 1.6 and 0.9, respectively) because similar cations are... 

Condensation of o-phenylenediamine or xV-methyl-o-phenylcne-diamine with alloxan (8) in neutral solution gives the ureides (9) and (10), respectively However, reaction of o-phenylenediamine with 1,3-dimethylalloxan (13) yields quinoxalin-3-one-2-carboxymethyl-amide (14), rather than the dimethyl ureide. Methylation of (9) in acetone in the presence of potassium carbonate gives the spiro-hydantoin (11). 

Treatment of an alkaline solution of quinoxalin-2-one or quinoxa-line-2,3-dione with an alkyl iodide or sulfate results in A-methylation. Thus methylation of 3-aminoquinoxalin-2-one (74) with methyl sulfate and alkali gives 3-amino-l-methylquinoxalin-2-one (75) and not as previously reported the isomeric 0-methyl derivative. ... 

Quinoxalin-2-ones are in tautomeric equilibrium with 2-hydroxy-quinoxalines, but physical measurements indicate that both in solution and in the solid state they exist as cyclic amides rather than as hydroxy compounds. Thus quinoxalin-2-one and its A -methyl derivative show practically identical ultraviolet absorption and are bases of similar strength. In contrast, the ultraviolet spectra of quinoxalin-2-one and its 0-methyl derivative (2-methoxyquinoxaIine) are dissimilar. The methoxy compound is also a significantly stronger base (Table II). Similar relationships also exist between the ultraviolet absorption and ionization properties of 3-methylquinoxalin-2-one and its N- and 0-methyl derivatives. The infrared spectrum of 3- (p-methoxy-benzyl)quinoxalin-2-one (77) in methylene chloride shows bands at 3375 and 1565 cm" which are absent in the spectrum of the deuterated... 

Ultraviolet and infrared spectroscopy indicate that quinoxaline-2,3-dione type structures are preferred to tlie tautomeric 3-hydroxy-quinoxalin-2 One or 2,3-dihydroxyquinoxaline forms. The light absorption properties (UV) of quinoxaline-2,3-dione have been compared with those of its NN -, ON-, and OO -dimethyl derivatives (79, 80, and 81), and also its N- and 0-monomethyl derivatives (43 and 82). The parent dicarbonyl compound and its mono- and di-A -methyl derivatives show very strong carbonyl absorption near to 1690 cm split into two peaks. 

The acidic strength of various quinoxaline derivatives is also listed in Table II. -Methyl groups have an acid-weakening effect and quinoxalin-2-one (2-hydroxyquinoxaline) is, as expected, a weaker acid than quinoxaline-2-thione (2-mercaptoquinoxaline), The marked enhancement of the acidic strength of 5-hydroxyquinoxaline 1-methiodide compared to 5-hydroxyquinoxaline itself, is due to the electron-attracting property of the positively charged nitrogen, ... 

Normal reactions are found again for systems containing C=N double bonds. An unstable triazoline is probably an intermediate product in the reaction of pteridin-7-one (117)to give a mixture of the 8-methyl (118) and 6,8-dimethyl derivatives (119). C-Methylation also occurs in the case of quinoxalin-2-one. ... 

Treatment of bis-lactim ether 420 with BuLi, then with cw-l,4-dichloro-2-butene in the presence of Nal afforded 3,4,9,9n-tetrahydro-6//-pyrido[l,2-fl]pyrazin-4-one (421) with 96% diastereomeric excess (97TA1855). Reaction of l,2-diphenyl-6-methyl-quinoxaline with 1,4-dichlorobutane in THF in the presence of Na at —78°C afforded a 3 1 mixture of 4a,5-diphenyl-9-methyl-l,2,3,4-tetrahydro-4a//-pyrido[l,2-n]quinoxaline and 4-(4-chlorobutyl)-2,3-diphenyl-6-methyl-1,4-dihydroquinoxaline (98JHC1349). 

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... 

It has been observed that photolysis of the fungicide, 6-methyldithiolo[4,5-fc]-quinoxalin-2-one (quinomethionate 546) in benzene during 8 h afforded not only 6-methyl-2,3(l//,4//)-quinoxalinedione (547) but also the isomeric phenylated products, 6-methyl- (548, Q = H, R = Me) and 7-methyl-3-phenyl-2(l//)-quinox-alinone (548, Q = Me, R = H). 

Iodoquinoxaline and 4-methyl-5-tributylstannyl-l,3-dithiol-2-one gave 2-(2-0X0-5 -methyl-1,3 -dithiol-4-yl)quinoxaline (63) (l-methyl-2-pyrrolidinone, 5°C, CuTC i, A, 40 min 44%). ... 

Carboxy-l-methylvinyloxy)quinoxaline (54) cyclized to 8-methyl-107/-pyrano 3,2-/]quinoxalin-10-one (54a) (polyphosphoric ester, no details).864... 

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