6- chloro-2-methyl-1.1 -dioxo-3-

Diaminopyridine has been condensed with glyoxal, benzil, - diacetyl,and the pyridils 4. ° Ethyl oxalate yields the 2,3-dioxo compound. The conditions employed for these condensations can be critical. Thus glyoxal in neutral solution yields an unidentified, insoluble, infusible solid, whereas in the presence of acetic acid the reaction readily provides the parent heterocycle.The preferred method makes use of glyoxal sodium bisulfite. Many symmetrical dicarbonyl compounds have been condensed with a variety of 2,3-diaminopyridines substituted in the pyridine ring by bromo, ° chloro, methyl, " or combinations of these substituents. ... 

Purines, N-alkyl-N-phenyl-synthesis, 5, 576 Purines, alkylthio-hydrolysis, 5, 560 Mannich reaction, 5, 536 Michael addition reactions, 5, 536 Purines, S-alkylthio-hydrolysis, 5, 560 Purines, amino-alkylation, 5, 530, 551 IR spectra, 5, 518 reactions, 5, 551-553 with diazonium ions, 5, 538 reduction, 5, 541 UV spectra, 5, 517 Purines, N-amino-synthesis, 5, 595 Purines, aminohydroxy-hydrogenation, 5, 555 reactions, 5, 555 Purines, aminooxo-reactions, 5, 557 thiation, 5, 557 Purines, bromo-synthesis, 5, 557 Purines, chloro-synthesis, 5, 573 Purines, cyano-reactions, 5, 550 Purines, dialkoxy-rearrangement, 5, 558 Purines, diazoreactions, 5, 96 Purines, dioxo-alkylation, 5, 532 Purines, N-glycosyl-, 5, 536 Purines, halo-N-alkylation, 5, 529 hydrogenolysis, 5, 562 reactions, 5, 561-562, 564 with alkoxides, 5, 563 synthesis, 5, 556 Purines, hydrazino-reactions, 5, 553 Purines, hydroxyamino-reactions, 5, 556 Purines, 8-lithiotrimethylsilyl-nucleosides alkylation, 5, 537 Purines, N-methyl-magnetic circular dichroism, 5, 523 Purines, methylthio-bromination, 5, 559 Purines, nitro-reactions, 5, 550, 551 Purines, oxo-alkylation, 5, 532 amination, 5, 557 dipole moments, 5, 522 H NMR, 5, 512 pJfa, 5, 524 reactions, 5, 556-557 with diazonium ions, 5, 538 reduction, 5, 541 thiation, 5, 557 Purines, oxohydro-IR spectra, 5, 518 Purines, selenoxo-synthesis, 5, 597 Purines, thio-acylation, 5, 559 alkylation, 5, 559 Purines, thioxo-acetylation, 5, 559... 

Dioxo derivatives of 474 are known, " as well as 5-chloro-1,2-dihydro-1 -methyl-3-oxo-l,2,4,6,8-pentaazanaphthalene. ... 

Linearly annelated 2-methyl-4,9-dioxo-4,9-dihydrooxazolo[4,5-g]quinoline 14 was prepared in 31% yield by cyclization of 6-acetamido-7-chloro-5,8-dioxo-5,8-dihydroquinoline in acetic anhydride and sulfuric acid (59LA108). 

Acetylation of 6-amino-7-chloro-5,8-quinolinedione and subsequent replacement of the chlorine atom to a -SH and then a -SMe group gave the final linear 2-methyl-4,9-dioxo-4,9-dihydrothiazolo[4,5-g]quinoline 40 (59LA108). 

Chemical Name 7-chloro-4-dimethylamino-1,4,4a,5,5a,6,11,12a octahydro-3,6,10,12,12a-pentahydroxy-6-methyl-1,11 -dioxo-2-naphthacenecarboxamide... 

V-[[l-[4-chloro-2-(2-chlorobenzoyl)phenyl]-3-[(dimethyl-amino)carbonyl]-l/f-l,2,4-triazol-5-yl]methyl]-l,3-dihy-dro-l,3-dioxo-2H-isoindole-2-acetamide (C29H22CI2NSO5 65699-00-5) see Rilmazafone... 

Demeclocycline Demeclocycline, 7-chloro-4-dimethylamino-l, 4,4a,5,5a,6,11,12a-octahy-dro-3,6,10,12,12a-pentahdroxy-l,ll-dioxo-2-napthacencarboxamide (32.3.4), is prodnced by a mntant strain of S. aureofaciens, in which the mechanism of transferring methyl gronps is disrapted, and thus demeclocycline or demethylchlorotetracycline differs from chlorotetracycline, oxytetracycline, and tetracycline in the absence of a methyl gronp at Cg of the hydronaphthacene system. As a result, an antibiotic is synthesized that is more resistant to acids and bases in comparison with the methyl homologs [215-221]. 

Chloro-4-hydroxy-2-methyl-1,1 -dioxo-1,2-dihydro-1 l6-thieno[2,3 e][1,2]thiazine-3-carboxylic acid pyridin-2-ylamide, 6-chloro-4-hydroxy-2-methyl-/V-(2-pyridyl)-2H-thieno[2,3-e]-1,2-thiazine-3-carbox-amide-1,1-dioxide, CnH,oC N30AS2, Mr 371.81, mp 225-230 °C (decomp.)... 

Chloro derivative 291 was obtained from dioxo derivative 70 by treatment of phosphoryl chloride in dimethylformamide at 100°C for 2 hours (80CPB3537). The treatment of chloro derivative 291 with methylhydra-zine in a mixture of ethanol and chloroform under reflux gave 2H-pyrido[ 1,2-a]pyrimidin-2-one 295 and rearranged pyridazino[3,4-6]-quinoxaline 296 in 4.8% and 78% yields, respectively (Scheme 21) (80CPB3537). 3,4-Dihydroquinoxalinone 70 could not be rearranged into pyridazino[3,4-6]quinoxaline 296 by treatment with methylhydrazine. When hydrazine hydrate was employed instead of methylhydrazine, tricyclic ethyl ester 297 (R1 = Et) was obtained. The latter reaction gave methyl ester 297 (R1 = Me) when carried out in a mixture of methanol and chloroform (80CPB3537). 

Alternative synthetic techniques towards TB derivatives were reported by Becker (93TL1889) and Cekavicus (01TL4239). Becker prepared a highly functionalized TB derivative by heating methyl 5-chloro-4-[(ethoxyoxoacetyl)amino]-2-methoxybenzo-ate in DMSO at 180°C. Cekavicus reported that the novel heterocyclic system 3 arose via the intermolecular Mannich reaction of l,l-dioxo-l,2-dihydro-ben-zo[i]thiophen-3-one (Scheme 4). 

Chemical Name l(2H)-Quinazolineacetic acid, 3,4-dihydro-3-((4-bromo-2-fluorophenyl)methyl)-7-chloro-2,4-dioxo-... 

Pyrazino[2,3-rf]pyridazine derivatives are also obtained by cyclocondensation of 4,5-diamino-pyridazines with a-dioxo compounds. Thus, 4,5-diamino-3-chloro-1 -methyl-6( 17/)-pyridazinone (96) and benzil (95) at reflux temperature in acetic acid give a 97% yield of pyrazino[2,3-d]py-ridazinone (97) (Equation (12)) <90MI 719-03). 

SYNS CHLOREPIN CLOBAZAM CLOREPIN FRISIUM H-4723 HR 376 LM-2717 l-PHENYL-5-METHYL-8-CHLORO-l,2,4,5-TETRAHYDRO-2,4-DIOXO-3H-1,5-BENZODIAZEPINE RU-4723 URBANYL... 

H-thieno[2,3-e][l,2]-thiazine-3-carboxamide, 6-chloro-4-hydroxy-2-methyl-N-(2-pyridyl)-l,l-dioxo. 

The following alkoxypyrazines have been prepared from the corresponding dichloropyrazines and alkoxide ions 2,3-dimethoxy-5,6-dimethyl(and diphenyl) (797) 2,3-dibenzyloxy (sodium benzyl oxide in benzyl alcohol at reflux for 24 hours (883)] [but 23-dichloropyrazine with sodium hydride and benzyl alcohol in xylene gave l,4-dibenzyl-2,3-dioxo-l,2,3,4-tetrahydropyrazine)(988)] 2-chloro-5-methoxy (838) 2,5-diethoxy-3,6-dimethyl (872) 2methanolic sodium methoxide refluxed for 2 h) 2,5-dimethoxy-3-phenyl (817) 2-chloro-5-methoxy(and ethoxy)-3,6-diphenyl (817) 2,5-dimethoxy-3,6-dimethyl (and diisopropyl) (844) 2,5-dimethoxy-3-isopropyl-6-methyl (methanolic potassium methoxide at reflux for 6 days) (844) 2(5)-s-butyl-3-chloro-6-ethoxy-5(2)-isobutyl (93) 2-chloro-6-methoxy (838, 883) 2,6-dimethoxy (reflux for 8h) (832) 2,6-diethoxy (reflux for 14 h) (883) 2-benzyloxy-6-chloro (1 equiv. of sodium hydride and benzyl alcohol in benzene at reflux) (832) 2,6-dibenzyloxy (5 equiv. of sodium benzyloxide in benzene at reflux gave 70%) (832) and 3,5-dimethoxy-2-methyl (535). 

Hydrolysis of 2-amino-3-hydroxy-l-methylpyrazinium toluenesulfonate (87) with aqueous sodium hydroxide at 95° afforded 3-hydroxy-l-methyl-2-oxo-l, 2-dihydropyrazine which was also prepared in poor yield from the action of nitrous acid on 3-amino-l-methyl-2-oxo-1,2-dihydropyrazine (832) and hydrolysis of 6-chloro-l-methyl-2-oxo-3,5-diphenyl-1,2-dihydropyrazine with boiling methanolic sodium methoxide (followed by acidification) gave 6-hydroxy-l-methyl-2-oxo-3,5-diphenyl-1,2-dihydropyrazine (873). 1,3,6-Trimethyl-2-oxo-1,2-dihydropyrazine methiodide has been converted through l,4,6-trimethyl-3-methylene-2-oxo-l,2,3,4-tetrahy dropy razine and 3-benzoylmethylene-1,4,6-trimethyl-2-oxo-1,2,3,4-tetra-hydropyrazine (in water) to 1,4,6-trimethyl-2,3-dioxo-l, 2,3,4-tetrahydropyrazine (1129). 

CPPHA (N-(4-chloro-2-[(l,3-dioxo-l,3-dihydro-2H-isoindol-2-yl)methyl] phenyl) -2 -hydroxybenzamide)... 

Bromo-l-chloro-4-methyl- 164, 1469, 2891 8-Bromo-l-chloro-7-methyl- 163 l-Brorno-2,7-dioxo-9,9-diphenyl- 2378 l-Bromo-2,7-dioxo-9-methyl-9-(4-methyl-phenyl)-2378... 

Starting from the corresponding 6-amino-3-methyluracils and the appropriate ethyl 3-chloro-2-formylacrylates, 7,8-disubstitutcd ethyl 3-methyl-2,4-dioxo-2,3,4,8-tetrahydropyrido[2,3-r/]-pyrimidine-6-carboxylates 14 are prepared by heating in dimethylformamide.231... 

Chlorosulfene, generated in situ from chloromethanesulfonyl chloride and triethylamine, reacted with l-methyl-4-(4-morpholinyl)-l,2,5,6-tetrahydropyridine to form 117a and 117b, the two possible stereoisomers of 7-chloro-8,8-dioxo-3-methyl-6-(4-morpholinyl)-8-thia-3-azabicyclo[4.2.0]octane, in a ratio of 56 to 44."5 The reaction of the... 

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