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1.
Several pyridazino[4,5-c]pyridazines substituted in the 5- and 8-positions with hydroxyl, mercapto and amino groups and in the 3-position with a methyl group or a hydrogen atom have been prepared. In the course of this work five previously unreported pyridazine derivatives have also been synthesized. 相似文献
2.
《Tetrahedron letters》1988,29(47):6171-6172
A new synthesis of imidazo [4,5-c] pyrazoles, obtained through cyclisation of 4-nitroso-5-alkylamino-pyrazoles, is described. 相似文献
3.
Tetsuo Yamasaki Eiji Kawaminami Fumi Uchimura Tadashi Okawara Mitsuru Furukawa 《Journal of heterocyclic chemistry》1991,28(4):859-865
The reaction of 5(4)-amino-4(5)-chloropyridazin-3(2H)-ones 1 (9 ) with methyl dithiocarbamates 2 gave 2-arylaminothiazolo[4,5-d]pyridazinones 3 (10 ). Treatment of 5(4)-alkylamino-4(5)-chloropyridazin-3(2H)-ones 5 (12 ) with 2 afforded the corresponding 2-aryliminothiazolo[4,5-d]pyridazinones 6 (13 ). Cyclization of 1a with phenylisothiocyanate produced 2-amino- and 2-iminothiazolo[4,5-d]pyridazinones 3a and 16 . 相似文献
4.
The parent imidazo[4,5-c]pyridazine (IV) has been prepared for the first time by three different routes. 1-Methylimidazo[4,5-c]pyridazine (XX) and 3-methylimidazo[4,5-c]pyridazine (XXVII) have been prepared by unequivocal syntheses. The constitution of the methylation product of imidazo[4,5-c]pyridazine-2-thiol (VIII) has been shown to be 2-methylthioimidazo[4,5-c]-pyridazine (IX) by the unequivocal syntheses of 1-methylimidazo[4,5-c]pyridazine-2-thiol (XXIII) and 3-methylimidazo[4,5-c]pyridazine-2-thiol (XXXIII). Likewise, the structure of the methylation product (XIII) was shown to be S-methylation by the unequivocal syntheses of 1-methyl-2-methylthio-6-chloroimidazo[4,5-c]pyridazine (XXIV) and 3-methyl-2-methylthio-6-chloroimidazo[4,5-c]pyridazine (XXXI), respectively. Several 7-substituted amino-v-triazolo-[4,5-c]pyridazines (XXXVIII) have been prepared from 7-chloro-v-triazolo[4,5-c]pyridazine (XXXVII). 相似文献
5.
Diethoxymethyl acetate was used to cyclize o-disubstituted aminopyridines to oxazolo[4,5-c]pyridines and imidazo[4,5-c]pyridines. All the possible imidazole-methylated imidazo[4,5-c]pyridines were prepared. A novel synthesis of 2-substituted thiazolo[5,4-c]pyridines and 4-amino-3-pyridinethiol was discovered. 相似文献
6.
A. Monge Vega I. Aldana M. M. Rabbani E. Fernandez-Alvarez 《Journal of heterocyclic chemistry》1980,17(1):77-80
This paper describes the synthesis of the previously unknown 11H-1,2,4-triazolo[4,3-b]pyridazino[4,5-b]indoles (2) and 11H-tetrazolo[4,5-b]pyridazino[4,5-b]indoles (3) from 4-hydrazino-5H-pyridazino[4,5-b]indoles (1) , as well as the synthesis of 1,2,4-triazolo[3,4-f]-1,2,4-triazino-[4,5-a]indoles (10) from 2-indolecarbohydrazide (4) . Compounds 2 were obtained by acylation of compounds 1 , followed of thermal cyclization and compounds 3 by treating compounds 1 with nitrous acid. The reactions of compound 4 with formic acid or ethyl orthoformiate gave 1,2-dihydro-1-oxo-1,2,4-triazino[4,5-a]indole (6) . Treating this last compound with phosphorus oxychloride or phosphorus pentasulfide, followed by hydrazine, gave 1-hydrazino-1,2,4-triazino-[4,5-a]indole (9) . Acylation of this last compound, followed of cyclization gave compounds 10 . All the compounds were characterized by elemental analysis and ir and 1H-nmr spectra. 相似文献
7.
Takenari Nakagome Raymond N. Castle Hirotaka Murakami 《Journal of heterocyclic chemistry》1968,5(4):523-532
The Hofmann reaction on 6-methylpyridazine-3,4-dicarboxamide (1) gave a mixture of 3-methylpyrimido[4,5-c]pyridazine-5,7-dione (2), 3-methylpyrimido[5,4-c]pyridazine-6,8-dione (3) and an acid (4) of unknown structure. The Hofmann reaction on pyridazine-3,4-dicarboxamide (9) gave a mixture of pyrimido[4,5-c]pyridazine-5,7-dione ( 10 ) and an acid ( 11 ) of unknown structure. The reaction of 3-amino-6-methylpyridazine-4-carboxamide ( 18 ) with ethyl orthoformate gave 3-methylpyrimido[4,5-c]pyridazin-5-one ( 21 ). 4-Aminopyridazine-3-carboxamide ( 36 ) upon fusion with urea gave pyrimido[5,4-c]pyridazine-6,8-dione ( 37 ) while with ethyl orthoformate 36 gave pyrimido[5,4-c]pyridazin-8-one ( 38 ). Pyrimido[5,4-c]-pyridazine-8-thione ( 39 ) was obtained by the action of phosphorus pentasulfide on 38. 4-Amino-3-cyanopyridazine ( 16 ) when treated with formamide produced 8-aminopyrimido[5,4-c]-pyridazine ( 41 ). The synthesis of 4-aminopyridazine-3-carboxamide ( 36 ) and 4-amino-3-cyanopyridazine ( 16 ), both key intermediates in the synthesis of the novel pyrimido[5,4-c]pyridazine ring system was accomplished by the Reissert reaction of 4-aminopyridazine-2-oxides and subsequent conversion of the nitrile to the amide. 相似文献
8.
Linneaus C. Dorman 《Journal of heterocyclic chemistry》1967,4(4):491-499
1,4-Bis(methyIthio)pyridazino[4,5-d]pyridazine (IV) was synthesized from 4,5-pyridazinedi-carboxylic acid in three steps. By employing IV as an intermediate, various 1,4-disubstituted pyridazino[4,5-d]pyridazine derivatives of classes 1,4-N,S; 1,4-N,O; 1,4-O,S; and 1,4-O,O were prepared by one-step or two-step nucleophilic substitution reactions. Steric, polar and resonance effects were observed in some of these reactions and are discussed. 相似文献
9.
Chiara B. Vicentini Augusto C. Veronese Maurizio Manfrini 《Journal of heterocyclic chemistry》1997,34(2):629-632
The synthesis of imidazo[4,5-c]pyrazol-5-ones ( 6 ) is reported. 5-Amino-4-ethoxycarbonylaminopyra-zoles 3a-g when heated at 200° for 2 hours afford 6a-g. In a similar manner imidazo[4,5-c]pyrazol-5-one ( 6a ) is readily obtained from 4-amino-5-ethoxycarbonylaminopyrazole ( 5a ). 相似文献
10.
11.
The synthetic chemistry of the relatively unknown pyridazino [4,5-d]pyridazine ring system has been extended. 1,4-Diaminopyridazino [4,5-d]pyridazine (VIII) has been prepared by two routes, the most interesting of these being the one-step conversion of 4,5-dicyanopyridazine into VIII with hydrazine. Upon nitration VIII gave only the mononitramine (X). Attempts to prepare 1,4-dichloropyridazino [4,5-d]pyridazine gave only 4-chloro-2H-pyridazino [4,5-d]pyridazin-1-one (XII). Pyrimido [4,5-d]pyridazine-1,3-dione (XIV) was prepared from pyridazine-4,5-dicarboxamide (IV). The hydrolysis of 5,8-dichloropyrazino [2,3-d]pyridazine (XV) gave 5-chloropyrazino [2,3-d]pyridazin-8-one (XVII) and likewise the ammonolysis of XV gave 5-amino-8-chloropyrazino [2,3-d]pyridazine (XX). As expected the hydrolysis of 5,8-dibromo-pyrazino [2,3-d]pyridazine (XXI) gave 5-bromopyrazino [2,3-d]pyridazin-8-one (XXII). Attempted catalytic dechlorination of 5-chloropyrazino [2,3-d]pyridazin-8-one (XVII) gave 1,2,3,4-tetrahydropyrazino [2,3-d]pyridazin-5-one (XIX). 相似文献
12.
The dihydropyridazine ring undergoes contraction to a dihydropyrrole ring to give 1-phenyl-2-benzylideneaminodihydropyrrolo[3,4-b]indol-3-ones when 1-phenyldihydropyridazino[4,5-b]indol-4-ones are treated with aromatic aldehydes under acid catalysis conditions. The reaction mechanism consists in the formation of a (3-indolyl)phenylmethyl cation, which leads to opening of the pyridazine ring and subsequent development of a bond between the carbonium center and the amide nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1406–1408, October, 1976. 相似文献
13.
14.
Eugene B. Frolov 《Tetrahedron letters》2004,45(24):4693-4696
A convenient and versatile synthetic approach to substituted 1,3-oxazolo[4,5-d]pyridazinones is developed. The oxazole ring was formed upon reaction of 5-amino-4-hydroxy-3(2H)-pyridazinone with various carboxylic acid derivatives using a microwave-assisted procedure, which favors the reaction time and purity of the resulting products. The developed methodology is suitable for rapid, parallel, automated synthesis of oxazolopyridazinone libraries. 相似文献
15.
16.
N. F. Kucherova L. A. Aksanova L. M. Sharkova V. A. Zagorevskii 《Chemistry of Heterocyclic Compounds》1973,9(7):835-837
The condensation of O-phenylhydroxylamine with piperidin-4-one and 3-methylpiperidin-4-one has given 1,2,3,4-tetrahydrobenzofuro[3,2-c]pyridine and 4-methyl-1,2,3,4-tetrahydro-benzofuro [3,2-c]pyridine, and these have been dehydrogenated to the corresponding heteroaromatic system of benzofuro[3,2-c]pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No.7, pp. 908–909, July, 1973. 相似文献
17.
Yutilov Yu. M. Smolyar N. N. Astashkina N. V. 《Russian Journal of Organic Chemistry》2002,38(3):419-423
Reduction of 1-substituted [1,2,3]triazolo[4,5-c]pyridines with nickel-aluminum alloy in aqueous alkali gave 2-azaspinaceamines. Reduction of imidazo[4,5-c]pyridine and [1,2,3]triazolo[4,5-c]pyridine derivatives with formic acid in the presence of triethylamine resulted in formation of 5-formylspinaceamines and 2-azaspinaceamines. The 5-formyl group in the latter can be removed by acid hydrolysis. Unsubstituted 2-azaspinaceamine, an aza analog of natural spinaceamine, was synthesized for the first time. 相似文献
18.
The compounds prepared in the novel pyridazino[4,3-e]-as-triazine ring system are: 8-chloro-4-methyl-3,4-dihydropyridazino[4,3-e]-as-triazine ( 21 ), 8-chloro-2,4-dimethyl-3,4-dihydropyridazino[4,3-e]-as-triazine ( 23 ), 8-chloro-2-ethyl-4-methyl-3,4-dihydropyridazino[4,3-e]-as- triazine ( 24 ), 4-methyl-3,4-dihydropyridazino[4,3-e]-as-triazine-8-thione ( 25 ), 4-methyl-3,4-dihydropyridazino[4,3-e]-as-triazine ( 26 ), 2,4-dimethyl-3,4-dihydropyridazino[4,3-e]-as-triazine ( 27 ), and 2-ethyl-4-methyl-3,4-dihydropyridazino[4,3-e]-as-triazine ( 28 ). In the novel pyridazino[4,5-e]-as-triazine ring system the following compounds were prepared: 1,2-dihydropyridazino[4,5-e]-as-triazine ( 31 ), 3-methyl-1,2-dihydropyridazino[4,5-e]-as-triazine ( 32 ), 3-ethyl-1,2-dihydropyridazino[4,5-e]-as-triazine ( 33 ), and 1-methyl-1,2-dihydropyridazino[4,5-e]-as-triazine ( 35 ). The preparation of a number of previously unreported intermediates and compounds for structure proof are also described. 相似文献
19.
The synthesis of novel imidazo[4,5-c]pyridines 11-13 and imidazo[4,5-b]pyridines 18-20 is described using 2 as the starting material. The synthesis is generally applicable for the introduction of a wide variety of substituents. 相似文献
20.
A new synthesis of three isomeric dihydrofuroquinolines is described. This route via ortholithiation of O-quinolyl carbamates is considerably more effective than that which proceeds via lithiation of alkoxyquinolines. 相似文献