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1.
To determine the structures of two isomeric products, 2-phenacylidene-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (2) and 3-phenacylidene-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (3) obtained by condensation of 2,3-diaminopyridine (1) with ethyl benzoylpyruvate [1–3], these compounds were hydrolyzed to give 2-methyl-4H-pyrido[2,3-b]pyrazin-3-one (4) and 3-methyl-1H-pyrido[2,3-b]pyrazin-2-one (5) , respectively [4,5]. Both hydrolysates 4 and 5 were hydrogenated to afford 2-methyl-1,2-dihydro-4H-pyrido[2,3-b]pyrazin-3-one (6) and 3-methyl-3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-one (7) . The latter compound was identical with an unequivocally synthesized compound providing proof for the structures of all these compounds. 相似文献
2.
Condensation of 2,3-diaminopyridine ( 1 ) with ethyl o-, m- and p-substituted benzoylpyruvates 2–9 gave two isomeric products. The preferential formation of one or the other isomer has been achieved by different reaction conditions. All the products appear to exist in the enamine form as evidenced by their 1H nmr and ir spectra. 相似文献
3.
George Bobowski 《Journal of heterocyclic chemistry》1987,24(2):473-479
Treatment of 2-(4,9-dihydro-3H-pyrido[3,4-b]indol-1-yl)-1-methylcyclohexanol ( 2a ) with acetic anhydride or methyl isocyanate gave 2-acetyl-2,3,4,9-tetrahydro-1-(6-oxoheptylidene)-1H-pyrido[3,4-b]indole ( 3 ) or 1,3,4,9-tetrahydro-N-methyl-1-(6-oxoheptylidene)-2H-pyrido[3,4-b]indole-2-carboxamide ( 4 ), respectively. Simpler analogues, 1-alkyl-4,9-dihydro-3H-pyrido[3,4-b]indoles, 7 , subjected to identical reaction conditions, gave 2-acetyl-1-alkylidene-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indoles 8 and 1,3,4,9-tetrahydro-N-methyl-1-alkyli-dene-2H-pyrido[3,4-b]indole-2-carboxamides 9 , respectively. A limited lanthanide shift reagent study to determine stereochemical assignments was also performed. 相似文献
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5.
A series of novel 2-hydrazinylpyrido[2,3-b]pyrazin-3(4H)-one derivatives were synthesized and evaluated for their cytotoxic activities against A549,MDA-MB-231 and HT-29 cell lines in vitro.Pharmacological data indicated that compounds 5b,5c,10a and 10g possessed marked cytotoxicity,especially 10a(with IC50 values of 0.81,2.56 and 1.63μmol/L against A549,MDA-MB- 23 1 and HT29 cell lines,respectively),which had emerged as a lead compound. 相似文献
6.
Harry L. Yale 《Journal of heterocyclic chemistry》1975,12(2):427-431
7.
Milo Budínský Jindich Symerský Jaroslav Podlaha Jana Podlahov Zdenk Polívka Miroslav Protiva 《Journal of heterocyclic chemistry》1989,26(5):1229-1235
The unexpected formation of 11H-pyrido[2,1-b]quinazolin-11-one derivative 6 from 5,11-dihydro-6H-pyrido[2,3-b]-1,4-benzodiazepin-6-one (2) has been observed. Its structure 6 was determined by X-ray crystallography. Detailed nmr study provided a complete set of proton and carbon-13 nmr parameters of compound 6 in solution. 相似文献
8.
Dario Giardina Roberto Ballini Marcello Ferappi Giovanni Casini 《Journal of heterocyclic chemistry》1978,15(6):993-995
The: title compounds were prepared from Michael adducts, obtained from acetoacetic esters and trans-3-hexene-2,5-dione, and from the corresponding dehydration products, by direct cyclization to oxygen rings or by reaction with ammonia (or methylamine) to give nitrogen rings. 相似文献
9.
10.
Yasumitsu Tamura Ling Ching Chen Masanobu Fujita Yasuyuki Kita 《Journal of heterocyclic chemistry》1980,17(1):1-4
The Synthesis of novel 1-substituted 3-anilino-4-diethylaminomethyl-5-oxo-3,4-dehydro-piperidines and 2-substituted 1,2,3,5,6,11-hexahydro-5-phenyl-4H-pyrido[3,4-b][1,5]benzo diazepin-4-ones from the β-arylaminovinylketones derived from N-substituted piperidine-3,5-diones is described. 相似文献
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12.
It is shown that derivatives of a new heterocyclic system, viz., thiazolo[3,4-b][1,2,4]triazole, the structure of which was established by means of their IR and PMR spectra, are formed in the reaction of 5-substituted 3-aminorhodanines with imidoyl chlorides.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 331–333, March, 1982. 相似文献
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14.
Several pyrido[2,1-b]thiazines and thiazolo[2,3-a]pyridines were synthesized by reactions of cinnamonitriles with appropriate halocarbonyl compounds. Hydrazones of 3-diazotized aminopyrazolo[3,4-b]pyridinones were synthesized by coupling of their corresponding diazonium salts with several active methylene reagents. The obtained hydrazones were cyclized in refluxing ethanol containing a catalytic amount of triethylamine to afford the corresponding pyrazolopyridotriazines. All structures were established by considering the data of elemental analyses, IR, 1H-NMR, and mass spectra. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9: 571–579, 1998 相似文献
15.
The synthesis of some pyrido[3,4-b]pyrano[3,4-b]indoles ( 3 ) from 3-hydroxy-4-(3-indolyl)piperidines ( 6 ) is reported. 相似文献
16.
The mass spectra of fifteen β-carbolines have been interpreted and proposed fragmentations have been substantiated by means of deuterium-labeling and accurate mass determinations. Most decompositions were predictable. An interesting fragmentation was observed in the spectra of 1-alkyl-1,2,3,4-tetrahydro-β-carbolines, which rearrange to expel an alkylamino (RNH) radical from the molecular ion. 相似文献
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18.
The synthesis and characterization of a number of 3-aryl-6H-isoxazolo[3,4-d]pyrazolo[3,4-b]pyridines and 3-aryl-6H-isoxazolo[5,4-d]pyrazolo[3,4–6]pyridines from common precursors, 5-benzoyl-4-chloro-1H-pyrazolo-[3,4-b]pyridines, has been described. The structures were determined by unambiguous chemical synthesis and by isolation and 13C nmr analysis of some key, isolated, intermediates. The ability of these compounds to displace [3H]flunitrazepam from CNS binding sites was also observed. 相似文献
19.
N. A. Kogan 《Chemistry of Heterocyclic Compounds》1976,12(8):947-948
20.
2-Amino-3-(o-bromobenzyloxy)pyridine ( 1 ) and ethyl acetoacetate gave 9-(o-bromobenzyl-oxy)-2-methyl-4H-pyrido[1,2-α]pyrimidin-4-one ( 2 ) in 2% yield. When 1 and methyl β-amino-crotonate ( 3 ) were reacted, benzyl ether cleavage occurred and the products were 9-hydroxy-2-methyl-4H-pyrido[1,2-α]pyrimidin-4-one ( 4 ) and its ammonium salt ( 5 ). These observations led to an alternative synthesis in which 2-amino-3-pyridinol ( 6 ) and either 3 or methyl acetoacetate, ( 8 ) in diethylbenzene at 185° gave 4 in 86 and 87% yields, respectively, and the anion of 4 and o-bromobenzyl bromide gave 2 in 61% yield. Even in diethylbenzene at 185°, 1 and 8 gave only trace amounts of 2 . Thus, o-bromobenzylation of the 3-hydroxyl group in 6 markedly decreased the reactivity of the amino group in 6 toward reactions with acetoacetic esters. 相似文献