Synthesis of some new hetarylpyranopyridazines, cinnolines, and hetarylpyridazine derivatives

Abdel-Megid, Mohamed; Gabr, Yassin; Awas, M. A. A.; Abdel-Fatah, Naser Mohamed

doi:10.1007/s10593-010-0433-1

Cited by 15 publications

(10 citation statements)

References 13 publications

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“…When this reaction was carried out in ethanol containing few drops of piperidine, 7-(6-chloro-4-oxochromen-3-yl)-3,4-diphenyl-6,7-dihydropyrano[2,3-c]-pyraidazin-5-one (8) was obtained in 55% yield, via intramolecular cycloaddition reaction in compound 7 (Scheme 4) [24].…”

Section: Condensation Reactions With Active Methyl Compoundsmentioning

confidence: 99%

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3-Formylchromones as diverse building blocks in heterocycles synthesis

et al. 2013

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Section: Condensation Reactions With Active Methyl Compoundsmentioning

confidence: 99%

“…2-(4-Oxo-4H-chromen-3-yl)vinylthiazoline (24) was synthesized by condensation of 3-formylchromone 1a with 2-methylthiazoline in glacial acetic acid containing sodium acetate (Scheme 11) [31].…”

Section: Scheme 10mentioning

confidence: 99%

3-Formylchromones as diverse building blocks in heterocycles synthesis

et al. 2013

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“…Most of these methods usually require rigorous conditions [15], long reaction times [16,17], and complex synthetic pathways [2]. As a part of our studies on diazines [18][19][20][21][22], the present investigation aims to search for simple and efficient routes for the synthesis of polynuclear heterocyclic systems having an uracil nucleus in their structure starting with 6-amino-1,3-dimethyluracil (1), which is considered as a versatile starting material of a typical synthon leading to the target polynuclear heterocyclic systems. The newly synthesized triheterocycles appear to be promising antimicrobial agents.…”

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A convenient route for the synthesis of some new bi- and triheterocondensed uracils

Abdel-Megid

2010

Chem Heterocycl Comp

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Some bifunctional heterocyclic systems having vicinal chlorocyano, chloroacetyl, and chloroethoxycarbonyl groups in their structures reacted with 6-amino-1,3-dimethyluracil to afford novel triheterocyclic systems having a pyrimidinedione moiety. Enaminones and α-cyanocinnamic acid derivatives in this reaction gave pyrido [2,3-d]pyrimidinediones. The antimicrobial activity of some new synthesized triheterocyclic systems was studied.Several bi-and oligocycles containing uracil rings were found to be an important class of compounds exhibiting biological and pharmacological activities. These compounds showed antitumor [1, 2], cardiotonic [3,4], antifungal [5,6], antibronchitic [7], antibacterial [6], and antifolate [8] activities. There are ample precedents for the synthesis of these fused heterocycles [9][10][11][12][13][14]. Most of these methods usually require rigorous conditions [15], long reaction times [16,17], and complex synthetic pathways [2]. As a part of our studies on diazines [18][19][20][21][22], the present investigation aims to search for simple and efficient routes for the synthesis of polynuclear heterocyclic systems having an uracil nucleus in their structure starting with 6-amino-1,3-dimethyluracil (1), which is considered as a versatile starting material of a typical synthon leading to the target polynuclear heterocyclic systems. The newly synthesized triheterocycles appear to be promising antimicrobial agents.It was found that the reaction of compound 1 with some heterocyclic systems having vicinal chlorocyano groups is an interesting one. Thus, when compound 1 was subjected to reaction with 2-chloro-4,6-dimethylpyridine-3-carbonitrile (2) in boiling ethanol containing triethylamine as a base, three possible compounds 3-5 may be produced. The structure of compound 4 was ruled out on the basis of spectral data as IR spectrum of the product exhibited a peak at 2222 cm -1 attributed to the CN function and elemental analysis showed the absence of chlorine. The 1 H NMR spectrum (DMSO-d 6 ) excluded the formation of compound 3 as it displayed a signal at δ 4.70 ppm corresponding to the NH 2 group with the absence of the H-5 signal at δ 5.73 ppm. These confirmed the formation of 2-(6-amino-1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)-4,6-dimethylpyridine-3-carbonitrile (5). Fusion of compound 5 above its melting point or increasing the reaction time between compounds 1 and 2 led to cycloaddition of the amino group of uracil to the cyano group of the other ring giving rise to 5-amino-2,4,7,9-tetramethylpyrimido[4,5-h][1,6]naphthyridine-8,10(7H,9H)-dione (6) (Scheme 1).

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“…As a part of our program directed to the synthesis of new polynuclear bioactive heterocyclic systems [14][15][16][17], the present synthetic strategy is designed to utilize 1,6-diamino-4-(4-chlorophenyl)-2-oxopyridine-3,5-dicarbonitrile (1) as a suitable starting material for the synthesis of nitrogen bridge-head pyrido[1,2,4]triazepines of expected biological activity.…”

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“…A few examples were seen in the literature such as thiazolo[1,2,4]triazepines [10,11], oxadiazolo-and isoxazolo[1,2,4]triazepines [12], and pyrazolopyrimido[1,2,4]triazepines [13]. As a part of our program directed to the synthesis of new polynuclear bioactive heterocyclic systems [14][15][16][17], the present synthetic strategy is designed to utilize 1,6-diamino-4-(4-chlorophenyl)-2-oxopyridine-3,5-dicarbonitrile (1) as a suitable starting material for the synthesis of nitrogen bridge-head pyrido[1,2,4]triazepines of expected biological activity.…”

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Synthesis of some new nitrogen bridge-head pyrido[1,2,4]triazepines

Abdel-Megid

2009

Chem Heterocycl Comp

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It has been shown that condensed triazepines exhibit important pharmacological activities [1][2][3][4]. Most of the reported condensed triazepines are from the types [1,2,5]-, [1,3,5]-, and [1,3,4]triazepines such as benzo[1,2,5]triazepines [5, 6], triazolo[1,2,5]triazepines [7], benzo[1,3,5]triazepines [8], and benzo-[1,3,4]triazepines [9]. In contrast, the biheterocyclic 1,2,4-triazepines are relativity rare. A few examples were seen in the literature such as thiazolo[1,2,4]triazepines [10, 11], oxadiazolo-and isoxazolo[1,2,4]triazepines [12], and pyrazolopyrimido[1,2,4]triazepines [13]. As a part of our program directed to the synthesis of new polynuclear bioactive heterocyclic systems [14][15][16][17], the present synthetic strategy is designed to utilize 1,6-diamino-4-(4-chlorophenyl)-2-oxopyridine-3,5-dicarbonitrile (1) as a suitable starting material for the synthesis of nitrogen bridge-head pyrido[1,2,4]triazepines of expected biological activity.It is well known that compounds having vicinal amino groups are good precursors for building many condensed heterocycles [18,19]. Compound 1 as an example of such compounds was used in the synthesis of triazolopyridines [20][21][22] and pyridotriazines [22,23], but until now only a few examples of pyrido[1,2-b]-[1,2,4]triazepines are known [22,24]. Therefore, we used compound 1 to synthesize some novel pyrido-[1,2-b][1,2,4]triazepines via ring closure reactions with some interesting 1,3-dielectrophiles. Thus, when 1,6-diamino pyridine derivative 1 was allowed to react with diethyl malonate in boiling DMF,4,3,[1,2,4]triazepine-8,10-dicarbonitrile (2) was obtained. The 1 H NMR spectrum of compound 2 showed a singlet signal at δ 3.35 ppm due to the CH 2 protons in addition to two exchangeable singlets at δ 5.67 and 8.52 ppm assigned to N−NH and C−NH protons, respectively. The treatment of compound 1 with ethyl ethoxymethylenecyanoacetate may afford two possible pyridotriazepine

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Synthesis of some new hetarylpyranopyridazines, cinnolines, and hetarylpyridazine derivatives

Cited by 15 publications

References 13 publications

3-Formylchromones as diverse building blocks in heterocycles synthesis

3-Formylchromones as diverse building blocks in heterocycles synthesis

A convenient route for the synthesis of some new bi- and triheterocondensed uracils

Synthesis of some new nitrogen bridge-head pyrido[1,2,4]triazepines

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