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1.
We report the synthesis of novel N-(4-phenylthiazol-2-yl)-substituted benzo[d]thiazole-, thiazolo[4,5-b]pyridine-, thiazolo[5,4-b]pyridine- and benzo[d]oxazole-2-carboximidamides, which were inspired by marine topsentines and nortopsentines. Condensation of 4,5-dichloro-1,2,3-dithiazolium chloride (Appel salt) with various ortho-halogenated anilines, aminopyridines and aminophenols gave the corresponding aryliminodithiazoles in good to excellent yields. Copper(I)-mediated or nucleophilic-assisted cyclization of aryliminodithiazoles furnished cyano-functionalized benzo[d]thiazoles, thiazolo[4,5-b]- and thiazolo[5,4-b]-pyridines and benzo[d]oxazoles. The latter were condensed with substituted 4-phenylthiazol-2-amines to furnish twenty seven new polyaromatic carboximidamides in moderate to good yields. 相似文献
2.
K.K. Abdul Khader Ayyiliath M. Sajith M. Syed Ali Padusha H.P. Nagaswarupa A. Muralidharan 《Tetrahedron letters》2014
In this Letter we report a rapid and facile access to C2-substituted imidazo[4,5-b]pyridine analogues utilizing palladium mediated Buchwald–Hartwig cross-coupling reactions. The use of enolizable heterocycles as cross-coupling partners resulted in a wide range of imidazo[4,5-b]pyridine analogues which are prone to have medicinal relevance. Xantphos and Pd(OAc)2 were found to be more effective for the coupling of 2-halo imidazo[4,5-b]pyridines with pyridone nucleophiles. A regioselective approach for the synthesis of 2-substituted 3H-imidazo[4,5-b]pyridine and 1H-imidazo[4,5-b]pyridine is also reported. 相似文献
3.
Magdi E.A. Zaki 《Tetrahedron》2007,63(18):3745-3753
1-Aryl-5-amino-4-cyanoformimidoyl imidazoles were reacted with acyl and sulfonyl acetonitriles, under mild experimental conditions, leading to imidazo[4,5-b]pyridines and imidazo[4,5-b]pyridine-5-ones. A reaction intermediate could be isolated in the reaction with methyl cyanoacetate, under carefully controlled experimental conditions. This intermediate cyclized to imidazo[4,5-b]pyridine-5-one, in the presence of DBU. Reaction between 5-amino-4-cyanoformimidoyl-1-(4-fluorophenyl)imidazole and acetylacetone, occurred by a different pathway to give a 6-carbamoylpurine. 相似文献
4.
Ayyiliath M. Sajith 《Tetrahedron letters》2012,53(9):1036-1041
A modified approach for the synthesis of 3-substituted 2-aryl/heteroaryl imidazo[4,5-b]pyridines utilising palladium catalysed cross-coupling reactions under microwave enhanced conditions has been achieved. utilisation of (A-taphos)2PdCl2-catalysed cross-coupling reactions enables rapid derivatization of this (imidazo[4,5-b]pyridines) pharmaceutically relevant core. This catalytic system is compatible with a broad spectrum of arylboronic acids—electron rich, electron poor, and heteroarylboronic acids. 相似文献
5.
Anatoliy M. Shestopalov Liudmila A. Rodinovskaya Alexander A. Shestopalov 《Tetrahedron》2010,66(46):8945-8948
A new combinatorial method for the preparation of substituted thiazolo[4,5-b]pyridines, which utilizes cyanoacetamide, heterocumulenes (isothiocyanates, carbon bisulfide), and ethyl-4-chloroacetoacetate in a new SN2→Thorpe-Ziegler→Thorpe-Guareschi domino reactions has been developed. The obtained thiazolo[4,5-b]pyridines were then used together with aldehydes and malononitrile in another Knoevenagel reaction→Michael reaction→hetero-Thorpe-Ziegler domino reaction for the synthesis of substituted 4,6-dihydro-5H-pyrano[2,3-d]thiazolo[4,5-b]pyridines. 相似文献
6.
Novel 6-chloropyrazolo[3,4-b]pyridine-5-carbaldehydes 5 have been synthesized from the 4,5-dihydropyrazolo[3,4-b]pyridine-6-ones 4 via Vilsmeier-Haack reaction. Further treatment of carbaldehydes 5 with acetophenones 6 and hydrazine hydrate afforded chalcone analogues 7 and dipyrazolo[3,4-b:4′,3′-e]pyridines 8, respectively. 相似文献
7.
A series of novel N-benzylcarboxamide derivatives of bicyclic compounds, 3,4-dihydropyrido[3,2-f][1,4]oxazepin-5(2H)-one and 2,3,4,5-tetrahydro-6H-pyrido[2,3-b][1,5]oxazocin-6-one, were synthesized by cyclization of N-benzyl-2-chloro-N-(2-hydroxyethyl)- [and -(3-hydroxypropyl)-] nicotinamides, respectively. Atropisomerism was observed in 5-[3,5-bis(trifluoromethyl)benzyl]-7-phenyl-2,3,4,5-tetrahydro-6H-pyrido[2,3-b][1,5]oxazocin-6-ones due to steric hindrance of the carboxamide moiety and restriction of its rotation. Cyclization of N-[3,5-bis(trifluoromethyl)benzyl]-2-chloro-N-[(2S)-3-hydroxy-2-methylpropyl]-5-methyl-4-phenylnicotinamide gave (3S)-5-[3,5-bis(trifluoromethyl)benzyl]-3,8-dimethyl-7-phenyl-2,3,4,5-tetrahydro-6H-pyrido[2,3b][1,5]oxazocin-6-one, which exists predominantly in the thermodynamically stable aR-conformer in CDCl3. This compound showed excellent NK1-antagonistic activity with IC50 value (in vitro inhibition of [125I]-Bolton-Hunter-substance P binding in human IM-9 cells) of 0.47 nM, which is ca. 200-fold more potent than that of its enantiomer, indicating that the atropisomer chirality affects NK1-receptor recognition. 相似文献
8.
Convenient synthesis of 7-aryl-3,4,5,6-tetrahydro-2H-pyrido[4,5-b]- and [2,3-b]-1,5-oxazocine-6-ones
Shigeki Seto 《Tetrahedron letters》2004,45(46):8475-8478
A convenient and diversity-oriented method for synthesis of the novel 7-aryl-3,4,5,6-tetrahydro-2H-pyrido[4,5-b]-1,5-oxazocine-6-one skeleton 1 and the very rarely described 7-aryl-3,4,5,6-tetrahydro-2H-pyrido[2,3-b]-1,5-oxazocine-6-one skeleton 2, featuring cyclization using nucleophilic aromatic substitution (SNAr) and Suzuki coupling, is described. 相似文献
9.
Vijendra Kumar Fulwa 《Tetrahedron letters》2009,50(46):6264-182
Heating a neat 1:2 mixture of 2-picolylamine and 2-cyanopyridine followed by treatment of the resultant red gummy substance with aqueous KOH resulted in the isolation of 2,4,5-tris(2-pyridyl)imidazole (1a) as the major product and N-(3-(2-pyridyl)imidazo[1,5-a]pyridine)picolinamidine (2a) in small amounts. Similarly, by using 3-picolylamine, 2,4,-bis(2-pyridyl)-5-(3-pyridyl)imidazole (1b) and N-(3-(3-pyridyl)imidazo[1,5-a]pyridine)picolinamidine (2b) were isolated, and by using 4-picolylamine, 2,4,-bis(2-pyridyl)-5-(4-pyridyl)imidazole (1c) and N-(3-(4-pyridyl)imidazo[1,5-a]pyridine)picolinamidine (2c) were isolated. The plausible mechanism of the formation of 1a-c and 2a-c is delineated. 相似文献
10.
Tatyana A. Stroganova Vladimir K. Vasilin Victor V. Dotsenko Nikolai A. Aksenov Gennady D. Krapivin 《Tetrahedron letters》2019,60(14):997-1000
The oxidation of 3-aminothieno[2,3-b]pyridine-2-carboxamides with commercially available bleach leads to the formation of dimeric pyrrolo[2′,3′:4,5]thieno[2,3-b]pyridines (7a,14a-diamino-7,14-bis(aryl)-7,7a,14,14a-tetrahydro-6H,13H-pyrido[3″″,2″″:4?,5?]thieno[2?,3?:4″,5″]pyrrolo-[3″,4″:3′,4′]pyrrolo[2′,3′:4,5]thieno[2,3-b]pyridine-6,13-diones) in moderate yields (37–52%). 相似文献
11.
Regioselective formylation behavior has been found in the reaction of pyrazolo[3,4-b]pyridines and pyrazolo[1,5-a]pyrimidines via Vilsmeier-Haack conditions. While the 4,5- and 6,7-dihydro derivatives afforded pyrazolo[3,4-b]pyridine-5-carbaldehydes and 4,7-dihydropyrazolo[1,5-a]pyrimidine-3,6-dicarbaldehydes, respectively, the aromatic analogs rendered the pyrazolo[1,5-a]pyrimidine-3-carbaldehyde only, and no reaction took place at the pyrazolopyridine derivatives. 相似文献
12.
The nitration of pyridine-3,4-diamine, its N,N′-diacetyl derivative, and N 4-alkylpyridine-3,4-diamines with excess nitric acid in concentrated sulfuric acid at 60°C was accompanied by cyclization with formation of the corresponding 1-substituted 4-nitro-1H-[1,2,3]triazolo[4,5-c]pyridine 2-oxides. 4-Chloro-1H-[1,2,3]triazolo[4,5-c]pyridine 2-oxide derivatives were obtained under analogous conditions from 2-chloropyridine-3,4-diamine, its N,N′-diacetyl derivative, and 2-chloro-N 4-methylpyridine-3,4-diamine. The nitration of these compounds at 80–90°C gave 4-chloro-7-nitro-1H-[1,2,3]triazolo[4,5-c]pyridine 2-oxides. 相似文献
13.
Tokuo Itoh Kazuo Ono Tomokazu Sugawara Yoshihisa Mizuno 《Journal of heterocyclic chemistry》1982,19(3):513-517
Reactions of some imidazo[4,5-b]pyridine 4-oxides with phosphoryl chloride are described. Treatment of N-1-substituted imidazo[4,5-b]pyridine 4-oxides with phosphoryl chloride led to the predominant formation of 7-chloro derivatives. This feature was successfully applied to the preparation of a chloroimidazo[4,5-b]pyridine nucleoside, which served as an important precursor of 1-deazaadenosine. 相似文献
14.
《Tetrahedron》2019,75(35):130473
An efficient CuI catalyzed intramolecular Ullmann-type C−N coupling reaction is described here. Newly substituted 1H-benzo[4,5]imidazo[1,2-a]pyrrolo[3,4-c]pyridine-1,3,5(2H, 11H)-trione has been easily synthesized from ortho halogenated N-substituted pyrrolo[3,4-c]pyridine-1,3,6(5H)-triones in presence of CuI catalyst and K2CO3 base without any ligand. This procedure is based on intramolecular Ullmann-type reaction and provides a proficient method of making fused tetracyclic heterocycles. 相似文献
15.
Gundurao Kolavi 《Tetrahedron letters》2006,47(16):2811-2814
Novel heterocyclic systems 2-alkyl/aryl-9-(2-hydroxybenzylidene)-7,9-dihydro-8H-[1,3,4]thiadiazolo[2′,3′:2,3]imidazo[4,5-d][1,2]diazepin-8-one and 9-(2-hydroxy-benzylidene)-3,3-dimethyl-3,4,7,9-tetrahydro-2H-11-thia-4b,6,7,10-tetraazaindeno[1,2-a]azulene-1,8-dione are synthesized via an intramolecular amidation reaction. An interesting ring opening and cyclization of 2-alkyl/aryl-6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde and 6,6-dimethyl-8-oxo-2-(2-oxo-2H-chromen-3-yl)-5,6,7,8-tetrahydroimidazo[2,1-b][1,3]benzothiazole-3-carbaldehyde are discussed. 相似文献
16.
The double addition of bis(trimethylsilyl) ketene acetals [R1, R2 = CH3, -(CH2)5-] to pyridine N-oxide promoted by triflic anhydride under mild conditions generates N-[(trifluoromethane)sulfonyl-1,2-dihydropyridine-2,4-dicarboxylic acids 2a-b. Subsequent reaction of these acids upon iodolactonization conditions affords tetrahydrofuro[3,2-b]pyridine-2(3H)-ones 3a-b containing an exo-insaturation on the products as a result of an unexpected decarboxylation. 相似文献
17.
G. A. Gazieva N. G. Kolotyrkina A. N. Kravchenko N. N. Makhova 《Russian Chemical Bulletin》2014,63(2):431-434
Diastereoselective [3+2] cycloaddition of azomethine ylide to 1,3-dimethyl-6-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-3a,9a-diphenyl-3,3a,9,9a-tetrahydroimidazo[4,5-e]thiazolo[3,2-b]-[1,2,4]triazine-2,7(1H,6H)-dione yields hitherto unknown 1,1′,3-trimethyl-3a,9a-diphenyl-3,3a,9,9a-tetrahydrodispiro(imidazo[4,5-e]thiazolo[3,2-b][1,2,4]triazine-6,3′-pyrrolidine-4′,3″-indole)-2,2″,7(1H,1″H)-triones. 相似文献
18.
The thermolysis of (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylic acids in Ac2O led to novel 3-methylene-2,5-dioxo-3H,9bH-oxazolo[2,3-a]isoindoles and chiral (9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindoles were obtained on FVP. Starting from l-cysteine methyl ester (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazines were obtained as single stereoisomers. The thermolysis of (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazine-3-carboxylic acid in Ac2O gave 5-acetyl-2-phenyl-2,3-dihydrothiazole. The structures of methyl (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylate 1a and methyl (2R,4R)-N-chlorocarbonyl-2-(2-hydroxyphenyl)thiazolidine-4-carboxylate 9 were determined by X-ray crystallography. 相似文献
19.
E. A. Kaigorodova A. A. Osipova L. D. Konyushkin G. D. Krapivin 《Russian Chemical Bulletin》2004,53(4):853-859
Reactions of 2,5-dimethoxytetrahydrofuran with 3-aminothieno[2,3-b]pyridines afford a number of substituted 3-(1H-pyrrol-1-yl)thieno[2,3-b]pyridines. The possibility of the reaction and the yield of the product are determined by the character of a substituent in position 2 of thieno[2,3-b]pyridine. The Curtius rearrangement of 2-acylazido-3(1H-pyrrol-1-yl)thieno[2,3-b]pyridines yields 4,5-dihydropyrido[3",2":4,5]thieno[2,3-e]pyrrolo[1,2-a]pyrazin-4-ones. The molecular and crystal structures of ethyl 4-methoxymethyl-6-methyl-3-(1H-pyrrol-1-yl)thieno[2,3-b]pyridine-2-carboxylate were determined by X-ray diffraction analysis. 相似文献
20.
The Compound 2-(N-Formyl-N-prop-2′-inyl)aminopyridine was cyclised in boiling formic acid to 3-methylimidazo[1,2-a]pyridine, with 3-methylene-2H-imidazo[1,2-a]pyridine as the intermediate. Under similar conditions the 1,3-diprop-2-inylpyrimido[4,5-b]quinoline-2,4-dione resulted from 1-methylimidazo[1,2-a]quinoline-4-carbonic acid-N-2-prop-2′-inylamide and from the 1-prop-2′-inylbenzo[b][1,8]naphthyridin-2-one the 1-methylbenzo[b]imidazo[1,2,3-ij]naphthyridine-4,7-dione as a new ring system, was obtained. 相似文献