Synthesis of Newly Substituted Pyrazoles and Substituted Pyrazolo[3,4‐<i>b</i>]Pyridines Based on 5‐Amino‐3‐Methyl‐1‐Phenylpyrazole

El‐Emary, Talaat I.

doi:10.1002/jccs.200700072

Cited by 36 publications

(12 citation statements)

References 37 publications

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“…In the case of EMCA it is relatively easy to isolate the adducts which are the direct products of Michael reaction [ 1 ]. Such adducts may possess the EMCA part connected with nitrogen (enamines) [ 30 – 32 ], carbon [ 33 ], and sulfur [ 34 ] atoms and may be further cyclized via ester [ 1 , 35 , 36 ] or cyano [ 1 , 37 , 38 ] group.…”

Section: Introductionmentioning

confidence: 99%

The pseudo-Michael reaction of 1-aryl-4,5-dihydro-1H-imidazol-2-amines with ethyl ethoxymethylenecyanoacetate

et al. 2013

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The pseudo-Michael reaction of 1-aryl-4,5-dihydro-1H-imidazol-2-amines with ethyl 2-cyano-3-methoxyprop-2-enoate (ethyl ethoxymethylenecyanoacetate) is investigated. At −10 °C reaction takes place on the exocyclic nitrogen atom, giving exclusively ethyl esters of 2-cyano-3-[(1-phenyl-4,5-dihydro-1H-imidazol-2-yl)amino]prop-2-enoic acid. The formation of isomeric enamines which may be a theoretical product of the reaction on N3 ring nitrogen atom is not observed. The N6 enamines, heated in boiling acetic acid, yield cyclic 1-aryl-5-oxo-2,3-dihydroimidazo[1,2-a]pyrimidine-6-carbonitriles. Heating of the enamines to the temperature of 120–140 °C without a solvent makes it possible to obtain a mixture of 1-aryl-5-oxo-2,3-dihydroimidazo[1,2-a]pyrimidine-6-carbonitriles and ethyl 1-aryl-5-imino-2,3-dihydroimidazo[1,2-a]pyrimidine-6-carboxylates. The reaction of the respective hydrobromides of 1-aryl-4,5-dihydro-1H-imidazol-2-amines with ethyl ethoxymethylenecyanoacetate in the presence of triethylamine gives selectively 1-aryl-5-oxo-1,2,3,5-dihydroimidazo[1,2-a]pyrimidine-6-carbonitriles.Graphical Abstract

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Section: Introductionmentioning

confidence: 99%

The pseudo-Michael reaction of 1-aryl-4,5-dihydro-1H-imidazol-2-amines with ethyl ethoxymethylenecyanoacetate

et al. 2013

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“…For the chemistry of pyrazolo [3,4-b]pyridines, see: Hä ufel & Breitmaier (1974); El-emary (2007); Dodiya et al (2013). For a similar structure, see: Wang & Zhu (2006 Table 1 Hydrogen-bond geometry (Å , ).…”

Section: Related Literaturementioning

confidence: 99%

Crystal structure of 3-methyl-1-phenyl-6-propylamino-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile

et al. 2015

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In the title compound, C17H17N5, the dihedral angle between the 1H-pyrazolo[3,4-b]pyridine ring system (r.m.s. deviation = 0.001 Å) and the attached phenyl group is 2.56 (6)°. The propylamino side chain has a contorted conformation [Car—N—C—C = −77.97 (16)° and N—C—C—C = −57.37 (17)°]. An intramolecular C—H⋯N interaction closes an S(6) ring. In the crystal, inversion dimers linked by pairs of N—H⋯N hydrogen bonds generate R 2 2(12) loops. Aromatic π–π stacking interactions [centroid–centroid distance = 3.5726 (8) Å] are also observed.

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“…The title compound was prepared according to our reported method (El-Emary, 2007). Crystals for X-ray diffraction analysis were obtained by slow evaporation of a dimethyl sulfoxide solution of the compound.…”

Section: Synthesis and Crystallizationmentioning

confidence: 99%

6-Amino-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyrazine-5-carboxamide

et al. 2016

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In the title compound, C 13 H 12 N 6 O, the pyrazolo [3,4-b]pyrazine ring system is planar (r.m.s. deviation for the nine fitted atoms = 0.024 Å ) and makes a dihedral angle of 5.72 (6) with the pendent phenyl ring. The molecular conformation is stabilized by intramolecular N-HÁ Á ÁO and C-HÁ Á ÁN hydrogen bonds, each generating an S(6) loop. In the crystal, pairs of molecules are connected into inversion dimers by strong N-HÁ Á ÁO hydrogen bonds, forming R 2 2 (8) ring motifs. These are linked into sheets parallel to (100) via N-HÁ Á ÁN hydrogen bonds; -interactions between symmetry-related pyrazole and phenyl rings [centroid-centroid distances = 3.4453 (9) Å ] within the sheets are also noted.

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Synthesis of Newly Substituted Pyrazoles and Substituted Pyrazolo[3,4‐b]Pyridines Based on 5‐Amino‐3‐Methyl‐1‐Phenylpyrazole

Cited by 36 publications

References 37 publications

The pseudo-Michael reaction of 1-aryl-4,5-dihydro-1H-imidazol-2-amines with ethyl ethoxymethylenecyanoacetate

The pseudo-Michael reaction of 1-aryl-4,5-dihydro-1H-imidazol-2-amines with ethyl ethoxymethylenecyanoacetate

Crystal structure of 3-methyl-1-phenyl-6-propylamino-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile

6-Amino-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyrazine-5-carboxamide

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