Synthesis of some new annulated pyrazolo-pyrido (or pyrano) pyrimidine, pyrazolopyridine and pyranopyrazole derivatives (original) (raw)
Related papers
Novel Synthesis Method of Pyrimidine and Pyrazole Derivatives
The chemistry of 2-pyrones has undergone considerable development owing to their presence in natural compounds and their application in biological and food industry. Dehydroacetic acid plays a pioneering role in the synthesis of different heterocyclic compounds such as pyrimidine, pyrazole, 1,5benzodiazepine. The choice of such compounds is mainly based on their pharmacological properties 1-3. Modified pyrimidines have keenly interested the chemist and pharmacologist because of their impact in the therapeutic field. Indeed, these compounds after some modifications showed antibiotic, anticancer, antiviral 4 and agrochemical properties 5-7. Pyrazoles, in their turn, constitute an important development in the field of fine chemistry because of their importance in medicinal chemistry or during the preparation of pesticides and insecticides 8. The pyrazole pattern is found in a large number of compounds known for their therapeutic value mainly as anti-inflammatory 9 , antitumor 10-15 hypnotic and sedative properties 16-18. Some of these structures have shown, in addition to their analgesic properties 19 and antimicrobial activity 20. In the context of the investigation dealing with the use of dehydroacetic acid 1 and its derivatives in heterocyclic synthesis, we report in this work the synthesis of new molecules (pyridopyrimidine, pyrazole) susceptible to present interesting pharmacological properties.
Synthesis of some novel pyrazolo[3,4-d]pyrimidine derivatives
Arkivoc, 2007
Reaction of ethyl imidates derived from N-aryl-5-amino-4-cyanopyrazoles with amines or arylhydrazines gave only 4-substituted pyrazolo[3,4-d]pyrimidines, resulting from cyclization followed by Dimroth rearrangement. From the reaction with arylhydrazines, a mixture of the hydrazines and their oxidized forms, the azo products, was obtained. This was proven by an independent synthesis starting from the corresponding 4-chloropyrazolo[3,4-d]pyrimidines as starting material. The structures of the compounds obtained were confirmed by mass spectrometry, 1 H and 13 C NMR.
ChemInform, 2005
Several new pyrazolo[3,4-d ]pyrimidines and pyrazolo[3,4-b]pyridine derivatives were prepared by condensation of 5-amino-1-(5,6-diphenyl-1,2,4-triazin-3-yl)-1H-pyrazole-4-carbonitrile with succinic anhydride, acetic anhydride, γ-chlorobutyl chloride, succinyl chloride, formic acid-formamide mixture, formamide, and active methylene reagents such as malononitrile, ethyl cyanoacetate, and ethyl acetoacetate under different reaction conditions.
Journal of Chemistry, 2013
Condensation of sodium 3-oxo-3-(1-phenyl-1H-pyrazol-4-yl)prop-1-en-1-olate (2) with several heterocyclic amines, cyanoacetamide, cyanothioacetamide, and 2-cyanoacetohydrazide gives pyrazolo[1,5-a]pyrimidines (5a-d), pyrido[2 ,3 :3,4]pyrazolo[1,5a]pyrimidine (9), benzo imidazo[1,2-a]pyrimidine (10), [1,2,4]triazolo[1,5-a]pyrimidine (11), and pyridine derivatives (12-14). Also, thieno[2,3-b]pyridines (15-18) were synthesized via pyridinethione (13) with -halo ketones and -halo ester. Structures of the newly synthesized compounds were elucidated by elemental analysis, spectral data, alternative synthetic routes, and chemical transformation whenever possible.
Synthesis of new pyrazole and antibacterial pyrazolopyrimidine derivatives
TURKISH JOURNAL OF CHEMISTRY, 2014
3-Substituted-1-phenyl-1 H-pyrazolo[3,4-d ]pyrimidin-4-amines 2a-c were synthesized by treating 5-aminopyrazole-4-carbonitriles 1a-c with formamide. The reactivity of compounds 1a-c towards some cyclic anhydrides was studied. The condensation of 5-aminopyrazole-4-carbonitrile 1b with triethylorthoformate gives imidate 7b, which reacts with a series of primary amines and leads to pyrazolo[3,4-d ]pyrimidine-4-amines 9 and 10. The reaction of imidate 7b with ammonia and hydroxylamine afforded pyrazolopyrimidine 2b and pyrazolo[3,4-d ]pyrimidin-5-(4 H)-ol 11, respectively. The synthesized compounds were completely characterized by 1 H NMR, 13 C NMR, IR, and HRMS. The antibacterial activity of some new synthesized compounds was evaluated and appeared to be significant.
Journal of The Iranian Chemical Society, 2018
Depending on the reaction conditions, two alternative cyclizations are possible for [3 + 3] cyclocondensation of pyrazolone derivative 1a and ethyl cyanoacetate of type pyrano [2,3-c] pyrazol-6(1H)-one 2 and pyrano [2,3-c] pyrazol-4(1H)-one 3. Keeping of enaminic system 3 and benzylidene malononitrile in the presence of catalytic amount of trimethylamine resulted in pyridine cyclization affording pyrazolopyranopyridine derivative 4, not 5. The pyrazolone derivative 6a was obtained as a result of the acid-mediated addition reaction between compound 1a, urea and/or ammonium thiocyanate. In addition, the bispyrazolone of type 6b was obtained from the condensation reaction of urea and pyrazolone derivative. The spiro compound 7 was obtained from the double-addition reaction of pyrazolone to cinnamoyl isothiocyanate. A one-pot three-component condensation of a 3-hydroxybenzaldehyde, pyrazolone 1a, urea and/or thiourea under Biginelli conditions resulted in tetrahydropyrazolo pyrimidine derivatives 8a and 8b, respectively. The acid-mediated reaction of benzaldehyde and pyrazolone derivative 1a in the presence of Ac 2 O yielded styrylpyrazole derivative 9. The polyfunctionalized product 9 reacted with hydrazine to furnish pyrazolotriazoloe of type 10. Treatment of styrylpyrazole derivative 9 with aniline furnished the aniline derivative 11 and none of the expected polyheterocyclic derivative 12 was obtained. Compound 9 undergoes pyridine cyclization to produce 13 under the effect of urea. N-phenyl pyrazolone converted into pyrano-dipyrazolone derivative 14. Pyran of type 14 underwent a ring transformation upon treatment with urea and/or thiourea to give the same dipyrazolo pyrimidine derivative 15. The newly synthesized compounds were characterized by FT-IR, 1 H-NMR, 13 C-NMR, ESI/LC-MS and elemental analysis.
Synthetic Communications, 2018
The versatile, 3-aminopyrazolo[4,3-c]pyridine-4,6-dione (2) was synthesized and allowed to react with aldehydes, aryldiazonium chlorides, chalcones and enaminones to afford regioselectively the novel pyrazolo [4,3-c]pyridine derivatives 4a-c, pyrazolo[4,5,1-ij][1,6] naphthyridines 9a-d and pyrido[4',3':3,4]pyrazlo[1,5-a]pyrimidines 19a-i. The structure of all the newly synthesized compounds was assigned from elemental analysis and spectral data. Also, the mechanistic aspects for the formation of the newly synthesized compounds is discussed.
A new series of pyrazole 4-7 and pyrazolo[1,5-a]pyrimidine 8-13 were synthesized by using a simple, efficient procedure, and screened for their in-vitro antimicrobial and antitumor activities. Symmetrical and asymmetrical 3,6-diarylazo-2,5,7-triaminopyrazolo[1,5-a]pyrimidine were synthesized by the conventional method and also subjected to microwave irradiation and under ultrasound conditions. The biological results revealed that most of the tested compounds proved to be active as antibacterial and antifungal agents. The antitumor activity of the synthesized compounds was evaluated against human cancer cell lines, MCF-7, HCT-116, and HepG-2, as compared with Doxorubicin as a control.