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Regioselective Synthesis of Some New Pyrazolo[1,5‐a]pyrimidines,Pyrazolo[1,5‐a]quinazoline and Pyrimido[4′,5′:3,4]pyrazolo[1,5‐a] pyrimidines Containing Thiazole Moiety
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Samir Bondock Abd El‐Gaber Tarhoni Ahmed A. Fadda 《Journal of heterocyclic chemistry》2015,52(6):1792-1799
A regioselective synthesis of novel pyrazolo[1,5‐a]pyrimidines, pyrazolo[1,5‐a]quinazoline and pyrimido[4′,5′:3,4]pyrazolo[1,5‐a]pyrimidines incorporating a thiazole moiety was described via the reactions of the versatile, readily accessible 5‐amino‐3‐(phenylamino)‐N‐(4‐phenylthiazol‐2‐yl)‐1H‐pyrazole‐4‐carboxamide 3 with appropriate 1,3‐biselectrophilic reagents namely, β‐diketones, enaminones, and α,β‐unsaturated cyclic ketone. The newly synthesized compounds were elucidated by elemental analysis, spectral data, and alternative synthetic route whenever possible. 相似文献
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Saleh M. Al‐Mousawi Mohammad A. Mohammad Mohamad H. Elnagdi 《Journal of heterocyclic chemistry》2001,38(4):989-991
While 3(5)‐aminopyrazole reacts with enaminonitrile to yield pyrazolo[1,5‐a]pyrimidines, 3‐amino‐5‐pyrazolone reacts with the same reagents to yields pyrazolo[3,4‐b]pyridines. 相似文献
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Condensations of 5‐(2‐hydroxyphenyl)pyrazoline 3a with 4‐carboxybenzaldehyde, glyoxylic acid and N,N‐carbonyldiimidazole leading to pyrazolobenzoxazine derivatives were studied. The observed diastere‐oselectivity is discussed. Reaction of 3a with Lawesson reagent gave rise to a new 5H‐pyrazolo[1,5‐c]‐[1,3,2]benzoxazaphosphorine heterocyclic system. 相似文献
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In this paper, we theoretically explore the motivation and behaviors of the excited‐state intramolecular proton transfer (ESIPT) reaction for a novel white organic light‐emitting diode (WOLED) material 4‐tert‐butyl‐2‐(5‐(5‐tert‐butyl‐2‐methoxyphenyl)thiazolo[5,4‐d]thiazol‐2‐yl)‐phenol (t‐MTTH). The “atoms in molecules” (AIM) method is adopted to verify the formation and existence of the hydrogen bond O? H···N. By analyzing the excited‐state hydrogen bonding behaviors via changes in the chemical bonding and infrared (IR) vibrational spectra, we confirm that the intramolecular hydrogen bond O? H···N should be getting strengthened in the first excited state in four kinds of solvents, thus revealing the tendency of ESIPT reaction. Further, the role of charge‐transfer interaction is addressed under the frontier molecular orbitals (MOs), which depicts the nature of the electronic excited state and supports the ESIPT reaction. Also, the electron distribution confirms the ESIPT tendency once again. The scanned and optimized potential energy curves according to variational O? H coordinate in the solvents demonstrate that the proton transfer reaction should occur in the S1 state, and the potential energy barriers along with ESIPT direction support this reaction. Based on the excited‐state behaviors reported in this work, the experimental spectral phenomenon has been reasonably explained. 相似文献
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Ahmed M. Hussein 《Journal of heterocyclic chemistry》2012,49(2):446-451
An easy and efficient route for synthesis of some pyrimido[1,6‐a]pyrimidine and pyrazolo[1,5‐a]pyrimidine derivatives was described through the reaction of sodium salts of formyl ketones with 6‐aminothiouracil and 5‐aminopyrazole derivatives, respectively. The characterization of the reaction products was confirmed by using elemental analysis and spectral data. J. Heterocyclic Chem., (2012). 相似文献
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Condensation of 3-amino-4-cyanopyrazole (1) with ethylacetoacetate, ethyl cyanoacetate, diethyl malonate and acetylacetone afforded pyrazolo[1,5-a]pyrimidine derivatives (2—8a). Other compounds (8b—h) of this ring system were obtained by treatment of 1 with arylidenemalononitrile and ethylarylidenecyanoacetate. And the reaction of compound (1) with activated acetylenes yeilded pyrazolo[1,5-a]pyrimidine derivatives (11a—b). 相似文献
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Abdou O. Abdelhamid Shokry A. Shokry Sayed M. Tawfiek 《Journal of heterocyclic chemistry》2012,49(1):116-124
Naphtho[2,1‐b]furan‐2‐yl)(8‐phenylpyrazolo[5,1‐c][1,2,4]triazin‐3‐yl)methanone, ([1,2,4]triazolo[3,4‐c][1,2,4]triazin‐6‐yl)(naphtho[2,1‐b]furan‐2‐yl)methanone, benzo[4,5]imidazo[2,1‐c][1,2,4]triazin‐3‐yl‐naphtho[2,1‐b]furan‐2‐yl‐methanone, 5‐(naphtho[2,1‐b]furan‐2‐yl)pyrazolo[1,5‐a]pyrimidine, 7‐(naphtho[2,1‐b]furan‐2‐yl)‐[1,2,4]triazolo[4,3‐a]pyrimidine, 2‐naphtho[2,1‐b]furan‐2‐yl‐benzo[4,5]imidazo[1,2‐a]pyrimidine, pyridine, and pyrazole derivatives are synthesized from sodium salt of 5‐hydroxy‐1‐naphtho[2,1‐b]furan‐2‐ylpropenone and various reagents. The newly synthesized compounds were elucidated by elemental analysis, spectral data, chemical transformation, and alternative synthetic route whenever possible. J. Heterocyclic Chem., (2012). 相似文献
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Hatem A. Abdel‐Aziz Nehal A. Hamdy Issa M. I. Fakhr Ahmad M. Farag 《Journal of heterocyclic chemistry》2008,45(4):1033-1037
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Carlo Mustazza Maria Rosaria Del Giudice Anna Borioni Franco Gatta 《Journal of heterocyclic chemistry》2001,38(5):1119-1129
This paper describes the preparation of some pyrazolo[1,5‐a]‐, 1,2,4‐triazolo[1,5‐a]‐ and imidazo[1,2‐a]‐pyrimidines substituted on the pyrimidine moiety by a 4‐[(N‐acetyl‐N‐ethyl)amino]phenyl group. A new synthesis of related benzo[h]pyrazolo[1,5‐a]‐, benzo[h]pyrazolo[5,1‐b]‐ and benzo[h]1,2,4‐triazolo[1,5‐a]‐quinazolines is also reported. 相似文献
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Cyclization of 5‐cyano‐1,6‐dihydro‐4‐methyl‐2‐phenyl‐6‐thioxopyrimidine 4 with excess of 85% hydrazine hydrate afforded the 3‐amino‐4‐methyl‐6‐phenylpyrazolo[3,4‐d]pyrimidine 5 , which can react with appropriate Mannich base derivatives 13a‐c and chalcones 27a,b to yield the corresponding 6,8‐disubstituted 7,8‐dihydropyrimido[2,3:4,3]pyrazolo[1,5‐a]pyrimidines 15a‐c and 30a,b , respectively. On the other hand, the 6,7,8‐trisubstituted pyrimido[2,3:4,3]pyrazolo[1,5‐a]pyrimidine derivatives 8a‐g, 20a‐e, 36 and 38 were obtained by treatment of compound 5 with appropriate 1,3‐diketones 6a‐g , 3‐dimethylamino‐1‐(substituted)prop‐2‐enones 18a‐e , 3‐aminocrotononitrile 3 , and ethoxymethylenemalononitrile 37 under acidic condition, respectively. 相似文献
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Anton V. Dolzhenko Shiqi Bai Anna V. Dolzhenko Wai Keung Chui 《Journal of heterocyclic chemistry》2012,49(4):763-767
A new convenient synthon for heterocyclic chemistry, namely 1H‐pyrazolo[3,4‐b]pyridin‐3‐ylguanidine was successfully prepared by selective guanylation of 1H‐pyrazolo[3,4‐b]pyridin‐3‐amine. A series of 3,4‐dihydropyrido[2′,3′:3,4]pyrazolo[1,5‐a][1,3,5]triazin‐2‐amines was synthesized from 1H‐pyrazolo[3,4‐b]pyridin‐3‐ylguanidine using aldehydes or ketones as one‐carbon inserting reagents. The tautomeric preferences of the products were determined using spectroscopic (e.g., 2D NOESY NMR) and single crystal X‐ray diffraction data. 相似文献
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Mukesh Kumar Elizabeth T. Papish Matthias Zeller 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(8):m197-m200
The X‐ray crystal structure of the title compound, [Zn(C2H5)(C24H40BN6)], or TptBu,MeZnEt [TptBu,Me is tris(3‐tert‐butyl‐5‐methylpyrazolyl)hydridoborate], reveals a distorted tetrahedral geometry around the Zn atom. The Zn center is coordinated by three N atoms of the borate ligand and by one C atom of the ethyl group. The present structure and other tetrahedral Tp zinc alkyl complexes are compared with similar Ttz ligands (Ttz is 1,2,4‐triazolylborate), but no major differences in the structures are noted, and it can be assumed that variation of the substitution pattern of Tp or Ttz ligands has little or no influence on the geometry of alkylzinc complexes. Refinement of the structure is complicated by a combination of metric pseudosymmetry and twinning. The metrics of the structure could also be represented in a double‐volume C‐centered orthorhombic unit cell, and the structure is twinned by one of the orthorhombic symmetry operators not present in the actual structure. The twinning lies on the borderline between pseudomerohedral and nonmerohedral. The data were refined as being nonmerohedrally twinned, pseudomerohedrally twinned and untwinned. None of the approaches yielded results that were unambiguously better than any of the others: the best fit between structural model and data was observed using the nonmerohedral approach which also yielded the best structure quality indicators, but the data set is less than 80% complete due to rejected data. The pseudomerohedral and the untwinned structures are complete, but relatively large residual electron densities that are not close to the metal center are found with values up to three times higher than in the nonmerohedral approach. 相似文献
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Thiazolylcyanothioacetanilides react with α‐haloketones and haloesters to give the corresponding thiophene or thiazole derivatives according to the reaction conditions. Pyrazolo[1,5‐a]pyrimidines and pyrazolo[5,1‐c]triazines were synthesized by reaction of 3‐amino‐4‐(4′‐arylthiazol‐2′‐yl)‐5‐phenylaminopyrazole with different reagents. Structures of the new compounds were confirmed by elemental analyses, spectral data, and alternative methods of synthesis whenever possible. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 508–516, 1999 相似文献
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Synthesis of Pyrido[2′,3′: 3,4]pyrazolo[1,5‐a]pyrimidine,Pyrido[2′,3′:3,4]pyrazolo[5,1‐c][1,2,4]triazine,and Pyrazolyl Oxadiazolylthieno[2,3‐b]pyridine Derivatives
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Nora M. Rateb 《Journal of heterocyclic chemistry》2014,51(5):1349-1356
6‐(2‐Thienyl)‐4‐(trifluoromethyl)‐1H‐pyrazolo[3,4‐b]pyridine‐3‐amine reacted with different active methylene compounds to afford pyridopyrazolopyrimidine derivatives. On the other hand, it reacted with some halo compounds to give the imidazo[1′,2′:1,5]pyrazolo[3,4‐b]pyridine derivatives. Also, it diazotized to give the corresponding diazonium chloride that is coupled with several active methylene compounds to give the corresponding triazine derivatives. Furthermore, compound 3‐amino‐6‐(2(thienyl)‐4‐(trifluoromethyl)thieno[2,3‐b]pyridine‐2‐carbohydrazide reacted with some β‐dicarbonyl compounds and some sulfur‐containing compounds to afford the corresponding pyrazolyl oxadiazolylthieno[2,3‐b]pyridine derivatives. 相似文献
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Jaime Portilla Jairo Quiroga Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(9):o471-o473
In the title compound, C14H19N3, the bond distances within the heterocyclic portion of the molecule indicate incomplete π delocalization. The molecules are linked into stacks by a combination of two C—H...π(pyrazole) hydrogen bonds and two independent π–π stacking interactions between inversion‐related pyrimidine rings. The significance of this study lies in its observation of significant differences in both molecular conformation and supramolecular aggregation between the title compound, an example of a 2‐alkylpyrazolo[1,5‐a]pyrimidine, and some analogous 2‐arylpyrazolo[1,5‐a]pyrimidines. 相似文献
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Sergey M. Desenko Evgeny S. Gladkov Svetlana V. Shishkina Oleg V. Shishkin Sergey A. Komykhov Valery D. Orlov Herbert Meier 《Journal of heterocyclic chemistry》2006,43(6):1563-1567