Unusual Coordination Modes of Tris(pyrazol‐1‐yl)borates: Synthesis and Solid State Structures of Sodium[(dimethylamino)tris(pyrazol‐1‐yl)borate], Potassium[(dimethylamino)tris(pyrazol‐1‐yl)borate], and Potassium[phenyltris(pyrazol‐1‐yl)borate]

We report the optimized syntheses and the solid state structures of the alkali metal tris(pyrazol‐1‐yl)borates M[Me₂NBpz₃] (M = Na⁺ ( 1 ), K⁺ ( 2 ); pz = pyrazol‐1‐yl) and K[PhBpz₃] ( 3 ). Even though 1 and 2 consist of polymeric chains in the solid state, it is possible to identify subunits where the [Me₂NBpz₃]^? ion acts as tridentate ligand towards Na⁺ and K⁺ and binds via two of its pyrazolyl rings and its dimethylamino nitrogen atom (κ³N_pz,N_pz,N_NMe). In 3 , the ligand [PhBpz₃]^? employs two pyrazolyl donors and the π‐face of its phenyl substituent for potassium coordination (κ³N,N,C).     

The synthesis of 1‐[(substituted)pyrazol‐5‐yl]‐iminomethyl‐2‐nitroiminoimidazolidine and its derivatives

In this article 1‐[(substituted)pyrazol‐5‐yl]iminomethyl‐2‐nitroimino imidazolidines ( II ) and their derivatives were synthesized. All the compounds were verified by elemental analysis, ¹H NMR and IR. In the reaction of II with halides, two different results were observed.     

Synthesis and conversion of 2‐(pyrazol‐1‐yl)quinoxaline 4‐oxides

The reaction of 6‐chloro‐2‐hydrazinoquinoxaline 4‐oxide 1b with acetylacetone or benzoylacetone gave 6‐chloro‐2‐(3,5‐dimethylpyrazol‐i‐yl)quinoxaline 4‐oxide 5a or 6‐chloro‐2‐(3‐methyl‐5‐phenylpyrazol‐1‐yl)quinoxaline 4‐oxide 5b , respXectively. Compound 5a or 5b was converted into the pyrrolo[1,5‐a]quinoxaline 6a or 6b , triazolo[4,3‐a]quinoxaline 9a or 9b , and tetrazolo[1,5‐a]quinoxaline 10.     

Synthesis of 1‐[(pyrazol‐3‐yl)methyl]pyridazin‐6‐ones

This paper presents the synthesis of 1‐[(pyrazol‐3‐yl)methyl]pyridazin‐6‐ones from ethyl 4‐(4,5‐dichloro‐6‐oxopyridazin‐1‐yl)‐3‐oxobutanoate.     

Synthesis,structure and biological activity of diorganotin derivatives with pyridyl functionalized bis(pyrazol‐1‐yl)methanes

Three pyridyl functionalized bis(pyrazol‐1‐yl)methanes, namely 2‐[(4‐pyridyl)methoxyphenyl] bis(pyrazol‐1‐yl)methane (L¹), 2‐[(4‐pyridyl)methoxyphenyl]bis(3,5‐dimethylpyrazol‐1‐yl)methane (L²) and 2‐[(3‐pyridyl)methoxyphenyl]bis(pyrazol‐1‐yl)methane (L³) have been synthesized by the reactions of (2‐hydroxyphenyl)bis(pyrazol‐1‐yl)methanes with chloromethylpyridine. Treatment of these three ligands with R₂SnCl₂ (R = Et, n‐Bu or Ph) yields a series of symmetric 2:1 adducts of (L)₂SnR₂Cl₂ (L = L¹, L² or L³), which have been confirmed by elemental analysis and NMR spectroscopy. The crystal structures of (L²)₂Sn(n‐Bu)₂Cl₂·0.5C₆H₁₄ and (L³)₂SnEt₂Cl₂ determined by X‐ray crystallography show that the functionalized bis(pyrazol‐1‐yl)methane acts as a monodentate ligand through the pyridyl nitrogen atom, and the pyrazolyl nitrogen atoms do not coordinate to the tin atom. The cytotoxic activity of these complexes for Hela cells in vitro was tested. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of 4‐(1‐phenyl‐1H‐pyrazol‐3‐yl)‐[1,2,4]triazolo[4,3‐a]quinoxalines and their 4‐halogenopyrazolyl analogs

Synthesis of {3‐[1‐(ethoxycarbonyl)‐[1,2,4]triazolo[4,3‐a]quinoxalin‐4‐yl]‐1‐phenyl‐1H‐pyrazol‐5‐yl}methyl ethyl oxalate ( 2 ), ethyl 4‐[5‐(acetoxymethyl)‐1‐phenyl‐1H‐pyrazol‐3‐yl]‐[1,2,4]triazolo[4,3‐a]quioxaline‐1‐carboxylate ( 4 ), [4‐halo‐1‐phenyl‐3‐(1‐phenyl‐[1,2,4]triazolo[4,3‐a]quioxalin‐4‐yl)‐1H‐pyrazol‐5‐yl]methyl acetate ( 11 ), {4‐halo‐3‐[1‐methyl‐[1,2,4]triazolo[4,3‐a]quinoxalin‐4‐yl]‐1‐phenyl‐1H‐pyraz‐ol‐5‐yl}methyl acetate ( 13 ), and [3‐([1,2,4]triazolo‐[4,3‐a]quinoxalin‐4‐yl)‐4‐halo‐1‐phenyl‐1H‐pyrazol‐5‐yl] methyl formate ( 15 ) was accomplished. The structural investigation of the new compounds is based on chemical and spectroscopic evidences. J. Heterocyclic Chem., (2011)     

Synthesis and herbicidal activity of 2‐(3‐(trifluoromethyl)‐5‐(alkoxy)‐1H‐pyrazol‐1‐yl)‐4‐aryloxypyrimidine derivatives

A series of 2‐(3‐(trifluoromethyl)‐5‐(alkoxy)‐1H‐pyrazol‐1‐yl)‐4‐aryloxypyrimidine derivatives were designed and synthesized. The structures of all the title compounds were confirmed by ¹H NMR and elementary analysis. These compounds were screened for herbicidal activity against rape and barnyard grass. Compound B13 exhibited moderate herbicidal activity.     

Simple and convenient synthesis of 2‐(substituted‐benzylsulfanyl)‐4,5‐dihydrothiazoles and their antimicrobial activity studies

A simple and convenient procedure for the preparation of 2‐(substitutedbenzylsulfanyl)‐4,5‐dihydrothia‐zoles by the reaction of 4,5‐dihydro‐thiazole‐2‐thiol and benzyl bromides in acetone/K₂CO₃ condition has been reported.     

Synthesis of 5‐[(4‐phenylpiperazin‐1‐yl)methyl]pyrrolo‐[2,3‐d]pyrimidine derivatives as potential dopamine D4 receptor ligands

A series of pyrrolo[2,3‐d]pyrimidine Mannich bases of type 9, 12, 15 and 16 have been prepared as potential dopamine D4 receptor ligands. The syntheses start from 4‐aminopyrimidin‐6‐one 3 with pyrrole annulations and Mannich reactions with formaldehyde and phenylpiperazines 8 as new amine components.     

Novel 5‐Methyl‐2‐[(un)substituted phenyl]‐4‐{4,5‐dihydro‐ 3‐[(un)substituted phenyl]‐5‐(1,2,3,4‐tetrahydroisoquinoline‐2‐yl)pyrazol‐1‐yl}‐oxazole Derivatives: Synthesis and Anticancer Activity

Eleven novel 5‐methyl‐2‐[(un)substituted phenyl]‐4‐{4,5‐dihydro‐3‐[(un)substituted phenyl]‐5‐(1,2,3,4‐tetrahydroisoquinoline‐2‐yl)pyrazol‐1‐yl}‐oxazole derivatives were synthesized and characterized by elemental analysis, ESI‐MS, ¹H NMR and ¹³C NMR. All of the compounds have been screened for their antiproliferative activities against PC‐3 cell (human prostate cancer) and A431 cell (human epidermoid carcinoma cancer) lines in vitro. The results revealed that compounds 4g , 4j and 4k exhibited the strong inhibitory activities against the PC‐3 cell lines (with IC₅₀ values of 2.8±0.11, 3.1±0.10 and 3.0±0.06 μg/mL, respectively).     

Synthesis and antimicrobial evaluation of new 1‐{[4‐(4‐Halogenophenyl)‐4H‐1,2,4‐ triazol‐3‐yl]sulfanyl}acetyl‐4‐substituted thiosemicarbazides and products of their cyclization

By the reaction of hydrazides of 4‐(4‐halogenophenyl)‐4H‐1,2,4‐triazol‐3‐yl‐sulfanyl acetic acid with isothiocyanate, 1‐acyl‐4‐substituted thiosemicarbazide derivatives ( 7–19 ) were obtained. The cyclization of compounds ( 7–19 ) in the presence of 2% NaOH led to the formation of compounds ( 20–26 ) containing two 1,2,4‐triazole rings connected by a methylenesulfanyl group. The new compounds were tested for their in vitro antimicrobial activity. Some of the tested compounds ( 9, 12, 18, 21, 22 ) showed activity against the reference strains of Gram‐positive bacteria with the MIC (minimal inhibitory concentration) = 125 to >1000 μg/mL. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:117–121, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20758     

An efficient and regiospecific preparation of trifluoromethyl substituted 4‐( 1H‐pyrazol‐1 ‐yl)‐7‐chloroquinolines

A new series of 4‐[3‐alkyl(aryl)(heteroaryl)‐5‐hydroxy‐5‐trifluoromethyl‐4,5‐dihydro‐1H‐pyrazol‐1‐yl]‐7‐chloroquinolines, where [alkyl = CH₃; aryl = C₆H₅, 4‐CH₃C₆H₄, 4‐FC₆H₄, 4‐ClC₆H₄, 4‐BrC₆H₄, 4‐CH₃OCgH₄, 4‐NO₂CgH₄, 4‐biphenyl, 1‐naphthyl; heteroaryl = 2‐furyl and 2‐thienyl] has been regiospecifi‐caly obtained from the reaction of 7‐chloro‐4‐hydrazinoquinoline with 4‐substituted‐l,1,1‐trifluoro‐4‐methoxybut‐3‐en‐2‐ones in 61 ‐ 96 % yield. Subsequently, dehydration reaction of 4,5‐dihydropyra‐zolylquinolines under acid conditions furnished a new series of 4‐(3‐substituted‐5‐trifluoromethyl‐1H‐pyra‐zol‐1‐yl)‐7‐chloroquinolines in 73 ‐ 96 % yield.     

Synthesis and antimicrobial activity of some new N‐(substituted phenyl)‐N′‐[2,3‐dihydro‐2‐oxido‐3‐(4′‐fluorophenyl)‐1H‐(1,3,2)benzoxazaphosphorin 2‐yl]ureas

Substituted benzoxazaphosphorin 2‐yl ureas were synthesized by reacting 2‐(4‐fluoro‐phenylamino)‐methylphenol (4) with different carbamidophosphoric acid dichlorides (3) in the presence of triethylamine in dry toluene at 45‐50 °C and characterized by spectral data. These compounds were found to possess good antimicrobial activity.     

Synthesis and antifungal activity of spiro[cyclopropane‐1,4′‐pyrazol‐3‐one] derivatives

A series of new spiro[cyclopropane‐1,4′‐pyrazol‐3‐one] derivatives 3a‐h were synthesized by the reaction of 4‐arylidene‐3H‐pyrazol‐3‐one 1 with secondary and tertiary carbanions derived from a methylene and methine group bearing both a leaving group and electron‐withdrawing group, e.g. methyl chloroacetate, ethyl chloroacetate, isopropyl chloroacetate, tert‐butyl chloroacetate, chloroacetonitrile, 2‐chloro‐N,N‐diethylacetamide, methyl 2‐chloropropionate and 2‐chloropropionitrile, in the presence of sodium hydride. All the synthesized compounds 3a‐h were active against Candida albicans with MIC ≤ 25 μg/mL in vitro.     

A Novel Diastereoselective Synthesis of 6‐Aryl‐5‐hydroxy‐2,3‐dihydropyrano[2,3‐c]pyrazol‐4(1H)‐ones

A novel one‐pot diastereoselective synthesis of trans‐6‐aryl‐5‐hydroxy‐2,3‐dihydro[2,3‐c]pyrazol‐4(1H)‐ones 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h is described via the Darzens condensation reaction of 2‐chloro‐1‐(5‐hydroxy‐3‐methyl‐1‐phenyl‐1H‐pyrazol‐4‐yl)ethanone ( 2 ) with different aromatic aldehydes in aqueous basic medium. The structures of the compounds prepared were determined by analytical and spectral analyses.     

Synthesis and biological evaluation of several 3‐(coumarin‐4‐yl)tetrahydroisoxazole and 3‐(coumarin‐4‐yl)dihydropyrazole derivatives

A series of novel 3‐(coumarin‐4‐yl)tetrahydroisoxazoles 5a,b, 7, 9 and 3‐(coumarin‐4‐yl)dihydropyra‐zoles 13a‐d, 14,15a,b were synthesized from coumarin‐4‐carboxaldehyde 1 via the intermediate N‐methyl nitrone 3 and N‐phenyl or N‐methyl hydrazones 11a,b . These coumarin derivatives were isolated, characterized and evaluated in vitro for their ability to inhibit trypsin, β‐glucuronidase, soybean lipoxygenase and to interact with the stable radical 1,1‐diphenyl‐2‐picrylhydrazyl. The compounds were tested in vivo as anti‐inflammatory agents in the rat carrageenin paw edema assay. Compound 15a seems to be a lead molecule to be modified in order to improve the lipoxygenase inhibition. The results are discussed in terms of structural characteristics.     

Synthesis and antifungal activity of novel 5‐substituted 4‐(1,3,4‐thiadiazol‐2‐yl)benzene‐1,3‐diols

5‐Substituted (amine, alkyl, aryl, heterocyclic) 4‐(1,3,4‐thiadiazol‐2‐yl)benzene‐1,3‐ diols were synthesized, and their antifungal properties were examined. The compounds were obtained by the one‐pot reaction of sulfinylbis((2,4‐dihydroxyphenyl)methanethione) with hydrazides or thiosemicarbazides. Their structures were identified from elemental, IR, ¹H NMR, and MS spectra analyses. The activities of the derivatives against five phytopathogenic fungi in vitro were measured. Moderate fungicidal effect of the compounds under consideration was found. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:533–540, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20645