N- pyrazoles

C3N2 N N — — — Pyrazole substituted pyrazoles A - and A -pyrazolines pyrazolinones pyrazolidines pyrazolidinones... 

Pyrazolo[3,4-c]pyrazole, tetrahydro-rearrangement, 5, 250 Pyrazolo[4,3-c]pyrazole, tetraaryl-electrophilic substitution, 6, 1035 oxidation, 6, 1034-1035 reduction, 6, 1035 vacuum pyrolysis, 6, 1035 Pyrazolo[ 1,2-n]pyrazole-1,5-diones synthesis, 6, 991 Pyrazolo[ 1,2-n]pyrazoles reactions, 6, 1038 ring opening, 6, 983... 

C CPMAS NMR studies of N -pyrazoles and indazoles (93CJC678) concluded (i) the tautomer present in the solid is also the major tautomer in solution (ii) 3(5)-ferrocenylpyrazole is a 50 50 mixture of both tautomers in the solid state (iii) certain pyrazole C-substituents (CF3, Br, Ar, Het) prefer position 3 (that is, they are 3-substituted pyrazoles (193)), others (Bu , Pr, CH3) prefer position 5 (that is, they are 5-substituted pyrazoles (194)). 

The possibility of formation of an O—O bond at a single Mn site of the OEC, on the other hand, seems remote, but nevertheless, two mononuclear model Mn-peroxo complexes, a peroxo-Mnm porphinato 64 [157] and a peroxo-Mn111 pyrazolylborato complex 65 [158], have been structurally characterized. Both complexes contain side-on peroxo groups. Complex 65 has been crystallized in two forms, one brown and one blue. A peroxo-H—N (pyrazole) hydrogen bond is found only in the blue form (Figure 29). 

Complexes were prepared by refluxing (5-10 min) equimolecular quantities of nickel acetate with the respective 4-aminomethylene derivatives of 1,3-substituted 5-thio(seleno)-N-pyrazoles in ethanol solution. All the complexes thus obtained were purified by repeated crystallization... 

To a solution of ethyl trifluoroacetate (1.90 ml, 16.0 mmol) in 7 ml of methyl tert-butyl ether was added 25% NaOMe (3.62 ml, 16.8 mmol). Next 4-chloroaceteophenone (2.08 ml, 16.0 mmol) in 2 ml of methyl tert-butyl ether was added. The mixture was stirred at room temperature overnight. To above solution was added 100 ml of 90% EtOH, followed by 4 N HCI (4.0 ml, 16 mmol) and 4-sulphonamidophenylhydrazine hydrochloride (3.58 g, 16 mmol). The mixture was heated to reflux for 3 hours. The mixture was concentrated. When 30 ml of water was added, a solid formed. The solid was filtered and washed with 20 ml of 60% EtOH to give 4.50 g of white solid. The filtrate was evaporated and taken up in ethyl acetate (100 ml), washed with saturated NaHC03, and brine, dried over MgS04, and concentrated. Heptane was added at boiling point of the mixture. After cooling down to 0°C, 1.01 g more product was obtained. The combined yield of the 4-(5-(4-methylphenyl)-3-trifluoromethyl-N-pyrazol-l-yl)benzenesulfonamide (Celecoxib) was 86%. 

Unsymmetrical /i-diketones can form two )S-keto-enol tautomers, (90a), (90b). The corresponding N//-pyrazoles— readily synthesized from the diketones—exhibit annular tautomerism, (91a), (91b). These tautomerisms have been probed via AMI semiempirical calculations that show that the two phenomena are related in each case the position of equilibrium is strongly influenced by whether or not the CC double bond is part of (another) ring system (the Mills-Nixon effect). 

A systematic study of annular tautomerism of N//-pyrazoles in the solid state has been published <88CJCl 141 > in each case the tautomer present in the solid state was identified and the conclusion is always in agreement with the result obtained by x-ray crystallography, when available. The only compound for which the solution was not clear was 3(5)-phenyl-5(3)-methylpyrazole (64)) (Section... 

The results of the electrooxidation of 1-aminopyrazoles in the presence of lithium perchlorate depends on the reaction medium employed 1,2,3-triazines, N//-pyrazoles are formed <90CPB1524>. In the presence of water A,A -dipyrazolyl-l,3-propanediimine (pz—N=CH—CHj—CH=N—pz) is formed. 

Velaparthi,S.,Brunsteiner,M.,Uddin,R., Wan, B., Franzblau, S.G., and Petukhov, P.A. (2008) 5-tert-butyl-N-pyrazol-4-yl-4,5,6,7-tetrahydrobenzo[d]isoxazole-3-carboxamide derivatives as novel potent inhibitors of Mycobacterium tuberculosis... 

H BRN 0621550 Butisan S 2-ChlotD-N-(2,6-dimethylphenyl)-N-(1 H-pyrazol-1-yi-methyl)-acetamide 2-Chloro-N-(pyrazol-1 -... 

Y-Chloropropyltrimethoxysilane. See 3-Chloropropyltrimethoxysilane 2-Chloro-N-(pyrazol-1-ylmethyl) acet-2, 6 -xylidide. See Metazachlor 2-Chloropyridine... 

Colombo V, Galli S, Choi HJ, Han GD, Maspero A, Palmisano G, et al. High thermal and chemical stabiUty i n pyrazolate-bridged metal-organic frameworks with exposed metal sites. Chem Sci 2011 2 1311-9. 

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