Pyrazole 1-methyl-3,4-dinitro

The nitration (fuming nitric acid) of 5-chloro-3-methyl-l-phenylpyrazole is reported to give a mononitro product (presumably the 4-nitrophenyl derivative) and a dinitro product 5-chloro-3-methyI-4-nitro-l-(4-nitro-phenyl)-pyrazole (1900CB2595 11LA329). 

The nitration of 3-methoxy-5-methyl-l-phenylpyrazole with nitric acids sulfuric acid at 0°C, followed by 3 h at 50°C, gives 3-methoxy-5-methyl-(4-nitrophenyl) pyrazole (51%), but reaction with mixed acid at 40°C for 24 h gives the 4-nitro-l-(4-nitrophenyl) product (85%). The preparative nitrations (using mixed acid) of the dinitro products are summarized in Table III. No n.m.r. evidence was found for the presence of ortho or meta nitrophenyl isomers. 

In some cases l-methyl-5-nitro- and l-methyl-3,5-dinitropyrazole can form as a result of deoxygenation [76], Nevetheless, the nitration of 2-benzylpyrazole 1-oxide by sulfuric-nitric acid mixture leads to 2-benzyl-3-nitropyrazole 1-oxide in quantitative yield. Further nitration takes place in the phenyl 4-position forming 3-nitro-2-(4-nitrobenzyl)pyrazole 1-oxide and then in the pyrazole 5-position to give 3,5-dinitro-2-(4-nitrobenzyl)pyrazole 1-oxide as the final product [77],... 

The chemical properties of 1,4-dinitropyrazole [654] and l,4-dimethyl-3,5-dini-tropyrazole obtained by the nitration of 1,4-dimethylpyrazole [655], nitrotriazoles [656-663], and other nitroazoles [662, 664-666] have been studied. 1,4-Dinitro-pyrazole undergoes ring transformation reactions with primary amines, hydrazines, hydroxylamine, and amidines [654], Acid hydrolysis of dinitropyrazole leads to (l-methyl-3,5-dinitropyrazol-4-yl)acetaldehyde, and the reaction with sodium nitrite in hydrochloric acid furnishes 2-hydroxymino-2-(l-methyl-3,5-dinitropyra-zol-4-yl)acetaldehyde [655],... 

Mass spectrometry has been used for the structural determination of isomeric I -methyl-3(5)-nitro-4-pyrazolcarbonitriles [302], l,5-dimethyl-3,4-dinitropyrazole [279], 4,4-dinitro-l,l-methylenedipyrazole [1291], 3-amino-5-bcnzylamino-4-nitro-yrazole [317], amino derivatives of 4-nitropyrazole [1292], antibacterial compounds 3-(3-mcthyl-4-nitro- lf/-pyrazole-5-yl)- and 3-(3-methyl-4-nitro-l-alkylpyrazole-5-yl)-5-methyl-4-nitroisoxazoles [500], some l-heteroaryl-4-nitropyrazoles [311]. 

Reaction of l-methyl-4-nitropyrazole with 1,1,1-trimethylhydrazinium halides in the presence of sodium methoxide or potassium fert-butoxide afforded 5-amino-l-methyl-4-nitropyrazoles <1999CHE1109>. Specifically, the primary radical anions of substrate in the vicarious nucleophilic substitution of hydrogen in 1-methyl-4-nitropyrazole 192 with 1,1,1-trimethylhydrazinium iodide yielded 5-amino-l-methyl-4-nitropyrazole 193, which was studied by electron spin resonance (ESR) (Equation 31) <2005MRC1023>. Reaction of 3,5-dinitropyrazole 194 with trimethylhydrazinium iodide in DMSO afforded 4-amino-3,5-dinitro-l//-pyrazole 195 via another vicarious nucleophilic substitution (Equation 32) <2001JHC1227>. 

Nitropyrazole derivatives such as 4-nitropyrazole, l-methyl-4-nitropyrazole and 4,4 -dinitro-l,r-methylene dipyrazole are known as antiparasitic agents <88Mi 30i-02>. It has been shown that 3,4-bis(2,4-dinitrobenzoyl-hydroxymethyl) pyrazole has remarkable antimicrobial activity it is more efficient than penicillin, levomycetin, and polymyxin <92Ml 30i-03>. The synthesis of A -pyrazoline-... 

In IH-Pyrazol (Dichlormethan) betragen die chemischen Verschiebungen fur C-3 und C-5 134,6 ppm, fur C-4 105,8 ppm. Mit wachsender Elektronegativitat der Substitucntcn in 1-Position verschieben sich alle Signale nach tieferem Feld (z.B. Benzyl < Benzoyl < Benzolsulfonyl % 4-Methyl-benzolsulfonyl < 4-Nitro-benzolsulfonyl < 2,4-Dinitro-benzolsulfonyl)1738. 

Geht man direkt von 1,3-Dinitro-alkanen aus, werden mit Hydrazin-Hydrat und 1,3-Dinitro-2-phenyl-butan oder 2,4-Dinitro-3-(4-methoxy-phenyl)-pentan 3(5)-Methyl-4-phenyl- (56% Schmp. 140-142°) bzw. 3,5-Dimelhyl-4-(4-methoxy-phenyl)-IH-pyrazol (68% Schmp. 153-155°) erhalten. 1-Nitro-l-alkene cyclisieren thermisch in Dimethylformamid mit D-Ga-lactose-phenylhydrazon2138 ... 

Arylhydrazone von 3-(l-Adamantyl)-3-chlor-acrolein und 3-(l-Adamantyl)-3-chlor-2-methyl-acrolein geben beim Erhitzen in einem Phosphorsaure/Essigsaure-Gemisch661 oder in Phos-phorsaure6625-( l-Adamantyl)-l-( 2,4-dinitro-phenyl)-(41 % Schmp. 163,5 165,5°), 5-( 1-Ada-mantyl)-l-(2,4-dinitro-phenyl)-4-methyl- (54% Schmp. 199,5-200,5°)661 bzw. 5-( 1-Adaman-tyl)-1-phenyl-lH-pyrazol (48% Schmp. 135-136°)662 ... 

Bei Verwendung von 87%iger Schwefelsaure wird 3,5-Dinitro-l-methyl-lH-pyrazol-2-oxid (Schmp. 186-188°) erhalten. 

Durch cine -Substitution (s.S. 587) an l,4-Dinitro-3-methyl-lH-pyrazol mit Trimethylphos-phit als Nukleophil gelingt die Herstellung von 5 ( 3 )-Dimethoxyphosphoryl-3 (5 )-methyl-4-ni-tro-lH-pyrazol (77% Schmp. 180-1820)1610. 

Die cine -Substitution an 1,4-Dinitro-lH-pyrazolen (s.a. S. 587) sowie an l-(2,6-Dimethyl-4-phenyl-pyridiniono)-2-methyl-pyrazolium-bis-tetrafluoroborat (s.S. 591) mit Alkalimetall-cyaniden ermoglicht die Synthese von 3(5)-Cyan-4-nitro-lH-pyrazolen125,1610 bzw. 5-Cyan-l-methyl-1 H-pyrazol [ 100% Sdp. 90°/8Torr (1,07kPa) Schmp. 23-270]169. 

Ci(H,BtClXsOg 5-Chlor-4-brom-l -phenyl-pyrazol-carbons4are-(3) 86 1530. CgoHtBrCIKgOg 5-Chlor-3-methyl-l - [4-brom-x-dinitro-phenyl].pyrazofoder 8-Chlor-4.nltro-3-methyl-l - [4-brom-2 (oder 3)-nitro-phenylj-pyrazol 83, 55. 

CuH,CI)(404 5-Chlor-3.methyl-l-[x-dinitro-4-methyl-phenylJ-pyrazol oder S-Ch)or-4-nitro-3-methyl-l-[2(oder 3)-nitiD-4-methyl-phenyl]-pyiazol 2 58. 

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