Nitrophenylhydrazone

Experimental details for the preparation of oximes, phenylhydrazones and p-nitrophenylhydrazones will be found under Aromatic Aldehydes, Section IV,135,4-6. 

Heat 0-25 g. of the compound with 3 ml. of alcohol, add 0-25 g. of p-nitrophenylhydrazine, and heat the suspension until the reaction appears complete. The p-nitrophenylhydrazone soon separates. Filter, preferably after standing overnight, wash with a little cold alcohol, and then recrystallise from alcohol. 

Compounds related to phenylhydrazine react in an analogous way p Nitrophenylhydrazine yields p nitrophenylhydrazones 2 4 dinitro phenylhydrazine yields 2 4 dinitrophenylhydrazones... 

The Frasca method for obtaining 1-arylindazoles also involves a C(3)—C(3a) ring closure (67CJC697). It consists in the cyclization of p-nitrophenylhydrazones of ketones and aldehydes with polyphosphoric acid. The Barone computer-assisted synthetic design program has found several new methods for preparing indazoles (79MI40409). The selected method involves the transformation of jV, jV -diphenylhydrazides (596) into 1-phenylindazoles (597) by means of trifluoromethanesulfonic anhydride. The yields vary from 2% (R = H) to 50% (R = Ph). 

Fractionally distd through a 12 plate column and fraction b 77"/4mm was collected. Also wet the acetylthiophene in order to remove and free thiophene which forms an azeotrope with H2O, b 68°, Store in a brown bottle and the clear colourless liquid remains thus for extended periods. [Org Synth 28 1 1948 J Am Chem Soc 69 3093 1947.] The red 4-nitrophenylhydrazone crysts from EtOH, m 181-182°. 

The product of the eoupling of (a) with p-nitrobenzenediazonium chloride is identieal with the p-nitrophenylhydrazone of [h). The oxidation of weostrychnidine to strychnidone by permanganate (1932) and of ncobrueidine to brucidone (1927) are probably analogous, and it is now found that by the aetion of p-nitrobenzenediazonium ehloride, neostrychnine is eonverted into stryehnone p-nitrophenylhydrazone. 

Aldehyde enamines react with aromatic diazonium salts in two ways, depending on the degree of substitution at the enamine earbon (130). Thus the piperidine enamine of butyraldehyde (60) reacted with p-nitrophenyl-diazonium chloride to give the p-nitrophenylhydrazone of the a-keto aldehyde (190). 

The enamine (191) from isobutyraldehyde on treatment with p-nitrophenyl-diazonium chloride, on the other hand, gave the p-nitrophenylhydrazone of acetone (192) and presumably N-formyl piperidine, although the latter was not isolated. 

Nitro(phenyl)methanone 2-nitrophenylhydrazone (1 2.4 g, 8.4 mmol) in aq MeOH was hydrogenated at atmospheric pressure in the presence of Raney nickel. The catalyst was filtered off and air was passed through the filtrate to yield the product yield 1.34 g (72%) red needles mp 118 C (MeOH containing a trace of Nll3). 

METAL NITROPHENOXIDES, METAL OXALATES METAL PYRUVATE NITROPHENYLHYDRAZONES metal OXOHALOGENATES (anion an oxo derivative of a halogen) metal oxometallates (anion an oxo derivative of a metal) metal oxonon-METALLATES (anion an oxo derivative of a non-metal) peroxoacid SALTS (anion a peroxo derivative of a metal or non-metal) There is a separate entry for... 

A number of other spectrophotometric reagents and combinations thereof have been used and compared with NBP 4-p3ridinecarboxaldehyde 4-nitrophenylhydra-zone 4-pyridinecarboxaldehyde 2-benzothiazolylhydrazone 4-acetylpyridine 4-nitrophenylhydrazone 4-acetylpyridine 2-benzothiazolylhydrazone [62]. S -Dodecylisothiouronium bromide has been used with primary and secondary alkyl halides [63]. 4-Nitrothiophenol has been claimed to be better than NBP, but only when used in combination with HPLC and not as a stand-alone reagent [64]. 

Ci4H,2N403 Phenylglyoxal 2-oxime l-(/7-nitrophenylhydrazone) Photometric Co 3... 

Regarding the amine-catalyzed rearrangement of the p-nitrophenylhydrazone [81JHC723 83JCS(P2)1203], all the amines catalyze the reaction nevertheless, depending on the nature of the amine, different catalysis laws are observed. Tertiary amines and secondary amines with great... 

Dehydrogenation of lupenone p-nitrophenylhydrazone with iodine and t-butox-ide followed by treatment with aqueous TiClj gave the A -3-ketone glochidone in 50% yield. " The trihydroxylupane (162) is formed on hydroboration of betulin. " ... 

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