Hydrazones 2,4-dinitrophenyl

Dissolve I g. of pinacol (preparation, p. 148) in 20 ml. of water, and add 20 ml. of the 5% aqueous sodium periodate solution. After 15 minutes, distil the clear solution, collecting the first 5 ml. of distillate. Treat this distillate with 2,4-dinitro-phenylhydrazine solution A (p. 263). Acetone 2,4-dinitrophenyl-hydrazone rapidly separates from the solution when filtered off, washed with a small quantity of ethanol, and dried, it has m.p. 126-127°, and after recrystallisation from ethanol it has m.p. 128°. 

Purified by distn and by recrystn from pet ether. The bis-2,4-dinitrophenyl hydrazone has m 221 dec. [Halford and Weissmann J Org Chem 17 1646 1952 Riemschneider and Kassahn Chem Ber 92 1705 7959.]... 

Yields are in the order of 50%. A more convenient sequence, but involving two extra steps, requires prior preparation of the 2,4-dinitrophenyl-hydrazone or semicarbazone followed by an acidic dehydration, and finally removal of the protecting group. 

Compound NPYR Species Rat Tissue Preparation Liver microsomes Comments identification of 4-hydroxybutyr-aldehyde (as its 2,4-dinitrophenyl-hydrazone) from a-hydroxylation Reference 9... 

Amines, amino acids, peptides 2,4-dinitrophenyl hydrazone PRE-CD with +1.10 217... 

Acyl-l,2,4-trioxolanes (61) are generally thermally labile, although their 2,4-dinitrophenyl-hydrazone (DNP) derivatives appear to be much more stable <9lCB94v>. In addition to the anhydrides (62), the previously unknown isomeric nonperoxide compounds (63) were found as products (Equation (5)). 

Bicyclo[3.3 l]nonan-9-one, (2,4-dinitrophenyl)hydrazone (8,9) (—) Monochloroborane diethyletherate Borane, chloro-, compound with ethyl ether (8), Borane, chloro-, compound with 1,1 -oxybis[ethane] (1 1) (9) (36594-41-9). 

A labile 4,6-dideoxy- /Z /cero-hexos-2,3-diulose (actinospectose) (60)288 2 8 has been isolated, as the crystalline bis-[(2,4-dinitrophenyl) hydrazone] of... 

The carbonyl group is determined by a reaction with 2,4-dinitrophenyl hydrazine which precipitates the 2,4-dinitrophenyl hydrazone of the aldehyde or ketone, which is then filtered off, dried, and weighed. The reaction is... 

Some commercial samples of precipitated manganese dioxide may be active enough for use directly in an oxidation process. To assess the activity of a sample of manganese dioxide, dissolve 0.25 g of pure cinnamyl alcohol in 50 ml of dry light petroleum (b.p. 40-60 °C) and shake the solution at room temperature for 2 hours with 2g of the sample of manganese dioxide (previously dried over phosphoric oxide). Filter, remove the solvent by evaporation and treat the residue with an excess of 2,4-dinitrophenylhydrazine sulphate in methanolt (Section 9.6.13, p. 1257). Collect the cinnamaldehyde 2,4-dinitrophenyl-hydrazone and crystallise it from ethyl acetate. An active dioxide should give a yield of the derivative, m.p. 255 °C (decomp.), in excess of 0.35 g (60%). 

Moreover, the presence of 2-furaldehyde was demonstrated by the isolation of its (2,4-dinitrophenyl)hydrazone in 20 % yield from 4-(D-xylosyl-amino)benzoic acid after standing for 20 hours in methanolic hydrogen chloride (0.4 N). This high yield, compared with observations by other workers,139 can be attributed to the very high concentration of acid. 

Aliphatic acids " Detected as 2.4 dinitrophenyl hydrazones Spectrometric 1 Pg L- [74]... 

Propionaldahyde, butyraldehyde, benz aldehyde Low capacity anion exchange resin Acetonitrile Separated as 2,4- dinitrophenyl hydrazones 0.06pg L [77]... 

Syringaldehyde — Apiezon nongranulated Teflon at220°C Hydrogen flame ionisation 2,4 dinitrophenyl hydrazone — [648]... 

The semicarbazone (96a), thiosemicarbazone (96b) and 2,4-dinitrophenyl hydrazone (96c) were all reacted with SOCl2 to yield 9//-l,2,3-thiadiazolo[4,5-a]-4,5,6,7-tetrahydropyrrolizine (97) <83IJC(B)822>. The reaction of varying amounts of benzylamine with 4-bromomethyl-5-benzoyl-1,2,3-thiadiazole (98) gave 5-benzyl-6-phenylpyrrolo[3,4-d]-1,2,3-thiadiazole (83) in low yields <78JHC473>. 

The reactivity of the carbonyl group in a,/3-unsaturated dialdoses was studied in more detail. The interaction with phenylhydrazine and its derivatives led to different results. 3-0-Benzyl-l,2-0-cyclo-hexyl idene-5,6-dideoxy-a-D-xyZo-hept-5-e nodialdo-l,4-furanose (56) gave57 a (2,4-dinitrophenyl)hydrazone. Action of (2,4-dinitrophenyl)-hydrazine on derivatives 67 led18 to complex mixtures. In the case of the acetylated derivatives (66), as well as of branched-chain derivatives (69), the interaction with (2,4-dinitrophenyl)hydrazine resulted in the formation of the expected hydrazones (Refs. 24 and 51, respectively). The interaction with phenylhydrazine was, however, proved to proceed by two paths in this case. Only the nitro derivatives (66, R = p-nitrophenyl) and (69, R = p-nitrophenyl) were shown24,51 to form the expected hydrazones. The phenyl derivative 66 (D-galacto, R = Ph) and p-methoxyphenyl derivative 69 (R = p-MeOC8H4) afforded substituted pyrazolines (74) (Ref. 24) and (75) (Ref. 51), respectively, as a result of subsequent intramolecular addition of a... 

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