3.5- Dinitropyridine

Among the molecules that have received greatest attention are 2,6-bis(picry1amino)-3,5-dinitropyridine (PYX) 3,6-dinitro-j -tetrazine ... 

A three-atom addition is observed when the tetrazoles 52 are heated with 2-chloro-3,5-dinitropyridine (99RCB1391). 

JHC785, 87JHC1357). High yields were also achieved in the preparation of 4-nitroderivative 384 from 4-chloro-3,5-dinitropyridine (383) (Scheme 59) (86JHC785). 

Nitrotetrazolo[l,5-/]furazano[4,5- ]pyridine 1-oxide 340 (NFP) was prepared by the extrusion of nitrogen from 2,6-diazido-3,5-dinitropyridine followed by ring closure (Scheme 85) <2005JEM99>. 

Azo-3,5-dinitropyridine, 3238 2-Benzylideneamino-4,6-dinitrophenol, 3600 Bis(2,4-dinitrophenyl) disulfide, 3449 Bis(2-nitrophenyl) disulfide, 3465... 

As an extension of this work, the aminodechlorination of 2-chloro-3,5-dinitropyridine was studied (85JOC484). Because of the high 77-electron deficiency of this compound, it appears that the amination does not require the presence of a strong nucleophilic amide ion liquid ammonia is already... 

The and spectroscopy of a solution of 2-chloro-3,5-dinitropyridine in liquid ammonia at-40°C showed the formation of the C-6 adduct (10). This adduct is rather stable, since after 1 hr standing, no change in the spectrum was observed. It is interesting that at a somewhat lower temperature (-60°C) the addition takes place at C-4, i.e., formation of (9). Apparently one deals with the interesting concept of kinetically and thermodynamically controlled covalent adduct formation. At -60°C the addition is kinetically controlled, and at -40°C the addition is thermodynamically favored. The higher stability of the C-6 adduct compared to the C-4 adduct is probably due to the more extended conjugate resonance system (Scheme II.9). 

Kinetically vs thermodynamically favored a-adduct formation is not an uncommon phenomenon it has, for example, also been observed in solutions of 2-chloro-3,5-dinitropyridine in liquid ammonia containing potassium amide (85JOC484) and in the a-adduct formation between quinoline and potassium amide in liquid ammonia (73JOC1947). 

In only a few cases are ring transformation reactions found in which a in-termolecular CCC transfragment reaction occurs. An example of this rearrangement has been observed in the reaction of 3,5-dinitropyridin-4(l//)-one (99) with diethyl sodio-3-oxopentanedioate. It provided in good yield 3,5-di(ethoxycarbonyl)pyridin-4-(lH)-one (102) and 1,3-dinitroacetone as second product (78H108). Its structure was proven by the formation of l-phenyl-3-nitro-4-hydroxy-5-phenylazopyrazole (103), obtained on heating of the diphenylhydrazone of 1,3-dinitroacetone (Scheme III.53). 

Pagoria and co-workers synthesized a number of thermally stable explosives from the reaction of the sodium salt of ANTA with chloro-substituted arylenes and A-heterocycles. These include the synthesis of (117) from picryl ehloride, PRAN (118) from 2-chloro-3,5-dinitropyridine, IHNX (119) from 2,4-dichloro-5-nitropyrimidine, (120) from 1,5-dichloro-2,4-dinitrobenzene, and (121) from 4-chloro-6-(3-nitro-l,2,4-triazolyl)-5-nitropyrimidine. Coburn and co-workers " reported the synthesis of the tetrazine (122) and the triazine (123) from the reaction of the sodium salt of ANTA with 3,6-dichlorotetrazine and cyanuric chloride respectively. 

PADP (171), an explosive synthesized from the reaction of 3,5-dinitro-2,6-bis-(hydrazino)pyridine with picryl chloride in DMF followed by oxidation with nitric acid, also exhibits high thermal stability. 2,4,6-Tris(picrylamino)-3,5-dinitropyridine (172) exhibits much lower thermal stability than both PYX (170) and PADP (171), a consequence of increased steric crowding around the pyridine ring. ° ... 

The direct nitration of 2,6-diaminopyridine (168) with mixed acid yields 2,6-diamino-3,5-dinitropyridine (ANPy) (173). Oxidation of ANPy (173) with peroxyacetic acid yields ANPyO (174) (calculated VOD 7840 m/s, d = 1.88 g/crc ) C-Amination of ANPyO (174) with hydroxylamine hydrochloride in aqueous base yields the triamine (175), an impact insensitive explosive of high thermal stability. ... 

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