2- Chloro-3,5-dinitropyridine

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

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). 

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. 

Arylation. Arylation of 2,4-diaryl-5(4//)-oxazolones 170 with activated aryl halides has been reported to proceed under phase-transfer conditions (Scheme 7.51). The yields of 2,4-diaryl-4-(2,4-dinitroaryl)-5(47/)-oxazolones 171 are often modest. Heteroarylation of 170 was accomplished using 2-chloro-3,5-dinitropyridine. Representative examples are shown in Table 7.19 (Fig. 7.21). 

Chloro-3,5-dinitropyridine [2578-45-2] M 203.5, m 62-65 , 63-65 , 64 . Dissolve in CHCI3, shake with saturated NaHCO3, dry (MgSO4), evaporate and apply to an AI2O3 column, elute with pet ether (b 60-80°), evaporate and recryst from CgHg or pet ether. [Chem Pharm Bull Japan 8 28 1960 Rec Trav Chim Pays Bas 72 573 1953. ... 

Amination of 2-chloro-3,5-dinitropyridine in liquid ammonia at —40°C and potassium permanganate gave 2,6-diamino-3,5-dinitropyridine. Its formation indicates that besides SNH at C-6, a SN(AE) amino-dechlorination occurs at C-2 (Scheme 6). 

NMR studies on a-adduct formation between 2-chloro-3,5-dinitropyridine and liquid ammonia show that the site of covalent addition is temperature dependent at — 60 °C the C-4 adduct is formed, at —40°C the C-6 adduct is obtained (85JOC484). Apparently, at — 60 °C the C-4 adduct is the kinetically favored one, and at —40°C the thermodynamically more stable C-6 adduct is obtained. The results are in agreement with those of the amination at —40 °C (Scheme 6). 

The l,3-dithiolo[4,5-6]pyridin-2-one (549) has been prepared in a two-step procedure (Scheme 69) (81JHC1581). Treatment of 2-chloro-3,5-dinitropyridine (547) with sodium dimethyldithiocarbamate in anhydrous acetone at 25 °C overnight afforded 3,5-dinitropyridyl-2-dimethyl-dithiocarbamate (548) (82%) as a stable crystalline solid. Heating (548) at reflux in acetone afforded a mixture of compounds from which 6-nitro-l, 3-dithiolo[4,5-h]pyridin-2-one (549) (7%), 2-dimethyl-... 

Plazek [28,28b] and Plazek and Talik [28a] stated recently that the reactivity of halogens in nitro derivatives of pyridine is much higher than in the similar benzene derivatives. Thus, at 20°C where only 0.5% of chloro-2,4-dinitrobenzene was subjected to nucleophilic displacement of chlorine by the amino group, the figure was 98.3% for 2-chloro-3,5-dinitropyridine. 

The ring closure of acylhydrazines can be applied to the synthesis of numerous 1,3,4-oxadi-azines fused to heterocyclic rings. Thus condensation of 2-chloro-3,5-dinitropyridine with l-benzoyl-2-phenylhydrazine, followed by cyclization as described above yields 7-nitro-2,4-diphenyl-4//-pyrido[2,3-e][l,3,4]oxadiazine (6) in 85% yield.55... 

In the reaction of 2-chloro-3,5-dinitropyridine (59) with potassium azide in methanol <92KGSi 145> formation of the tetrazolo[l,5-a]pyridine ring system was followed by addition of the methoxide ion to give the potassium salt (60) (Scheme 9). 

Chloro-3,5-dinitropyridines give 2-alkoxy-3 -dinitropyridines with various alcohols in a sealed tube at 140 for 3 to 5 hours R, these compounds over PtO gives the corresponding diamino derivatives... 

Fluoro-3-nitropyridines are prepared from the corresponding 2-aminopyri-dines in only fair yield but are hydrolyzed in good yield to the 2-pyridinols. 2-Fluoro-6-methyl-5-nitropyridine, 2-fluoro-3,5-dinitro4-methylpyridine, 2-fluoro-3,5-dinitro-6-methylpyridine and 2-chloro-3,5-dinitropyridine ... 

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