1-BOC-4-(5-NITRO-2-PYRIDYL)PIPERAZINE

2-Bromo-5-nitro-pyridine (11.39 g, 56.1 mmol), tetrabutylammonium iodide (TBAI) (1.04 g, 0.05 mmol), potassium carbonate (8.53 g, 61.7 mmol) and piperazine-1-carboxylic acid tert-butyl ester (11.5 g, 61.7 mmol) were mixed together in DMSO (100 mL) and gently warmed to 50 C. for 3 hours and cooled to room temperature overnight. The reaction was diluted with EtOAc (200 mL), the salts were filtered and then the EtOAc was evaporated to leave the DMSO solution. This was diluted with water and a precipitate formed. This precipitate was filtered, washed with water, and then dried in an oven vacuum to give 4-(5-nitro-pyridin-2-yl)-piperazine-1-carboxylic acid tert-butyl ester (16.1 g, 93percent) as a light orange solid. In a 5 mL glass microwave tube were placed 2-bromo-5-nitro pyridine 1 (1015 mg, 5 mmol), 1-Boc-piperazine 2a (930 mg, 5 mmol), KBINAP [[ (R)-2, ] 2'-Bis [(DIPHENYLPHOSPHINO)-1, ] [1APOS;-BINAPHTHYL]] (2.5 g, 3.94088 mmoles) and tris (dibenzylidene acetone) dipalladium (o) (7.2 g, 7.88177 mmoles) were taken in dry toluene (400 ml) and stirred under argon atmosphere at room temperature for 15 minutes. 2-Bromo-5-nitro-pyridine (40 g, 197.044 mmoles) was dissolved in toluene (200 ml) and added to the reaction mixture followed by N-t-butoxycarbonyl piperazine (44 g, 236.45 mmoles). To this cesium carbonate (90 g, [275, ] 862 mmoles) was added at room temperature under argon atmosphere. The reaction mixture was heated to [80 °C] for 1-2 hours under argon atmosphere and was cooled to RT and filtered through celite. Washed the residue thoroughly with ethylacetate. The combined filtrates were washed with water and brine solution. Dried over anhydrous sodium sulphate and concentrated to dryness and purified over silica gel column using dichloromethane and methanol as eluent to yield the title compound (42.4 g, yield 70percent).Example 197a Step 1 : t-Butyl 4-(5-nitropyridin-2-yl)piperazine-1-carboxylate (B-2) To 5-nitro-2-chloropyridine (10.0 g, 0.0631 mol) and N-BOC-piperazine (17.6 g, 0.0946 mol) dissolved in DMF (200 ml_) was added NIntermediate B-54-(5-Aminopyridin-2-yl)-N-(2-fluorophenyl)piperazine- 1 -carboxamide (B-5) Step 1 : t-Butyl 4-(5-nitropyridin-2-yl)piperazine-l-carboxylate (B-2)To 5-nitro-2-chloropyridine (10.0 g, 0.0631 raol) and N-BOC-piperazine (17.6 g, 0.0946 mol) dissolved in DMF (200 mL) was added N, N-diisopropylethylamine (24.5 g, 31.3 mL, 0.189 mol). The reaction mixture was heated at 100 °C for 16 h then cooled to RT and concentrated. Water (300 mL) was added, and the aqueous solution was extracted with CH2G2. The combined organic extract was dried (MgS0 ), filtered, and concentrated.Purification by vacuum filtration through silica gel (eluant: 5percent EtOAc-CFkCL.) gave t-butyl 4-(5-nitropyridin-2-yl)piperazine-l-carboxylate (B-2) as a yellow solid (19.45 g, 100percent yield). MS (M+l): 309.N-BOC piperazine (0.5g) and 2-chloro-5-nitropyridine (0.424g) in DMF (16ml) were treated with potassium carbonate (0.744g) and DIPEA (1.41ml). The resulting mixture was heated at 120N-BOC piperazine (0.5g) and 2-chloro-5-nitropyridine (0.424g) in DMF (16ml) were treated with potassium carbonate (0.744g) and DIPEA (1.41ml). The resulting mixture was heated at 120Potassium carbonate (1.7g, 12.31 mmol) was added to a solution of 2-Chloro- 5-nitropyridine (1.33g, 8.38mmol) and piperazine-1-carboxylic acid tert-butyl ester (1.57g, 8.42mmol) in dioxane (10ml) then stirred at reflux for 4hours. The reaction was cooled, and solvent evaporated. The residue was extracted with MeCIA suspension of 2-chloro-5-nitropyridine (7.90 g), piperazine-1-carboxylic acid tert-butyl ester (11.2 g) and potassium carbonate (6.90 g) in acetonitrile (250 mL) was heated under reflux for four hours. The reaction mixture was concentrated and diluted with ethyl acetate and washed with water and saturated brine and dried over sodium sulfate and filtered and concentrated. The residue was vigorously stirred in ethyl acetate/isopropyl ether, collected by filtration and dried under reduced pressure, and 16.1 g (87percent) of the title compound was obtained as a yellow solid. MS(FAB) m/z:309 (M + H)To a solution of tert-butyl piperazine-1-carboxylate (64 g, 346 mmol) in 600 ml. of THF at OPlace 2-chloro-5-nitro-pyridine (1.0 g, 6.31 mmol), piperazine-1-carboxylic acid tert-butyl ester (1.76 g, 9.45 mmol), and triethylamine (1.76 mL, 12.6 mmol) in ra-butanol (20 mL). Heat to 120 °C for 17 hours. Cool to room temperature and add ethyl acetate and water. Separate organic layer and wash with water and saturated aq. sodium chloride. Collect organic layer, dry over MgTo a solution containing 5.8 g (31.5 mmol) of tert-butyl 1-piperazinecarboxylate and 20 mL of THF at 0To a solution containing 5 8 g (31 5 mmol) of fert-butyl 1-pιperazιnecarboxylate and 20 mL of THF at 0 °C was added 1 5 g (37 mmol) of a 60percent dispersion of NaH in mineral oil The reaction mixture was allowed to stir for 20 mm and 5 0 g (31 5 mmol) of 2-chloro-5-nιtropyrιdιne was added The reaction mixture was heated at 50 °C overnight, quenched by the addition of HTo a solution of 2-chloro-5-nitropyridine (LXV) (2.0 g, 12.6 mmol) in EtOH (20 mL) was added tert-butyl piperazine-l-carboxylate (XCVI) (7.05 g, 37.9 mmol). The reaction was headed at 70°C for 16 h. The reaction was concentrated under vacuum and then dissolved in EtOAc. The EtOAc was washed with 1 M NaOH, brine and then dried over MgS04 to give tert-butyl 4-(5-nitropyridin-2-yl)piperazine-l- carboxylate (XCVII) as a yellow solid (4.94 g). ESIMS found for CStep 1 To a solution of 2-chloro-5-nitropyridine (LXV) (2.0 g, 12.6 mmol) in EtOH (20 mL) was added fert-butyl piperazine-l-carboxylate (XCVI) (7.05 g, 37.9 mmol). The reaction was headed at 70°C for 16 h. The reaction was concentrated under vacuum and then dissolved in EtOAc. The EtOAc was washed with 1 M NaOH, brine and then dried over MgS04 to give tert-butyl 4-(5-nitropyridin-2-yl)piperazine-l-carboxylate (XCVII) as a yellow solid (4.94 g). ESIMS found for C14H20N4O4 mlz 309.0 (M+H).

Molecular Weight:308.33
XLogP3:1.8
Hydrogen Bond Acceptor Count:6
Rotatable Bond Count:3
Exact Mass:308.14845513
Monoisotopic Mass:308.14845513
Topological Polar Surface Area:91.5
Heavy Atom Count:22
Complexity:410
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes