Hydrochloric Acid → [4-(3-Amino-azetidin-1-yl)-pyrimidin-2-yl]butyl-amine

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Reaction Steps

[1-(2-Chloro-pyrimidin-4-yl)-azetidin-3-yl]-carbamic acid tert-butyl ester To a flask containing 2,4-dichloropyrimidine (1.6 g, 10.7 mmol) and N,N-diisopropylethylamine (3.5 mL, 20.1 mmol) in i-PrOH (40 mL) was added azetidin-3-yl-carbamic acid tert-butyl ester monohydrochloride (2.1 g. 12.2 mmol). The reaction mixture was heated to 70° C. for 72 h. The reaction was cooled to room temperature, concentrated and the crude residue was purified by flash chromatography on SiO2 (100% hexane increasing gradient to 60% EtOAc-Hexane) to yield two isomeric products. The minor upper Rf product was obtained as a white solid (326 mg, 11%), and the desired major lower Rf product was also obtained as a white solid (2.1 g, 69%). [1-(2-Butylamino-pyrimidin-4-yl)azetidin-3-yl]-carbamic acid tert-butyl ester. To a solution of [1-(2-chloro-pyrimidin-4-yl)-azetidin-3-yl]-carbamic acid tert-butyl ester (250 mg, 0.778 mmol) in i-PrOH (3.0 mL) was added butylamine (600 μL, 6.0 mmol). The reaction mixture was heated to 95° C. in a sealed tube for 36-48 h followed by cooling to room temperature. The reaction mixture was then concentrated and the crude residue purified by flash chromatography on SiO2 using (100% EtOAc increasing the gradient gradually to 5% 2M NH3-MeOH) to yield the desired product (260 mg, 92%). [4-(3-Amino-azetidin-1-yl)-pyrimidin-2-yl]-butyl-amine. To a solution of [1-(2-butylamino-pyrimidin-4-yl)-azetidin-3-yl]-carbamic acid tert-butyl ester (250 mg, 0.778 mmol) in formic acid (4 mL) was added 6N HCl (300 μL). The reaction mixture was stirred at room temperature for 15-30 minutes. Then, MeOH (10 mL) was added and stirred for 10 minutes. The contents were then concentrated and the crude residue purified by flash chromatography on SiO2 using an increasing gradient of (0 to 10% NH3/MeOH in CH2Cl2) to yield the desired product (225 mg, 98%) as the free base. MS (ESI): mass calcd. for C11H19N5, 221.3 m/z found, 222.2 [M+H]+. 1H NMR (CD3OD): 7.61 (d, J=7.3, 1H), 5.99 (d, J=7.1, 1H), 4.6-4.7 (m, 2H), 4.28-4.48 (m, 3H), 3.40 (bs, 1H), 1.54-1.62 (m, 2H), 1.31-1.41 (m, 2H), 0.90 (t, J=7.4, 3H). The compounds in Example 85 through Example 94 were prepared using methods analogous to those described for Example 84.

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