1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → N-((3-chloropyrazin-2-yl)methyl)-3-methylenecyclobutanecarboxamide

C-(3-Chloropyrazin-2-yl)-methylamine bis-HCl (1.0 g, 4.62 mmol), N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide (EDC) (1.31 g, 6.47 mmol, 1.4 eq.), 4-dimethylamino pyridine (DMAP) (0.141 g, 1.15 mmol, 0.25 eq.), and DIEA (2.42 mL, 1.79 g, 13.9 mmol, 3.0 eq.) were dissolved in anhydrous CH2Cl2 (25 mL). To this solution, a solution of 3-methylenecyclobutanecarboxylic acid (0.622 g, 5.54 mmol, 1.2 eq.) in anhydrous CH2Cl2 (25 mL) was added under N2 and the reaction was allowed to stir overnight at rt. Reaction mixture was concentrated in vacuo and the resulting residue was dissolved in EtOAc, washed with water (2×), NaHCO3 (1×), water (1×), and brine (1×), dried over Na2SO4, filtered, and concentrated in vacuo, giving crude title compound, as a brown oil. The crude material was purified by chromatography on silica gel [Jones Flashmaster, 20 g/70 mL cartridge, eluting with 10% hexane in ethyl acetate, affording the title compound as a pale yellow solid. Additionally, the title compound could be prepared by the following route: 1,1′-Carbonyldiimidazole (CDI) (0.824 g, 5.08 mmol, 1.1 eq.) and 3-methylenecyclobutanecarboxylic acid (0.570 g, 5.08 mmol, 1.1 eq.) were dissolved in anhydrous THF (12 mL) and allowed to stir at 60° C. for 2 h. A solution of C-(3-chloropyrazin-2-yl)-methylamine bis-HCl (1.0 g, 4.62 mmol) and DIEA (2.42 mL, 1.79 g, 13.9 mmol, 3.0 eq.) in anhydrous CH2Cl2 (13 mL) was added to the acid mixture and the reaction was allowed to stir at 60° C., under N2, overnight. The reaction mixture was concentrated in vacuo and the resulting residue was dissolved in EtOAc, washed with NaHCO3 (2×) and brine (1×), dried over Na2SO4, filtered, and concentrated in vacuo, giving crude title compound, as a brown oil. The crude material was purified by chromatography on silica gel [Jones Flashmaster, 20 g/70 mL cartridge, eluting with 10% hexane in ethyl acetate, affording the title compound as a pale yellow solid; 1H NMR (CDCl3, 400 MHz) δ 2.86-2.96 (m, 2H), 3.03-3.19 (m, 3H), 4.72 (dd, J=4.4, 0.8 Hz, 2H), 4.79-4.84 (m, 2H), 6.78 (s, —NH), 8.32-8.34 (m, 1H), 8.46 (d, J=2.8 Hz, 1H); MS (ES+): m/z 238.19 (90) [MH+]; HPLC: tR=2.67 min (OpenLynx, polar 7 min).

1. customReaction mixture
2. concentrationwas concentrated in vacuo
3. dissolutionthe resulting residue was dissolved in EtOAc
4. washwashed with water (2×), NaHCO3 (1×), water (1×), and brine (1×)
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customgiving crude title compound
9. customThe crude material was purified by chromatography on silica gel [Jones Flashmaster, 20 g/70 mL cartridge
10. washeluting with 10% hexane in ethyl acetate

ORD record

ord-fa825010e2414180987ef51d5cb8e0e9

Source dataset

uspto-grants-2013_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08481733B2