To a solution of (S)-4-amino-5(piperidine-3-ylmethoxy)-1H-benzo[c][1,2,6]thiadiazin 2,2-dioxide hydrochloride (Example 2a, 694 mg, 2.0 mmol) in H2O/ACN (5 mL, 1:1) was added triethylamine (228 uL, 2.0 mmol). After stirring at room temperature for 5 min a solution of 2-cyclopropylacetic acid (200 mg, 2.0 mmol), HOBt (272 mg, 2.0 mmol), and EDCI-HCl (382 mg, 2.0 mmol) in H2O/ACN (5 mL, 1:1) was added to the mixture. An additional equivalent of triethylamine (228 uL, 2.0 mmol) was added and the reaction mixture was stirred at room temperature overnight. The product crashed out of solution and is collected by vacuum filtration. The compound was purified via preparative RP HPLC (10 to 90% EtOH in water) then diluted with 10 mL water and 200 mg of NaHCO3 was added. The solution was heated at 90° C. for 20 minutes until all the compound was dissolved then cooled to 0° C. and neutralized with 1N HCl solution. The product precipitated out and was collected by filtration and dried to provide the title compound (410 mg, 52.3%). 1H NMR (DMSO-d6, 400 MHz, 80° C.): 0.12 (br s, 2H), 0.44 (m, 2H), 0.96 (br s, 1H), 1.42 (m, 2H), 1.70 (m, 1H), 1.88 (m, 1H), 1.98 (br s, 1H), 2.09 (m, 1H), 2.26 (br s, 2H), 2.91 (m, 2H), 3.67 (br s, 0.5H), 3.85 (br s, 0.5H), 4.09 (m, 3H), 6.65 (d, J=8.4 Hz, 1H), 6.71 (d, J=8.4 Hz, 1H), 7.46 (t, J=8.4 Hz, 1H), 7.75 (br s, 1H), 8.16 (br s, 1H), 10.79 (s, 1H). M+H=393.
