The synthesis steps for NK94827 are as follows:
(1) Add oxalyl dichloride (6 mL, 70 mmol) and DABCO (Triethylene Diamine, 112 mg, 1 mmol) to the stirred solution of sulfonamide (20 mmol) in dry toluene (50 mL) at 60°C.
(2) Leave the reaction on at 60-65°C for 6 h with continual stirring and warm to 110°C slowly.
(3) Reflux for 10-12 h and remove the resulting precipitate by filtration.
(4) Cool the reaction to room temperature and condense in vacuo.
(5) Dilute with 50 mL acetonitrile.
(6) Add the above-mentioned sulfonyl isocyanate solution (4 mL) into a solution of amine (1 mmol) in dry acetonitrile (2 mL).
(7) Leave the reaction on at room temperature over night with continual stir and filter the precipitate.
