Potassium Carbonate → 4-[5-(6-Amino-5-benzothiazol-2-ylpyridin-3-yl)-thiazol-2-yl]-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 4-(5-bromothiazol-2-yl)-piperazine-1-carboxylic acid tert-butyl ester (0.079 g, 0.229 mmol), 3-benzothiazol-2-yl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-pyridin-2-ylamine (BB8) (0.105 g, 0.298 mmol), potassium carbonate (0.101 g, 0.732 mmol), and Pd(PPh3)4 (0.018 g, 0.016 mmol) in previously degassed DME/H2O (4:1) (4.0 mL) was placed in a microwave tube and evacuated and charged with N2 (2×). The reaction mixture was heated in the microwave reactor to 100° C. for 30 min. The reaction mixture was diluted with EtOAc, washed with water and brine, dried over Na2SO4, filtered and concentrated in vacuo. The crude material was purified on prep-TLC eluting with 3% 7M NH3 in MeOH/DCM yielding 4-[5-(6-amino-5-benzothiazol-2-ylpyridin-3-yl)-thiazol-2-yl]-piperazine-1-carboxylic acid tert-butyl ester, MS (ES+): m/z=495.06 [MH+]. To a solution of this compound in DCM (1.0 mL) was added 1M HCl in ether (2.0 mL, 2.0 mmol), and the mixture was stirred at room temperature overnight. The solid that formed was filtered off and purified on the MDP. To a solution of the material thus obtained in DCM (1.0 mL) was added 1M HCl in ether (1.0 mL, 1.0 mmol). The precipitate was filtered off and dried in vacuo, yielding the title compound as yellow solid. 1H NMR (400 MHz, CD3OD): δ=2.95-3.00 (m, 4H), 3.46-3.53 (m, 4H), 7.40 (s, 1H), 7.42-7.48 (m, 1H), 7.53 (dd, J=15.3, 1.1 Hz, 1H), 7.98-8.05 (m, 2H), 8.07 (d, J=2.3 Hz, 1H), 8.23 (d, J=2.3 Hz, 1H). MS (ES+): m/z=395.06 (55) [MH+]. HPLC: tR=2.11 min (ZQ2, polar—5 min).

Provenance & Evidence