Potassium Carbonate → (S)-2-(2-Amino-7-(4-chlorophenyl)-5-methylbenzo[d]thiazol-6-yl)-2-tert-butoxyethyl pivalate

Participants

Reaction Conditions

Reaction Steps

2 separate microwave tubes were each charged with (S)-2-(2-Amino-7-bromo-5-methylbenzo[d]thiazol-6-yl)-2-tert-butoxyethyl pivalate (768 mg, 1.74 mmol), K2CO3 (960 mg, 6.96 mmol), 4-chlorophenylboronic acid (325 mg, 2.09 mmol), Pd(PPh3)4 (200 mg, 0.174 mmol), dioxane (8.0 mL), and H2O (2.0 mL). The two sealed vessels were separately heated at 110° C. for 3 h. The reactions were cooled to 23° C. and combined. H2O (50 mL) was added, and the system was extracted with EtOAc (3×50 mL). The combined extracts were dried (Na2SO4), filtered, and concentrated. The residue was treated with benzene and purified via chromatography on silica gel (80 g “gold” ISCO column; Hex/EtOAc) giving (S)-2-(2-Amino-7-(4-chlorophenyl)-5-methylbenzo[d]thiazol-6-yl)-2-tert-butoxyethyl pivalate (1.55 g, 90% yield). LCMS-ESI+: calc'd for C25H31ClN2O3S: 475.2 and 477.2 (M+H+); found: 475.3 and 477.3 (M+H+). 1H-NMR: 400 MHz, (CDCl3) δ: 7.49-7.41 (m, 2H), 7.36-7.32 (m, 2H), 7.22 (d, J=7.3 Hz, 1H), 5.19 (s, broad, 2H), 4.67 (dd, J=9.0, 2.7 Hz, 1H), 4.36 (dd, J=11.7, 9.0 Hz, 1H), 4.23 (dd, J=11.7, 2.7 Hz, 1H), 2.68 (s, 3H), 1.14 (s, 9H), 0.94 (s, 9H).

Provenance & Evidence