(3-ISOCYANATO)BENZENEBORONIC ACID, PINACOL ESTER synthesis

Yield:787591-43-9 77%

Reaction Conditions:

with triethylamine in tetrachloromethane; for 7 h;Heating / reflux;

Steps:

93.2 Example 93; 1-[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea; Step 2

A 1 L round bottomed flask fitted with a water-cooled condenser, was charged with J (10 g, 0.04 mol), triphosgene (4.38 g, 0.147 mol) and triethylamine (12 mL). Carbon tetrachloride (500 mL) was added and the reaction was gently heated to reflux. The reflux was continued for 7 h under a positive nitrogen pressure. The reaction mixture was cooled and washed with water (2×100 mL). The organic layer was dried over Na2SO4 and condensed. The oil thus obtained was taken in heptane (200 mL), filtered and condensed to give pure K (8.62 g, 77% crude yield). [0932] 1H NMR (CDCl3) δ 1.34 (s, 12H), 7.15 (d, 1H, J=7.9 Hz), 7.29-7.34 (t, 1H, J=7.6 Hz), 7.53 (s, 1H), 7.61 (d, 1H, J=7.3 Hz).

References:

US2004/220189,2004,A1 Location in patent:Page 46-47