Yield:5813-90-1 85%

Reaction Conditions:

with pyridine;di-tert-butyl dicarbonate;ammonium bicarbonate in 1,4-dioxane at 20; for 12 h;

Steps:

11.1

10 g (44.2 mmol) of xanthen-9-carboxylic acid and 11.6 g (53.0 mmol, 1.2 eq) of EPO (Boc)₂O were added. Then, 2.1 g (26.5 mmol, 0.6 eq) of pyridine and 5.3 g (66.3 mmol, 1.5 eq) Of NH₄HCO₃ were added thereto. Then, 100 ml of 1,4-dioxane was added thereto to dissolve them. Thereafter, the solution was stirred for 12 hours at room temperature. After the reaction was completed, the reactant was extracted with an organic layer by using EA/H₂O. The organic layer was concentrated, and then diethyl ether was added for crystallization thereto. The resultant solution was stirred for 1 hr and then filtered to obtain 8.47 g (85%) of 9H-xanthen-9-carboxamide.¹H NMR (200 MHz, CDCl₃) δ 7.8(brs, IH) 7.33~7.24(m, 4H) 7.13~7.05(m, 5H) 4.88(s, IH)

References:

WO2007/15632,2007,A1 Location in patent:Page/Page column 38-39