A solution of 2-[[3-(2-amino-1,2-dioxoethyl)-2-methyl-1-(2-bromobenzyl)-1,6,7,8-tetrahydrocyclopent[g]indol-4-yl]oxy]acetic acid methyl ester (106 mg, 0.21 mmol) in methanol (3 mL) was treated with 1 N lithium hydroxide solution (1 mL). The solution was heated to reflux then allowed to cool to room temperature. The mixture was diluted with water and acidified with 1 N hydrochloric acid. The resulting precipitate was collected via vacuum filtration and washed carefully with ethyl acetate to provide 36 mg (35%) of the title compound as a tan solid: mp 261-262° C. (dec). 1H NMR (DMSO-d6) δ 12.88 (bs, 1H), 7.72 (m, 2H), 7.43 (bs, 1H), 7.26 (m, 2H), 6.46 (s, 1H), 6.18 (m, 1H), 5.48 (s, 2H), 4.62 (s, 2H), 2.80 (m, 4H), 2.43 (s, 3H), 1.93 (quintet, J=7.3 Hz, 2H); IR (KBr, cm−1) 3431, 1735, 1628, 1213.
