A solution of 5-chloro-2,4-dihydroxy-benzoic acid (176 mg, 0.93 mmol) in DMF (5 mL) was treated with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (179 mg, 0.93 mmol) then HOBt (126 mg, 0.93 mmol). After 45 min, the solution of the activated acid was added to a mixture 5-(4-methyl-piperazin-1-yl)-2,3-dihydro-1H-isoindole dhihydrochloride (290 mg, 0.78 mmol) and triethylamine (0.28 mL, 2 mmol) then the mixture was stirred at r.t. for 3 h. The solvent was removed in vacuo then the residue was partitioned between ethyl acetate and water (×3). Each extract washed with saturated sodium bicarbonate solution and brine then dried (MgSO4), combined and concentrated. Some insoluble material remained and this was dissolved in 1N hydrochloric acid and methanol then combined with the organic extracts. The pH was adjusted to 14 with solid sodium hydroxide and the mixture allowed to stand overnight. The pH was adjusted to 7 with 1N hydrochloric acid and the resulting precipitate was filtered off then subjected to purification by preparative HPLC to afford the title compound as a red solid. This was converted to its hydrochloride salt by treatment with 4M HCl in dioxane, concentration in vacuo and trituration with ether which gave a brown solid (91 mg, 27%). 1H NMR (DMSO-d6) 11.10 (1H, br.s), 10.50 (1H, br.s), 7.26-7.15 (2H, m), 7.02-6.93 (2H, m), 6.69 (1H, s), 4.72-4.61 (4H, m), 3.78-3.72 (2H, m), 3.45 (2H, br.s), 3.12 (4H, br.s), 2.78 (3H, s). MS: [M+H]+ 386/388.
