8-(Methylsulfanyl)-1H-pyrazolo[4,3-h]quinazoline-3-carboxamide 50 mg (0.193 mmol) in DMF (8 ml), were reacted with 2,2,2-trichloroethyl 3-[(methylsulfonyl)oxy]-8-azabicyclo[3.2.1]octane-8-carboxylate 200 mg (0.52 mmol) and cesium carbonate 140 mg (0.43 mmol) at 90° C. for 4 hours. The mixture was cooled at r.t. and portioned between ethyl acetate and water. The organic phase was washed with brine, dried over Na2SO4 and evaporated. The crude was purified by column chromatography eluting with DCM/EtOH 9/1 to provide 2,2,2-trichloroethyl 3-[3-carbamoyl-8-(methylsulfanyl)-1H-pyrazolo[4,3-h]quinazolin-1-yl]-8-azabicyclo[3.2.1]octane-8-carboxylate as a off-white solid 73 mg (70%). The compound (134 mmol) was dissolved in THF (5 ml), acetic acid (5 ml) and zinc dust 35 mg (0.536 mmol) were added. The mixture was heated up to 50° C. and stirred 18 hours. The volatiles were removed in vacuum and the residue was purified by chromatography eluting with DCM/MeOH 95/5. A further purification was required and was performed by prep-HPLC method 1, to obtain the title compound 25 mg (50%). LC/MS (254 nm) HPLC method 2 Rt 4.08 min. 1H NMR (401 MHz, DMSO-d6) δ 9.50 (s, 1H), 8.25 (d, J=8.67 Hz, 1H), 7.62-7.79 (m, 3H), 7.52-7.60 (m, 1H), 6.21-6.54 (m, OH), 3.68 (br. s., 2H), 2.76 (s, 2H), 2.22-2.36 (m, 2H), 2.02 (br. s., 2H), 1.78-1.98 (m, 5H). HRMS (ESI) calcd for C18H20N6OS [M+H]+ 369.1492 found 369.15.
