A solution of 1-6 (164 mg, 0.691 mmol) in DMF (4 ml) was treated with 1-7 (154 mg, 0.760 mmol), EDC (159 mg, 0.829 mmol), HOBT (127 mg, 0.829 mmol), and TEA (0.289 ml, 2.073 mmol). After stirring at RT for 30 min, the mixture was diluted with EtOAc, washed with water (3×s) and once with brine. The organic phase was dried over Na2SO4, filtered and concentrated. The crude material was purified by gradient elution on silica gel (0 to 100% EtOAc in Hex) to yield 1-8 as a pale yellow oil. Data for 1-8: LRMS m/z (M+H): 423.1.
