Reaction Steps
Sodium ascorbate (28 mg, 140 μmol), tris-(benzyltriazolylmethyl)amine (15 mg, 28 μmol) and copper sulfate (4.5 mg, 28 μmol) were added to a solution of (E)-2-[[3-(3-methoxy-4-propargyloxyphenyl)-1-oxo-2-propenyl]amino]benzoic acid (0.50 g, 1.4 mmol) and 2-azido-N-phenylacetamide (0.25 g, 1.4 mmol) in DMSO (20 mL) and water (5.0 mL). The solution was stirred at rt for 16 h and diluted with water. The suspension was filtered and the filter cake was washed with water and dried. The crude product was recrystallised from acetonitrile to afford (E)-2-[[3-(3-methoxy-4-((1-(2-oxo-2-(phenylamino)ethyl)-1H-1,2,3-triazol-4-yl)methoxy)phenyl)-1-oxo-2-propenyl]amino]benzoic acid (0.60 g, 80%) as a colourless solid; mp 220-222° C.; δH (400 MHz, DMSO-d6) 3.82 (s, 3H, OCH3), 5.21 (s, 2H, CH2), 5.36 (s, 2H, CH2), 6.80 (d, J=15.6 Hz, 1H, CH═CHCO), 7.08 (t, J=8.0 Hz, 1H, H4″), 7.16 (t, J3,4=J4,5=8.0 Hz, 1H, H4), 7.21-7.28 (m, 2H, H6′, H5′), 7.39 (s, 1H, H2′), 7.31 (t, J2″,3″=J3″,4″=J4″,5″=J5″,6″=8.0 Hz, 2H, H3″, H5″), 7.56-7.63 (m, 4H, CH═CHCO, H5, H2″, H6″), 8.00 (d, J3,4=8.0 Hz, 1H, H3), 8.27 (s, 1H, C═CHN), 8.62 (d, J5,6=8.0 Hz, 1H, H6), 10.48 (s, 1H, NH), 11.30 (s, 1H, NH), 13.60 (br s, 1H, CO2H); δC (100 MHz, DMSO-d6) 52.2, 55.6, 61.4, 110.5, 112.9, 116.6, 119.2, 120.1, 120.4, 122.6, 122.8, 123.8, 126.6, 127.6, 129.0, 131.2, 134.1, 138.5, 141.1, 141.7, 142.2, 149.1, 149.4, 164.2, 169.5; HRMS (ESI) calculated for C28H25N5O6 [M+Na]+ 550.1697. found 550.1691; vmax 1239, 1585, 1665, 2605, 3000, 3250 cm−1.
