Reaction Steps
2-[1-(3-Hydroxy)phenyl)-1-methoxymethylene]tricyclo[3.3.1.13,7]decane 3a (520 mg), triethylamine (800 μl) and benzotriazol-1-yloxytris(dimethylamino)-phosphonium hexafluorophosphate (BOP) (950 mg) were added to a solution of 4,5-dimethoxy-2-[(phenylacetamino)methyl]phenylacetic acid 7 (656 mg, 1.91 mmol) in anhydrous DMF (10 ml). The reaction mixture was stirred at ambient temperature for 6 hours. The mixture was concentrated under vacuum. Chromatography on silica gel using cyclohexane/EtOAc (v/v:40/60) as eluent gave the ether of 3-(adamantan-2-ylidene-methoxymethyl)phenyl enol ester of [4,5-dimethoxy-2-(phenylacetylaminomethyl)phenyl]-acetic acid 2 (606 mg, 53%) in the form of a white powder. M.p. 95° C. 1H NMR (CDCl3, 300 MHz) δ 7.21 (t, J=7.9 Hz, 1H), 7.15-7.00 (m, 6H), 6.91 (t, J=2.3 Hz, 1H), 6.84 (ddd, J=7.9 Hz, 2.3 Hz, 0.8 Hz, 1H), 6.80 (s, 1H), 6.77 (s, 1H), 4.44 (d, J=5.3 Hz, 2H), 3.88 (s, 3H), 3.85 (s, 2H), 3.81 (s, 3H), 3.53 (s, 2H), 3.30 (s, 3H), 3.25 (br s, 1H), 2.66 (br s, 1H), 1.90-1.55 (m, 12H). 13C NMR (CDCl3, 75 MHz) δ 150.6, 148.6, 148.5, 142.6, 137.3, 134.9, 132.9, 129.4, 129.1, 128.9, 127.3, 127.1, 124.1, 122.1, 120.4, 113.5, 112.9, 58.0, 56.1, 56.0, 43.9, 41.4, 39.3, 39.1, 38.3, 37.2, 32.2, 30.3, 28.3. M.S. (Maldi-T of, positive mode) m/z 634.27 [M+K]+, 618.30 [M+Na]+. Analysis calculated for C37H41NO6: C=74.60, H=6.94 and N=2.35. Analysis measured: C=74.25, H=7.09 and N=2.41.
