Reaction Steps
Following the procedure as described in EXAMPLE 4 and making non-critical variations using tert-butyl-3-bromomethyl-1-cyclopropyl carbamate to replace 2-(bromomethyl)tetrahydro-2H-pyran, and spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one to replace 5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one, tert-butyl [1-cyclopropyl-3-(2′-oxospiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-1′(2′H)-yl)propyl]carbamate was obtained (91%) as a fluffy yellow solid: 1H NMR (300 MHz, CDCl3) δ7.28 (dd, J=7.7, 7.7 Hz, 1H), 7.13 (d, J=6.9 Hz, 1H), 7.02 (dd, J=7.2, 7.2 Hz, 1H), 6.90 (d, J=7.8 Hz, 1H), 6.47 (s, 1H), 6.11 (d, J=4.9 Hz, 1H), 5.83 (d, J=5.5 Hz, 2H), 4.88 (dd, J=8.9, 7.0, Hz, 1H), 4.69 (br, 1H), 4.62 (dd, J=8.9, 1.7 Hz, 1H), 3.93-3.73 (m, 2H), 2.99 (br, 1H), 2.14-1.81 (m, 2H), 1.30 (s, 9H), 0.95-0.80 (m, 1H), 0.58-0.19 (m, 4H); 13C NMR (75 MHz, CDCl3) δ177.3, 177.3, 155.9, 155.7, 155.6, 148.8, 142.3, 142.2, 132.4, 129.0, 123.9, 123.3, 119.5, 119.4, 108.6, 103.1, 103.0, 101.5, 93.6, 80.4 (2C), 65.9, 58.2, 37.8, 37.5, 32.9, 32.7, 28.4, 16.1 (2C), 15.3, 3.9, 3.8, 3.0, 2.9; MS (ES+) m/z 501.3, (M+23), 479.28 (M+1), 423.2 (M−56), 379.3 (M−100).
