Reaction Steps
Following the procedure as described in EXAMPLE 12 and making non-critical variations using 2-thiophenemethylamine to replace cyclohexanemethylamine, and 4-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]benzoic acid to replace 3-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]benzoic acid, 4-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]-N-(thiophen-2-ylmethyl)benzamide was obtained (48%) as a colorless solid: mp 167-168° C.; 1H NMR (300 MHz, CDCl3) δ7.81-7.73 (m, 2H), 7.43-7.37 (m, 2H), 7.27-7.16 (m, 3H), 7.07-7.00 (m, 2H), 6.99-6.95 (m, 1H), 6.75-6.70 (m, 1H), 6.48-6.40 (m, 3H), 4.99 (ABq, 2H), 4.84 (ABq, 2H), 4.83-4.78 (m, 2H), 4.59-4.50 (m, 2H), 3.09-2.90 (m, 2H); 13C NMR (75 MHz, CDCl3) δ178.0, 166.5, 161.9, 161.3, 141.7, 140.6, 139.4, 133.7, 132.6, 128.7, 127.7, 127.5, 126.9, 126.2, 125.3, 124.0, 123.6, 120.0 (2C), 118.8, 109.1, 93.3, 80.6, 72.4, 57.7, 43.8, 38.8, 29.0; MS (ES+) m/z 509.2 (M+1).
