methyl 2-[(2'-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b']difuran-3,3'-indol]-1'(2'H)-yl)methyl]benzoate → 4-[(2'-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b']difuran-3,3'-indol]-1'(2'H)-yl)methyl]benzoic acid

Participants

Reaction Steps

Following the procedure as described in EXAMPLE 11.30 and making non-critical variations using methyl 4-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]benzoate to replace methyl 2-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]benzoate, 4-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3-indol]-1′(2′H)-yl)methyl]benzoic acid was obtained (95%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ12.93 (s, 1H), 7.90 (d, J=8.1 Hz, 2H), 7.43 (d, J=8.1 Hz, 2H), 7.22 (dd, J=7.4 Hz, 1H), 7.16 (d, J=7.4 Hz, 1H), 7.00 (dd, J=7.4 Hz, 1H), 6.94 (d, J=7.4 Hz, 1H), 6.45 (s, 1H), 6.40 (s, 1H), 4.98 (ABq, 2H), 4.77 (ABq, 2H), 4.47 (t, J=8.9 Hz, 2H), 3.01-2.85 (m, 2H); MS (ES+) m/z 414.1 (M+1).

Provenance & Evidence