Triphenylphosphine → Phosphoric acid dibenzyl ester 3-oxo-2,3-dihydro-7-oxa-1,2-diazabenzo[de]anthracen-10-ylmethyl ester

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Reaction Steps

To a solution of compound 57 (0.25 mmol) in anhydrous DMF was added dibenzyl phosphate (0.80 mmol) and triphenylphosphine (0.80 mmol). The reaction mixture was stirred while diisopropyl azodicarboxylate was added slowly. The reaction mixture was stirred at room temperature for 3 hours. Solvent was removed in vacuo. To the residue, 100 mL of ethyl acetate was added. The organic layer was washed with water and brine, then dried with MgSO4. The Solvents were removed to afford a yellow oil. The oil was re-crystallized in EtOAc/Hexanes to afford an off-white solid 60 in 40% yield. MS (ES+): 527; Mp: 223-225° C.; 1H-NMR (CDCl3, 400 MHz): 9.91 (s, 1H), 8.13 (d, J=2.0 Hz, 1H), 8.11 (dd, J=8.0 and 1.0 Hz, 1H), 7.85 (t, J=8.0 Hz, 1H), 7.59 (dd, J=8.0 and 1.0 Hz, 1H), 7.45 (dd, J=8.5 and 1.0 Hz, 1H), 7.36-7.26 (m, 11H), 5.08 (m, 6H). Anal. Calcd. for C29H23N2O6P.(0.15hydrazine): C, 65.56; H, 4.48; N, 6.06. Found: C, 65.55; H, 4.33; N, 6.09.

Provenance & Evidence