p-Toluenesulfonic acid → 9-Benzoylamino-6,10-dioxo-1,2,3,4,7,8,9,10-octahydro-N-(2-isopropoxy-5-oxo-tetrahydro-furan-3-yl)-6H-pyridazino[1,2-a][1,2]diazepine-1-carboxamide

Participants

Reaction Steps

A solution of 214e (101 mg, 0.23 mmol) in isopropanol (10 ml) was stirred at room temperature with a catalytic amount of p-toluenesulfonic acid (10 mg). After 75 minutes, the reaction mixture was poured into saturated NaHCO3 and extracted with CH2Cl2. The combined extracts were dried over Na2SO4 and concentrated. Flash chromatography (SiO2, CH2Cl2 to EtOAc) afforded 56 mg (51%) of 2100a as a white solid: 1H NMR (CDCl3; mixture of diastereomers) δ7.9-7.8 (2H,m), 7.6-7.5 (1H, m), 7.5-7.4 (2H, m), 7.1 (0.5H, d), 6.9 (0.5H, d), 6.4 (0.5H,d), 5.6 (0.5H, d), 5.3 (0.5H, s), 5.2-5.1 (1H, m), 4.95 (0.5H, m), 4.75-4.5 (1.5H, m), 4.35 (0.5H, t), 4.1 (0.5H, m), 3.98 (0.5H, m), 3.3-2.75 (4H, m), 2.5-2.4 (2H,m), 2.25 (1H, m), 2.1-1.9 (3H,m) 1.75-1.55 (2H,m).

Provenance & Evidence