2,2-Dimethylsuccinic anhydride → HCID 66858177, compound

Participants

Reaction Steps

To a stirred solution of tert-butyl 2-(6-(2-((1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-9-hydroxy-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysene-3a-carboxamido)ethyl)-2,2-dimethyl-1,3-dioxan-4-yl)acetate (Example 79, 0.5 g, 0.80 mmol) in pyridine (5 ml), dimethyl amino pyridine (0.2 g, 1.6 mmol) and 3,3-dimethyldihydrofuran-2,5-dione (0.82 ml) were added. Contents were refluxed for about 16 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate (30 ml). The organic layer was washed with 5% aqueous HCl, water followed by brine, dried over Na2SO4 and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using 5% MeOH in DCM as eluent to furnish the title compound (0.25 g) as a white solid. 1H NMR (300 MHz, CDCl3): 0.95-1.16 (m, 19H); 1.23-1.78 (m, 23H); 2.15-2.59 (m, 11H); 2.77-3.58 (m, 16H); 4.33-4.70 (m, 4H); 5.58-5.60 (s, 1H); 5.78-5.80 (s, 1H); 7.44-7.47 (s, 1H); ES Mass: 806 [M+Na].

Provenance & Evidence