Trifluoroacetic acid → HCID 89618399, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of tert-butyl (3Z)-3-(dimethylaminomethylene)-2-oxo-5-(2-trimethylsilylethynyl)-4,8b-dihydro-3aH-indeno[1,2-b]pyrrole-1-carboxylate D2 (Example 2, Step 2, 0.13 g, 0.3 mmol) in dioxane (5 mL) was added HCl (37%, 0.321 mL). The solution was stirred 2 h at room temperature and was then diluted with water, extracted with ethyl acetate, washed with brine, dried and concentrated to give 0.130 g of a mixture of tert-butyl (3Z)-3-(hydroxymethylene)-2-oxo-5-(2-trimethylsilylethynyl)-4,8b-dihydro-3aH-indeno[1,2-b]pyrrole-1-carboxylate and (3Z)-3-(hydroxymethylene)-5-(2-trimethylsilylethynyl)-1,3a,4,8b-tetrahydroindeno[1,2-b]pyrrol-2-one. A solution of 0.13 g of a mixture of tert-butyl (3Z)-3-(hydroxymethylene)-2-oxo-5-(2-trimethylsilylethynyl)-4,8b-dihydro-3aH-indeno[1,2-b]pyrrole-1-carboxylate and (3Z)-3-(hydroxymethylene)-5-(2-trimethylsilylethynyl)-1,3a,4,8b-tetrahydroindeno[1,2-b]pyrrol-2-one in dichloromethane (18 mL) was added trifluoroacetic acid (2 mL) at 0° C. The solution was stirred for 1 h at 0° C. A saturated solution of sodium hydrogenocarbonate was added and the aqueous layer was extracted with dichloromethane. The combined organic layers were washed with a saturated solution of sodium hydrogenocarbonate, dried and concentrated in vacuo to give ((3Z)-5-ethynyl-3-(hydroxymethylene)-1,3a,4,8b-tetrahydroindeno[1,2-b]pyrrol-2-one C2 (70 mg, 72%). LC-MS (Method C) RT 0.67 min, ES− 224 (M−H+), ES+226 (M+H+).

Provenance & Evidence