Methanol → HCID 86707238, compound

To a stirred solution of 3-methyl-2,5-dioxo-1′,3′-dihydrospiro[imidazolidine-4,2′-indene]-5′-carboxylic acid (4.50 g, 17.3 mmol) in MeOH (500 mL) was added conc. H2SO4 (1 mL, 18 mmol) and the resulting mixture was heated at reflux for 24 h. The reaction mixture was concentrated in vacuo to a volume of about 150 mL and then partitioned between saturated aqueous sodium bicarbonate (200 mL) and CHCl3 (500 mL). The aqueous layer was extracted further with CHCl3 (250 mL). The combined organic extracts were washed with brine, dried over sodium sulfate, filtered, and concentrated to dryness in vacuo to give the racemic product. Separation of the enantiomers was achieved by SFC on a ChiralPak AD-H column, eluting with CO2:i-PrOH-70:30, to give methyl (4S)-3-methyl-2,5-dioxo-1′,3′-dihydrospiro[imidazolidine-4,2′-indene]-5′-carboxylate, the title compound, as the first major peak, and methyl (4R)-3-methyl-2,5-dioxo-1′,3′-dihydrospiro[imidazolidine-4,2′-indene]-5′-carboxylate as the second major peak. MS: m/z=274.9 (M+1).

1. temperaturethe resulting mixture was heated
2. temperatureat reflux for 24 h
3. concentrationThe reaction mixture was concentrated in vacuo to a volume of about 150 mL
4. custompartitioned between saturated aqueous sodium bicarbonate (200 mL) and CHCl3 (500 mL)
5. extractionThe aqueous layer was extracted further with CHCl3 (250 mL)
6. washThe combined organic extracts were washed with brine
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated to dryness in vacuo
10. customto give the racemic product
11. customSeparation of the enantiomers
12. washeluting with CO2

ORD record

ord-906b0aa6c0e74ab896ec184856216a71

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09227973B2