1,1'-Carbonyldiimidazole → 4-O-tert-butyl 1-O-[(Z)-(1,2-diamino-2-oxoethylidene)amino] (2R)-2-(3-cyclohexylpropyl)butanedioate

(R)-2-[2-(tert-Butoxy)-2-oxoethyl]-5-cyclohexylpentanoic acid (Preparation 1) (3.47 g, 11.6 mmol) in dimethylformamide (21 ml) was treated with 1,1′-carbonyldiimidazole (1.97 g, 12.2 mmol) and the mixture was stirred at ambient temperature for 1 hour. N-Dimethylaminopyridine (1.43 g, 11.7 mmol) was then added in one portion, followed by the addition of 2-amino-2-(hydroxyimino)acetamide (1.25 g, 12.1 mmol, Helv.Chim.Acta; 47; 1964; 33-46). The resulting mixture was stirred at room temperature for 24 hours. The mixture was partitioned between ethyl acetate and a 10% solution of citric acid in demineralised water. The layers were separated and the aqueous phase was extracted with ethyl acetate. The combined organic layers were washed with demineralised water (×4) and brine, dried over anhydrous magnesium sulfate, filtered and the solvent removed under reduced pressure. The residue was crystallised from n-hexane, the precipitate was collected by filtration and dried in vacuo to afford the title compound as a colourless solid (3.30 g, 74% yield).

1. stirringThe resulting mixture was stirred at room temperature for 24 hours
2. customThe mixture was partitioned between ethyl acetate
3. customThe layers were separated
4. extractionthe aqueous phase was extracted with ethyl acetate
5. washThe combined organic layers were washed with demineralised water (×4) and brine
6. dry with materialdried over anhydrous magnesium sulfate
7. filtrationfiltered
8. customthe solvent removed under reduced pressure
9. customThe residue was crystallised from n-hexane
10. filtrationthe precipitate was collected by filtration
11. customdried in vacuo

ORDレコード

ord-a283d8b2f6e64b36a91608fe16b4e662

出典データセット

uspto-grants-2005_05

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US06897306B2