Acetic Anhydride → (5R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-7-yl acetate
Reaktionsgleichung
[Cl:1][C:2]1[N:7]=[CH:6][N+:5]([O-])=[C:4]2[CH2:9][CH2:10][C@@H:11]([CH3:12])[C:3]=12.[CH3:13][C:14]([O:16]C(C)=O)=[O:15]>>[C:14]([O:16][CH:9]1[C:4]2[N:5]=[CH:6][N:7]=[C:2]([Cl:1])[C:3]=2[C@H:11]([CH3:12])[CH2:10]1)(=[O:15])[CH3:13]Komponenten
3
Versuchsvorschrift
A solution of the (R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine 1-oxide (5.5 g, 29.8 mmol) in Ac2O (40.5 mL, 429 mmol) was heated to 110° C. for 3 hours. After cooling, the acetic anhydride was evaporated, and the resulting residue was taken up in DCM. This solution was added to a stirring cold solution of saturated NaHCO3. The layers were extracted with DCM, dried MgSO4, filtered, and concentrated. The crude oil was chromatographed (Biotage) eluting with 20% EtOAc/hexane, to provide (5R)-4-chloro-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-7-yl acetate (3.0 g, 44.4%).