9H-Purin-2-amine, 6-chloro-9-[2-(2,2-dimethyl-1,3-dioxan-5-ylidene)ethyl]- → 6-Chloro-9-[2-(2,2-dimethyl-1,3-dioxan-5-yl)ethyl]-9H-purin-2-amine
Reaction equation
[CH3:1][C:2]1([CH3:21])[O:7][CH2:6][C:5](=[CH:8][CH2:9][N:10]2[CH:18]=[N:17][C:16]3[C:11]2=[N:12][C:13]([NH2:20])=[N:14][C:15]=3[Cl:19])[CH2:4][O:3]1>[Pd].O1CCCC1>[NH2:20][C:13]1[N:12]=[C:11]2[C:16]([N:17]=[CH:18][N:10]2[CH2:9][CH2:8][CH:5]2[CH2:4][O:3][C:2]([CH3:1])([CH3:21])[O:7][CH2:6]2)=[C:15]([Cl:19])[N:14]=1Participants
Procedure
5% Palladium on carbon (1.5 g) in tetrahydrofuran (40 ml) was prehydrogenated for 30 min at 50 p.s.i. 2,2-Dimethyl-5-[2-(2-amino-6-chloropurin-9-yl)]ethylidene-1,3-dioxane (3.0 g) in tetrahydrofuran (80 ml) was added and washed in with tetrahydrofuran (30 ml). The mixture was hydrogentated overnight at 50 p.s.i. with stirring. The catalyst was removed by filtration to give a colourless solution. The solvent was removed under reduced pressure and the residue recrystallised from IPA to give the title compound (1.92 g, 62.2% yield). Analysis: Found C: 49.98; H: 5.82; N: 22.42%; Required: C: 50.08; H: 5.82; N: 22.46%. 5-[2-(2-Amino-6-chloropurin-9-yl)ethyl]-2,2-dimethyl-1,3-dioxane can be converted to penciclovir using techniques known in the art such as those described in EP 141927.
Workup
- washwashed in with tetrahydrofuran (30 ml)
- customThe catalyst was removed by filtration
- customto give a colourless solution
- customThe solvent was removed under reduced pressure
- customthe residue recrystallised from IPA
Sources & evidence
- ORD record
- ord-8de46968aa714828914c92a8962e6479
- Source dataset
- uspto-grants-2003_04
- Patent number
- US06555685B1
Reaction notes
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