- STEREOSELECTIVE SYNTHESIS OF (+/-)-threo-2-AMINO-1-(4-NITROPHENYL)-1,3-PROPANEDIOL
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Addition of hypobromic acid to styrene afforded styrene bromohydrin (I) which was dehydrated to ω-bromostyrene (II).Prince reaction of II with aqueous formaldehyde gave 5-bromo-4-phenyl-1,3-dioxane (III).The bromine atom in III was replaced with amino group by treatment with methanolic ammonia at 150 deg C and 6 - 8 MPa and the obtained threo-5-amino-4-phenyl-1,3-dioxane (IVa) was hydrolyzed to give (+/-)-threo-2-amino-1-phenyl-1,3-propanediol (V).Suitably chosen method of nitration converted the free base IVa or its N-acetyl derivative IVb into 5-amino-4-(4-nitrophe nyl)-1,3-dioxane (VIa) or its N-acetyl derivative VIb which without isolation were hydrolyzed to threo-2-amino-1-(4-nitrophenyl)-1,3-propanediol (VII), isolated as hydrochloride.The liberated base was resolved into enantiomers and dichloroacetylated in the known manner to give D-(-)-threo-2-dichloroacetylamino-1-(4-nitrophenyl)-1,3-propanediol (chloramphenicol).
- Cervinka, Otakar,Dudek, Vaclav,Fabryova, Anna,Kolar, Jiri,Lukac, Juraj,et al.
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p. 2748 - 2752
(2007/10/02)
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