Oxabicyclooctane system

An example of this methodology was its use in the synthesis of vitamin Be, pyridoxine 12. Cycloaddition of oxazole 9, prepared from ethyl A-acetylalanate and P2O5, with maleic anhydride initially gave 10. Upon exposure to acidic ethanol, the oxabicyclooctane system fragments to afford pyridine 11. Reduction of the ester substituents with LiAlIU generated the desired product 12. 

Cycloaddition of oxazole 229 with maleic anhydride initially gave the oxabicyclooctane system 230. Upon exposure to acidic ethanol, 230 fragmented to afford pyridine 231. Reduction of the ester 231 with LiAlH4 generated vitamin 65, pyridoxine (3). °... 

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See also in sourсe #XX -- [ ]

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