Brombenzoic acid

The esters of monochlor- and brombenzoic acids also yield the corresponding ethers and alcohols. 

The relative stereochemistry of 10 was described by Brondz et al. [41] based on X-ray data of the 3,5-dinitrobenzoic acid ester of 10. The same group finally published the absolute configuration of hyperforin 10 from single crystal X-ray analysis of its p-brombenzoic acid ester 17 [42]. As the structure of hyperforin 10 was elucidated primarily on the basis of chemical degradation, attempts to prove its structure by complete synthesis have failed [43]. 

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