Acetyl bromide groups, determination

The acetyl bromide procedure was developed by Johnson et al. (1961) to determine lignin content in small samples from woody species. This method uses acetyl bromide (4.10) to acetylate unbound hydroxyl groups in the lignin (4.11), while the hydroxyl group on the a-carbon is substituted with a bromine group. The substituted lignin derivative (4.12) is soluble under acidic conditions, and its concentration can be measured with a spectrophotometer at 280 nm. 

There is very little known about the structure of the Lycopodium alkaloids. Where the determinations have been made, the nitrogen atoms have always proved to be tertiary without A -methyl, and methoxyl groups are absent. The oxygen in lycopodine is ketonic (19) as indicated by its infrared spectrum, the formation of a hydrazone, reduction to a carbinol, and reaction with phenyllithium to yield a tertiary alcohol although phenyl magnesium bromide does not react with it (20). Dihydrolycopodine (9) yields an 0-acetyl derivative melting at 96° and this and its perchlorate proved to be identical with alkaloid L2 and its perchlorate, respectively. When heated with selenium at about 310°, lycopodine generates 7-methyl-... 

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