Pinononic acid

When submitted to oxidation by a 2 per cent, solution of permanganate, bicyclic system is convertible into a monocyclic system by boiling with 25 per cent, sulphuric acid, with the formation of acetone and 3-methylcyclohexene-(2)-one-(l). This cyclohexenone has been characterised by its semi-carbazone (melting-point 198° C.) and by its conversion into y-acetobutyric acid (melting-point 36° C). The oily liquid, which did not react with sulphite, was submitted to benzoylation after dilution with pyridine. It thus gave rise to a benzoate from which was... 

Oxidative cleavage of monocyclic and bicyclic allylic alcohols to keto acids and di-acids respectively is effected by RuClj/aq. Na(IO )/CCl -CH3CN thus trans-verbenol gave (+)-c/x-pinononic acid and (+)-frani-pinocarveol yielded (-)-cis-pinic acid (Table 3.6) [237]. The double bond in diphenylcholene was cleaved by RuOj/aq. Na(IO )/CCl to aldehyde and acid (Table 3.4) and the adjoining phenyl rings destroyed [238]. 

Verbenone epoxide (261) with alkaline hydrogen peroxide undergoes further oxidation to pinononic acid (262), the mechanism of which has been discussed by Temple. The aluminium-chloride-catalysed reaction of verbenone epoxide to (263) and then to p-mentha-l,4(8)-dien-2-ol-3-one (264) has also been described. ... 

A different approach converted the ketone moiety in cis-pinononic acid [7.75, derived by permanganate oxidation of (-)-2-hydroxy pinocamphone] to an oxime (7.16). Raney nickel reduction and Beckmann rearrangement of the oxime gave 7.77. Subsequent treatment with hydrazine gave 3-amino-2,2-dimethyl-cyclobutane carboxylic acid (7.75). 

Pinononic acid, T8 Pinoresinol, Y7 Pipecolic acid, AlO Piperazic acid. All... 

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