Dicrotalic acid

Dicrotalic acid (LXIX) is the only other acid having six carbon atoms. 

The only representative of this category is dicrotalic acid, CeHioOs, from dicrotaline, which was found by titration with standard alkali to be a dibasic acid (4). 

Matteuorienates A and B, potent inhibitors of aldose reductase, are C-flavone glucoside dicrotalic acid esters. ... 

CeHjoOs Dicrotalic Cl Acids C7H12O3 Dicrotaline Trichodesmine 109 ... 

Complications arise when two esters of different acids are present or when acylation occurs on the aglycone. One must then rely on partial hydrolysis. The tactics are examplified hy the Entada saponins which contain C2 and Cjq acids (89). The acetate was selectively removed hy 0.025 % K2CO3 while both adds were removed by 1 % KOH. Comparison of C NMR spectra of the parent compound and of derivatives allowed determination of the points of acylation. The dicrotalic (3-hydroxy 3-methyl glutaric add) esters of the tubeistemosides and related compoimds (29-32) provide more complicated examples where the double anchoring of the diadd transforms a prochiral carbon atom into a center of chirality. 

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