Sarracinic acid

Oxidation with lead dioxide in 5% phosphoric acid yielded acetaldehyde and formaldehyde. Catalytic reduction in the presence of platinum resulted in the absorption of 1.5 mole equivalents of hydrogen and the isolation, by its steam volatility, of nearly 0.6 mole of a-methylbutyric acid. The carbon skeleton of sarracinic acid was thus determined, and the accompanying hydrogenolysis (some nonvolatile acid was also obtained) established that the double bond and hydroxyl constituted an allylic alcohol moiety. Since further data (spectroscopic data would be especially valuable) were not available, Danilova and Kuzovkov (127) were limited to the conclusion that sarracinic acid could be represented by one of three possible structures (CLXIa-c) ... 

The assignment of the trans arrangement in sarracinic acid was derived from a study of chemical shift in NMR spectra. Edwards et al. (142) have now synthesized both forms and confirm the structures assigned. Acet-oxypyruvic acid was allowed to react with ethylidenetriphenyl-phosphorane to give a mixture of the cis and trans forms, LXVa and LXVIa, which on hydrolysis yielded sarracinic acid (LXVb) and its cis... 

The most frequently occurring carboxylic adds with five carbon atoms per molecule are (Z)-2-methylbut-2-enoic acid, also known as (Z)-2,3-dimethylacrylic or angelic acid, its isomer (E)-2-methylbut-2-enoic acid, known as ( )-2,3-dimethylacrylic (tiglic) acid, (Z)-3-methylbut-2-enoic acid (senecioic) acid (8-62) and (Z)-2-hydroxymethylbut-2-enoic (sarracinic) acid (10-14). 

Senecio argunensis Turcz. S. nemorensis L. S. scandens Buch-Ham ex D. Don Qian Li Guang (Ragwort) (aerial part) Lavoxanthin, macrophylline, cynarin, chlorogenic acid, chrysanthemaxanthin, sarracine.33,48 Antibacterial, antiplasmodial, treat acute bacterial dysentery and bronchitis. 

Fig. 13.16 HPLC-ESI-ion trap MS/MS spectra for peak 2 (top) and peak 4 (bottom) in the extract of Senecio ovatus (Figure 13.14). The differences in the fragmentation pattern support the extra hydroxylation of sarracine-N-oxide in the C-9 esterifying acid for peak2 ratherthan in the necine base to yield 2-hydroxysarracine-N-oxide (peak 4, Figure 13.14).

Sarracine and sarracine iV-oxide on catalytic hydrogenation gave tetrahydrosarracine, C18H31NO5 (picrate, mp 70°-71° iV-oxide picrate, mp 127°) which on hydrolysis gave angelic acid and 2-methylbutyric acid. 

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