Homovanillic acid methyl ester

Hydroxy-3,5-dimethoxy-benzeneacetic acid, methyl ester (methyl homosyringate) 4-Hydroxy-3,5-dimethoxy-benzoic acid (syringic acid) 4-Hydroxy-3,5-dimethoxy-benzoic acid ethyl ester (ethyl syringate) 4-Hydroxy-3,5-dimethoxy-benzoic acid methyl ester (methyl syringate) 4-Hydroxy-3,5-dimethoxybenzaldehyde (syringaldehyde) 4-Hydroxy-3-methoxy-benzeneacetic acid methyl ester (methyl homovanillate) 4-Hydroxy-3-methoxy-benzoic acid (vanillic acid)... 

Fig. 4.2 Chromatogram of standard phenolic acids separated as their methyl ester-trimethylsilyl ether derivatives on a 6 ft column (0.004 m i.d.) packed with 10 per cent F-60 on silanized Gas Chrom P (80-100 mesh) using temperature programming from 100°C to 240°C at 2°C min" Peak identifications are 1, 2-hydroxyphenylacetate 2, 3-hydroxyphenylacetate 3, 4-hydroxyphenylacetate 4, indoleacetate 5, homovanil-late 6, homogentisate 7, vanillylmandelate 8, 5-hydroxyindoleacetate 9, nonadecanoate (standard). (Redrawn with modifications from Horning etal, 1966)...

The neutral and acidic metabolites in cerebrospinal fluid were examined using gas-liquid chromatography, by Waterbury and Pearce (1972). These authors, using ethyl acetate and diethyl ether extraction and methyl ester, trimethylsilyl ether derivatives, observed citric, homovanillic, 3,4-dihydroxyphenylacetic, palmitic, stearic and 5-hydroxyindoleacetic acids, with palmitic acid predominating. No quantitative levels were recorded. 

Diazomethane would be a reasonable candidate for simultaneous methylator of carboxylic and phenolic functions (both acidic), were it not for its reputation for erratic behavior toward phenolic groups. However, satisfactory results were reported [226] in the conversion of acids such as homovanillic to the corresponding ethyl ether-esters with diazoethane, CH CHNj. This reagent is specific for carboxylic and... 

---