Methyl quinaldate

Although these peak areas were sufficient to quantify quinaldic acid on Carbowax columns, residual water present in the extracts of the ion-exchange resins interfered in previous experiments using water-sensitive polydimethylsiloxane stationary phases. The change to a polyethylene glycol stationary phase eliminated the water interferences, and good linear calibration curves for methyl quinaldate were then obtained. 

As previously noted the low-pressure reduction of l-benzoyl-1,2-dihydroquinaldonitrile (7) led to the tetrahydro compound (46). The purity of 46 ha.s been improved and an alternative synthesis from methyl quinaldate reported. ... 

Oxidation of macrorine with permanganate gives quinoline-2-carboxyamide and a second product, identified as the acylurea XCII by its spectral characteristics and by methanolysis with methanolic hydrochloric acid to methyl quinaldate and methylurea. Similar... 

Comparison of kobs for PVA-QA with the rate constants reported for metal promoted hydrolysis of methyl quinaldate (Table 1) shows the latter is more rapid and the difference between metals is greater.The difference in the solvent (water vs. 50% aq. ethanol) and the ester alkyl groups does not allow any conclusions about the contribution of the polymeric environment to the kinetics. 

Table 1. Equilibrium and first order reaction constants of metal complexes of methyl quinaldate and PVA-QA. ...

Each of the methods had trouble recovering the more highly water-soluble or volatile model compounds such as trimesic acid, furfural, glucose, glycine, caffeine, and methyl isobutyl ketone. Quinaldic acid, an amphoteric substance of moderate water solubility, was also poorly recovered by each method, except for the QXAD-4 procedure. 

Many classes of organic compounds adsorbed by this resin can be desorbed by solvents such as ether (or acidic methanol and ether). The acidic solvents can be concentrated to remove inorganic acid, but some residual inorganic acid always remained in the concentrated eluants. Residual acid, or possible trace of water in the concentrated eluants, caused analytical variances when methylation was attempted. Therefore, quinaldic acid, trimesic acid, and 5-chlorouracil were analyzed by HPLC rather than by GC-FID. 

Recovery experiments were conducted with the following standards, which were used as received without further purification 5-chlorouracil (Calbiochem), furfural (Aldrich), crotonaldehyde (Aldrich), caffeine (Aldrich), isophorone (Aldrich), 2,4-dichlorophenol (Aldrich), anthraquinone (Aldrich), biphenyl (Ultra Scientific), 2,4 -dichlorobiphenyl (Ultra Scientific), 2,6-bis(l,l-dimethylethyl)-4-methylphenol (Aldrich), 2,2, 5,5 -tetrachlorobiphenyl (Ultra Scientific), benzo[e]pyrene (Aldrich), bis(2-ethylhexyl) phthalate (Scientific Polymer Products), 4-methyl-2-pentanone (Aldrich), quinoline (Kodak), 1-chloro-dodecane (Eastman), stearic acid (Kodak), quinaldic acid (Aldrich), trimesic acid (Aldrich), glucose (Aldrich), glycine (Aldrich), and chloroform (Burdick and Jackson). 

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