M-Methoxybenzoic acid

Ewins has synthesised both substances from m-methoxybenzoic acid, which on nitration gave 2-nitro-3-methoxybenzoic acid, and this, on reduction and treatment with methyl iodide, yielded damasceninic acid, which, by esterification with methyl alcohol, furnished damascenine. Kaufmann and Rothlen found that the additive product of 8-methoxy-quinoline and methyl sulphate, on oxidation with permanganate, yields formyldamasceninic acid, MeO. CgH3(NMe. CHO). COOH, which can be transformed into damasceninic acid by warming with dilute hydrochloric acid. ... 

It has been prepared synthetically by Ewins in the following manner Meta-oxybenzoic acid is converted with the aid of dimethyl sulphate into m-methoxybenzoic acid, which is then nitrated, and from the nitration products 2-nitro-3-methoxybenzoic acid is separated. This is reduced to 2-amino-3-methoxybenzoic acid which on heating with methyl iodide, yields 2-methylamino-3-methoxybenzoic acid. On warming this with freshly precipitated silver chloride it yields damascenine hydrochloride. 

Sodium in liquid ammonia and ethanol reduced benzoic acid to 1,4-dihy-drobenzoic acid. Reduction of p-toluic acid was more complicated and afforded a mixture of cis- and rranj-l,2,3,4-tetrahydro-p-toluic acid and cis-and tra j-l,4-dihydrotoluic acid. m-Methoxybenzoic acid yielded 1,2,3,4-tetrahydro-5-methoxybenzoic acid, and 3,4,5-trimethoxybenzoic acid gave l,4-dihydro-3,5-dimethoxybenzoic acid in 87% yield (after hydrogenolysis of the methoxy group para to carboxyl) [984. In the case of 4 -methoxy-biphenyl-4-carboxylic acid, sodium in isoamyl alcohol at 130° reduced completely only the ring with the carboxylic group, thus giving 92% yield of 4-(p-methoxyphenyl)cyclohexanecarboxylic acid [955]. 

Methanol dehydrogenase, 45 359, 360, 364 Methemerythrin, 33 216 Melhionine, H NMR, 36 10-11 m-Methoxybenzoic acid, metal carbonyl derivatives, 8 51... 

Benzoic Acid p-Chlorobenzoic Acid m-Methoxybenzoic Acid... 

Lithiation. m-Methoxybenzoic acid and 3,5-dimethoxybenzoic acid are lithiated at C-4.2... 

Acrolein cyanhydrin 211 was converted into its methoxymethyl ether 212, in turn alkylated with 1,3-dibromopropane to give the key 6-carbon synthon 213. m-Methoxybenzoic acid was utilized as the ring A component. Reductive alkylation via dianion 215 led to dihydroaromatic intermediate 216 which was decarboxylated with ensuing aromatization using lead tetraacetate (or, alternatively, anodic oxidation) to afford 217 in excellent yield. Unmasking of the carbonyl function generated known enone 218 ° (see Volume 2, pp. 693,697), which was condensed with 2-methyl-1,3-cyclopentanedione 12 to produce prochiral trione 219 in high yield. The latter had been cyclized previously to (+) 15c and thence converted into estrone. Alternatively, trione 219 was cyclo-dehydrated to the well-known estrone precursor estrapentaene 193 (see Volume 2, pp. 697, 701, 705). 

Me ether 2 4-dicbloro-m-methoxybenzoic acid. CgHgOsClg. MW, 22l . Needles. M.p. 163°. 

Me ether-. 3-methoxyanthranUic acid, 2-amino-m-methoxybenzoic acid. CgHaOoN. MW, 167. Leaflets from AcOH. M.p. 170-1°. Acetyl needles. M.p. 208°. 

Also obtained by reaction of m-methoxybenzoic acid with phenol in the presence of polyphosphoric acid at 100° for 20 min (15%) [149]. 

A mixture of 12.5 g. m-methoxybenzoic acid, 16 g. chloral hydrate, and H2SO4 well shaken and stored 24 hrs. at room temp. 24 g. 3-trichloromethyl-6-methoxyphthalide, 19 g. dissolved in glacial acetic acid, Zn-dust added in small portions during 1.5 hrs. at room temp., stirring continued ca. 0.5 hr.. 

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