4-Methoxy-2-methylbenzoic acid

There is still little synthetic work toward the main terpenes of the o-menthane group (see Vol. 4, p. 527). Synthesis of the methyl ether 683 and its isomer 684 from, respectively, 2-methoxy-6-methylbenzoic acid and 3-methoxy-2-methylbenzoic acid showed that e substance isolated by Bohlmann from Piqueria trinervia was 683, and not 684, as he had believed. ... 

Sparassol. 2-Hydroxy-4-methoxy-6-methylbenzoic acid methyl ester 4-methoxy-2,6-cresotic acid methyl ester everninic acid methyl ester orseJJinic acid methyl ester 4-methyl ether. CMH1204 mol wt 196.20. C 61.21%, H 6.17%, O 32.62%. Antibiotic substance produced by the fungus Sparassis ramose Falck, Ber. 56, 2555 (1923). Also obtained in methanol extracts of the lichen Evernla prunasti-Stenhouse, Ann. 68, 55 (1848) Spath, Jeschki, Ber. 57, 471 (1924). Structure Fischer. Hoesch, Ann. 391, 347 (1912) Wedekind. Fleischer, Ber. 56, 2556 (1923). Synthesis <3. Nicollier el at. Helv. Chim. Acta 61, 2899 (1978). 

Processes for the synthesis of metrafenone have been described in two BASF patents [19, 20]. The benzophenone can be obtained by an iron(iii) chloride catalyzed Friedel-Crafts acylation of 3,4,5-trimethoxytoluene. The appropriate benzoyl chloride is easily accessible by bromination of 2-methoxy-6-methylbenzoic acid and subsequent conversion into the acid chloride. (Scheme 22.2)... 

Formylbutyl)-2-methoxy-3-methylbenzoic acid, methyl ester, Y11.4 Isophotosantonic lactone, T22.14... 

Chloroeverninic acid, 2-Hydroxy-3-chloro-4-methoxy-6-methylbenzoic acid... 

Iso-eveminic acid, 2-Methoxy-4-hydroxy-6-methylbenzoic acid (Iso-everninsaure, 2-Methoxy-4-hydroxy-6-methylbenzoesaure)... 

Needles (MeOH-H O), mp 163-164 °C React FeClj (EtOH) red, PD yellow Deriv Methyl 2-methoxy-4-hydroxy-5-formyl-6-methylbenzoate, needles, mp 135 °C (EtOH), from 2-methoxy-4-hydroxy-5-formyl-6-methylbenzoic acid with the calculated amount of CHjNj in EtjO at 0°C... 

Treatment of methyl p-methylbenzoate with 1.2 equiv of trimethylsilyldiethylarnine and 1.3 equiv of methyl iodide in toluene, followed by gradual heating to 90 °C over a period of 4h and additional stirring at 100-110 °C provides the corresponding trimethyl silyl ester. Subsequent hydrolysis affords p-methylbenzoic acid in 85% yield based on 90% conversion (reaction monitored by GC) (eq 8). Benzoic esters substituted with an electron-donating substituent such as methyl or methoxy groups are more readily dealkylated in contrast with electron-deficient esters, such as with chlorine atom substituent, or aliphatic carboxylic acid esters. 

As a typical example of tridepside synthesis, the preparation of 5-0-methylhiascic acid (227) is depicted in Scheme 35 122). Persulfate oxidation of ethyl 4-benzyloxy-2-hydroxy-6-methylbenzoate (273) in potassium hydroxide solution gave the corresponding 5-hydroxy derivative (274) from which 2,4-dibenzyloxy-5-methoxy-6-methylbenzoic acid (275) was prepared. Condensation of this acid with benzyl lecanorate (276) gave the... 

Obtained by reaction of 4-ace-toxy-2-methoxy-6-methylbenzoic acid with 2-chloro-3,5-di-meth-oxyphenol in the presence of Irif-luoroacetic anhydride at 20° for 18h(17%) [1189] or at 25° (50%) [1190,1191]. 

Preparationbydemethylationof3, 4-dichloro-2,5-di-methoxy-4 -methylbenzophenone OH (SM) with boron tribromide in methylene chloride at 0° for 15-17 h (70-95%). SM was prepared by reaction of 3-chloro-4-methylbenzoic acid with 2-chloro-l,4-dime-thoxy-benzene in the presence of polyphosphoric acid at 60-70° for 6-7 h (40-83%) [1250],... 

Preparation by hydrogenolysis of 2, 2 -bis (benzyloxy)-3,5,5 -trichloro-4, 4 -dimethoxy-6,6 -dimethylbenzo-phenone (SM) with hydrogen in the presence of 10% Pd/C in ethyl acetate containing concentrated hydrochloric acid (5 drops) (>90%) [1339]. SM was obtained by Friedel-Crafts acylation of 5-(benzyloxy)-2-chloro-3-methoxy-toluene with 2-(benzyloxy)-3,5-dichloro-4-methoxy-6-methylbenzoic acid in the presence of trifluoroacetic anhydride in refluxing ethylene dichloride for 5 h (28%). 

Obtained by addition of 4-acetoxy-2-methoxy-6-methylbenzoic acid to 2-fluoro-3,5-dimethoxy-phenol in the presence of trifluoroacetic anhydride, first at 0°, then at 20-25° for 20 h (21%) [1191]. 

Preparation by hydrogenolysis of 2,2, 4 -tris-(benzyloxy)-3,5-dibromo-6-methoxy-4,6 -dimethyl-benzophenone (SM) in ethanol/trifluoroacetic acid mixture in the presence of 10% Pd/C at atmospheric pressure (quantitative yield). SM was obtained by condensation of 0-benzyl-0-methyl-3,5-dibromo-y-orsellinic acid— 2-(benzyloxy)-3,5-dibromo-6-methoxy-4-methylbenzoic acid—with orcinol dibenzyl ether in the presence of nifluoroacetic anhydride/trifluoroacetic acid mixture under nihogen in refluxing chloroform for 6.25 h [1376]. m.p. and Spectra (NA). 

Obtained (by-product) by reaction of orcinol with 2-methoxy-4-0-methoxy-carbonyl-6-methylbenzoic acid in trifluo-roacetic anhydride, first at 0° for 30 min, then at 20° for 15 h (11%) [754]. 

Also obtained by reaction of 2-acetoxy-4-methoxy-6-methylbenzoic acid on orcinol with trifluoroacetic anhydride at 25° (5%) [2692],... 

Dioxocin. 2H,6H-l,5-Dioxocin [292-95-5], 74, 225-226, 235, 238 Dioxybenzone. 2,2 -Dihydroxy-4-methoxybenzophenone, 432 Disyringylmethane. 4,4 -Dihydroxy-3,3, 5,5 -tetramethoxydiphenylmethane, 450 Epichlorohydrin. l-Chloro-2,3-epoxypropane, 104 Ethylcellosolve. Cellosolve or 2-Ethoxyethanol, 13 Everninic acid. 2-Hydroxy-4-methoxy-6-methylbenzoic acid, 482-483 Exifone. 2,3,3, 4,4, 5 -Hexahydroxybenzophenone, 40,495-496,498, 575 9-Fluorenone. 9-Oxofluorene, 5, 57, 149,167, 280... 

Xanthoparmelia duplicata From 4-benzyloxy-2-methoxy-3,6-di-methylbenzoic acid and benzyl 2,4-dihydroxy-3,6-dimethylbenzoate with TFAA and subsequent ddienzylation (199)... 

Hydroxy-4-0-methylgyrophoric acid 183 183-184 By condensation of 2,3-dibenzyloxy-4-methoxy-6-methylbenzoic acid and benzyl lecanorate with TFAA and subsequent debenzylation (223)... 

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