10-Hydroxy-2-methoxybenzo

To a solution of 10.0 g 2-hydroxy -methoxybenzoic acid (59.5 mmol) and 8.0 g NaOH (200 mmol) in 90 mL water at 10°C was added a solution of 17.0 g potassium persulfate (62.9 mmol) in 300 mL water over a 4-h period. The reaction mixture was then allowed to warm to room temperature and was stirred for 24 h, resulting in a purple solution. The mixture was neutralized with 1 N hydrochloric acid and extracted with ether (3 x 150 mL). The combined organic extracts were washed with brine and dried over MgS04. Concentration and recrystallization from ethanol and water afforded 3.21 g 2,5-dihydroxy-4-methoxybenzoic acid as colorless rectangular rods, in a yield of 30%, m.p. 200-202°C (dec). 

C H 3C103 1071-71-2) see Dopexamine Thioctic acid ethyl 5-allyl-2-hydroxy-3-methoxybenzoate... 

The 4-methoxybenzoate monooxygenase from Pseudomonas putida shows low substrate specificity. Although it introduces only a single atom of oxygen into 3-hydroxy- and 4-hydroxybenzoate, it accomplishes the conversion of 4-vinylbenzoate into the corresponding side-chain diol (Wende et al. 1989). 

Both 2- and 3-alkoxybenzo[6 Jthiophenes may be obtained by alkylation of the appropriate hydroxy derivative, but there are competing side reactions (70AHC(11)177). 2-Methoxy-benzo[6 Jthiophene can be prepared by heating 2-bromobenzo[6 Jthiophene with sodium methoxide, and 3-methoxybenzo[7> Jthiophene is obtained by similar treatment of 3-bromobenzo[6 Jthiophene. Alkylation of 3-hydroxybenzo[6 Jthiophene-2-carboxylic ester is more efficient, giving the 3-alkoxy derivative in good yield, and this in turn can be hydrolyzed and decarboxylated in adequate yields (equation 81). 

Chromones are readily oxidized by permanganate or dichromate with opening of the pyran ring and the formation of a salicylic acid (402). Flavones and isoflavones are also degradatively oxidized for example oxidation of munetone (403) with alkaline hydrogen peroxide yields 2-methoxybenzoic acid and 4-hydroxy-2-isopropylbenzofuran-5-carboxylic (isotubaic) acid. 

Hydroxybenzo[6]thiophene has been isolated from coal tar.42 It may be prepared from 6-aminobenzo[fr]thiophene by standard procedures.241 6-Methoxybenzo[h]thiophene may be prepared by decarboxylation of the corresponding 2-carboxylic acid,341 and 6-ethoxybenzo[6]thiophene is obtained by reduction of 6-(ethoxy)-thioindoxyl (Section VI, 1,2). 6-Methoxy-5-methylbenzo[6]thiophene is obtained by cyclization of (3-methoxy-4-methylphenylthio)-acetaldehyde dimethyl acetal (Section IV,B).617 The product previously described542 as 6-hydroxy-3-phenylbenzo[6]thiophene has now been shown to be the 2-phenyl isomer.307 6-Methoxy-818 and 6-methoxy-5-methyl-benzo[6]thiophene617 are demethylated by pyridine hydrochloride. 

Methyl 4-hydroxy-3 -methoxybenzoate, m445 2,2 -Methyliminobis(acetaldehyde diethyl... 

By appropriate choice of the reactants and the reaction conditions, a phenol-substituted carboxylic acid may react with an organotin compound to give both an organotin ester and an organotin aryl oxide within the same molecule. The reaction of trimethyltin chloride with 4-hydroxy-3-methoxybenzoic acid (HVAH) in the presence of water and pyridine at 130 °C in a sealed tube gave the unique two-dimensional coordination polymer 134 (equation 2)286. 

One great advantage of the decarboxylative halogenation with O-acyl esters of A-hydroxy-2-thiopyridone is that the reaction does not require any heavy metal such as Ag or Hg, unlike the Hunsdiecker reaction [24, 25]. Moreover, decarboxylative bromination of p-methoxybenzoic acid can be also carried out in good yield, while it does not proceed with the Hunsdiecker reaction instead, electrophilic bromination on the aromatic ring occurs. 

The phenolic acids of interest here [caffeic acid (3,4-dihydroxycinnamic acid), ferulic acid (4-hydroxy-3-methoxycinnamic acid), p-coumaric acid (p-hydroxycinnamic acid), protocatechuic acid (3,4-dihydroxybenzoic acid), sinapic acid (3,5-dimethoxy-4-hydroxyxinnamic acid), p-hydroxybenzoic acid, syringic acid (4-hydroxy-3,5-methoxybenzoic acid), and vanillic acid (4-hydroxy-3-methoxybenzoic acid)] (Fig. 3.1) all have been identified as potential allelopathic agents.8,32,34 The primary allelopathic effects of these phenolic acids on plant processes are phytotoxic (i.e., inhibitory) they reduce hydraulic conductivity and net nutrient uptake by roots.1 Reduced rates of photosynthesis and carbon allocation to roots, increased abscisic acid levels, and reduced rates of transpiration and leaf expansion appear to be secondary effects. Most of these effects, however, are readily reversible once phenolic acids have been depleted from the rhizosphere and rhizoplane.4,6 Finally, soil solution concentrations of... 

In order to find the best candidate for practical applications to protect conifer seedling against the pine weevil, a set of 55 benzoic acid derivatives were tested for their antifeedant activity.5 This study centered on natural oxygenated aromatic compounds found in the bark of some conifers. It yielded five new highly effective antifeedants, methyl 2,4-dimethoxybenzoate (317), isopropyl 2,4-dimethoxybenzoate (318), methyl 2-hydroxy-3-methoxybenzoate (319), methyl (3,5-dimethoxyphenyl)acetate (320), methyl (2,5-dimethoxyphenyl)acetate (321), and methyl 3,5-dimethoxybenzoate (322). All these compounds reduced feeding by more than 77% at the application of 100 (il of a 50mmoll 1 solution. 

Vanillic acid (= 4-Hydroxy-3-methoxybenzoic acid) (phenolic acid)... 

A two-step synthesis of cicerfuran was achieved using McMurry cross coupling of 4-benzyloxy-2-hydroxy-benzoaldehyde with 6-methoxybenzo 1 3]-dioxole-5-carbaldehyde, followed by an oxidative cyclization <07JOC10283>. 

In another study, the substrate was 3,4-dihydroxybenzoic acid, and the reaction products were 3-methoxy-4-hydroxybenzoic acid and 3-hydroxy-4-methoxybenzoic acid. The substrate and the two products were separated by HPLC on a reversed-phase column (LiChrosorb) with a mobile phase of 0.05 M acetic acid in methanol-water (1 4, v/v), pH 3.2 Figure 9.12 shows the separation obtained under these conditions. 

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