303-07-1

Basic information

• Product Name: 2,6-Dihydroxybenzoic acid
• Synonyms: RESORCINOL-2-CARBOXYLIC ACID;2,6-dihydroxy-benzoicaci;2,6-Dihydroxylbenzoicacid;2-Carboxyresorcinol;6-Hydroxysalicylic acid;6-hydroxysalicylicacid;nsc49172;G-RESORCYLIC ACID
• CAS NO: 303-07-1
• Molecular Formula: C₇H₆O₄
• Molecular Weight: 154.12
• EINECS: 206-134-8
• Product Categories: Aromatic Carboxylic Acids, Amides, Anilides, Anhydrides & Salts;Organic acids;intermeidate;Isoquinolines ,Quinolines ,Quinaldines
• Mol File: 303-07-1.mol

Chemical Properties

• Melting Point: 165 °C (dec.)(lit.)
• Boiling Point: 237.46°C (rough estimate)
• Flash Point: 175.839 °C
• Appearance: Off-white/Crystalline Powder
• Density: 1.3725 (rough estimate)
• Vapor Pressure: 2.65E-05mmHg at 25°C
• Refractive Index: 1.6400 (estimate)
• Storage Temp.: Store below +30°C.
• Solubility: 25g/l
• PKA: pK1:1.30 (25°C)
• Water Solubility: 9.56g/L(temperature not stated)
• BRN: 2209755
• CAS DataBase Reference: 2,6-Dihydroxybenzoic acid(CAS DataBase Reference)
• NIST Chemistry Reference: 2,6-Dihydroxybenzoic acid(303-07-1)
• EPA Substance Registry System: 2,6-Dihydroxybenzoic acid(303-07-1)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38
• Safety Statements: 26-36
• WGK Germany: 3
• RTECS: DG8578000
• TSCA: Yes
• Hazardous Substances Data: 303-07-1(Hazardous Substances Data)

Usage

Uses

Used in Pharmaceutical Industry:
2,6-Dihydroxybenzoic acid is used as an intermediate in the synthesis of various pharmaceutical compounds, such as analgesics, antipyretics, and anti-inflammatory drugs. Its ability to form derivatives with diverse biological activities makes it a valuable component in the development of new medications.
Used in Antioxidant Applications:
2,6-Dihydroxybenzoic acid serves as a potent antioxidant, protecting cells from oxidative stress and damage caused by reactive oxygen species. It is used in the formulation of antioxidant supplements and nutraceutical products to support overall health and well-being.
Used in Chemical Synthesis:
As a versatile building block, 2,6-dihydroxybenzoic acid is used in the synthesis of various organic compounds, including dyes, pigments, and polymers. Its reactivity and functional groups make it an essential component in the chemical industry for creating a wide range of products.
Used in Analytical Chemistry:
2,6-Dihydroxybenzoic acid is employed as a standard or reference compound in analytical chemistry for the calibration of instruments and the development of new analytical methods. Its well-defined chemical structure and properties make it an ideal candidate for such applications.
Used in Environmental Applications:
2,6-Dihydroxybenzoic acid is utilized in environmental studies to evaluate the microbial metabolism of various sources of polyphenols in the colon area. This helps in understanding the role of these compounds in the environment and their potential impact on human health.
Used in Cosmetics Industry:
Due to its antioxidant and anti-inflammatory properties, 2,6-dihydroxybenzoic acid is used in the formulation of cosmetics and personal care products. It helps in protecting the skin from oxidative stress, reducing inflammation, and promoting overall skin health.

Purification Methods

Dissolve the acid in aqueous NaHCO3 and the solution is washed with ether to remove non-acidic material. The acid is precipitated by adding H2SO4, and recrystallised from water. Dry it under va

InChI:InChI=1/C7H6O4/c8-4-2-1-3-5(9)6(4)7(10)11/h1-3,8-9H,(H,10,11)/p-1

Synthetic route

glycerol (56-81-5) + recorcinol (108-46-3) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With carbon dioxide at 100℃; for 24h;	89%

2-(2,6-dihydroxyphenyl)acetic acid (64700-73-8) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With iodine; dimethyl sulfoxide at 120℃; for 27h; Sealed tube; Green chemistry;	82%

1-(2,6-dihydroxyphenyl)butane-1,3-dione → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With oxygen; sodium hydrogencarbonate In acetonitrile for 4h; Molecular sieve; Irradiation;	75%

carbon dioxide (124-38-9) + recorcinol (108-46-3) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With potassium hydroxide under 10501.1 - 26252.6 Torr; for 4h; Reagent/catalyst;	54.6%
Stage #1: carbon dioxide; recorcinol With potassium carbonate In ethanol; water at 170℃; under 17251.7 - 18751.9 Torr; for 5h; Stage #2: With sulfuric acid In ethanol; water at 98 - 100℃; for 11h; pH=5.5 - 6; Solvent; Reagent/catalyst;
With potassium carbonate; phenol In water at 120℃; for 16h; Reagent/catalyst;

salicylic acid (69-72-7) → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With dihydrogen peroxide In water at 20℃; for 1h; UV-irradiation; Green chemistry;	A 7% B 8%

2,6-dihydroxylacetophenone (699-83-2) → 2,6-Dihydroxybenzoic acid (303-07-1)

4-hydroxysalicylic acid (89-86-1) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
Isomerisierung ueber das Natrium- oder das Kalium-Salz;

2-6-dimethoxybenzoic acid (1466-76-8) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With aluminium trichloride
With aluminium trichloride; benzene

2,6-dihydroxy-4-(toluene-4-sulfonyloxy)-benzoic acid → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With nickel; potassium hydrogencarbonate

n-butyllithium (109-72-8, 29786-93-4) + diethyl ether (60-29-7) + recorcinol (108-46-3) → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
anschliessendes Behandeln mit festem CO2;

sodium methylate (124-41-4) + methylammonium carbonate (15719-64-9, 15719-76-3, 97762-63-5) + recorcinol (108-46-3) → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
at 100℃; under 4560 Torr;

methylammonium carbonate (15719-64-9, 15719-76-3, 97762-63-5) + recorcinol (108-46-3) → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With sodium methylate at 100℃; under 4560 Torr;

recorcinol (108-46-3) → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With n-butyllithium; diethyl ether anschliessend Behandeln mit Kohlendioxid;
With carbon dioxide; potassium hydrogencarbonate at 120℃;
With salicylic acid decarboxylase from Trichosporon moniliiforme; potassium hydrogencarbonate at 30℃; for 24h; pH=8.5; aq. phosphate buffer; Enzymatic reaction;

1-hydroxynaphthalene-5-sulphonic acid (117-59-9) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
at 27℃; for 24h; Product distribution; Pseudomonas sp. TA-2 cells, phosphate buffer; metabolism, degradation pathway;

salicylic acid (69-72-7) → 4-hydroxysalicylic acid (89-86-1) + 2,3-Dihydroxybenzoic acid (303-38-8) + 2,5-dihydroxybenzoic acid. (490-79-9) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With dihydrogen peroxide; iron(II) sulfate In water at 37℃; for 0.0833333h; hydroxylation; Further byproducts given. Title compound not separated from byproducts;

carbon dioxide (124-38-9) + recorcinol (108-46-3) + KHCO3 → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
at 120℃;

carbon dioxide (124-38-9) + water (7732-18-5) + recorcinol (108-46-3) + KHCO3 → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
at 93 - 130℃;

recorcinol (108-46-3) + (NH4)2 CO3 → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1) + 2.4-dioxy-benzenedicarboxylic acid

methylammonium carbonate (15719-64-9, 15719-76-3, 97762-63-5) + glycerol (56-81-5) + recorcinol (108-46-3) + KHCO3 → 4-hydroxysalicylic acid (89-86-1) + 4,6-dihydroxyisophthalic acid (19829-74-4) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
at 210℃;

methylammonium carbonate (15719-64-9, 15719-76-3, 97762-63-5) + 1.3-bis--benzene → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With n-butyllithium; diethyl ether anschliessend Behandeln mit wss. Salzsaeure;

aluminium trichloride (7446-70-0) + 2-6-dimethoxybenzoic acid (1466-76-8) + benzene (71-43-2) → 2,6-Dihydroxybenzoic acid (303-07-1)

recorcinol (108-46-3) → 2,6-Dihydroxybenzoic acid (303-07-1) + β-resorcylic acid , α-resodicarboxylic acid

Conditions	Yield
With ammonium carbonate; water at 120 - 130℃;
With sodium hydrogencarbonate; glycerol at 135℃;

recorcinol (108-46-3) + sodium bicarbonate → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With glycerol at 135℃;

2,6-dimethoxybenzonitrile (16932-49-3) + potash → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
beim Schmelzen;

acide 2,4,6-trihydroxybenzoique (83-30-7) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
Multi-step reaction with 2 steps 2: Raney nickel; aqueous KHCO3 View Scheme

potassium hydrogencarbonate (298-14-6) + recorcinol (108-46-3) → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With Trichosporon moniliiforme WU-0401 salicylic acid decarboxylase at 30℃; for 1h; pH=7; enzymatic Kolbe-Schmitt reaction; aq. phosphate buffer; Enzymatic reaction; regioselective reaction;

recorcinol (108-46-3) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With 2,6-dihydroxybenzoic acid decarboxylase from Rhizobium species; potassium hydrogencarbonate at 30℃; for 24h; pH=8.5; aq. phosphate buffer; Enzymatic reaction; regioselective reaction;

potassium hydrogencarbonate (298-14-6) + recorcinol (108-46-3) → 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With 2,6-dihydroxybenzoatedecarboxylase fromRhizobium sp In aq. phosphate buffer at 30℃; for 24h; Kolbe-Schmidt Synthesis; Enzymatic reaction; regioselective reaction;

carbon dioxide (124-38-9) + recorcinol (108-46-3) → 4-hydroxysalicylic acid (89-86-1) + 2,6-Dihydroxybenzoic acid (303-07-1)

Conditions	Yield
With potassium carbonate at 120℃; for 5.7h; Temperature;

2,6-Dihydroxybenzoic acid (303-07-1) + benzyl bromide (100-39-0) → benzyl 2,6-dibenzyloxybenzoate (129749-69-5)

Conditions	Yield
With potassium carbonate In acetone for 11h; Heating;	100%
With 18-crown-6 ether; potassium carbonate In acetone
With 18-crown-6 ether; potassium carbonate In acetone Esterification; Heating;

2,6-Dihydroxybenzoic acid (303-07-1) → 2,6-dihydroxybenzoic-3,5-d2 acid (1195947-64-8)

Conditions	Yield
With water-d2; hydrogen chloride for 1h; Inert atmosphere; Reflux;	99%

diazomethane (186581-53-3, 908094-01-9) + 2,6-Dihydroxybenzoic acid (303-07-1) → methyl 2,6-dihydroxybenzoate (2150-45-0)

Conditions	Yield
In tetrahydrofuran Ambient temperature;	98%
	60%

2,6-Dihydroxybenzoic acid (303-07-1) + acetone (67-64-1) → 5-hydroxy-2,2-dimethyl-4H-benzo[d][1,3]dioxin-4-one (154714-19-9)

Conditions	Yield
With dmap; thionyl chloride In 1,2-dimethoxyethane Cyclization;	96%
With dmap; thionyl chloride In 1,2-dimethoxyethane	96%
With dmap; thionyl chloride In 1,2-dimethoxyethane at 0 - 20℃; for 24h; Inert atmosphere;	96%

2,6-Dihydroxybenzoic acid (303-07-1) + benzyl bromide (100-39-0) → 2,6-dibenzyloxybenzyl alcohol (25983-52-2)

Conditions	Yield
Stage #1: 2,6-Dihydroxybenzoic acid; benzyl bromide With potassium carbonate In N,N-dimethyl-formamide at 80℃; for 2h; Stage #2: With lithium aluminium tetrahydride In tetrahydrofuran at 20℃; for 20h; Further stages.;	94%

2,6-Dihydroxybenzoic acid (303-07-1) + methyl iodide (74-88-4) → methyl 2,6-dihydroxybenzoate (2150-45-0)

Conditions	Yield
With ammonium hydroxide; silver nitrate In water at 0 - 20℃; for 18.5h;	89%
With sodium hydrogencarbonate In N,N-dimethyl-formamide	77%
With sodium hydrogencarbonate In N,N-dimethyl-formamide at 20℃; for 96h; Methylation;	77%
With potassium carbonate In N,N-dimethyl-formamide for 24h; Ambient temperature;
With ammonia; silver nitrate In water at 0 - 5℃; for 12.5h;

2,6-Dihydroxybenzoic acid (303-07-1) + chloroacetyl chloride (79-04-9) → 6-hydroxy-3-oxo-2,3-dihydrobenzofuran-7-carboxylic acid (1344890-32-9)

Conditions	Yield
With aluminum (III) chloride In ethyl acetate; nitrobenzene at 40℃; for 12h;	89%

pentaphenylantimony (2170-05-0) + 2,6-Dihydroxybenzoic acid (303-07-1) → Ph4Sb[O(O)CC6H3(OH)2-2,6]

Conditions	Yield
In toluene for 1h; Sealed tube; Heating;	89%

2,6-Dihydroxybenzoic acid (303-07-1) + di-tert-butylsilyl bis(trifluoromethanesulfonate) (85272-31-7) → C15H22O4Si

Conditions	Yield
With 2,6-dimethylpyridine In acetonitrile at 0 - 22℃; for 16h; Inert atmosphere;	87%

2,6-Dihydroxybenzoic acid (303-07-1) → 2,6-dihydroxy-3,5-dichlorobenzoic acid (26754-76-7)

Conditions	Yield
With hydrogenchloride In 1,4-dioxane at 20℃;	85%
With sulfuryl dichloride
With sulfuryl dichloride

2,6-Dihydroxybenzoic acid (303-07-1) + 4,6-dimethoxypyrimidin-2-yl methyl sulfone (113583-35-0) → bispyribac (125401-75-4)

Conditions	Yield
With tetrabutylammomium bromide; potassium carbonate In toluene Reagent/catalyst; Solvent; Reflux;	85%
Stage #1: 2,6-Dihydroxybenzoic acid; 4,6-dimethoxypyrimidin-2-yl methyl sulfone With sodium hydride In N,N-dimethyl acetamide; toluene; paraffin oil at 100℃; for 5h; Stage #2: With methanol at 20℃; for 1h; Solvent; Temperature;	83%

potassium molybdate(VI) + 2,6-Dihydroxybenzoic acid (303-07-1) + tetraphenyl phosphonium chloride (2001-45-8) → 2P(C6H5)4(1+)*MoO2(2+)*2H(1+)*2C6H3(O)2COO(3-)*3H2O=[P(C6H5)4]2[MoO2(C7H4O4)2]*3H2O

Conditions	Yield
In water addn. of 2 equiv. of ligand to K2MoO4, filtration, addn. of 2 equiv. ofPPh4Cl (pptn.); filtration, washing (H2O), drying in air; elem. anal.;	82%

Tetramethylpyrazine (1124-11-4) + 2,6-Dihydroxybenzoic acid (303-07-1) → 1.5C8H12N2*3C7H6O4

Conditions	Yield
In ethanol; water	81%

2,6-Dihydroxybenzoic acid (303-07-1) + 6-chloro-4-nitrosoresorcinol (109755-36-4) → 2-chloro-6-carboxyresorufin

Conditions	Yield
With sulfuric acid In water	81%

2,6-Dihydroxybenzoic acid (303-07-1) + ethyl bromoacetate (105-36-2) → ethyl 2-(2-acetyl-3-hydroxyphenoxy)acetate (6769-65-9)

Conditions	Yield
With potassium carbonate In acetonitrile for 2h; Reflux;	81%

methanol (67-56-1) + 2,6-Dihydroxybenzoic acid (303-07-1) → methyl 2,6-dihydroxybenzoate (2150-45-0)

Conditions	Yield
With thionyl chloride at 0℃; Reflux; Inert atmosphere;	80%
With sulfuric acid for 168h; Heating;	67%
With sulfuric acid for 36h; Heating;	65%

2,6-Dihydroxybenzoic acid (303-07-1) + α-bromoacetophenone (70-11-1) → 2,6-Dihydroxy-benzoic acid 2-oxo-2-phenyl-ethyl ester (74304-63-5)

Conditions	Yield
With potassium hydrogencarbonate In N,N-dimethyl-formamide	80%

zinc nitrate tetrahydrate + erbium(III) nitrate pentahydrate + 2,6-Dihydroxybenzoic acid (303-07-1) + acetonitrile (75-05-8) + N,N′-dimethyl-N,N′-bis(2-hidroxy-3-formyl-5-bromo-benzyl)ethylenediamine (181575-45-1) → [Zn(μ-N,N’-dimethyl-N,N’-bis(2-hydroxy-3-formyl-5-bromobenzyl)ethylenediamine)(μ-2,6-dihydroxybenzoate)Er(NO3)2]·2CH3CN

Conditions	Yield
With triethylamine at 80℃; for 0.5h;	80%

2,6-Dihydroxybenzoic acid (303-07-1) → 2,6-dihydroxy benzohydrazide (90151-18-1)

Conditions	Yield
Stage #1: 2,6-Dihydroxybenzoic acid With potassium carbonate; dimethyl sulfate In acetone at 55℃; for 24h; Stage #2: With hydrazine hydrate In methanol at 20℃; for 2h;	80%
Multi-step reaction with 2 steps 1: potassium carbonate / acetone / 24 h / 55 °C 2: hydrazine hydrate / methanol / 2 h / 20 °C View Scheme

2,6-Dihydroxybenzoic acid (303-07-1) + 2-amino-phenol (95-55-6) → isoeuxanthone (5042-08-0)

Conditions	Yield
With polyphosphoric acid at 200℃; for 4h;	79%

2,6-Dihydroxybenzoic acid (303-07-1) + triphenylantimony (603-36-1) → bis(2,6-dihydroxybenzoato)triphenylantimony

Conditions	Yield
With dihydrogen peroxide In diethyl ether; water	77%

2,6-Dihydroxybenzoic acid (303-07-1) + p-toluidine (106-49-0) → 2,6-dihydroxy-N-(4-methylphenyl)benzamide

Conditions	Yield
With phosphorus trichloride In chlorobenzene at 135℃; for 0.333333h; Microwave irradiation;	76%
With phosphorus trichloride

2,6-Dihydroxybenzoic acid (303-07-1) + 1,1,1,3,3,3-hexamethyl-disilazane (999-97-3) → 2,6-bis[(trimethylsilyl)oxy]benzoic acid trimethylsilyl ester (3782-85-2)

Conditions	Yield
With iodine In neat (no solvent) at 20℃; for 16h; Green chemistry;	76%
With pyridine

2,6-Dihydroxybenzoic acid (303-07-1) + dimethyl sulfate (77-78-1) → methyl 2,6-dihydroxybenzoate (2150-45-0)

Conditions	Yield
With potassium carbonate In acetone for 5h; Inert atmosphere;	76%
With potassium carbonate In acetone at 55℃; for 24h;

lead(II) nitrate + 2,6-Dihydroxybenzoic acid (303-07-1) → Pb(2+)*2C7H5O4(1-)

Conditions	Yield
In water Sonication;	75.4%

Upstream product

• 298-14-6 potassium hydrogencarbonate 
• 108-46-3 recorcinol 
• 15719-64-9 methylammonium carbonate 
• 56-81-5 glycerol 
• 124-38-9 carbon dioxide 
• 7732-18-5 water 
• 69-72-7 salicylic acid 
• 117-59-9 1-hydroxynaphthalene-5-sulphonic acid 
• 124-41-4 sodium methylate 
• 109-72-8 n-butyllithium 
• 60-29-7 diethyl ether 
• 1466-76-8 2-6-dimethoxybenzoic acid 
• 89-86-1 4-hydroxysalicylic acid 
• 699-83-2 2,6-dihydroxylacetophenone 

Downstream Products

• 395-20-0 2,6-dihydroxy-3-phenylazo-benzoic acid 
• 1466-76-8 2-6-dimethoxybenzoic acid 
• 2065-27-2 methyl 2,6-dimethoxybenzoate 
• 3782-85-2 2,6-bis[(trimethylsilyl)oxy]benzoic acid trimethylsilyl ester 
• 92157-15-8 2,6-Diaethoxy-benzoesaeure-aethylester 
• 74304-63-5 2,6-Dihydroxy-benzoic acid 2-oxo-2-phenyl-ethyl ester 
• 42594-48-9 2,6-Dihydroxy-benzoic acid 4-hydroxy-2,6-dimethyl-phenyl ester 
• 51754-13-3 2.6-Dihydroxybenzoesaeure-2'-methoxy-4'-chloranilid 
• 851594-52-0 5-allyl-2-phenylbenzo[1,3]dioxin-4-one 
• 851594-55-3 5-(2-oxopropyl)-2-phenylbenzo[1,3]dioxin-4-one 
• 851594-63-3 trifluoromethanesulfonic acid 4-oxo-2-phenyl-4H-benzo[1,3]dioxin-5-yl ester 
• 387-46-2 2,6-dihydroxybenzaldehyde 
• 100-52-7 benzaldehyde 
• 25983-53-3 3-((3-(benzyloxy)-2-formylphenoxy)methyl)benzene 

Relevant articles and documents

Quantitation of the hydroxyl radical adducts of salicylic acid by micellar electrokinetic capillary chromatography: Oxidizing species formed by a Fenton reaction

There has been controversy concerning the products formed by a Fenton reaction. We determined the hydroxyl radical (.OH) generated in a Fenton reaction system with no iron chelator using micellar electrokinetic capillary chromatography (MECC). The hydroxyl radical generated in this Fenton system attacked salicylic acid to produce major products of 2,3- and 2,5-dihydroxybenzoic acid (DHB), 2,3-DHB being prominent. Hydroxyl radical scavengers, such as mannitol, ethanol, thiourea and a ferric chelator, Desferal, significantly diminished the peaks for DHBs, showing production of .OH. We compared the MECC method with the electron paramagnetic resonance (EPR) spin trapping technique. The quantity of DHBs obtained by MECC increased dose-dependently up to 1 μM Fe2+ at a fixed concentration of H2O2, whereas that of the spin adduct by EPR showed a bell-shaped curve. This quantitation of .OH adducts by MECC supports the proposal that the oxidizing species formed by a Fenton reaction with no chelator is .OH. The EPR spin trapping method appears to be erroneous, particularly when iron is present at a higher concentration than hydrogen peroxide. The application of this method to the paraquat effect in vitro is demonstrated, and the possibility for analysis of .OH in vivo is also discussed.

HPLC study on Fenton-reaction initiated oxidation of salicylic acid. Biological relevance of the reaction in intestinal biotransformation of salicylic acid

Fenton-reaction initiated in vitro oxidation and in vivo oxidative biotransformation of salicylic acid was investigated by HPLC-UV-Vis method. By means of the developed high performance liquid chromatography (HPLC) method salicylic acid, catechol, and all the possible monohydroxylated derivatives of salicylic acid can be separated. Fenton oxidations were performed in acidic medium (pH 3.0) with two reagent molar ratios: (1) salicylic acid: iron: hydrogen peroxide 1:3:1 and (2) 1:0.3:1. The incubation samples were analysed at different time points of the reactions. The biological effect of elevated reactive oxygen species concentration on the intestinal metabolism of salicylic acid was investigated by an experimental diabetic rat model. HPLC-MS analysis of the in vitro samples revealed presence of 2,3- and 2,5-dihydroxybenzoic acids. The results give evidence for nonenzyme catalysed intestinal hydroxylation of xenobiotics.

Method for producing 2,6-dihydroxybenzoic acid

The invention discloses a method for producing 2,6-dihydroxybenzoic acid. The method is characterized in that in the carboxylation reaction of 2,6-dihydroxybenzoic acid, self-suction airfoil axial flow stirring is used as the stirring pattern of a carboxylation reactor, so that gas, liquid and solid phases in the reaction system of the carboxylation reaction are fully mixed and contacted; besides,a phase transfer catalyst is added in the carboxylation reaction process, homogenization of the gas-liquid-solid three-phase reaction is improved, and one-time yield of the reaction product is increased. The one-time yield of the reaction product can be increased by 5%-10% with the method.

A promising catalyst for exclusive: Para hydroxylation of substituted aromatic hydrocarbons under UV light

Herein, we describe a waterborne polymer/carbon dot nanocomposite system as an efficient, resourceful and sustainable photocatalyst for para-selective hydroxylation of substituted aromatic compounds using H2O2 under UV light. The polymer matrix and carbon dot generate a synergistic catalytic system. A unique structural attribute of the functionalities in this catalytic system attracts the aromatic substrates into close proximity and activates them. Additionally, the flexible molecular box-like structure of the hyperbranched polymer provides the ability for favorable three-point interaction with several substrates having various sizes by means of their multiple force networks and the increased accessibility of the active sites. The catalyst can be stored on the bench top for months and is reusable without considerable loss in its activity. The reaction was exclusively selective toward para hydroxylation irrespective of the nature of the substituents (electron donating or electron withdrawing) in the aromatic hydrocarbons. Hence, it is one of the most promising catalysts for selective hydroxylation of substituted aromatic hydrocarbons.

6-sulfonate pyrimidyl salicylate compound and preparation method and application thereof

The invention relates to the field of herbicides and discloses a 6-sulfonate pyrimidyl salicylate compound and a preparation method and application thereof. The compound has a structure as shown in a formula (1). The method for preparing the 6-sulfonate pyrimidyl salicylate compound comprises the steps of (1) carrying out first contact reaction on the compound as shown in a formula (2) and R2SO2Cl to obtain a compound as shown in a formula (3); and (2) carrying out second contact reaction on the compound as shown in the formula (3) and trifluoroacetic acid. The 6-sulfonate pyrimidyl salicylate compound has a good inhibition effect on acetohydroxyacid synthase, and has significant resistance inhibition effect on weeds which are resistant to an acetohydroxyacid synthase inhibitor herbicide, thereby controlling weed resistance plants caused by acetohydroxyacid synthase. The formulas are as shown in the specification.

Metal-Free Dehomologative Oxidation of Arylacetic Acids for the Synthesis of Aryl Carboxylic Acids

A novel I2-promoted direct conversion of arylacetic acids into aryl carboxylic acids under metal-free conditions has been described. This remarkable transformation involves decarboxylation followed by an oxidation reaction enabled just by using DMSO as the solvent as well as an oxidant. Notably, aryl carboxylic acids are isolated by simple filtration technique and obtained in good to excellent yields. This protocol is free from chromatographic purification, which makes it applicable for large-scale synthesis.

[Ru(bpy)3]Cl2-catalyzed aerobic oxidative cleavage β-diketones to carboxylic acids under visible light irradiation

A mild and highly efficient method for the preparation of carboxylic acids is developed through a visible-light-mediated aerobic oxidative cleavage of β-diketones. This process provides a potential general, practical and scalable protocol for both laboratory synthesis and industrial production of carboxylic acids in a green manner.

2, 6-aminodihydroxybenzoic acid manufacturing method

PROBLEM TO BE SOLVED: To provide a process suitable for industrial production of 2,6-dihydroxybenzoic acid by a reaction of resorcin and carbon dioxide in the presence of an alkali metal compound at a favorable production rate even under mild conditions. SOLUTION: The process for production of 2,6-dihydroxybenzoic acid includes reacting resorcin with carbon dioxide in the presence of the alkali metal compound, wherein the ratio of (A) the total mole number of resorcin and a univalent phenol in the presence or absence of the univalent phenol and (B) the mole number of the alkali metal of the alkali metal compound, (A)/(B), is in a range of 2.2 through 100. COPYRIGHT: (C)2013,JPOandINPIT

PROCESSES FOR THE PREPARATION OF BISPYRIBAC SODIUM AND INTERMEDIATES THEREOF

The present disclosure relates to a process for the preparation of Bispyribac-sodium by condensing 2,6-dihydroxy benzoic acid with 2-(alkyl sulfonyl)-4,6-dialkoxy pyrimidine in the presence of at least one base and at least one solvent. The present disclosure also relates to processes for the preparation of 2,6-dihydroxy benzoic acid and 2-(alkyl sulfonyl)-4,6- dialkoxy pyrimidine.

Regioselective ortho-carboxylation of phenols catalyzed by benzoic acid decarboxylases: A biocatalytic equivalent to the Kolbe-Schmitt reaction

The enzyme catalyzed carboxylation of electron-rich phenol derivatives employing recombinant benzoic acid decarboxylases at the expense of bicarbonate as CO2 source is reported. In contrast to the classic Kolbe-Schmitt reaction, the biocatalytic equivalent proceeded in a highly regioselective fashion exclusively at the ortho-position of the phenolic directing group in up to 80% conversion. Several enzymes were identified, which displayed a remarkably broad substrate scope encompassing alkyl, alkoxy, halo and amino- functionalities. Based on the crystal structure and molecular docking simulations, a mechanistic proposal for 2,6-dihydroxybenzoic acid decarboxylase is presented.