O-hydroxybenzoate

Dissolve 10 g. of salicylic acid (o-hydroxybenzoic acid) in 7 ml. of dry pyridine contained in a too ml. conical flask. Then without delay (since this solution if allowed to stand tends to become a semi-solid mass) run in 7 5 ml. (8 3 g.) of acetyl chloride, adding about i ml. of the chloride at a time, and shaking the mixture continuously during the addition. The heat of the reaction causes the temperature of the mixture to rise rapidly ... 

Methyl salicylate is the methyl ester of o hydroxybenzoic acid Intramolecular (rather than mtermolecular) hydrogen bonding is responsible for its relatively low boiling point... 

Kolbe-Schmitt reaction (Section 24 10) The high pressure re action of the sodium salt of a phenol with carbon dioxide to give an o hydroxybenzoic acid The Kolbe-Schmitt reac tion IS used to prepare salicylic acid in the synthesis of as pinn... 

Chemical Designations - Synonyms o-Hydroxybenzoic acid Retarder W Chemical Formula 1,2-HOCsHiCOOH. 

Conversion of Acid Anhydrides into Esters Acetic anhydride is often used to prepare acetate esters from alcohols. For example, aspirin (acetylsalicylic acid) is prepared commercially by the acetylation of o-hydroxybenzoic acid (salicylic acid) with acetic anhydride. 

Bromomethyl-3-methylquinoxaline (273) and m-hydroxybenzoic acid (274) gave either 2-(m-hydroxybenzoyloxymethyl)-3-methylquinoxaline (275) [KOH (1 mol), EtOH, reflux, 2h 69%] or 2-(m-carboxyphenoxymethyl)-3-methylquinoxaline (276) [KOH (2 mol), EtOH, 50°C—>reflux, 1 h 44%] p-hydroxybenzoic acid reacted similarly but o-hydroxybenzoic acid (salicylic acid) gave only the isomer of product (275) even in the presence of KOH (2 mol). It would seem that the substrate (275) preferred to react at the phenolic anion rather than at the carboxylate anion when both were present... 

The effect is very pronounced, but falls off sharply as soon as the carboxyl groups are separated by more than one saturated carbon atom. C/ s-butenedioic(maleic) acid (5, pKal = 1-92) is a much stronger acid than trans-butenedioic(fumaric) acid (6, pX,1 = 3-02), due to the intramolecular hydrogen bonding that can take place with the former, but not with the latter, leading to relative stabilisation of the cis (maleate, 7) mono-anion (cf. o-hydroxybenzoic acid above) ... 

The product is almost exclusively sodium o-hydroxybenzoate (salicylate, 71) only traces of the p-isomer being obtained if, however, the reaction is carried out on potassium phenoxide the salt of the p-acid becomes the major product. It has been suggested that the preferential o-attack with sodium phenoxide may result from stabilisation of the T.S. (72) through chelation by NaP in the ion pair ... 

In 1983, Nixon and Scheimann reported that 2-acyl(or formyl, methoxycarbonyl)-phenol can add to 4-(methoxycarbonyl)-2,3-butenoate to yield 4-(methoxycarbonyl)-3-(phenoxy)-3-buteneate 522. o-Hydroxyphenyl ketone, o-hydroxybenzaldehyde or o-hydroxybenzoic acid esters reacted with 4-methoxycarbonyl-2,3-butenoate in a... 

This effect decreased the formation of o-hydroxybenzo-phenone. 

The selective alkylation of a chemically distinct phenohc site on a perfluorinated aromatic has been achieved following a polymer assisted solution phase protection of an alternative o-hydroxybenzoic acid unit as the dioxin-4-one (19) (Scheme 2.45) [66]. A diverse set of 22 different alkyl and benzyl bromides were then attached to the free phenol using cesium fluoride as the base, followed by treatment with Amberlyst 15 and Amberlyst A-21 as the work-up. Subsequent hydrolysis of the dioxin-4-one group with NaOH proceeded smoothly and was quenched... 

Ruthenium(in) catalyses the oxidative decarboxylation of n-butyric acid and isobutyric acid by ceric sulfate in aqueous acid. A mechanism for the Ru(III)-catalysed oxidation of o-hydroxybenzoic acid by an acidic solution of bromamine-B (PhS02-NNaBr, BAB) has been proposed based on a kinetic smdy. An ionic mechanism is suggested for the ruthenium(III) analogue of the Udenfriend-type system Ru(III)-EDTA-ascorbate-02, for the selective oxygen-atom transfer to saturated and unsaturated hydrocarbons. The kinetics of the oxidation of p-XC6H4CHPhOH(X =... 

Problam 16.14 Although p-hydroxy benzoic acid is less acidic than benzoic acid, salicyclic (o-hydroxybenzoic) acid (X, = 105 x 10 ) is 15 times more acidic than benzoic acid. Explain. M... 

Whistles, Pyrotechnic. US projectile ground-burst and booby-trap flash simulators precede their flash and expin with a whistling sound. The fact that certain compns whistle when compressed into a tube and ignited has been used in the fireworks industry for many years. The active substance most often used in pyrot whistles is gallic acid (3,4,5-trihydroxybenzoic acid). The K salts of benzoic acid of 2,4-dinitrophenol and of picric acid (2,4,6-trinitrophenol) and the Na salt of salicylic acid (o-hydroxybenzoic acid) are also effective. They are combined with K chlorate,... 

The acetyl 1CH3C - J derivative of o-hydroxybenzoic acid is the active ingredient in aspirin... 

In Section 9-3, we considered o- and p-hydroxybenzoic acids, designated HA. Now consider their conjugate bases. For example, the salt sodium o-hydroxybenzoate dissolves to give Na+ (which has no acid-base chemistry) and o-hydroxybenzoate. which is a weak base. The acid-base chemistry is the reaction of o-hydroxybenzoate with water ... 

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