Acetic anhydride with phenols

Uses ndReactions. The Prins reaction of 3-carene with formaldehyde in acetic acid gives mainly 2-carene-4-methanol acetate, which when saponified produces the 2-carene-4-methanol, both of which are commercial products of modest usage (60). 3-Carene (28) also reacts with acetic anhydride with a catalyst (ZnCl2) to give 4-acetyl-2-carene (29) (61), which is also a commercial product. Although 3-carene does not polymerize to produce terpene resins, copolymerization with phenol has been successfully commercialized by DRT in France (62). 

These can be prepared as for the benzoates using either acetic anhydride with 3N NaOH or acetyl chloride in pyridine. They are hydrolysed as described for the benzoates. This hydrolysis can also be carried out with aqueous 10% NaOH solution, completion of hydrolysis being indicated by the complete dissolution of the acetate in the aqueous alkaline solution. On steam distillation, acetic acid also distils off but in these cases the phenols (see above) are invariably solids which can be filtered off and recrystallised. 

Schotfev-Bauviann reaction (p. 209).—This maybe applied to tile pure phenol in order to obtain the benzoyl deiii ative, and the melting-point deteimined, or the acetyl deri -ative maybe pie-pared by boiling for a minute with acetic anhydride with the same object. 

The production of moisture resistant particleboard by treatment with a maleic anhydride -glycerol mixture and using phenol formaldehyde as the matrix material has been investigated (Fujimoto etal., 1987). Boards prepared from modified wood showed considerable improvements in modulus of elasticity and internal bond strength when compared to control boards. Composites made from aspen fibres modified with SA, MA or acetic anhydride using phenol-formaldehyde (PF) or polypropylene as binder have also been studied (Clemons etal., 1992 Rowell etal., 1993b). The reaction of wood with MA was found to proceed at a slower rate than with SA. The volume increase due to modification... 

Phenoxy-substituted 2H, 8 -naphtha [l,2,3-de]-benz[/j]-2,8-quinolinedione (IIIC, R2 = hydrogen, R3 = CH3) was synthesized by cyclization of TV-chloro-acetyl-6-aminonaphthacenequinone in pyridine to the corresponding naphthacenepyrido-nyl-3-pyridinium chloride, with the subsequent reductive elimination of the pyridi-nium residue.39 The 3-acetyl derivative was obtained by the interaction of 6-amino-ll-chloro-5,12,naphthacenequinone with acetic anhydride in phenol in the presence of anhydrous sodium carbonate.39... 

Note that acetic acid is eliminated during the reaction. What effect would sodium acetate have How might boron fluoride etherate or sulfuric acid affect the nucleophilic attack of the phenolic oxygen on acetic anhydride With what might the base, pyridine, associate ... 

The reaction of acetic anhydride with salicylic acid (o-hydroxybenzoic acid) is used to synthesize aspirin. In this reaction, the phenolic hydroxyl group is acetylated (converted to its acetate ester). 

Preparation by reaction of acetic anhydride with 4-(3-phe-nylpropyl)phenol in the presence of boron trifluoride-acetic acid complex at 100° [2270],... 

Tertiary alcohols have been esterified in good yield using acetic anhydride with calcium hydride or calcium carbide. f-Butanol can be esterified to f-butyl acetate in 80% yield under these conditions. High pressure (15 kbar) has been used to introduce the acetate group using acetic anhydride in methylene chloride. Yields range from 79-98%. Chemoselectivity is achieved using acetic anhydride and boron trifluoride etherate in THF at 0 °C. Under these conditions, primary or secondary alcohols are acetylated in the presence of phenols. ... 

Diacetoxybiphenyl [2] was prepared via the reaction of acetic anhydride with 4,4 -dihydroxybiphenyl which in turn was obtained by enzymatic oxidation of phenol [1] by horseradish peroxidase.Stereospecific bis-hydroxylation of benzene [3] by Pseudomonas putida and subsequent acetylation gave cis l,2-diacetoxy-3,5-cyclohexadine [4]. Condensation of [TMA] and 4-aminobenzoic acid [6] in DMAc at 150 C gave N-(4-carboxyphenyl) trimellitimide [7] in excellent yield.22... 

Although the acetylation of alcohols and amines by acetic anhydride is almost invariably carried out under anhydrous conditions owing to the ready hydrolysis of the anhydride, it has been shown by Chattaway (1931) that phenols, when dissolved in aqueous sodium hydroxide solution and shaken with acetic anhydride, undergo rapid and almost quantitative acetylation if ice is present to keep the temperature low throughout the reaction. The success of this method is due primarily to the acidic nature of the phenols, which enables them to form soluble sodium derivatives, capable of reacting with the acetic... 

Crystalline derivatives, suitable for identification and characterisation are dealt with in Section IV, 114, but the preparation of the following, largely liquid, derivatives will be described in the following Sections. When phenols are dissolved in aqueous sodium hydroxide solution and shaken with acetic anhydride, they undergo rapid and almost quantitative acetylation if the temperature is kept low throughout the reaction. This is because phenols form readily soluble sodium derivatives, which react with acetic anhydride before the latter undergoes appreciable hydrolysis, for example ... 

Acetates. The acetates of monohydric phenols are usually liquids, but those of di and tri-hydric phenols and also of many substituted phenols are frequently crystaUine sohds. They may be prepared with acetic anhydride as detailed under Amines, Section IV,100,7. 

Phenols, unlike amines, cannot be acetylated satisfactorily in aqueous solution acetylation proceeds readily with acetic anhydride in the presence of a little concentrated sulphuric acid as catalyst. Salicylic acid (o-hydroxy-benzoic acid) upon acetylation yields acetylsalicylic acid or aspirin ... 

Phenacetin may be conveniently prepared in the laboratory from p-amino-phenol. The latter is readily acetylated with acetic anhydride to give p-acetyl-aminophenol this Is ethylated in the form of the sodio derivative to yield acetyl p-phenetidine (phenacetin) ... 

Other substituents which belong with this group have already been discussed. These include phenol, anisole and compounds related to it ( 5.3.4 the only kinetic data for anisole are for nitration at the encounter rate in sulphuric acid, and with acetyl nitrate in acetic anhydride see 2.5 and 5.3.3, respectively), and acetanilide ( 5.3.4). The cations PhSMe2+, PhSeMe2+, and PhaO+ have also been discussed ( 9.1.2). Amino groups are prevented from showing their character ( — 7 +717) in nitration because conditions enforce reaction through the protonated forms ( 9.1.2). 

Sulfonated styrene—divinylbensene cross-linked polymers have been appHed in many of the previously mentioned reactions and also in the acylation of thiophene with acetic anhydride and acetyl chloride (209). Resins of this type (Dowex 50, Amherljte IR-112, and Permutit Q) are particularly effective catalysts in the alkylation of phenols with olefins (such as propylene, isobutylene, diisobutylene), alkyl haUdes, and alcohols (210) (see Ion exchange). Superacids. 

Bisa.codyl, 4,4 -(2-PyridyLmethylene)bisphenol diacetate [603-50-9] (Dulcolax) (9) is a white to off-white crystalline powder ia which particles of 50 p.m dia predominate. It is very soluble ia water, freely soluble ia chloroform and alcohol, soluble ia methanol and ben2ene, and slightly soluble ia diethyl ether. Bisacodyl may be prepared from 2-pyridine-carboxaldehyde by condensation with phenol and the aid of a dehydrant such as sulfuric acid. The resulting 4,4 -(pyridyLmethylene)diphenol is esterified by treatment with acetic anhydride and anhydrous sodium acetate. Crystallisation is from ethanol. 

Reactions. Saligenin [90-01-7] undergoes the typical reactions of phenols and benzyl alcohol. When heated above 100°C, it transforms into a pale yellow resinous material. Amorphous condensation products are obtained when saligenin reacts with acetic anhydride, phosphoms pentachloride, or mineral acids. Upon boiling with dilute acids, saligenin is converted into a resinous body, saliretin, a condensed form of saligenin. Condensation reactions of saligenin with itself in the absence of any catalysts and in the presence of bases have also been studied. 

In 1979, workers investigating " the dienone-phenol rearrangement treated (3) with acetic anhydride and got an unknown compound believed to be (4), Treatment with strong acid gave (5), they supposed, but they wanted to synthesise an authentic sample of (5) to check their assignment. This is a tricky problem... 

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