Acetic anhydride, condensation with

Acetic anhydride, condensation with and acetylation of glycine, 46, 1 in cyclization of c-formylphenoxy-acetic acid to coumarone, 46, 28 in cyclization of hippuric acid to 2-phenyl-5-oxazolone, 47, 101 reaction with N-nitroso-N-phenyl-glycine to yield 3-phenylsydnone, 46,96... 

In the Perkin reaction, acetic anhydride condenses with an aromatic aldehyde to yield a cinnamic acid. The reaction takes place by a mixed carbonyl condensation of the anhydride with the aldehyde to yield an a,/l-unsaturated intermediate that undergoes hydrolysis to yield the cinnamic acid. What is the structure of the unsaturated intermediate ... 

That sodium acetate, and not the acetic anhydride, condenses with the benzaldehyde, is proved by the following facts If, instead of sodium acetate, sodium proprionate is used, and this is heated with benzaldehyde and acetic anhydride, cinnamic add is not obtained, but inethyl cinnamic acid ... 

Friedel-Crafts Acylation. The Friedel-Crafts acylation procedure is the most important method for preparing aromatic ketones and thein derivatives. Acetyl chloride (acetic anhydride) reacts with benzene ia the presence of aluminum chloride or acid catalysts to produce acetophenone [98-86-2], CgHgO (1-phenylethanone). Benzene can also be condensed with dicarboxyHc acid anhydrides to yield benzoyl derivatives of carboxyHc acids. These benzoyl derivatives are often used for constmcting polycycHc molecules (Haworth reaction). For example, benzene reacts with succinic anhydride ia the presence of aluminum chloride to produce P-benzoylpropionic acid [2051-95-8] which is converted iato a-tetralone [529-34-0] (30). 

Phthalic anhydride condenses with the aniline derivative in the presence of zinc or aluminum chlorides to yield the intermediate benzoyl-benzoic acid, which subsequently reacts with l,3-bis-V,V-dimethylaniline in acetic anhydride to yield the phthalide. The above compound gives a violet-gray image when applied to a clay developer. Clearly this synthesis is also very flexible and variations in shades of color formers have been obtained by varying the aniline components and also by using phthalic anhydrides substituted, for example, by nitro groups or chlorine atoms. Such products have excellent properties as color formers and have been used commercially. Furthermore, this synthetic route is of great importance for the preparation of heterocyclic substituted phthalides, as will be seen later. 

The use of activated anthranihc acid derivatives facUitates the preparation of the amides in those cases where the amines are either umeactive or difficult to obtain. Thus, reaction of (87-1) with phosgene gives the reactive the isatoic anhydride (89-1). Condensation of that with ortho-toluidine leads to the acylation product (89-2) formed with a simultaneous loss of carbon dioxide. This is then converted to the quinazolone (89-3) by heating with acetic anhydride. Reaction with sodium borohydride in the presence of aluminum chloride selectively reduces the double bond to yield the diuretic agent metolazone (89-4) [99]. 

Polysorbate 60 occurs as a yellow to orange colored, oily liquid or semigel. It is a mixture of stearate and palmitate partial esters of sorbitol and sorbitol anhydrides condensed with approximately 20 moles of ethylene oxide (C2H40) for each mole of sorbitol and its mono- and dianhydrides. It is soluble in water, in aniline, in ethyl acetate, and in toluene, but it is insoluble in mineral oil and in vegetable oils. 

Incidental reactions that have been reported include the preparation of derivatives of 5-(hydroxymethyl)-2-furaldehyde by reaction of D-fructose in acetic or propionic acid in the presence of the respective anhydride.158 The condensation of D-glucose with phenol has been effected in acetic acid in the presence of dry hydrogen chloride, prior to resinification,157 and the reaction of sucrose with thionyl chloride in acetic acid-acetic anhydride produced partially acetylated chlorodeoxysucroses.158 Sucrose has been condensed with maleic anhydride in acetic anhydride mixed with acetic acid or formic acid, to give solid products having an undetermined structure.159... 

Methylation with dimethyl sulfate in alkali gave the methyl derivatives 28 and 29. Although formaldehyde attacks at N-2, aldol condensation of 10 with benzaldehyde gave the 3a-hydroxybenzyl compound (30) which is dehydrated to the 2-acetyl-3-benzylidene compound (31) with acetic anhydride.27 With acid anhydrides the2-acyl derivatives are obtained however, with acid chlorides in pyridine or dimethylaniline the bicyclic ketone (32) is formed.31 Despite the occurrence of the bicyclic product (32) and the bicyclic intermediate (13) there is no evidence for the existence of a bicyclic tautomer of 10.37... 

For some time considerable confusion existed as to whether the salt or the anhydride condensed with the aldehyde,9 10 for when benzaldehyde was heated with acetic anhydride and sodium butyrate, ethylcinnamic acid was found to be the main product.11 It is now quite clear, however, that it is the anhydride which undergoes condensation and that the sodium salt is simply the strongest commonly used base that will not destroy the anhydride. Thus acetic anhydride will condense with benzaldehyde in the presence of pyridine or triethyl amine whereas benzaldehyde, sodium acetate, and pyridine will not undergo the same reaction.12 When an acid salt different from the anhydride is employed, an equilibrium... 

Cinnamic acid is manufactured by the so-called Perkin synthesis, which has been applied to the preparation of a large number of unsaturated acids. When benzoic aldehyde is heated with anhydrous sodium acetate in the presence of acetic anhydride, condensation takes place as the result of the loss of water CeHs.CHO + CHg.COONa = CeHB.CHrCH.COONa + H2O A similar condensation takes place between benzoic aldehyde and homologues of acetic acid. The hydrogen atoms which are eliminated from the salt of the fatty acid are those in the a-posi-tion —... 

Heating of (280) with acetic anhydride proceeds with elimination of the t-butyl group, giving dibenzothiophen. Condensation of (281) with (282)... 

Place a mixture of 5 g. of camphor, 6 g. of powdered selenium dioxide and 5 ml. of acetic anhydride in flask fitted with a reflux water-condenser. Heat the flask in an oil-bath for 3 hours at 140-150 so that gentle boiling occurs shake the mixture from time to time. 

When the reaction has subsided, boil the reaction-mixture under reflux for 2 hours then make it alkaline with sodium hydroxide solution, and distil it in steam until oily drops no longer come over in the aqueous distillate (1 2 litres). Extract the distillate thoroughly with ether ca. 150 ml.), and dry the ethereal extract over powdered sodium hydroxide. Filter the dry extract through a fluted filter-paper moistened with ether into a 200 ml. flask. Fit the flask with a distillation-head, or a knee-tube , and distil off the ether. Now replace the distillation-head by a reflux water-condenser, add 10 ml. of acetic anhydride, and boil the mixture under reflux for 10 15 minutes. 

Acetylation. Place 1 ml. of the substance (or, if solid, i g. of the powdered amine) in a small flask fitted with a reflux condenser (or in a test-tube fitted with a cold-finger, as in Fig. 35, p. 62), add 5 ml. of an acetic anhydride-acetic acid mixture (equal volumes) and reflux... 

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