Acetylbenzoate

It was found that utilization of QAS with increased steric accessibility of exchange center, containing nitrogen atom with three methyl substituents and one super lipophilic substituent, - tris(2,3,4-dodecyloxy)benzyl, - leads to dramatic, up to 7 orders, increase of ISE s selectivity towards sulfate in the presence of single-charged anions. Incorporation of hexyl 4-trifluoro-acetylbenzoate into membrane leads to additional substantial increase - up to 4 orders - in sulfate selectivity. 

Hydrazones of 3-hydroxy-2-acetylbenzo[fe]furan are reported to exist as aminovinylketones 33 and 34 (90ZOR1540). The ratio of (Z, E) isomers depends upon and R. ... 

Methoxyphenylurea, 31,10,13 Methyl -acetylbenzoate, 32, 81 Methyl acrylate, 30, 65 32, 86 y-Methylallophanate, 32, 62 Methylamine, 30, 60 4 -Methyl-2-aminobenzophenone, 32,12 N-Methylaniline, 30, 62 31,110 N-Methylarylamines, preparation by reductive alkylation, 30, 59, 60 Methylation, of e-caprolactam, 31, 72 of quinacetophenone, with dimethyl sulfate, 31, 91 with methyl iodide, 31, 90 2-Methyl-3,l,4-benzoxaz-4-one, 32, 12 N-Methyl-a-bromo-n-butyranilide, 30, 63... 

Condensation of 3-(lH-pyrrol-l-yl)propylamine 391 with acetylbenzoic acids and formyl benzoic acids such as 392 under Dean and Stark water-removal conditions results in the formation of the fused angular 5 6 5 system 393 in good yield (Equation 105) <2002TL2831>. In a similar manner, l-(3-aminoethyl)-3-methylindole reacts with 2-formyl-benzoic acid to give the cyclized product in 82% yield <2002TL2831>. 

Newman and his co-workers (Newman and Hishida, 1962 Newman and Leegwater, 1968) have studied the effects of 6-methyl and 6-chloro substituents on the rates of alkaline hydrolysis of methyl 2-benzoyl- and 2-acetylbenzoates [17]. The 6-substituted esters hydrolysed faster than the... 

The BINAP/l,2-diamine-RuCl2 complexes require the addition of alkaline base to form reactive RuH2 species for the hydrogenation of simple ketones to neutralize releasing HC1. trans-RuH( /1-BH4)(xylbinap)(dpen) (31G) produces the active species without an additional base, while an even higher rate is obtainable in the presence of an alkaline base (Fig. 32.31) [102]. The base-free procedure can be applied to the hydrogenation of several base-sensitive ketones. For example, the reaction of ethyl-4-acetylbenzoate catalyzed by (S,SS)-31G quantitatively yields ethyl (R)-4-(l-hydroxyethyl)benzoate in 99% ee [102]. No transesterification is observed. 

It is noteworthy that, although 4-bromoanisole produces anisic acid in high yield, 4-hydroxybenzoic acid is isolated in only 17% yield from the corresponding reaction of 4-bromophenol. Also, 4-bromoacetophenone, which may react by a normal SN reaction, is readily converted into 4-acetylbenzoic acid, whereas 4-bromonitro-benzene produces 4-nitrobenzoic acid in only 17% yield, together with nitrobenzene (17%). 

The inductive effect in 4-hydroxybenzoic acid is electron withdrawing, but this is a modest effect compared with the electron-donating resonance effect. This significantly destabilizes the conjugate base, and 4-hydroxybenzoic acid (p a 4.6) is less acidic than benzoic acid. The last example, 4-acetylbenzoic acid, is the most acidic of the group, and this is primarily the result of an electron-withdrawing resonance effect, though there is also a favourable inductive effect. 

It is interesting to note that although in principle ketone 48 can undergo secondary Norrish type II cleavage to give a mixture of methyl 4-acetylbenzoate... 

A general route to both benzo[/)]furans and benzo[/>]thiophenes depends upon the cyclodehydration of either 2-hydroxy- or 2-sulfanylbenzyl ketones or aldehydes (Scheme 7.23a). 2-Acetylbenzo[6]furan can be obtained by reacting the sodium salt of 2-formylphenol with chloroace-tone (chloropropanone) (Scheme 7.23b). A similar reaction using sodium 2-formylbenzenethiolate yields 2-acetylbenzo[Z)]thiophene. 

METHYL p-ACETYLBENZOATE (Benzoic acid, p-acetyl-, methyl ester)... 

The benzene serves to keep the methyl p-acetylbenzoate in solution. If crystallization occurs, the mixture should be warmed to dissolve the ester before filtration. 

Methyl />-acetylbenzoate has been prepared by the esterification of -acetylbenzoic acid with methanol in the presence of hydrogen chloride,6 by the hydrogenation of methyl -trichloro-acetylbenzoate in the presence of a palladium on calcium carbonate catalyst,6 and by the air oxidation of methyl / -ethyl-benzoate.4... 

An unusual chemical shift is found in the (E)-oxime (117) of 2-acetylbenzo[6]furan, the 3-proton of which resonates at 8 7.95 p.p.m. Since the Z isomer resonates normally at 8 7.20 it seems that the hydroxy group in (117) is close enough to the 3-proton to deshield it rather strongly, yet without bringing into play bulk repulsions and in what seems to be contradiction to the conformational preference discussed earlier (75AcH(84)38l). 

Benzofuran-3(2/f)-ones (396) exist in the keto form but undergo ready enolization. Acetylation with acetic anhydride and sodium acetate affords 3-acetoxybenzo[6]furans, but reaction under acidic conditions usually supplies these products admixed with 3-acetoxy-2-acetylbenzo[6]furans. Alkylation usually furnishes a mixture of O- and C-alkylated products. 3-Acetoxy-6-methoxy-4-methylbenzo[6]furan, on Vilsmeier reaction, supplies the 3-chlorobenzo[6]furan-2-carbaldehyde, the product expected from an enolizable ketone (72AJC545). Benzofuran-3(2//)-ones react normally with carbonyl reagents. Grignard reagents react in the expected way and dehydration of the intermediate affords a 3-substituted benzo[6]furan. The methylene group is reactive so that self condensation, condensation with aldehydes and ketones and reaction with Michael acceptors all occur readily. 

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