Acyl resorcinols

Other ketones may be reduced by this same procedure. The submitters report that the following have been reduced with yields of 70-90 per cent 0- and p-butyryl phenols, 0- and p-valeryl phenols, 0- and />-caproyl phenols, 0- and />-heptanoyl phenols, 0- and -octanoyl phenols, o- and />-pelargonyl phenols, o- and />-undecylyl phenols. The same procedure applies to acyl resorcinols and acyl chlororesorcinols. Caproyl and octanoyl resorcinols reduce to the corresponding alkyl derivatives in yields of 70-80 per cent. Butyryl, valeryl, caproyl, heptanoyl,... 

Primary alkyl phenols have been prepared by the reduction of acyl phenols 1 by the demethylation of the corresponding ethers 12 by the diazotization of the corresponding amines 3 and by the alkali fusion of sulfonates.4 Alkyl resorcinols have been prepared by the reduction of acyl resorcinols.1 5 6 Alkyl chlororesorcinols have been prepared from the corresponding acyl chlororesorcinols by reduction.7... 

Alkyl Resorcinols from Acyl Resorcinols CA 72,66922(1970) Compounds I-III may be able to give active THC analogs if used in place of olivetol for synthesis. 

Phosphorus oxychloride (POCI3) has proven useful as a promoter in a range of Pechmann condensations employing sterically encumbered 3-keto ester coupling partners and electronically deactivated phenols, reactions which fail using sulfuric acid as a promoter. Thus POCI3 has been found to successfully promote the condensation of a-benzylacetoacetate and 1-naphthol as well as the reaction of ethyl acetoacetate with 4-acyl-resorcinols. ... 

The synthesis of 2,4-dihydroxyacetophenone [89-84-9] (21) by acylation reactions of resorcinol has been extensively studied. The reaction is performed using acetic anhydride (104), acetyl chloride (105), or acetic acid (106). The esterification of resorcinol by acetic anhydride followed by the isomerization of the diacetate intermediate has also been described in the presence of zinc chloride (107). Alkylation of resorcinol can be carried out using ethers (108), olefins (109), or alcohols (110). The catalysts which are generally used include sulfuric acid, phosphoric and polyphosphoric acids, acidic resins, or aluminum and iron derivatives. 2-Chlororesorcinol [6201-65-1] (22) is obtained by a sulfonation—chloration—desulfonation technique (111). 1,2,4-Trihydroxybenzene [533-73-3] (23) is obtained by hydroxylation of resorcinol using hydrogen peroxide (112) or peracids (113). 

In a series of publications, Eckert and co-workers have shown the efficacy of carrying out a reaction in SC water and SC polar solvents, which might even dispense with the use of acid and base catalysts. Reference may also be made to a reeent publication, which describes the acylation of resorcinol with acetic acid in a near SC acetic acid medium (Tc = 319 °C) without any catalyst at 290 °C nearly 50 mol % yield was realized, which is close to the equilibrium value (Brown et al., 2000). 

Acylation of resorcinol by 4-ethylbenzoic acid gave 2,4-dihydroxy-4 -ethylbenzophenone in 72% yield. Attempted bromination of this compound with NBS yielded not the benzylic bromide, but rather ring-brominated products. Since ring-... 

With this purpose, several different types of solid acid catalysts have been investigated for the acylation of aromatics, but the best performances have been obtained with medium-pore and large-pore zeolites (3-9). In general, however, the use of acylating agents other then halides, e.g., anhydrides or acids, is limited to the transformation of aromatic substrates highly activated towards electrophilic substitution. In a previous work (10), we investigated the benzoylation of resorcinol (1,3-dihydroxybenzene), catalyzed by acid clays. It was found that the reaction mechanism consists of the direct 0-benzoylation with formation of resorcinol monobenzoate, while no primary formation of the product of C-benzoylation (2,4-dihydroxybenzophenone) occurred. The latter product formed exclusively by... 

Problem 15.58 Translate the following description into a chemical equation Friedel-Crafts acylation of resorcinol( 1,3-dihydroxybenzene) with CH,(CH2)4COCI produces a compound which on Clemmensen reduction yields the important antiseptic, hexylresorcinol. 

The dihydrobenzoxathiin 408, a potent selective estrogen receptor alpha modulator, is metabolized to the bridged dibenzo[, 4]thiopyran derivative 409. It seems logical to assume that 409 is formed by initial cleavage of the O-C bond followed by an intramolecular acylation to generate the thiopyran ring. A 19-step total synthesis from resorcinol confirmed the structure of 409 (Equation 115) <20050L411>. 

The regioselective acylation (or alkylation) of one OH group per resorcinol unit... 

If this isomerization comprises all four resorcinol units, a C4-symmetrical molecule is converted in its enantiomer. This racemization may be the reason for the difficulty encountered with the chromatographic separation of the enantiomers.214 In fact, on-column racemization could be demonstrated for slightly elevated temperatures. In principle, this racemization should be prevented by acylation or alkylation (see below) of the remaining hydroxy groups, which however, proved to be rather difficult.215... 

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