Phenol reactions with substituted

As reactions of the diaminochlorocyclopropenium ion other than above, the reaction with substituted aromatics will be introduced. For instance, reaction with phenol or thiophenol gives exclusively the prod-... 

The values of Pi g for reaction of phenolate ions with substituted phenyl esters of diphenylphosphoric acid ((PhO)2PO-OAr) are -0.52, -0.68 and -0.81 respectively for phenolate ion, 4-acetylphenolate ion and 4-formylphenolate ion nucleophiles.Attack of phenolate ions on 4-nitrophenyldiphenylphosphate ester has Pnuc 0.53. Given that the values of 4-nitro-, 4-formyl-, 4-acetyl- and parent phenols are 7.14, 7.66,... 

Figure 11 More O Ferrall-Jencks diagram for the identity reactions of substituted phenolate ions with substituted phenyl esters (data from reference 24). See text for the identities of the three identity reactions...

The reaction of substituted phenolate ions with substituted phe-noxytriazines has the Bronsted data given in Table 2. 

Bisphenol A and analogous compounds yield 9,9-dimethylxanthones on reaction with substituted phenols in the presence of MeSOsH chroman (45) and spiroketal (46) are intermediates <97JOC1058>. 

The dioxybiphenyl derivative (146) has also been used as starting material for the preparation of thiophenolate-substituted analogues. Formation of the compounds (185a-d) from (146) and RC6H4-SH appears to be a two-step process, the second step being much faster than the first. This is in contrast with reactions with substituted phenols RC6H4-OH, where the first substitution step is faster than the second one and consequently mono-substitution products can be isolated under appropriate conditions. 

In general, the xanthenes are synthesized by the reaction of two moles of a nucleophilic / -substituted phenol (10) with an electrophilic carbonyl compound (11), the reaction occurring most readily with an acid catalyst at temperatures of 100—200°C. 

A popular alternative to the step utili2ing chromogen is to substitute -hydroxyben2enesulfonate for phenol in the reaction with the pyridine nucleotide ... 

In keeping with its aromatic character, pyrrole is relatively difficult to hydrogenate, it does not ordinarily serve as a diene for Diels-Alder reactions, and does not undergo typical olefin reactions. Klectrophilic substitutions are the most characteristic reactions, and pyrrole has often been compared to phenol or... 

Sulfur monochloride also reacts with substituted phenols to give condensation products useful for mbber compounding (qv) (150). Elf Atochem NA manufactures products known as Vultacs by the reaction of amylphenols and sulfur monochloride (153). 

Cyanuiic chloiide is a convenient piecuisoi to alkyl oi aiyl cyanurates by reaction with alcohols or phenols, or to substituted melamines by reaction with amines alkaline conditions ate employed in both cases and yields are generally high. 

In general it is considered essential that the bulk of the phenol used initially should not be substituted, i.e. should be reactive, at the o- and p-positions and is thus trifunctional with respect to the reaction with formaldehyde. 

Mono-substitution occurs most readily in the stepwise replacement of the halogen substituents of 2,4,6-trichloro-s-triazine with aqueous methanol and sodium bicarbonate (30°, 30 min), the monomethoxy derivative (324) is obtained on heating (65°, 30 min), the disubstitu-ted derivative is formed and on brief heating (65°) with the more basic sodium carbonate or methanolic sodium hydroxide (25°, 3 hr) complete methoxylation (320) occurs. Ethanolic ethoxide (25°, 1 hr) or sodium carbonate (35°) is sufficient to give complete ethoxy-dechlorination. The corresponding phenoxy derivatives are obtained on treatment with one (0°), two (15°, 1 hr), or three equivalents (25-70°, 3 hr) of various sodium phenoxides in aqueous acetone. The stepwise reaction with phenols, alcohols, or thiols proceeds in better yield in organic solvents (acetone or chloroform) with collidine or 2,6-lutidine as acid acceptors than in aqueous sodium bicarbonate. ... 

Substituted TMM complexes also cycloadd to aldehydes in the presence of a tin cocatalyst such as MesSnOAc and MesSnOTs [31]. Reaction of 2-heptenal with methyl precursor (6) gave a mixture of methylenetetrahydrofurans (68) and (69). This regioselectivity is reversed with 10-undecenal and methyl precursor (5), where adduct (70) now predominates over (71). As in the carbocyclic system, the phenylthio group also functions as a regiocontrol element in reaction with cyclohexyl aldehyde. The initially formed adduct (72) eliminates the element of thio-phenol on attempted allyl rearrangement, and the overall process becomes a cycloaddition approach to furans (Scheme 2.21) [20]. 

Arenediazonium ions 1 can undergo a coupling reaction with electron-rich aromatic compounds 2 like aryl amines and phenols to yield azo compounds 3. The substitution reaction at the aromatic system 2 usually takes place para to the activating group probably for steric reasons. If the para position is already occupied by a substituent, the new substitution takes place ortho to the activating group. 

The same conclusion was reached in a kinetic study of solvent effects in reactions of benzenediazonium tetrafluoroborate with substituted phenols. As expected due to the difference in solvation, the effects of para substituents are smaller in protic than in dipolar aprotic solvents. Alkyl substitution of phenol in the 2-position was found to increase the coupling rate, again as would be expected for electron-releasing substituents. However, this rate increase was larger in protic than in dipolar aprotic solvents, since in the former case the anion solvation is much stronger to begin with, and therefore steric hindrance to solvation will have a larger effect (Hashida et al., 1975 c). 

Alkyl-substituted phenols have different reactivities than phenol toward reaction with formaldehyde. Relative reactivities determined by monitoring the disappearance of formaldehyde in phenol-paraformaldehyde reactions (Table 7.3) show that, under basic conditions, meta-cresol reacts with formaldehyde approximately three times faster titan phenol while ortho- and para-cresols react at approximately one-third the rate of phenol.18 Similar trends were observed for the reactivities of acid-catalyzed phenolic monomers with formaldehyde. 

As the reactions proceed, the disappearance of phenol is delayed due to competition for reaction with formaldehyde between phenol and the faster reacting hydroxymethyl-substituted phenols. Competition also exists between formaldehyde substitution reactions and condensation reactions between rings. Condensation reactions between two ortho-hydroxymethyl substituents are the least favorable condensation pathway. Depending on the reaction conditions, substitutions occur... 

The simultaneous reaction of sulfur dioxide and chlorine with paraffins, named sulfochlorination, was discovered by Reed and Horn in the 1930s [9]. The primary products of this reaction are the alkanesulfochlorides [10], which can be saponified to alkanesulfonates by sodium hydroxide solution or treated with substituted phenolates to give plasticisers. In a short time the process was industrially realized to secure detergent production during World War II in Germany [11]. 

As in the case of benzimidazole, a parallel synthesis of benzoxazoles was described. The authors report that mixing directly differently substituted o-amino phenols 193 with acylating agents 194 and heating at 200 °C for 10-15 min under microwave irradiation, a collection of benzoxazoles 195 was obtained (Scheme 70). With this reaction, a 48-member library of benzoxazoles with different substituents on the aromatic rings was obtained [125]. 

Another hydroxylation reaction is the Elbs reaction In this method, phenols can be oxidized to p-diphenols with K2S20g in alkaline solution. Primary, secondary, or tertiary aromatic amines give predominant or exclusive ortho substitution unless both ortho positions are blocked, in which case para substitution is found. The reaction with amines is called the Boyland-Sims oxidation. Yields are low with either phenols or amines, generally under 50%. The mechanisms are not clear, but for the Boyland-Sims oxidation there is evidence that the S20 ion attacks at the ipso position, and then a migration follows. ... 

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