O-formyl phenol

In alkaline solution, the phenol 1 is deprotonated to the phenolate 4, which reacts at the ort/zo-position with dichlorocarbene 3. The initial addition reaction product 5 isomerizes to the aromatic o-dichloromethyl phenolate 6, which under the reaction conditions is hydrolyzed to the o-formyl phenolate." ... 

Mn(II) > Mg(II).270 It should be underlined that titanium and zirconium alkoxides are efficient catalysts for both stages of reaction. Lanthanide compounds such as 2,2/-bipyridyl, acetylacetonate, and o-formyl phenolate complexes of Eu(III), La(III), Sm(III), Er(III), and Tb(III) appear to be even more efficient than titanium alkoxides, Ca or Mn acetates, Sb203, and their mixtures.273 Moreover, PET produced with lanthanides has been reported to exhibit better thermal and hydrolytic stability as compared to PET synthesized with the conventional Ca acetate -Sb203 catalytic system.273... 

The formylation of a phenol 1 with chloroform in alkaline solution is called the Reimer-Tiemann reaction. It leads preferentially to formation of an ortho-formylated phenol—e.g. salicylic aldehyde 2 —while with other formylation reactions, e.g. the Gattermann reaction, the corresponding /jara-formyl derivative is obtained as a major product. The Reimer-Tiemann reaction is mainly used for the synthesis of o-hydroxy aromatic aldehydes. 

Taylor and coworkers have prepared o-fluoromethyl and o-difluoromethyl estrone sulfates82 and shown that these compounds are good substrates for steroid sulfatases.83 The phenol product of hydrolysis of o-fluoromethyl estrone sulfate undergoes heterolytic cleavage to form a quinone methide that inactivates the steroid sulfatase (Scheme 20C).83 The phenol product of hydrolysis of o-difluoromethyl estrone sulfate breaks down first to a quinone methide and then to the o-formyl estrone, which also inactivates the steroid sulfatase.83... 

Salicylaldehydes. o-Formylation of phenols with paraformaldehyde takes place under the influence of MgCl2-Et3N. 

Furthermore, porphyrins react like extremely electron-rich aromatic compounds, comparable to phenol, aniline, or pyrrole. Central metal ions, in particular zinc(II) and copper(II), further activate them in electrophilic substitution reactions, l pical examples of the di- and tetrachlorination, mono- and dinitration, and most important Vilsmeier mono me o-formylation are given (Scheme 6.4.3) (Bonnett and Stephenson, 1965). Vilsmeier formylation of tetraphenylpor-phyrins gives mono (3-formyl products, which have been used to attach side chains to an imidazole end. Five coordinated metal complexes thus become accessible (not shown). 

Formylamines s. Formamides C-Formyiation (s. a. C-Hydroxy-methylenation, Aldehyde groups, introduction) 20, 600 —, o-formylation, preferential, of phenols 20, 558 N-Foriiiylation... 

Auch Li t hi urn a I ana t reduziert die o- und p-standig mit elektronenliefemden Gruppen (z.B. Amino, Dial-kylamino, Methoxy) substituierten aromatischen Aldehyde und Ketone mcist nur unter cncrgischen Bedingun-gen zu Kohlenwasserstoffen (z. B. in Dibutylather mehrere Tage bei 80-90°). Formyl- und Acyl-phenole werden nicht reduziert1. 

In this route a dihydroisoquinoline (58) is N alkylated with a highly functionalized o -bromoacetophenone (59) to give a quaternary salt (60), which is treated with base and cyclizes to a pyrroloisoquinoline (60). The pyrrole nucleus is then formylated under Vilsmeier-Haack conditions at position 5 and a proximate mesylated phenolic group is deprotected with base to yield a pen-tasubstituted pyrrole (61). Subsequent oxidative cyclization of this formylpyr-role produces the 5-lactone portion of lamellarin G trimethyl ether (36). This sequence allows for rapid and efficient analog synthesis as well as the synthesis of the natural product. 

In 1983, Nixon and Scheimann reported that 2-acyl(or formyl, methoxycarbonyl)-phenol can add to 4-(methoxycarbonyl)-2,3-butenoate to yield 4-(methoxycarbonyl)-3-(phenoxy)-3-buteneate 522. o-Hydroxyphenyl ketone, o-hydroxybenzaldehyde or o-hydroxybenzoic acid esters reacted with 4-methoxycarbonyl-2,3-butenoate in a... 

Carbon tetrachloride. Chloroform, 2-Chlorophenol, Cyclohexanol, Cyclopentene, 1,1-Dichloroethylene, irans-l, 2-Dichloroethylene, IV.yV-Dimethylaniline, lV,lV-Dimethylformamide, 2,4-Dimethylphenol, 2,4-Dinitrotoluene, 1,4-Dioxane, 1,2-Diphenylhydrazine, Ethyl formate. Formaldehyde, Glycine, Methanol, Methylene chloride. Methyl formate, 2-Methvlphenol. Monuron, 4-Nitrophenol, Oxalic acid, Parathion, Pentachlorophenol, Phenol, l idine. Styrene, Trichloroethylene, Vinyl chloride Formylacetic acid, see cis-l,3-Dichloropropylene, irans-1,3-Dichloropropylene IV-Formylcarbamate of 1-naphthol, see Carbaryl Formyl chloride, see Chloroethane, Chloroform, sym-Dichloromethyl ether, ds-1,3-Dichloropropylene, irans-ES-Dichloropropylene, Methyl chloride. Methylene chloride. Trichloroethylene, Vinyl chloride lV-Formyl-4-chloro-o-toluidine, see Chlornhenamidine. 

The formylation of phenols with the electron-rich olefin to give imidazolidin-2-yl-phenols is very selective and avoids mixtures of o- and p-isomers which are frequently obtained by methods commonly employed for the synthesis of phenolaldehydes. Para substitution of the cyclic aminal group in the phenol is preferred. If the p-position is blocked or sterically hindered, the reaction proceeds via the ortho- aminals to salicylaldehydes. Incorporation of more than one aldehyde group in the benzene nucleus is often achieved with hydroxy- and aminophenols. 

A convenient and inexpensive method to transfoim election rich aromatic aldehydes to phenols, or a,3-unsaturated aldehydes to vinyl formates, utilizes 30% hydrogen peroxide cat yzed by bis(o-nitro-phenyl) diselenide. A two-step formylation/MCPBA oxidation procedure (Scheme 25) was utilized by Kishi and coworkers in the 100 g scale conversion of 2,6-dimethoxytoluene to the mitomycin precursor (76). An organic peroxy acid was not required for the conversion of 9-formyl-6-methylellipticine (77) to 9-hydroxyellipticine (78 Scheme 26). Under these conditions, the pyridine nitrogen was not oxidized. 

Examples of the selective substitution of phenol units in partially O-alkylated (or 0-acylated) calixarenes (reaction c)) are the bromination , iodination, nitration , formylation , chloromethylation , alkylation and coupling with diazonium salts. ... 

The first total synthesis of chiral cherylline (55), a rare phenolic Amaryllidaceae alkaloid, has been fully described.31 Resolution of the previously synthesized ( )-phenethylamine (53) with (—)-diacetone-2-keto-L-gulonic acid gave the (2RH+)- and (2S)-( — )-L-gulonate salts, which were transformed into the diastereomeric hydrobromides the latter were formylated, subjected to Bischler-Napieralski cyclization conditions, and debenzylated to yield the (4R)-(+)-and (4S)-(—)-dihydroisoquinoline (54) hydrochlorides. These were separately selectively O-demethylated, quaternized with methyl iodide, and reduced with... 

In addition to phenols, naphthols, their alkyl derivatives and the heterocyclic compounds mentioned above, a large variety of substituted monocyclic as well as condensed phenols have been subjected to the Reimer-Tiemann reaction. Although with a few exceptions the yields are only moderate, the facile reaction conditions, at least on a laboratory scale, have assured the reaction a permanent place among the variety of methods by which an aldehyde group can be attached to an aromatic nucleus. For example, phenolphthalein (1) has been formylated under standard Reimer-Tiemann conditions by van Kampen to yield the o-hydroxy aldehyde in 59% yield (equation 5)."... 

SalicylaTdehydes. Formylation of phenols generally gives mixtures of o- and... 

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