Tiemann reaction

C7H6O2 Oily liquid of aromatic odour b.p. 196°C. (t is prepared by the action of chloroform and caustic potash on phenol (the Reimer-Tiemann reaction) or by the oxidation of the glucoside salicin. It is easily reduced to salicyl alcohol or oxidized to salicylic acid. 

From phenols by interaction with chloroform and sodium hydroxide solution (Reimer - Tiemann reaction), for example ... 

This is a nifty little way to turn catechol or guaiacol into protocate-chualdehyde or vanillin using what is called the Riemer-Tiemann reaction [137 p824, 138], It is a really ancient reaction and only works on benzene molecules that have an OH group. One needs to use KOH instead of NaOH because it is better at promoting para substitutions (don t ask). And if one is going to make vanillin from guaiacol then there needs to be a little ethanol in the reaction as well. 

Phenyhsonitrile has a powerful characteristic odor it is used as a qualitative test (the carbylamine test) for chloroform or primary aromatic amines. Chloroform reacts with phenols in alkaline solution to give hydroxyaromatic aldehydes in the Reimer-Tiemann reaction eg, phenol gives chiefly Nhydroxyben2aldehyde and some sahcylaldehyde (11) (see Hydroxybenzaldehydes). 

Aminotriazole is carboxylated at the 5-position by heating with aqueous sodium bicarbonate in a Kolbe-type reaction (7lJCS(C)l50l). 2-Thiazolinones undergo the Gatter-mann and Reimer-Tiemann reactions at the 4-position, and 3- and 4-pyrazolinone anions on alkylation give 4-alkyl as well as O- and N-alkyl derivatives. 

Using Reimer-Tiemann reaction conditions on 3-alkyl-6-hydroxy-1,2-benzisoxazoles results in formylation occurring at the 7-position (77UC(B)1056). 

Reimer-Tiemann reaction, 2, 209-210 Oxycarboxin as fungicide, 1, 193 Oxydimethiin... 

Pyrrolo[2,3-6]pyridine, 2-methyl-Reimer-Tiemann reaction, 4, 508 Pyrrolo[2,3-6]pyridine, 4-methyl-hydrogen exchange, 4, 502 reaction with aldehydes, 4, 503 reaction with benzaldehyde, 4, 511... 

The Ciamician-Dennstedt reaction can be thought of as the complement to the Reimer-Tiemann reaction (Scheme 8.3.2). The first step of both reactions is cyclopropanation of one of the carbon-carbon double bonds of a pyrrole with a dichlorocarbene, resulting in intermediate 3. The Ciamician-Dennstedt reaction results from cleavage of the internal C-C bond and elimination of chloride (path a), while the Reimer-Tiemann reaction results from cleavage of the exocyclic bond, and subsequent hydrolysis of the dichloromethyl moiety to furnish aldehyde 5 (path b). 

Under conditions more similar to those of the Reimer-Tiemann reaction 3-bromopyridine was obtained from pyrrole and bromo-form. Treatment of pyrrole with chloroform and aqueous alkali gave pyrrole-2-aldehyde curiously, the formation of 3-chloropyridine under these conditions does not appear to have been reported, in spite of being frequently quoted. However, indole gave both indole-3-aldehyde and 3-chloroquinoline under these conditions [Eq. (10)]. 

The Reimer-Tiemann reaction has also been used to formylate 2,5-dimethylpyrrole and its iV-methyl derivative and indoles having methyl, methoxyl, and phenyl substituents. Significantly, 3-methylindole gave only 3-chloro-4-methylquinoline. ... 

A variant of the Reimer-Tiemann reaction, using chloroform or bromoform with ethanohc sodium ethoxide, has been apphed (mainly by Plancher and co-workers) to certain pyrroles and indoles with interesting results. Thus Bocchi has shown that 2,5-dimethylpyrrole gave 3-halogeno-2,6-dimethylpyridine, and 2,4-dimethylpyrrole with bromoform gave two isomeric bromodimethylpyridines [Eq. (11)]. 

The latter reaction has been repeatedly misquoted (e.g. ref. 50) as involving 2,3-dimethylpyrrole, but the Reimer-Tiemann reaction of this pyrrole has not been investigated. In this case the methyl groups should activate the 2,3-bond sufficiently to make the 3-halogeno-2,4-dimethylpyridine the major—if not the sole— product. 

The structure of the product of the Reimer-Tiemann reaction of 1,2,3-trimethylindole (24) has been confirmed as 3-dichloromethyl-1,3-dimethyl-2-methyleneindoline (25) by spectroscopy and oxidation to the iV -methyloxindole when the dichlorocarbene was generated under neutral conditions a ring-expanded product, 3-chloro-1,4-dimethyl-2-methylene-1,2-dihydroquinoline (26) could be isolated and oxidized to the corresponding a-quinolone. These reactions presumably proceed by mechanisms similar to those discussed for 2,3-di-... 

While the Friedel-Crafts acylation is a general method for the preparation of aryl ketones, and of wide scope, there is no equivalently versatile reaction for the preparation of aryl aldehydes. There are various formylation procedures known, each of limited scope. In addition to the reactions outlined above, there is the Vdsmeier reaction, the Reimer-Tiemann reaction, and the Rieche formylation reaction The latter is the reaction of aromatic compounds with 1,1-dichloromethyl ether as formylating agent in the presence of a Lewis acid catalyst. This procedure has recently gained much importance. 

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. 

The applicability of the Reimer-Tiemann reaction is limited to the formylation of phenols and certain reactive heterocycles like pyrroles and indoles. Yields are usually below 50%. In contrast to other formylation procedures, the Reimer-Tiemann reaction is ort/zo-selective it is therefore related to the Kolb e-Schmitt reaction. 

Formylation with Chloroform The Reimer-Tiemann Reaction... 

In the Reimer-Tiemann reaction, chloroform and hydroxide ion are used to... 

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