Ein neuer präparativer Zugang zur Pyrrolchemie

Dobeneck, Henning Von; Messerschmitt, Thilo

doi:10.1002/jlac.19717510105

Cited by 20 publications

(2 citation statements)

References 8 publications

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“…Under the influence of the Vilsmeier complex the N-unsubstituted 3,4-dimethylpyrrol-2-one 20 gives a good yield of the immonium salt 20a, the alkaline hydrolysis of which gives 2-formyl-5-chloropyrrole 21 [59][60][61]. N-Substituted pyrrol-2-ones dimerize with N-R-pyrrolid-2-ones during the action of protic and aprotic acids with yields of up to 79% [63].…”

Section: Pocl 3 Naohmentioning

confidence: 98%

Reactivity of pyrrol-2-ones. (review)

Egorova

Timofeeva

2004

Chem Heterocycl Compd

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Published data on the chemical transformations of pyrrol-2-ones are reviewed and analyzed. The extensive synthetic possibilities of compounds containing a pyrrolone ring in the synthesis of various heterocyclic compounds with complex structures are demonstrated. The reactions are arranged according to the reaction centers of the pyrrol-2-ones: The methylene unit, the C=C double bond, the electron-deficient carbon atom of the carbonyl group.

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Section: Pocl 3 Naohmentioning

confidence: 98%

Reactivity of pyrrol-2-ones. (review)

Egorova

Timofeeva

2004

Chem Heterocycl Compd

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“…In connection with other studies in progress in these laboratories, it became necessary to develop a synthesis of 5-chloropyrrole-2-carboxaldehydes that was more convenient than those in existence. Such compounds have been prepared by the action of Vilsmeier-Haack reagents on 2-chloropyrrole derivatives (1) or 3-pyrroline-2-ones (2,3). The first method does provide the aldehydes in good yields but the notorious instability of 2-chloropyrroles (1) makes this process distinctly unattractive.…”

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confidence: 99%

Vilsmeier–Haack reaction with succinamidals. A convenient synthesis of 5-chloropyrrole-2-carboxaldehydes and 5-chloropyrrole-2,4-dicarboxaldehydes

Guzmán¹,

Romero²,

Muchowski³

1990

Can. J. Chem.

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It is shown that the reaction of N-alkylsuccinamidals (2) with the Vilsmeier–Haack reagent derived from DMF and phosphorus oxychloride can be controlled to preferentially produce either 5-chloropyrrole-2-carboxaldehydes (8) or 5-chloropyrrole-2,4-dicarboxaldehydes (9). The corresponding N-unsubstituted aldehydes are obtained when N-tert-butoxycarbonylsuccinamidal (11) is the substrate in the above reactions. Keywords: Vilsmeier–Haack reaction, succinamidals, 5-chloropyrrole-2-carboxaldehydes, 5-chloropyrrole-2,4-dicarboxaldehydes.

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TheVilsmeier Reaction of Fully Conjugated Carbocycles and Heterocycles

Jones

Stanforth

1996

Organic Reactions

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In 1925 Fischer, Müller, and Vilsmeier published a paper describing the reaction between phosphoryl chloride and N ‐methylacetanilide, giving a number of products, including the quinolinium salt and another salt. The probable course of the reaction was given in a paper by Vilsmeier and Haack in 1927, and they made the important discovery that the reagent obtained from N ‐methylformanilide and phosphoryl chloride, represented as a salt, would react with N,N ‐dimethylaniline, giving 4‐ N,N ‐dimethylaminobenzaldehyde. No 2‐substituted products were observed in this reaction. Other N,N ‐dialkylaniline derivatives, including 3, N,N ‐trimethylaniline and 1‐ N,N ‐dimethylaminonaphthalene were also successfully used as substrates to prepare aromatic aldehyde derivatives. The gradual development of the reagent for synthesis was accompanied by interest in the nature of the reagent. It was discovered that other acid chlorides (e.g., thionyl chloride, carbonyl chloride, and oxalyl chloride) could be used in the reaction and that substituted amides other than formamides gave ketones, although in generally poorer yields. Thionyl chloride frequently gives sulfur‐containing products. The most commonly used amide is dimethylformamide (DMF) and there is now a consensus that the reagent formed from DMF and most acid chlorides, other than phosphoryl chloride, can be represented by the structure given in the chapter, and this is illustrated for the reaction between DMF and carbonyl chloride. The salt is a stable compound and is often isolated before being reacted with a substrate. It seems likely that the most commonly used reagent, that made from DMF and phosphoryl chloride, is an equilibrium mixture of iminium salts. Recent unpublished spectroscopic studies have indicated that in DMF solution there is an equilibrium mixture of iminium compounds. One of the electrophilic chloroiminium salts then reacts with a substrate in an electrophilic substitution process yielding an iminium salt, which is usually hydrolyzed to the aromatic aldehyde. Vinylogous chloroiminium salts can be prepared from the corresponding vinylogous formamide derivatives and these yield, after hydrolysis, α,β‐unsaturated products. This particular reaction is generally limited to more reactive substrates. The formation of carbon–carbon bonds to fully conjugated carbocycles and heterocycles is the subject of this chapter; a subsequent chapter considers carbon–carbon bond‐formation reactions in alkenes (including heterosubstituted alkenes such as enamines and enol ethers), alkynes, and activated methyl and methylene compounds (aldehydes, ketones, carboxylic acid derivatives, and nitriles). It is not surprising that the Vilsmeier reaction has been the subject of many review articles of varying scope and length. With so many excellent reviews dealing with the Vilsmeier reaction, its mechanism, and the structure of the various electrophilic reagents, coverage is restricted to important concepts rather than reiterate all the literature material. A brief description of the mechanism and regiochemistry of the Vilsmeier reaction is presented and this is elaborated with appropriate cases that deal with specific compound types.

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Ein neuer präparativer Zugang zur Pyrrolchemie

Cited by 20 publications

References 8 publications

Reactivity of pyrrol-2-ones. (review)

Reactivity of pyrrol-2-ones. (review)

Vilsmeier–Haack reaction with succinamidals. A convenient synthesis of 5-chloropyrrole-2-carboxaldehydes and 5-chloropyrrole-2,4-dicarboxaldehydes

TheVilsmeier Reaction of Fully Conjugated Carbocycles and Heterocycles

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