Vilsmeier-Haack reaction of 1-methyl-34-dihydroisoquino lines-unexpected formation of 2,3-bisdimethylamino-5,6-dihydropyrrolo [2,1-]isoquinolines

Nagarajan, K.; Rodrigues, Patrick J.; Nethaji, Munirathinam

doi:10.1016/s0040-4039(00)60880-8

Cited by 7 publications

(2 citation statements)

References 6 publications

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“…The isoquinoline ring may be aromatic [37,149], but in the overwhelming majority of cases it is hydrogenated. A new pyrroloisoquinoline (LXXXIII) was obtained from 1-methyl-3,4-dihydroisoquinoline by the action of phosphorus oxychloride and DMFA in the Vilsmeier-Haack reaction [156]. Thus, for example, the papaverine derivative (LXXXI) gives compound (LXXXLD when treated with formic acid in DMFA [154,155].…”

Section: Cyelization By the Chichibabin Methods And With The Use Of Enmentioning

confidence: 99%

Pyrrolo[2,1-a]isoquinolines (review)

Михайловский¹,

Shklyaev²

1997

Chem Heterocycl Compd

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Section: Cyelization By the Chichibabin Methods And With The Use Of Enmentioning

confidence: 99%

Pyrrolo[2,1-a]isoquinolines (review)

Михайловский¹,

Shklyaev²

1997

Chem Heterocycl Compd

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“…On the other hand, the Vilsmeier reaction, one of the most useful synthetic methods for the introduction of one or more formyl groups into electron-rich aromatic and heteroaromatic compounds since its discovery by Vilsmeier and Haack, , has also shown great usefulness in the construction of a large number of heterocyclic systems, such as pyridines,pyridones, , pyrroles, pyrans, pyrones, , pyrimidines, pyrazoles, oxazoles, , quinolines, and so on . Among them, the Meth-Cohn quinoline synthesis, which involves the conversation of acylanilides into 2-chloro-3-substituted quinolines by the action of Vilsmeier reagent in hot POCl 3 solution, is of particular interest because of its ease of operation, wide general applicability, and the great importance of the products .…”

Section: Introductionmentioning

confidence: 99%

Regioselective Syntheses of 2- and 4-Formylpyrido[2,1-b]benzoxazoles

Guo

et al. 2009

J. Org. Chem.

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o-Acetaminophenols (2) reacted with Vilsmeier reagent under Meth-Cohn conditions to yield 2-formylpyrido[2,1-b]benzoxazoles (5) unexpectedly besides the known compounds 2-(benzoxazol-2'-yl)-3-dimethylaminoacroleins (4). Refluxing 4 in acetic anhydride gave 4-formylpyrido[2,1-b]benzoxazoles (6), an isomer of 5. Both 5a and 6a were structurally characterized by X-ray crystallography. A mechanism for the formation of 5 involving sequential chlorination, dimerization, intramolecular elimination of HCl to form the oxazole ring, formylation twice, and regioselective intramolecular nucleophilic cyclization to construct the pyridone ring is proposed.

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The Vilsmeier Reaction of Non‐Aromatic Compounds

Jones

Stanforth

2000

Organic Reactions

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This chapter extends the discussion to reactions between the Vilsmeier‐Haack reagent (subsequently referred to as the Vilsmeier reagent for brevity) and any other compounds in which a carbon‐carbon bond is formed. The discussion thus excludes reactions in which the Vilsmeier reagent acts as a chlorinating agent (for example in the preparation of acid chlorides), or in which it forms carbon‐oxygen or carbon‐nitrogen bonds, unless these are accompanied by formation of a carbon‐carbon bond. For a discussion of the nature of the reagent and of the mechanism of the reaction, the earlier chapter in vol. 49 should be consulted. There are also a number of reviews that deal at length with mechanisms of reactions involving the Vilsmeier reagent, notably those by Jutz and Marson, and hence this chapter will concentrate on applications, with brief mention of mechanisms when necessary. Wizinger has pointed out that alkenes could react with the Vilsmeier reagent, but his only examples were styrenes where the intermediate carbocation has considerable stability. Hydrolysis gives the cinnamaldehyde. In principle, any alkene which is not too sterically hindered can undergo this reaction, but the Vilsmeier reagent has low reactivity as an electrophile, and in practice activation is often necessary. The addition depends on the HOMO of the alkene, and anything increasing the HOMO energy will aid reaction, as for example further conjugation (dienes, trienes, etc.) or the presence of an electron‐donating substituent. Hence aldehydes and ketones are active in their enol forms, and enol ethers and enamines are good substrates. Indeed, all additions covered by this chapter can be regarded as alkene additions, even those on active methyl groups attached to electron‐deficient rings. As with any reaction involving carbocation intermediates, rearrangements are possible; the initial products are sometimes enamines, and this can give rise to polysubstitution. The substrates are grouped into eleven major subsections; references to reviews of particular relevance will be found in the appropriate subsection.

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Vilsmeier-Haack reaction of 1-methyl-34-dihydroisoquino lines-unexpected formation of 2,3-bisdimethylamino-5,6-dihydropyrrolo [2,1-]isoquinolines

Cited by 7 publications

References 6 publications

Pyrrolo[2,1-a]isoquinolines (review)

Pyrrolo[2,1-a]isoquinolines (review)

Regioselective Syntheses of 2- and 4-Formylpyrido[2,1-b]benzoxazoles

The Vilsmeier Reaction of Non‐Aromatic Compounds

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