Dehydrogenation and methylation of 1,2,3,4-tetrahydro-9-methylcarbazoles during Vilsmeier–Haack formylation

Bruck, P.

doi:10.1039/c29700001690

Cited by 10 publications

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“…Methods have been developed to calculate kinetic constants from TGA curves Stivala and Reich, 1965). Thus, for polyimides good agreement was found by Bruck (1964aBruck ( , 1964b for activation energies and frequency factors derived from TGA and those obtained from isothermal thermogravimetry.…”

Section: A Definition and Evaluation Of Thermal Stabilitymentioning

confidence: 95%

“…For a basic understanding of thermal or thermoxidative stability, data on the volatile degradation products, their sequence and rate of formation as a function of temperature, and the changes that occur in structure and molecular weight of the residual material are required. Examples of high-temperature polymers on which basic studies were made include polybenzimidazoles (Shulman and Lochte, 1967) and polymides (Bruck, 1965a(Bruck, , 1965b.…”

Section: A Definition and Evaluation Of Thermal Stabilitymentioning

confidence: 99%

“…For polymers containing alkyl substituents on the benzene ring, decomposition commenced at 32b330" C. Similarly, for polymers containing side-chain methyl groups, as in the case of polyimides derived from 2,2-bis(4-aminophenyl)propane7 decomposition occurred at 330" C. The most stable polymers were derived from p-phenylenediamine and 4,4'-diaminobiphenyl. Bruck (1964aBruck ( , 1964bBruck ( , 1965aBruck ( , 1965b…”

Section: Isothermal Weight Loss Of Pyromellitimidesmentioning

confidence: 99%

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Stability of high‐temperature polymers

Arnold¹

1979

J. Polym. Sci. Macromol. Rev.

170

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Section: A Definition and Evaluation Of Thermal Stabilitymentioning

confidence: 95%

Section: A Definition and Evaluation Of Thermal Stabilitymentioning

confidence: 99%

Section: Isothermal Weight Loss Of Pyromellitimidesmentioning

confidence: 99%

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Stability of high‐temperature polymers

Arnold¹

1979

J. Polym. Sci. Macromol. Rev.

170

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“…127 In 1970, Bruck reported an unusual product of a Vilsmeier-Haack reaction with N-methyl-1,2,3,4-tetrahydrocarbazole. 128 Later, Murakami et al investigated this reaction and subsequently applied it to the synthesis of ellipticine and olivacine (Scheme 36). 97,129 When 9-benzyl-1,2,3,4-tetrahydrocarbazoles 172a & b were treated with two equivalents of phosphorous oxychloride in dimethylformamide at 0 uC, 9-benzyl-1-formyl-1,2,3,4-tetrahydrocarbazoles 173 were isolated in good yields.…”

Section: Cranwell-saxton Based Approachesmentioning

confidence: 99%

Isolation, biological activity and synthesis of the natural product ellipticine and related pyridocarbazoles

Miller

McCarthy

2012

RSC Adv.

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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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Dehydrogenation and methylation of 1,2,3,4-tetrahydro-9-methylcarbazoles during Vilsmeier–Haack formylation

Abstract: Sunznzavy Formylation of 1,2,3,4-tetrahydro-9-methylcarbazoles under Vilsmeier-Haack conditions affords 3-formpl-1,9-dimethylcarbazoles, in contrast to a previous report.

Cited by 10 publications

References 0 publications

Stability of high‐temperature polymers

Stability of high‐temperature polymers

Isolation, biological activity and synthesis of the natural product ellipticine and related pyridocarbazoles

The Vilsmeier Reaction of Non‐Aromatic Compounds

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