Heterocyclic enaminones: Photochemical synthesis of 6,7,8,9-tetrahydro-5H-pyrido[2,3-b]indol-9-ones

Blache, Yves; Sinibaldi-Troin, Marie-Eve; Hichour, Mohammed; Benezech, Véronique; Chavignon, Olivier; Gramain, Jean-Claude; Teulade, Jean‐Claude; Chapat, Jean‐Pierre

doi:10.1016/s0040-4020(98)01212-5

Cited by 22 publications

(11 citation statements)

References 28 publications

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“…Irradiation of secondary enaminone 2 0 7 using a pyrex immersion well aparatus and a medium pressure mercury UV lamp (400 W) in benzene led to 6,7,8,9-tetrahydro-5H-pyrido[2,3-b]indol-9-ones 208 ( Figure 74). Considering charge and orbital control of the reaction as outlined in the frontier molecular concept from HOMOC2enaminone/LUMOC-13pyridine controlled process as well as from net atomic charge estimations, the reaction produced 6,7,8,9-tetrahydro-5H-p y r i d o [ 2 , 3 -b] i n d o l -9 -ones 208 [124].…”

Section: Reactions Of Enaminones With Basesmentioning

confidence: 99%

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Negri

Kascheres

2004

Journal of Heterocyclic Chem

179

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Enaminoketones and esters are gaining increased interest, particularly cyclic-β-enaminoesters, which are known as important intermediates for the synthesis of heterocycles and natural products, because the enantioselective preparation of highly functionalized compounds is of central importance in synthetic chemistry. Enaminones are versatile synthetic intermediates that combine the ambident nucleophilicity of enamines with the ambident eletrophilicity of enones. Enaminoketones and enaminonitriles have proven to be versatile building blocks for the synthesis of various heterocycles such as pyridine, pyrimidine and pyrrole derivatives. Enaminones systems have "enone" character, and may act as acceptors in both 1,2 and 1,4-additions. In this way the enaminone serves as a scaffold for annulation, and can gain access to systems such as pyrroles indolizidines, quinolizidines and perhydroindoles, all of which are common motifs in alkaloid structures. Enaminones are frequently employed as building blocks for the preparation of a variety of bicyclic compounds of biological interest and have been recently recognized as potential anticonvulsant compounds. Since a large number of developments in the use of enaminones in heterocyclic synthesis have occurred, a review of the recent developments in the synthetic approaches, covering the literature since 1995 until 2004, to these interesting molecules and their useful chemical transformations and biological activity can be considered of considerable value.J. Heterocyclic Chem., 41, 461 (2004).Enaminoketones. Introduction.The term enaminone was introduced by Greenhill to define the enamine of a 1,3-diketone, β-ketoester or similar 1,3-difunctional reagents, and is used to indicate any compound containing the conjugated system N-C=C-C=O [1]. Enaminones are versatile synthetic intermediates that combine the ambident nucleophilicity of enamines with the ambident eletrophilicity of enones. The chemistry of the enaminocarbonyl group 1 is potentially an area of considerable scope when one considers that there are present in this moiety, three nucleophilic sites (a, c and e) and two electrophilic sites (b and d) [2][3][4] (Figure 1).Theorically, primary and secondary acyclic enaminones can exist in three tautomeric forms: ketamino form, iminoenol form and oxoimino form [1][2][3]. There is also evidence that cyclic enaminones exist primarily in the enaminoketo form. A study of cyclic enaminoketones shows that these compounds have a significant steric fator in the six-membered ring. The six-membered ring enaminoketones are only slightly stronger bases than the saturated amines, whereas five-and-seven membered rings are much stronger bases than saturated amines. This has been attributed to a large steric strain present in six-membered enaminoketones [5].β-Aminoenones or enaminoketones can exist in four conformations owing to restricted rotations around the C=C double and C-C=O single bonds [3]. Enaminones with primary or secondary amino groups can exist in both Z-and E-forms. If there is a...

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Section: Reactions Of Enaminones With Basesmentioning

confidence: 99%

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Negri

Kascheres

2004

Journal of Heterocyclic Chem

179

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“…In 1999, the first synthesis of azaindoles via Heck reaction was demonstrated by Blache and coworkers [ 18 ]. This approach consisted of enamine formation in the presence of Pd(Ph 3 ) 4 and NaHCO 3 in HMPA at 140 °C, consisting of a Hegedus–Mori–Heck reaction.…”

Section: Metal-catalyzed Cross-coupling Reactionsmentioning

confidence: 99%

Metal-Catalyzed Cross-Coupling Reactions on Azaindole Synthesis and Functionalization

2018

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Azaindoles are rare in nature but extremely attractive for drug discovery programs. Azaindoles can be obtained by diverse methods, including those involving metal-catalyzed reactions. This important core has been fascinating the scientific community due to their challenging synthesis and relevant bioactivity. This paper highlights the diverse synthetic methodologies developed to date involving metal-catalyzed reaction to attain azaindoles and its functionalization.

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“…Enaminones of type 148, on irradiation in a mixture of benzene/methanol solvent, undergo a smooth cyclization (Scheme 8.43) to produce the corresponding indolones 150 in high yield [73][74][75].…”

Section: Photochemical Electrocyclization Reactions: Synthesis Of Fusmentioning

confidence: 99%

Formation of a Five‐Membered Ring

Pandey

Gadre

2009

Handbook of Synthetic Photochemistry

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Heterocyclic enaminones: Photochemical synthesis of 6,7,8,9-tetrahydro-5H-pyrido[2,3-b]indol-9-ones

Cited by 22 publications

References 28 publications

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Metal-Catalyzed Cross-Coupling Reactions on Azaindole Synthesis and Functionalization

Formation of a Five‐Membered Ring

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