Preparation of Pyrroles by Dehydrogenation of Pyrrolidines with Manganese Dioxide

Bonnaud, B.; Bigg, D. C. H.

doi:10.1055/s-1994-25500

Cited by 28 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Substituted pyrrolidines can also be transformed into the corresponding pyrroles by boiling with a fivefold excess of MnO 2 in THF [56]. In a number of cases cis-3,4-substituted pyrrolidines give higher yields of pyrroles than the analogous trans isomers.…”

Section: Dehydrogenation Of Partly Saturated Heterocyclesmentioning

confidence: 99%

Oxidation of heterocyclic compounds by manganese dioxide (Review)*

Солдатенков

Polyanskii

Kolyadina

et al. 2009

Chem Heterocycl Comp

View full text Add to dashboard Cite

Section: Dehydrogenation Of Partly Saturated Heterocyclesmentioning

confidence: 99%

Oxidation of heterocyclic compounds by manganese dioxide (Review)*

Солдатенков

Polyanskii

Kolyadina

et al. 2009

Chem Heterocycl Comp

View full text Add to dashboard Cite

“…In the subsequent step different oxidation methods were attempted using potassium permanganate [22] and manganese dioxide [23,24], but the yields were poor. Taking the clue from the facile nature of oxidation process using nitrobenzene from literature [25], an attempt to oxidize 7 and 10 to 2-substituted-5,7-dimethyl pyrido [2,3-d]pyrimidin-4(1H )-ones (8 and 11) resulted in good yields (65e92%).…”

Section: Chemistrymentioning

confidence: 99%

Synthesis of new 2-substituted pyrido[2,3-d]pyrimidin-4(1H)-ones and their antibacterial activity☆

Narayana

Rao

Rao³

2009

European Journal of Medicinal Chemistry

View full text Add to dashboard Cite

“…Examples of [30] Very surprisingly, oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) did not provide the expected product 37, but instead afforded cyclisation precursor 21 b in 71 % yield. The detailed mechanism of this unusual fragmentation is not clear; however, a related oxidative transformation was reported by Singh et al [31] Smooth epoxidation of 23 was achieved under standard conditions with m-chloroperbenzoic acid (mCPBA) affording quantitatively pentacyclic compound 39.…”

Section: Subsequent Transformationsmentioning

confidence: 99%

A New, Efficient and Stereoselective Synthesis of Tricyclic and Tetracyclic Compounds by Samarium Diiodide Induced Cyclisations of Naphthyl‐Substituted Arylketones—An Easy Access to Steroid‐Like Skeletons

Aulenta

Berndt

Brüdgam

et al. 2007

Chemistry A European J

View full text Add to dashboard Cite

In this report, we present the application of samarium diiodide induced cyclisations of naphthyl-substituted ketones towards an easy and stereoselective access to tri- and tetracyclic-functionalised compounds. Typical naphthalene derivatives were studied to investigate the scope and limitations of this novel cyclisation process. The model substrates studied demonstrate that the samarium ketyl cyclisations are essentially restricted to the formation of six-membered rings. The diastereoselectivity of these reactions is strongly influenced by the connection of the alkyl side chain to the naphthalene core. Gamma-naphth-1-yl-substituted ketones furnished cyclisation products, such as 17 or 22-26, as single diastereomers, whereas gamma-naphth-2-yl-substituted precursors gave mixtures of diastereomers--as demonstrated by the conversion of model compound 10 into tricyclic products 18 a/18 b, or that of cyclohexanone derivative 33 into tetracyclic diastereomers 34 a/34 b. Cyclic ketones as ketyl precursors furnished steroid-like tetracyclic skeletons; however, due to the cis/cis fusion of rings B/C and C/D these products have an "unnatural" bowl-like shape. Several of the cyclisation products have been identified by X-ray analyses, which not only proved the constitutions, but also the relative configurations and the preferred conformations. Steroid analogue 23 was subjected to subsequent transformations, which demonstrate that the styrene-like double bond of such compounds can be used for further structural diversification. First attempts to synthesise related azasteroids by incorporating nitrogen atoms into the ketone moiety are also reported. Thus, pyrrolidine derivatives 44 and 47 as well as piperidine derivatives 50 and 52 were subjected to samarium diiodide induced cyclisations. The expected tetracyclic products 48, 49 a/49 b, 51 and 53 a/53 b were obtained in moderate to good yields. The stereoselectivities observed follow the rules already established for the all-carbon precursors. The resulting products, bearing a nitrogen atom in ring D, are interesting azasteroid analogues with "unnatural" configuration.

show abstract

Preparation of Pyrroles by Dehydrogenation of Pyrrolidines with Manganese Dioxide

Cited by 28 publications

References 0 publications

Oxidation of heterocyclic compounds by manganese dioxide (Review)*

Oxidation of heterocyclic compounds by manganese dioxide (Review)*

Synthesis of new 2-substituted pyrido[2,3-d]pyrimidin-4(1H)-ones and their antibacterial activity☆

A New, Efficient and Stereoselective Synthesis of Tricyclic and Tetracyclic Compounds by Samarium Diiodide Induced Cyclisations of Naphthyl‐Substituted Arylketones—An Easy Access to Steroid‐Like Skeletons

Contact Info

Product

Resources

About