Microwave-assisted synthesis of pyridylpyrroles from N-acylated amino acids

Harju, Kirsi; Manevski, Nenad; Yli‐Kauhaluoma, Jari

doi:10.1016/j.tet.2009.09.094

Cited by 15 publications

(7 citation statements)

References 38 publications

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“…Elemental analysis was performed on a HEKAtech Euro EA Analyzer. L -Leucine benzyl ester hydro- p -tosylate ( 8 ) and L -leucine allyl ester hydro- p –tosylate ( 9 ) were prepared following the procedures described in [ 25 ] and [ 26 ]. N-Boc-1,6-diaminohexane ( 16 ) was prepared following the procedure in [ 27 ].…”

Section: Methodsmentioning

confidence: 99%

“…N-2-(Triphenylsilyl)ethoxycarbonyl- L -leucine benzyl ester ( 13 ). The protected leucine derivative 13 was prepared following general procedure A from L -leucine benzyl ester hydro- p -tosylate [ 25 ] (369 mg, 0.94 mmol, 1.1 eq.). The crude product was purified by silca gel column chromatography with the eluent mixture n -hexane/ethyl acetate 8.25:1.75 yielding protected amino acid 13 (456 mg, 0.83 mmol, 98%) as a colorless gum.…”

Section: Methodsmentioning

confidence: 99%

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The 2-(Triphenylsilyl)ethoxycarbonyl-(“Tpseoc”-) Group: A New Silicon-Based, Fluoride Cleavable Oxycarbonyl Protecting Group Highly Orthogonal to the Boc-, Fmoc- and Cbz-Groups

Golkowski

Ziegler

2011

Molecules

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Starting from 2-(triphenylsilyl)ethanol a new oxycarbonyl protecting group cleavable by fluoride ion induced Peterson-elimination has been developed. Known 2-(triphenylsilyl)ethanol has been prepared from commercially available triphenylvinyl-silane by a hydroboration-oxidation sequence using the sterically hindered borane reagent 9-BBN. The silyl alcohol was subsequently transformed into its chloroformate, imidazolylcarboxylic acid ester and p-nitrophenyl carbonate and used in standard protocols for the formation of carbamates and carbonates. The Tpseoc group proved to be highly resistant against acidic conditions applied in removal of tert-butyl esters and the t-Boc-group. It also withstood catalytic hydrogenation, treatment with morpholine, methylhydrazine and Pd-reagents/allyl-scavanger combinations, conditions required to cleave Cbz-, Fmoc-, phthalimide- and Alloc-groups. The Tpseoc-group is cleaved upon treatment with TBAF/CsF at 0 °C or r.t. with cleavage times reaching from <10 min. to 24 h. Its orthogonality, ease of cleavage and UV-detectability makes the Tpseoc-group a promising alternative to other widely used silicon based amine protecting groups like the Teoc- and SES-groups.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The 2-(Triphenylsilyl)ethoxycarbonyl-(“Tpseoc”-) Group: A New Silicon-Based, Fluoride Cleavable Oxycarbonyl Protecting Group Highly Orthogonal to the Boc-, Fmoc- and Cbz-Groups

Golkowski

Ziegler

2011

Molecules

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“…In Radleys reaction tubes, parallel catalytic hydrogenation gave pyridyl‐substituted amino acids. Cycloaddition with a dehydrating reagent and dimethyl acetylene dicarboxylate or methyl propiolate led to highly functionalized pyrroles .…”

Section: Microwave‐assisted Organic Synthesesmentioning

confidence: 99%

Microwave‐activated Synthesis of Pyrroles: A Short Review

Sharma

Piplani

2015

Journal of Heterocyclic Chem

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In the current scenario for continuous requirement of better drugs, medicinal chemists must visage the challenging task of preparing novel patentable compounds, combining high activity and selectivity, good drug‐likeness, and pharmacokinetic properties. There is an acute need of new molecules in both lead identification and lead optimization. Chemists thoroughly scrutinize ways to simplify synthetic protocols using green chemistry approaches, for example, microwaves. Reduction in the reaction time by the use of microwaves has emerged as a promising method for bringing out new leads in organic synthesis. Among the azaheterocyclic systems, synthesis of pyrrole moiety has been a highly attractive and an inspiring proposition. It has been found to be an inbuilt pharmacophore of various momentous pharmacologically active compounds in medicinal chemistry. This article outlines the basic principles of microwave technology and its use in the synthesis of pyrrole derivatives wherein this technology has made a tremendous impact.

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“…Following addition the mixture was set to reflux for 20 h while fitted with a Dean-Stark apparatus to remove water. The reaction mixture was cooled to room temperature, and then stored in the freezer for 3 h. The precipitate was filtered and washed with toluene to yield l-methionine benzyl ester p-toluenesulfonate salt (23) (24): [33] l-Leucine benzyl ester p-toluenesulfonate (24) (0.30 g, 0.76 mmol, 70 %), white powderwas prepared following the same procedure as described for compound (23 …”

Section: L-methionine Benzyl Ester P-toluenesulfonate (23)mentioning

confidence: 99%