Activated Cyclic Derivatives of Amino Acids

Sheehan, John C.; Hasspacher, Klaus; Yeh, Ying Lieh

doi:10.1021/ja01531a062

Cited by 41 publications

(10 citation statements)

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“…Lactonization with the carboxyl C atom is caused by bases, with elimination of the methyl ester. Similar reactions have been known for Ser and Thr (Sheehan et al, 1959), but the elongated backbone of the -amino acid promotes lactonization. This method conveniently yields amino-lactones, whose chirality is derived from threonines.…”

Section: Commentsupporting

confidence: 56%

4(R)-(N-Benzoylamino)-5(R)-methyltetrahydrofuran-2-one: anL-β-threonine analogue

Doi

Asano

2003

Acta Cryst E

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Section: Commentsupporting

confidence: 56%

4(R)-(N-Benzoylamino)-5(R)-methyltetrahydrofuran-2-one: anL-β-threonine analogue

Doi

Asano

2003

Acta Cryst E

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“…Conceptually,¯-lactones can be prepared by activation of either the hydroxyl or carboxyl groups of monoesters Scheme 7. Reagents and conditions: (a) D1AD, TPP, THF, room temperature, 3 h. [16][17][18][19][20][21][22]. Among the different methods of lactonization of¯-hydroxyacids described in the literature, we chosen the Mitsunobu reaction [23,24].…”

Section: Resultsmentioning

confidence: 99%

Synthesis of new α, α′, β-trisubstituted β-lactones as monomers for hydrolyzable polyesters

Barbaud¹,

Abdillah²,

Faÿ³

et al. 2003

Designed Monomers and Polymers

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Abstract-Novel ®,® 0 ,¯-trisubstituted¯-lactones have been prepared by a concise and ef cient synthesis in ve steps from commercial racemic diethyl oxalpropionate. These lactones with different lateral groups can be polymerized or co-polymerized for obtaining polyesters with high molecular weight. Chemical modi cation of these functionalized hydrolyzable polymers will be used to adjust their properties to the selected temporary applications.

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“…Possible reasons for this unsatisfactory yield are the low solubility of the AH6-purinyl)amino acid and/or the participation of the reactive ring nitrogen atoms in reactions similar to those described for histidine. For instance, Sheehan et al' 24 ' described the formation of a lactam ring during the activation of histidine by carbodiimides. Here the TV 1 -group reacts with the carboxyl group to a pyrrolidone derivative of 2,3-diaminobutyric acid.…”

Section: Resultsmentioning

confidence: 99%

The Synthesis and Some Biological Properties of N-(6-Purinyl)peptides

Schäfer¹,

Büllesbach²,

Jollès³

et al. 1986

Biological Chemistry Hoppe-Seyler

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The chemical synthesis and biological properties of N-(6-purinyl)peptides are described. W-(6-Purinyl)amino-acid derivatives were synthesized and condensed with amino acid esters and peptide esters using the dicyclohexylcarbodiimide/AMiydroxysuccinimide method. The products were isolated via gel filtration on Sephadex G-10 in 0.05M NH 4 HCO 3 followed by either ion exchange chromatography on SP-Sephadex or by preparative HPLC. The methyl esters were saponified and the tertbutyl ester group was removed by treatment with trifluoroacetic acid without damaging the purinyl residue. AK6-Purinyl)peptides were characterised by Chromatographie and spectroscopic methods.Acid hydrolysis of AK6-purinyl)-L-amino acids caused the racemization of the neighbouring L-amino acid. Model studies were performed with AH6-purinyl)-L-alanine, AH6-purinyl)-Dalanine, AH6-purinyl)-L-alanyl-L-leucine and Af-(6-purinyl)-D-alanyl-L-leucine. After acid hydrolysis the AK6-purinyl)amino acids were totally racemized and the 7V-(6-purinyl)dipeptides formed 14% of the enantiomer of alanine.The 7V-(6-purinyl)-co-amino acids and the 7V-(6-purinyl)peptides were screened in a limited number of tests as immunomodulators (antibody-secretion, phagocytosis, cytostatic activity of macrophages) and as cytotoxic agents. Synthese und einige biologische Eigenschaften von N-/6-PurinyDpeptidenZusammenfassung: Die Darstellung und biologische Eigenschaften einiger 7V-(6-Purinyl)peptide werden beschrieben. AM6-Purinyl)aminosäuren wurden synthetisiert und mit Aminosäure-und Peptidestern nach der Dicyclohexylcarbodiimid/A^Hydroxysuccinimid-Methode kondensiert. Mittels Gelchromatographie an Sephadex G-10 in 0.05M NH 4 HCO 3 und lonenaustauschchromatographie an SPSephadex oder präparativer HPLC konnten die Produkte rein erhalten werden. Methylester wurden verseift; te/t-Butylester ließen sich mittels Trifluoressigsäure abspalten, ohne daß eine Schädigung des Purinringes beobachtet wurde. Die AH6-Purinyl)peptide wurden mittels chromatographischer und spektroskopischer Methoden charakterisiert. Die saure Hydrolyse von 7V-(6-Purinyl)-L-aminosäuren führte zu einer Razemisierung der ankondensierten Aminosäure, die möglicherweise durch den Purinring kataly-

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Activated Cyclic Derivatives of Amino Acids

Cited by 41 publications

References 0 publications

4(R)-(N-Benzoylamino)-5(R)-methyltetrahydrofuran-2-one: anL-β-threonine analogue

4(R)-(N-Benzoylamino)-5(R)-methyltetrahydrofuran-2-one: anL-β-threonine analogue

Synthesis of new α, α′, β-trisubstituted β-lactones as monomers for hydrolyzable polyesters

The Synthesis and Some Biological Properties of N-(6-Purinyl)peptides

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