Solid-Phase Transimidation for the Removal of N-Phthalimido- and N-Tetrachlorophthalimido Protecting Groups on Carbohydrates

Stangier, Peter; Hindsgaul, Ole

doi:10.1055/s-1996-5356

Cited by 26 publications

(10 citation statements)

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“…Nevertheless, the common application of the tetrachlorophthalimido protecting group has been limited to sugar chemistry. [2][3][4] To date, no efforts have been made towards the synthesis of a wide range of N-TCP protected amino acids suitable for SPPS (solidphase synthesis of peptides). 5 In general, N-substituted phthalimides are formed by condensation of phthalic anhydride and an amine by reflux [2][3][4] (Dean-Stark water separator 6 ) or by direct fusion procedures.…”

mentioning

confidence: 99%

“…[2][3][4] To date, no efforts have been made towards the synthesis of a wide range of N-TCP protected amino acids suitable for SPPS (solidphase synthesis of peptides). 5 In general, N-substituted phthalimides are formed by condensation of phthalic anhydride and an amine by reflux [2][3][4] (Dean-Stark water separator 6 ) or by direct fusion procedures. 7 The phthaloyl group has also been introduced by reacting the amine with 2-(ethoxycarbonyl)benzoic acid activated by PyBOP (benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluoro phosphate), followed by the thermally induced cyclization of the resulting phthalamic ester.…”

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confidence: 99%

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Synthesis of Nα-Tetrachlorophthaloyl (TCP)-Protected Amino Acids under Microwave Irradiation (MWI)

Cros¹,

Planas²,

Bardajı́³

2001

Synthesis

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confidence: 99%

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confidence: 99%

Synthesis of Nα-Tetrachlorophthaloyl (TCP)-Protected Amino Acids under Microwave Irradiation (MWI)

Cros¹,

Planas²,

Bardajı́³

2001

Synthesis

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“…Methyl 6‐ O ‐acetyl‐2‐deoxy‐2‐tetrachlorophthalimido‐ β ‐ D ‐glucopyranoside (7) : Acetyl chloride (0.115 mL, 1.62 mmol) was added dropwise to compound 6 23 (653 mg, 1.42 mmol) and sym ‐ collidine (0.940 mL, 7.09 mmol) in CH 2 Cl 2 (25 mL) under a nitrogen atmosphere at −42 °C. The reaction was continued at −20 °C for 4 hours, then additional acetyl chloride (0.025 mL, 0.352 mmol) and sym‐collidine (0.400 mL, 3.0 mmol) were added.…”

Section: Methodsmentioning

confidence: 99%

Low Micromolar Inhibitors of Galectin‐3 Based on 3′‐Derivatization ofN‐Acetyllactosamine

et al. 2002

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A strategy for generating potential galectin inhibitors was devised based on derivatization at the C-3' atom in 3'-amino-N-acetyllactosamine by using structural knowledge of the galectin carbohydrate recognition site. A collection of 12 compounds was prepared by N-acylations or N-sulfonylations. Hydrophobic tagging of the O-3 atom in the N-acetylglucosamine residue with a stearic ester allowed rapid and simple product purification. The compounds were screened in a galectin-3 binding assay and three compounds with significantly higher inhibitory activities compared to the parent N-acetyllactosaminide were found. These three best inhibitors all carried an aromatic amide at the C-3' position of the galactose moiety, which indicates that favorable interactions were formed between the aromatic group and galectin-3. The best inhibitor had an IC50 value (4.4 microM) about 50 times better than the parent N-acetyllactosaminide, which implies that it has potential as a valuable tool for studying galectin-3 biological functions and also as a lead compound for the development of galectin-3-blocking pharmaceuticals.

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“…The N‐phtalimido and N‐tetrachlorophtalimido groups on carbohydrate derivatives are removed using alkyl diamines immobilized on polystyrene, thereby leaving the protecting group on the resin while the free sugar remains in solution (Scheme ) 185…”

Section: Stoichiometric Polymer‐supported Reagentsmentioning

confidence: 99%

Functionalized Polymers-Emerging Versatile Tools for Solution-Phase Chemistry and Automated Parallel Synthesis

Kirschning

Monenschein

Wittenberg

2001

Angew. Chem. Int. Ed.

379

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As part of the dramatic changes associated with the need for preparing compound libraries in pharmaceutical and agrochemical research laboratories, industry searches for new technologies that allow for the automation of synthetic processes. Since the pioneering work by Merrifield polymeric supports have been identified to play a key role in this field however, polymer‐assisted solution‐phase synthesis which utilizes immobilized reagents and catalysts has only recently begun to flourish. Polymer‐assisted solution‐phase synthesis has various advantages over conventional solution‐phase chemistry, such as the ease of separation of the supported species from a reaction mixture by filtration and washing, the opportunity to use an excess of the reagent to force the reaction to completion without causing workup problems, and the adaptability to continuous‐flow processes. Various strategies for employing functionalized polymers stoichiometrically have been developed. Apart from reagents that are covalently or ionically attached to the polymeric backbone and which are released into solution in the presence of a suitable substrate, scavenger reagents play an increasingly important role in purifying reaction mixtures. Employing functionalized polymers in solution‐phase synthesis has been shown to be extremely useful in automated parallel synthesis and multistep sequences. So far, compound libraries containing as many as 88 members have been generated by using several polymer‐bound reagents one after another. Furthermore, it has been demonstrated that complex natural products like the alkaloids (±)‐oxomaritidine and (±)‐epimaritidine can be prepared by a sequence of five and six consecutive polymer‐assisted steps, respectively, and the potent analgesic compound (±)‐epibatidine in twelve linear steps ten of which are based on functionalized polymers. These developments reveal the great future prospects of polymer‐assisted solution‐phase synthesis.

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Solid-Phase Transimidation for the Removal of N-Phthalimido- and N-Tetrachlorophthalimido Protecting Groups on Carbohydrates

Cited by 26 publications

References 0 publications

Synthesis of Nα-Tetrachlorophthaloyl (TCP)-Protected Amino Acids under Microwave Irradiation (MWI)

Synthesis of Nα-Tetrachlorophthaloyl (TCP)-Protected Amino Acids under Microwave Irradiation (MWI)

Low Micromolar Inhibitors of Galectin‐3 Based on 3′‐Derivatization ofN‐Acetyllactosamine

Functionalized Polymers-Emerging Versatile Tools for Solution-Phase Chemistry and Automated Parallel Synthesis

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