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Stability Studies of N-Acylimidazoles
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2002
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Proton NmrAntifungal AgentBioorganic ChemistryBiochemistryDrug ResistanceStability StudiesNatural SciencesBioconjugationOligonucleotidePeptide SynthesisOrganic ChemistryPeptide ScienceCommon Temporary ProtectionMedicineOligonucleotide SynthesisBiomolecular EngineeringDrug Analysis
Studies of the stabilities of a series of N-acylimidazoles towards acidic and basic conditions of potential usefulness for the removal of common temporary protection in peptide and oligonucleotide synthesis are presented. N-Acylimidazoles with a variety of substituents in the acyl component were prepared and treated with 3% trifluoroacetic acid (TFA) in chloroform and with 2% 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in N,N-dimethylformamide (DMF), the extent of their degradation being determined by proton NMR. N-(2,4,6-Trimethylbenzoyl)imidazole (1) and N-(2,6-dimethoxybenzoyl)imidazole (2) remained unaffected under the above acidic and basic conditions after 4 d and 2 d, respectively. In addition, 1 and 2 were resistant to treatment with a solution of 2% piperidine/2% DBU in DMF for 24 h. Under ammonolytic conditions, 2 was rapidly cleaved (less than 1 h), whereas 1 was 64% degraded after 48 h, as ascertained by reversed-phase HPLC. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)