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Stability Studies of N ‐Acylimidazoles
Author(s) -
Zaramella Simone,
Strömberg Roger,
Yeheskiely Esther
Publication year - 2002
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200208)2002:15<2633::aid-ejoc2633>3.0.co;2-u
Subject(s) - chemistry , trifluoroacetic acid , imidazole , chloroform , piperidine , dimethylformamide , high performance liquid chromatography , medicinal chemistry , organic chemistry , stereochemistry , solvent
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)