title: Use of phthaloyl protecting group for the automated synthesis of 3'-[(hydroxypropyl)amino] and 3'-[(hydroxypropyl)triglycyl] oligonucleotide conjugates.
abstract: The chemical stability of oligonucleotides (ODNs) containing 3'-propanolamine was investigated. Invariably, all the ODNs synthesized from Fmoc-protected 3-aminopropane-1,2-diol-CPG support gave a mixture of three compounds at the end of automated synthesis as analyzed by denaturing PAGE and HPLC. On the basis of analytical procedures, these compounds were identified to be 3'-[N-acetyl-N-(hydroxypropyl)amino],3'-[(hydroxypropyl)amino], and 3'-hydroxyl ODNs. The instability of the amino protecting group under the synthesis conditions was responsible for this observed heterogeneity. In order to evaluate the stability, a comparative study on the chemical stability of the ODN containing amino-protecting groups such as [(9-fluorenylmethyl)oxy]carbonyl (Fmoc), trifluoroacetyl (TFA), and phthaloyl was undertaken. The results indicate that the phthaloyl group provided the best stability for the synthesis of 3' amine-modified ODNs, and the protecting group is cleaved and deprotected in concentrated ammonium hydroxide:40% aqueous methylamine, 1:1, for 5-10 min, at 56 degrees C. The 3'-hydroxypropyl)triglycyl] ODN conjugates were also synthesized from Fmoc- and phthaloyl-protected (hydroxypropyl)triglycine-CPG supports.
authors.affiliation: Triplex Pharmaceutical Corporation, Woodlands, Texas 77380, USA.
authors.forename: H
authors.initials: H
authors.lastname: Vu
authors.forename: N
authors.initials: N
authors.lastname: Joyce
authors.forename: M
authors.initials: M
authors.lastname: Rieger
authors.forename: D
authors.initials: D
authors.lastname: Walker
authors.forename: I
authors.initials: I
authors.lastname: Goldknopf
authors.forename: T S
authors.initials: TS
authors.lastname: Hill
authors.forename: K
authors.initials: K
authors.lastname: Jayaraman
authors.forename: D
authors.initials: D
authors.lastname: Mulvey
mesh_terms: D001483:Base Sequence; D004355:Drug Stability; D005449:Fluorenes / Q000138:chemical synthesis / Q000737:chemistry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis* / Q000737:chemistry*; D010795:Phthalic Acids / Q000138:chemical synthesis / Q000737:chemistry; D011412:Propanolamines / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D005449:Fluorenes; D009838:Oligodeoxyribonucleotides; D010795:Phthalic Acids; D011412:Propanolamines