title: Modification of the thiourea linkage of a fluorescein-oligonucleotide conjugate to a guanidinium motif during ammonia deprotection.
abstract: During the preparation of a fluorescent conjugate based on a manganese cationic porphyrin carboxylate derivative linked to a 5'-amino-3'-fluorescein-labeled oligonucleotide, we observed the chemical transformation of the thiourea linkage to a guanidinium function during the deprotection in ammonia of the 3'-fluorescein-oligonucleotide from CPG support. We also noted a secondary reactivity of the activated carboxylate group of the metalloporphyrin precursor with the fluorescein entity of the conjugated oligonucleotide.
authors.affiliation: Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France.
authors.forename: I
authors.initials: I
authors.lastname: Dubey
authors.forename: G
authors.initials: G
authors.lastname: Pratviel
authors.forename: B
authors.initials: B
authors.lastname: Meunier
mesh_terms: D000641:Ammonia / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D005452:Fluoresceins / Q000737:chemistry*; D006146:Guanidines / Q000138:chemical synthesis*; D008345:Manganese / Q000737:chemistry; D013058:Mass Spectrometry; D008665:Metalloporphyrins / Q000737:chemistry; D015394:Molecular Structure; D009841:Oligonucleotides / Q000737:chemistry*; D013053:Spectrophotometry; D013890:Thiourea / Q000031:analogs & derivatives*
chemical_list: D005452:Fluoresceins; D006146:Guanidines; D008665:Metalloporphyrins; D009841:Oligonucleotides; D008345:Manganese; D000641:Ammonia; D013890:Thiourea; D016650:Fluorescein-5-isothiocyanate