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New Protected Protecting Groups for the 5′‐Hydroxy Group of Deoxynucleosides by Use of 2‐(Hydroxymethyl)‐ and 2‐[(Methylamino)methyl]benzoyl Skeletons and Oxidatively Cleavable Tritylthio and (4‐Methoxytrityl)thio Groups
Author(s) -
Seio Kohji,
Utagawa Eri,
Sekine Mitsuo
Publication year - 2004
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200490207
Subject(s) - chemistry , substituent , hydroxymethyl , stereochemistry , thio , protecting group , intramolecular force , organic chemistry , alkyl
The new protecting groups 1a , b and 2a , b were developed for the 5′‐OH group of deoxynucleosides by utilizing the unique characters of the sulfenate and sulfenamide linkage. These new protecting groups have a 2‐(hydroxymethyl)benzoyl or 2‐[(methylamino)methyl]benzoyl skeleton whose hydroxy O‐atom or amino N‐atom was blocked with a tritylthio‐type substituent. They are removable by intramolecular cyclization following the oxidative hydrolysis of the tritylthio‐type substituents under mildly oxidative conditions ( Schemes 3 and 6 ). Among them, 2‐{{[(4‐methoxytrityl)sulfenyl]oxy}methyl}benzoyl (MOB; 2b ) was found to be the most preferable for protection of the 5′‐OH function of deoxynucleosides. MOB can be introduced at the 5′‐OH groups of various deoxynucleosides without the protection of the 3′‐OH functions ( Scheme 5 ). The applicability of the MOB group to a new oligodeoxynucleotide synthesis protocol without acid treatment was demonstrated by the solid‐phase synthesis of a tetrathymidylate ( Scheme 8 ).