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Nucleotides. Part LXXV
Author(s) -
Maier Thomas,
Pfleiderer Wolfgang
Publication year - 2009
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.200900198
Subject(s) - chemistry , moiety , oligomer , trimer , mitsunobu reaction , cytidine , derivative (finance) , stereochemistry , fluorescein , nucleotide , combinatorial chemistry , fluorescence , organic chemistry , dimer , enzyme , biochemistry , financial economics , economics , gene , physics , quantum mechanics
The reactivity of the 2′‐deoxy‐ N 4 ‐(phenoxycarbonyl)cytidine derivatives 3 and 4 with aromatic amines was studied to form new types of urea derivatives (see 5 – 10 ). On the same basis, labeling of 3 and 4 with 5‐aminofluorescein ( 14 ) was achieved to give the conjugates 15 and 17 , respectively ( Scheme 1 ). Treatment of 17 with 2‐(4‐nitrophenyl)ethanol in a Mitsunobu reaction led to double protection of the fluorescein moiety (→ 18 ) and desilylation yielded 19 . Dimethoxytritylation (→ 20 ) and subsequent phosphitylations afforded the new building blocks 21 and 22 . Synthesis of the fully protected trimer 28 was achieved by condensation of 21 with 23 to 26 which after detritylation (→ 27 ) was coupled with 25 to give 28 ( Scheme 2 ). Deprotection of all blocking groups was performed with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in one step to give 29 . The synthesis of the decamer 5′‐d(C Flu CCG GCC CGC)‐3′ ( 33 ) started from 30 which was attached to the solid support and then elongated with 31, 32 , and 22 at the 5′‐terminal end (C Flu =deprotected phosphate derivative of 22 ). Hybridization with the complementary oligomer 5′‐d(G GGC CGG GCG)‐3′ ( 34 ) showed the influence of the fluorescein label on the stability of the duplex.