- Protection of the amino group of adenosine and guanosine derivatives by elaboration into a 2,5-dimethylpyrrole moiety
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(Matrix presented) Protection of the amino group of adenine and guanine nucleosides was effected by heating the substrates in 2,5-hexanedione. The resulting 2,5-dimethylpyrrole adducts were stable toward bases but were hydrolyzed with TFA/H2O to regenerate the amino function.
- Nowak, Ireneusz,Robins, Morris J.
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- Self-complementary hydrogen-bond interactions of guanosine: a hub for constructing supra-amphiphilic polymers with controlled molecular structure and aggregate morphology
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A supra-amphiphilic polymer (SAP) with controlled molecular structures is constructed, in this work, via self-complementary hydrogen bonding of guanosine groups between a hydrophilic block, poly(N-isopropylacrylamide), and a hydrophobic block, poly(ε-caprolactone). By simply changing the mixing ratio of the guanosine-capped hydrophilic and hydrophobic blocks, a series of SAPs with tailored nanostructures are constructed, which can further self-assemble into different nano-aggregates in solution, including spheres, vesicles and large vesicle micelles. The thermo-induced phase transition of the hydrophilic block induces the fusion and aggregation of the nanoparticles into irregular particles upon heating, which further transform to large compound vesicles after cooling.
- Xiao, Qian,Song, Fei,Nie, Wu-Cheng,Wang, Xiu-Li,Wang, Yu-Zhong
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- Pyridine-free and solvent-free acetylation of nucleosides promoted by molecular sieves
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A practical method for the acetylation of purine and pyrimidine nucleosides employing a combination of acetic anhydride and potassium-exchanged molecular sieves is described. Besides the high yields obtained for the acylated nucleosides, the procedure is simple, inexpensive and environmentally benign, avoiding the use of pyridine or co-solvents as additives. Georg Thieme Verlag Stuttgart.
- Sá, Marcus Mandolesi,Meier, Lidiane
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p. 3474 - 3478
(2007/10/03)
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- 2-(N-Acyl) and 2-N-acyl-N6-substituted analogues of adenosine and their affinity at the human adenosine receptors
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A series of 2-(N-acyl) and 2-(N-acyl)-N6-alkyladenosine analogues have been synthesized from the intermediate 2-amino-6-chloroadenosine derivatives (2b and 7) and evaluated for their affinity at the human A 1, A2A, and A3 receptors. We found that 2-(N-acyl) derivatives of adenosine showed relatively low affinity at A 2A and A3 receptors, while the N6-cyclopentyl substituent in 4h and 4i induced high potency [A1 (K i)=20.7 and 31.8 nM respectively] at the A1 receptor and resulted therefore in increased selectivity for this subtype. The general synthetic methods and their binding studies are presented herein.
- Jagtap, Prakash G.,Chen, Zhiyu,Szabo, Csaba,Klotz, Karl-Norbert
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p. 1495 - 1498
(2007/10/03)
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