141018-30-6Relevant articles and documents
Linear and convergent approaches to 2-substituted adenosine-5′-N-alkylcarboxamides
Foitzik, Richard C.,Devine, Shane M.,Hausler, Nicholas E.,Scammells, Peter J.
experimental part, p. 8851 - 8857 (2009/12/26)
Herein we report both linear and convergent pathways for the preparation of 2-alkynyl substituted adenosine-5′-N-ethylcarboxamides via the versatile synthetic intermediate, 2-iodoadenosine-5′-N-ethylcarboxamide (13). The linear approach afforded 13 in an overall yield of 30% from guanosine over eight synthetic steps. The convergent approach was shorter, but proceeded in lower yield (five steps, 20% yield). Both approaches compare favourably with previously reported syntheses of 13, which has been prepared in 15% yield from guanosine over nine steps. 2-Iodoadenosine-5′-N-ethylcarboxamide (13) was subsequently converted to HENECA (2) and PHPNECA (3) to exemplify the utility of this approach for the preparation of?potent A2A adenosine receptor agonists. The linear approach was also amenable to the synthesis of 2-fluoropurine ribosides, which were subsequently elaborated into 2-alkylaminoadenosine-5′-N-ethylcarboxamides. Furthermore, both of these synthetic approaches are readily amenable to the synthesis of adenosine analogues with varied 2-, 6- and 5′-substitution patterns.
Nucleosides and Nucleotides. 112. 2-(1-Hexyn-1-yl)adenosine-5'-uronamides: A New Entry of Selective A2 Adenosine Receptor Agonists with Potent
Homma, Hiroshi,Watanabe, Yohko,Abiru, Toichi,Murayama, Toshihiko,Nomura, Yasuharu,Matsuda, Akira
, p. 2881 - 2890 (2007/10/02)
Chemical modifications of the potent A2 adenosine receptor agonist 2-(1-hexyn-1-yl)adenosine (7, 2-HA) at the 5'-position have been carried out to find more potent and selective A2 agonists. these analogues were evaluated for adenosine A1 and A2 receptor binding affinity in rat brain tissues and antihypertensive effects in spontaneously hypertensive rats (SHR).Among the series of compounds, 2-(1-hexyn-1-yl)adenosine-5'-N-cyclopropyluronamide (16d) had the most potent affinity to the A2 receptor with a Ki of 2.6 nM, which is essentially the same as that of the parent agonist, 2-HA.However, the most selective agonist for the A2 receptor was 2-(1-hexyn-1-yl)adenosine-5'-N-methyluronamide (16b) with a Ki of 11 nM and a 162-fold selectivity.The N-alkyl substituents of 5'-uronamide derivatives did not seem to potentiate the A2 binding affinity but drastically reduced the A1 affinity compared with the parent 2-HA.Therefore, the A1/A2 selectivity was consequently increased.Other 5'-deoxy-5'-substituted derivatives of 2-HA such as the chloro (20), carboxamide (27, 28), sulfonamide (29), urea (30), and thiourea (22) analogues were also prepared.Among these nucleosides, no active compounds with potent or selective affinities to both receptors were found except 20.Although glycosyl conformations and sugar-puckering of these nucleosides were studied by 1H NMR spectroscopy, there were no positive correlations between active and inactive agonists. 2-(1-Hexyn-1-yl)adenosine-5'-uronamide (16a) and 16d had a potent hypotensive effect at ED30 values of 0.18 and 0.17 μg/kg, respectively, upon iv administration to anesthetized SHR.
