References
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- Drabikowska , A. K. , Lissowska , L. , Veres , Z. and Shugar , D. 1987 . Biochem. Pharmacol. , 36 : 4125 b) S. H. Chu, Z. Y. Weng, Z. H. Chen, E. C. Rowe, E. Chu, F. N. M. Naguib, M. H. el Kouni, S. Cha and M. Y. Chu, Nucleosides & Nucleotides 7, 91 (1988). c) Z. Veres, A. Szabolcs, I. Szinai, G. Dénes, M. Kajtár-Peredy and L. Ötvös, Biochem. Pharmacol., 34, 1737 (1985). d) Z. Veres, A. Neszmélyi, A. Szabolcs and G. Dénes, Eur. J. Biochem., 178, 173 (1988). e) Z. Veres, A. Neszmélyi, A. Szabolcs, A. I. Kiss, and G. Dénes, Arch. Biophys. Biochem., 286, 1 (1991)
- Ueda , T. 1985 . Nucleosides & Nucleotides , 4 : 67 b) Y. Yamagata, K. Tomita, H. Usui, T. Sano and T. Ueda, Chem. Pharm. Bull., 37, 1971 (1989).
- A preliminary account of portions of this work was presented at the 201st ACS National Meeting, Atlanta, Georgia, April 1991: See B. A. Otter, S. A. Patil, M. R. Spada, R. S. Klein and L. A. Jelicks, Abstr. CARB 25.
- Sasson , I. M. , Gagnier , R. P. and Otter , B. A. 1983 . J. Heterocycl. Chem. , 20 : 753
- Otter , B. A. , Sasson , I. M. and Gagnier , R. P. 1981 . J. Org. Chem. , 47 : 508
- Otter , B. A. and Sodum , R. S. unpublished results
- Sodum , R. S. and Otter , B. A. 1986 . Nucleosides & Nucleotides , 5 : 385 As far as we know, 9 was the first example of a cyclonucleoside in which a methano group joins O5′ to a base carbon atom. A recent attempt to construct a 1-β-D-ribofuranosylbenzene incorporating the equivalent of an O5′,6-methano linkage (via an intramolecular Carylation reaction) was not successful. See Y. Araki, E. Mokubo, N, Kobayashi, J. Nagasawa, and Y. Ishido, Tetrahedron Lett., 30, 1115 (1989).
- Crisp , G. T. and Flynn , B. L. 1990 . Tetrahedron Lett. , 31 : 1347
- Scott , W. J. , Crisp , G. T. and Stille , J. K. 1986 . J. Am. Chem. Soc. , 106 : 4630 1984, W. J. Scott and J. K. Stille, J. Am. Chem. Soc., 108, 3033 (1986).
- Saenger , W. 1984 . “ Principles of Nucleic Acid Structure ” . New York : Springer-Verlag . See also Abbreviations and Symbols for the Description of Conformation of polynucleotide chains, Eur. J. Biochem.131, 9 1983.
- Rosemeyer , H. , Tóth , G. and Seela , F. 1989 . Nucleosides & Nucleotides , 6 : 587
- A complete description of the furanose ring conformation must await a more exhaustive analysis of the vicinal coupling constants. It is noted that the sum (6. 9 Hz) of Jv. 2. (4. 2 Hz) and J3′,4′. (2. 7 Hz) for the title compound 4 is about 3 Hz less than that generally seen for unconstrained anti pyrimidine-β-D-ribonucleosides, and that J2′. 3′ (4. 8 Hz) is slightly smaller than usual14. The furanose conformation of the isopropylidene compounds evidently differs from that of the deblocked compounds 4 and 16 because J3′. 4′ decreases to < 1 Hz, J1′. 2′ decreases to an average of 1. 5 Hz, and J2′. 3′ increases to an average of 6. 1 Hz.
- Davies , D. B. 1978 . Prog. Nucl. Magn. Reson. Spectr. , 12 : 135
- Davies , D. B. , Rajani , P. , MacCoss , M. and Danyluk , S. S. 1985 . Magn. Reson. in Chem. , 23 : 72
- The coupling constant 3JC2. H1′ could not be obtained for the parent compound 4 because the C2 and C6 resonances overlap in the coupled spectrum. Davies and coworkers17 also proposed that the magnitude of the geminal coupling constant 1JC1′. H1′ varies in Karplus fashion as a function of the dihedral angle C2,N1,C1′,H1′. The average value of 173 Hz found for compounds 4, 8, 15, 16 and 17 corresponds to a dihedral angle of about 25°, a somewhat smaller value than that indicated by 3JC2. H1′, but still closer to that expected for II than for III. However, the geminal method may not be entirely reliable because some of our compounds (the syn-nucleosides 5 and 13) show couplings (165 Hz and 163 Hz, respectively) that are considerably smaller than the values predicted by the Karplus-type equation proposed17. In fact, all of these J/dihedral angle relationships should be used with caution, particularly in the absence of other evidence. Thus, using a set of Karplus parameters for 3JC2. H1′ that preceded those of reference 15, we previously proposed8 a conformation akin to III for the imidazole cyclonucleoside 9; our subsequent NOE studies show that the basic conformation of 9 is essentially the same as that of the O5′,6- methanouridines, namely II.
- Davies , D. B. , MacCoss , M. and Danyluk , S. S. 1984 . J. Chem. Soc. Chem. Commun. , 536
- Yoshimura , Y. , Matsuda , A. and Ueda , T. 1989 . Chem. Pharm. Bull. , 37 : 660 and references therein
- The x values for the carbon-bridged cyclonucleosides shown in figure 3 are derived from X-ray crystallographic determinations. Since the compounds are rigid, the solution values are expected to be essentially unaltered. Indeed, analysis of the long-range coupling constants shown by the 5′R-and s-hydroxy derivatives of cyclo-nucleoside 3 suggested20 a x value of −120°, which is very close to the value of − 117° found by crystallography3b for the parent 6,5′-methano nucleoside 3.
- Sasson , I. M. and Otter , B. A. 1987 . J. Heterocycl. Chem. , 24 : 1439
- Molecular modeling was done with the QUANTA/CHARMm Version 3. 0 from Polygen Corporation, and the Adopted Basis Newton-Raphson method was used for energy minimizations.
- Otter , B. A. , Taube , A. and Fox , J. J. 1971 . J. Org. Chem. , 36 : 1251
- Otter , B. A. , Falco , E. A. and Fox , J. J. 1976 . J. Org. Chem. , 41 : 3133
- Cacchi , S. , Morera , E. and Ortar , G. 1984 . Tetrahedron Lett. , 25 : 4821
- Hirota , K. , Yamada , Y. , Kitade , Y. and Senda , S. 1981 . J. Chem. Soc. Perkin I , 2943
- In view of the recent report that certain 1′,2′-seco nucleoside tosylates unexpectedly undergo inter- rather than intramolecular cyclization27, a reviewer has suggested that 8 might really be a symmetrical cyclic dimer formed when the 5′-hydroxyl groups of two molecules of 6 (R = H) attack each other's methylene groups. However, this possibility has been ruled out by the observation of the MH+ peak expected for the monomeric product 8. In addition, inspection of Dreiding models strongly suggests that such dimers would show different patterns of NOEs and J4′. 5′(5′') coupling constants than those actually observed for 8 and the compounds derived from it.
- Cichy , A. F. , Saibaba , R. , El Subbagh , H. I. , Panzica , R. P. and Abushanab , E. 1991 . J. Org. Chem. , 56 : 4653
- Values given for coupling constants for 13 were checked by spectral simulations
- HPLC also shows that the product decomposes on longer heating in 80% acetic acid to give more polar products. These have not been investigated
- Triflate 14 is hydrolyzed smoothly at this pH (isosbestic points at 251 and 290nm) to give the 5-hydroxy nucleoside 8. Under comparable conditions (ca. 2 × 10−4M nucleoside, 7 mM sodium hydroxide), triflate 14 is hydrolyzed about seven times more slowly than the acetate 17.
- In this case, the shielding properties of the neighboring formyloxy group evidently cause H5′s to resonate downfield of H5′R.