- Email: [email protected]
Nucleosides and related substances
263
NOTES
tion from ethanol (approximately 17 parts) gave benzyl @arabinopyranoside (59.7 g, 7533, m.p. 171-172.5”, [cY]~ +208.6” (c 0.4, water). The experiments recorded in Table I were performed by essentially the above method, with appropriate adjustments in the concentration of hydrogen chloride. ACKNOWLEDGMENTS
I am indebted to Dr. V. C. Barry and Dr. J. F. O’Sullivan for helpful discussion, and to Mr. G. McSherry for technical assistance. This investigation was supported
financially by May and Baker Ltd., Dagenham, England, and Irish Hospitals Trust Ltd. Laboratories of the Medical Researclt Council of Ireland, Trinity
CoUege,
Dublin
JOAN E. MCCORMICK
2 (Ireiand)
REFERENCES 1 2 3 4
H. G. FLETCHER, JR., Merhods Cmbohydrote Chem., 2 (1963) 386. C. E. BALLOU, S. ROSEMAN, AND K. P. LINK, J. Am. Chem. Sot., 73 (1951) 1140. F. WOLD, J. Org. Chem., 26 (1961) 197. E. FISCHERANDL.BEENSCH, Ber.,27 (1894)2478.
Received January 4th, 1967) Carbohyd. Res.. 4 (1967) 262-263
Nucleosides and related substances Part VI’. The synthesis of 9-a-D-ribofuranosyladenine
Naturally
occurring
nucleosides
and nucleic
(a-adenosine)
acid-nucleosides
generally
have
the aglycon and the hydroxyl group at C-2 of the carbohydrate moiety in trans relationship. Only a few nucleosides having the cis relationship (a-nucleosides) have in certain vitamins’, and in yeast been found, for example, in spongonucleosidesl, ribonucleic acid3. a-Nucleosides are of increasing interest from the chemical and biological point of view, and their chemical synthesis has recently been investigated4. The present paper describes a new synthesis of 9-a-D-ribofkranosyladenine (a-adenosine). Condensation of 2,3,5-tri-O-acetyl-D-ribofuranosyl bromide with 6-benzamidopurine was carried out in N,N-dimethylformamide containing phosphorus pentaoxide, and a-adenosine (4-5x) was successfully isolated from the reaction *For Part V, see Ref. 7 Carbohyd.
Res., 4 (1967) 263-266
NOTES
264
mixture. In the n.m.r. spectrum of a-adenosine, the H-l ’ signal appeared at 6 6.38 (doublet, .7r,,2. 4.8 c.P.s.), whereas that of 9-/I-D-ribofuranosyladenine (adenosine) appeared at 6 6.02 (doublet, .I1321 5.9 c.P.s.). Other peaks in the spectrum were similar to those of adenosine, with a slight difference of the chemical shift of the H-8 signal. The H-2 signal of both of the anomers appeared at 6 8.05, but the H-8 signal of a-adenosine appeared at S 8.32, and that of adenosine at 6 8.25. Similar observations were also made with the picrates: the H-l ’ signal of a-adenosine picrate and adenosine picrate appeared at 6 6.36 (doublet, JL,,2, 5.3 c.p.s.) and 6 5.99 (doublet, .ii,,2, 5.5 c.P.s.), respectively. The infrared spectrum of a-adenosine picrate had essentially the same absorption peaks as that of adenosine picrate, but a slight difference was found in the 810-850 cm’-’ region, which may be due to the C-H-deformation vibration at the anomeric carbon atom’. The position of substitution (N-9) of the adenine residue in or-adenosine was established on the basis of the ultraviolet absorption characteristics in different solvent@. The a-D configuration was supported by the plain, positive, o.r.d. curve. All of these data support the structure of a-adenosine for the substance showing Rodenine0.47. In addition to the method described in the experimental part, two other procedures have been tested for the synthesis of a-adenosine. Firstly, the reaction of 2,3,5D-i-O-acetyl-D-ribofuranose or 2,3,5-tri-O-benzoyl-/I-D-ribofuranose with 6-benzamidopurine, when performed in NJWimethylformamide containing phosphorus pentaoxide according to the procedure reported previously’, yielded adenosine and a-adenosine in yields of 10 and l-2%, respectively_ Secondly, the fusion reaction of l-O-acetyl-2,3,5-tri-O-benzoyl-/I-D-ribofuranose with 6-benzamidopurine in the presence of zinc chloride’ gave only a trace of a-adenosine (detected chromatographitally), adenosine being the main product. The mechanism of the formation of a-adenosine in the Koenigs-Knorr reaction described above is still unknown, but it is of interest to note that Shimizu and Miyakig isolated 3-N-alkylpurines as intermediates in the formation of 9-N-alkylpurines by the reaction of purines with alkyl halides, and the same observation was also made with 9-N-ribosylpurines. A similar mechanism might apply in the formation of a-adenosine in the present work. This is partly supported by the fact that the reaction of2,3,5-tri-O-acetyl-D-ribofuranosyl bromide with theophylline gave neither 7-a-D- nor 9-a-D-ribofuranosyltheophylline. It is also of interest that no nucleoside was detected when 2,3,4,6-tetra-U-acetyl-a-D-glucopyranosyl bromide was used in place of 2,3,5-tri-O-acetyl-D-ribofuranosyl bromide in this procedure. ExPERlMENTAL
N.m.r. spectra were recorded at 60 Mc.p.s. with a Varian A-60 spectrometer at its normal operating temperature. Chemical shifts are given on the 6 scale in parts per million (p.p.m.) downfield displacement from sodium 2,2-dimethyl-2-silapentane-5sulphonate (6 0.00, internal standard for solutions in deuterium oxide), or from tetramethylsilane (6 0.00, internal standard for solutions in dimethyl sulphoxide-ds). Carboltyd Res., 4
(1967) 263-266
NOTES
266
described above, and an anomeric mixture of 9-D-ribofuranosyladenines was found to be present, mainly in the aqueous layer. Adenosine, m.p. and mixed m.p. 231-232”, (21% yield); c+adenosine (4%) was isolated as a syrup. The infrared spectrum of the syrupwas icIenticaI with that ofcr-adenosineobtainedabove.
Reaction of 2,3,.5-Pi-0-acetyl-D-ribofuranosyl bromide (1)with theophylline (4). Condensation of 1 with4, in a manner similar to that described above, afforded only 7-/3-D-ribofuranosyltheophylline (16x), m.p. 191-192”, [a]kl + 10” (c 0.5, water); e*: 272 rnp (E 8.7 x 103). And. Calc. for C12H16N406 - H,O: C, 43.60; H, 5.49; N, 16.96. Found: C, 43.34; H, 5.48; N, 17.34. The water of crystallization was lost on drying for 2 h at 100° in vacua. Laboratory
Department Kyoto
of Biochemistry,
of Agriculturai Chemistry,
University,
Kyoto
(Japan)
KONOSHIN SHIGEHIRO FUMIYA
ONODERA HIRANO MAXJDA
REFERENCES 1 W. BERGMANN AND R. 3. FEENY, J. Am. Chem. SOL, 72 (1950) 2809, J. Org. Chem., 16 (1951) 981; W. BERGMANN AND D. C. BURKE, J. Org. Chem., 20 (1955) 1501, Angelo. Chem., 67 (1955) 127. 2 N. G. BRINK AND K. FOLKERS, J. Am. Chem. Sot., 74 (1952); F. W. HOLLY, C. H. SHUNK, E. W. PEER, J. J. CAHILL, J. B. LAVIGNE, AND K. FOLKERS, J. Am. Chem. Sot., 74 (1952) 4521; A. W. JOHNSON,G. W. MILLER, J. A. FRILLS,AND A. R. TODD, J. Chem. Sot., 3061 (1953); W. FRIEDERICH AND K. BERNHAIJER,Angelo. Chem., 68 (1956) 580, Ber., 89 (1958) 250; J. A. MONTGOMERY AND H. J. THOMAS, J. Am. Chem. Sot., 87 (1965) 5442. 3 H. G. GASSEN AND H. J. THOMAS, J. Am. Chem. Sot., 87 (1965) 244. 4 R. S. WFUGHT, G. M. TENER, AND H. G. KHORANA, .l. Am. Chem. Sot., 80 (1958) 2004; K. ONODERA, S. HXRANO, AND F. MASUDA, Tetrahedron Letters, (1966) 2189; T. NAITO AND T. KAWAKAMI, Chem. Pharm. Bull. (Tokyo), 10 (1962) 627; L. PICHAT, P. D~JFAY, AND Y. LAMORE, Compt. Rend., 259 (1964) 2458; K. ONODERA, S. HIRANO, H. FUKUMI, AND F. MASUDA, Carbohyd. Res., 1 (1965) 254, and references cited therein. 5 H. SPEDDING, Aduan. Carbohydrate Chem., 19 (1964) 23. 6 E. CHARGAFF AND J. N. DAVIDSON, The Nucleic Acids, Vol. 1, Academic Press, New York, 1955, p. 509. 7 K. ONODERA,S.HJRANO,N.KASHIMURA, F. MASUDA,T. YN~A,AND N. MIYAZAKI, J. Org. Chem., 31 (1966) 1291. 8 K. ONODERA, S. HIRANO, AND H. FUKUMI, Agr. Biol. Chem. (Tokyo), 28 (1964) 173. 9 B. SHIMIZU AND M. MIYAKI, Chem. Ind. (London), (1966) 664. 10 E. RECONDO AND H. RINDERKNECHT, Web. Chim. Acta, 42 (1959) 1171. (Received August 24th, 1966; in revised form, December 7th, 1966) Carbohyd. Res., 4 (1967) 263-266
NOTES
tion from ethanol (approximately 17 parts) gave benzyl @arabinopyranoside (59.7 g, 7533, m.p. 171-172.5”, [cY]~ +208.6” (c 0.4, water). The experiments recorded in Table I were performed by essentially the above method, with appropriate adjustments in the concentration of hydrogen chloride. ACKNOWLEDGMENTS
I am indebted to Dr. V. C. Barry and Dr. J. F. O’Sullivan for helpful discussion, and to Mr. G. McSherry for technical assistance. This investigation was supported
financially by May and Baker Ltd., Dagenham, England, and Irish Hospitals Trust Ltd. Laboratories of the Medical Researclt Council of Ireland, Trinity
CoUege,
Dublin
JOAN E. MCCORMICK
2 (Ireiand)
REFERENCES 1 2 3 4
H. G. FLETCHER, JR., Merhods Cmbohydrote Chem., 2 (1963) 386. C. E. BALLOU, S. ROSEMAN, AND K. P. LINK, J. Am. Chem. Sot., 73 (1951) 1140. F. WOLD, J. Org. Chem., 26 (1961) 197. E. FISCHERANDL.BEENSCH, Ber.,27 (1894)2478.
Received January 4th, 1967) Carbohyd. Res.. 4 (1967) 262-263
Nucleosides and related substances Part VI’. The synthesis of 9-a-D-ribofuranosyladenine
Naturally
occurring
nucleosides
and nucleic
(a-adenosine)
acid-nucleosides
generally
have
the aglycon and the hydroxyl group at C-2 of the carbohydrate moiety in trans relationship. Only a few nucleosides having the cis relationship (a-nucleosides) have in certain vitamins’, and in yeast been found, for example, in spongonucleosidesl, ribonucleic acid3. a-Nucleosides are of increasing interest from the chemical and biological point of view, and their chemical synthesis has recently been investigated4. The present paper describes a new synthesis of 9-a-D-ribofkranosyladenine (a-adenosine). Condensation of 2,3,5-tri-O-acetyl-D-ribofuranosyl bromide with 6-benzamidopurine was carried out in N,N-dimethylformamide containing phosphorus pentaoxide, and a-adenosine (4-5x) was successfully isolated from the reaction *For Part V, see Ref. 7 Carbohyd.
Res., 4 (1967) 263-266
NOTES
264
mixture. In the n.m.r. spectrum of a-adenosine, the H-l ’ signal appeared at 6 6.38 (doublet, .7r,,2. 4.8 c.P.s.), whereas that of 9-/I-D-ribofuranosyladenine (adenosine) appeared at 6 6.02 (doublet, .I1321 5.9 c.P.s.). Other peaks in the spectrum were similar to those of adenosine, with a slight difference of the chemical shift of the H-8 signal. The H-2 signal of both of the anomers appeared at 6 8.05, but the H-8 signal of a-adenosine appeared at S 8.32, and that of adenosine at 6 8.25. Similar observations were also made with the picrates: the H-l ’ signal of a-adenosine picrate and adenosine picrate appeared at 6 6.36 (doublet, JL,,2, 5.3 c.p.s.) and 6 5.99 (doublet, .ii,,2, 5.5 c.P.s.), respectively. The infrared spectrum of a-adenosine picrate had essentially the same absorption peaks as that of adenosine picrate, but a slight difference was found in the 810-850 cm’-’ region, which may be due to the C-H-deformation vibration at the anomeric carbon atom’. The position of substitution (N-9) of the adenine residue in or-adenosine was established on the basis of the ultraviolet absorption characteristics in different solvent@. The a-D configuration was supported by the plain, positive, o.r.d. curve. All of these data support the structure of a-adenosine for the substance showing Rodenine0.47. In addition to the method described in the experimental part, two other procedures have been tested for the synthesis of a-adenosine. Firstly, the reaction of 2,3,5D-i-O-acetyl-D-ribofuranose or 2,3,5-tri-O-benzoyl-/I-D-ribofuranose with 6-benzamidopurine, when performed in NJWimethylformamide containing phosphorus pentaoxide according to the procedure reported previously’, yielded adenosine and a-adenosine in yields of 10 and l-2%, respectively_ Secondly, the fusion reaction of l-O-acetyl-2,3,5-tri-O-benzoyl-/I-D-ribofuranose with 6-benzamidopurine in the presence of zinc chloride’ gave only a trace of a-adenosine (detected chromatographitally), adenosine being the main product. The mechanism of the formation of a-adenosine in the Koenigs-Knorr reaction described above is still unknown, but it is of interest to note that Shimizu and Miyakig isolated 3-N-alkylpurines as intermediates in the formation of 9-N-alkylpurines by the reaction of purines with alkyl halides, and the same observation was also made with 9-N-ribosylpurines. A similar mechanism might apply in the formation of a-adenosine in the present work. This is partly supported by the fact that the reaction of2,3,5-tri-O-acetyl-D-ribofuranosyl bromide with theophylline gave neither 7-a-D- nor 9-a-D-ribofuranosyltheophylline. It is also of interest that no nucleoside was detected when 2,3,4,6-tetra-U-acetyl-a-D-glucopyranosyl bromide was used in place of 2,3,5-tri-O-acetyl-D-ribofuranosyl bromide in this procedure. ExPERlMENTAL
N.m.r. spectra were recorded at 60 Mc.p.s. with a Varian A-60 spectrometer at its normal operating temperature. Chemical shifts are given on the 6 scale in parts per million (p.p.m.) downfield displacement from sodium 2,2-dimethyl-2-silapentane-5sulphonate (6 0.00, internal standard for solutions in deuterium oxide), or from tetramethylsilane (6 0.00, internal standard for solutions in dimethyl sulphoxide-ds). Carboltyd Res., 4
(1967) 263-266
NOTES
266
described above, and an anomeric mixture of 9-D-ribofuranosyladenines was found to be present, mainly in the aqueous layer. Adenosine, m.p. and mixed m.p. 231-232”, (21% yield); c+adenosine (4%) was isolated as a syrup. The infrared spectrum of the syrupwas icIenticaI with that ofcr-adenosineobtainedabove.
Reaction of 2,3,.5-Pi-0-acetyl-D-ribofuranosyl bromide (1)with theophylline (4). Condensation of 1 with4, in a manner similar to that described above, afforded only 7-/3-D-ribofuranosyltheophylline (16x), m.p. 191-192”, [a]kl + 10” (c 0.5, water); e*: 272 rnp (E 8.7 x 103). And. Calc. for C12H16N406 - H,O: C, 43.60; H, 5.49; N, 16.96. Found: C, 43.34; H, 5.48; N, 17.34. The water of crystallization was lost on drying for 2 h at 100° in vacua. Laboratory
Department Kyoto
of Biochemistry,
of Agriculturai Chemistry,
University,
Kyoto
(Japan)
KONOSHIN SHIGEHIRO FUMIYA
ONODERA HIRANO MAXJDA
REFERENCES 1 W. BERGMANN AND R. 3. FEENY, J. Am. Chem. SOL, 72 (1950) 2809, J. Org. Chem., 16 (1951) 981; W. BERGMANN AND D. C. BURKE, J. Org. Chem., 20 (1955) 1501, Angelo. Chem., 67 (1955) 127. 2 N. G. BRINK AND K. FOLKERS, J. Am. Chem. Sot., 74 (1952); F. W. HOLLY, C. H. SHUNK, E. W. PEER, J. J. CAHILL, J. B. LAVIGNE, AND K. FOLKERS, J. Am. Chem. Sot., 74 (1952) 4521; A. W. JOHNSON,G. W. MILLER, J. A. FRILLS,AND A. R. TODD, J. Chem. Sot., 3061 (1953); W. FRIEDERICH AND K. BERNHAIJER,Angelo. Chem., 68 (1956) 580, Ber., 89 (1958) 250; J. A. MONTGOMERY AND H. J. THOMAS, J. Am. Chem. Sot., 87 (1965) 5442. 3 H. G. GASSEN AND H. J. THOMAS, J. Am. Chem. Sot., 87 (1965) 244. 4 R. S. WFUGHT, G. M. TENER, AND H. G. KHORANA, .l. Am. Chem. Sot., 80 (1958) 2004; K. ONODERA, S. HXRANO, AND F. MASUDA, Tetrahedron Letters, (1966) 2189; T. NAITO AND T. KAWAKAMI, Chem. Pharm. Bull. (Tokyo), 10 (1962) 627; L. PICHAT, P. D~JFAY, AND Y. LAMORE, Compt. Rend., 259 (1964) 2458; K. ONODERA, S. HIRANO, H. FUKUMI, AND F. MASUDA, Carbohyd. Res., 1 (1965) 254, and references cited therein. 5 H. SPEDDING, Aduan. Carbohydrate Chem., 19 (1964) 23. 6 E. CHARGAFF AND J. N. DAVIDSON, The Nucleic Acids, Vol. 1, Academic Press, New York, 1955, p. 509. 7 K. ONODERA,S.HJRANO,N.KASHIMURA, F. MASUDA,T. YN~A,AND N. MIYAZAKI, J. Org. Chem., 31 (1966) 1291. 8 K. ONODERA, S. HIRANO, AND H. FUKUMI, Agr. Biol. Chem. (Tokyo), 28 (1964) 173. 9 B. SHIMIZU AND M. MIYAKI, Chem. Ind. (London), (1966) 664. 10 E. RECONDO AND H. RINDERKNECHT, Web. Chim. Acta, 42 (1959) 1171. (Received August 24th, 1966; in revised form, December 7th, 1966) Carbohyd. Res., 4 (1967) 263-266