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Characterization of N7 and N9 alkylated purine analogues by 1H and 13C nmr
ss.oo+ .oo
Terrahedrm Vol. 42. No. 23. pp. 6541 to 6544, 1986 Pnnkd in Great Britain.
e
co4&4020/86 1986 Pergamon Journals
CHARACTERIZATION OF N7 AND N9 ALKYLATED PURINE ANALOGUES BY lH AND 13C NMR Jonas Kjellberg* and Nils Gunnar Johansson* Department of AntIviral Chefaotherapy, Research 6 Development Laboratories Astra Alab AB, S-151 85 SiidertElje, Sweden (Received in UK 16 September 1986) Abstract: derivatives
The use of ‘H and I3 c NMRfor differentiating is described.
N? and N9 alkylated
guanine
Some acyclfc guanosjne analogues show potent antiviral activity: ac$zlovir (g-(2hydroxyethoxymethyl)guanine)l.
buciclovir ((RI-9-(3,Cdihydroxybutyl)guanlr1e)~
and
g-(1,3-dihydroxy-2-propoxymethyl)guanine 3. They are open-chain analogues to guanoslne and they are phosphorylated by herpes virus thymidine kinase4. Recently it has been shown that some H9 alkylated derivatives of 2-aminopurine are substrates for XafIthlne
oxidases.
The synthesis of N9 substltuted purines usually involves alkylation of the unsubstltuted purines in the presence of a base. We have studied the alkylation of various guanine precursors, and have obtained mixtures of primarily N7 and N9 alkylated products6. The compounds are purified by flash chromatography in combination wlth recrvstallization. The regio-isomers, orlginally synthesized by unambiguous pathways, have been characterlzed by UV and NM
methods 7, but In many cases the ultraviolet spectra are not very
distinct. However, the regfo-isomeric N7 and M9 pairs of alkylated guanine and guanine precursors exhibit characteristic shift differences In their 1H and 13C NW
spectra, that
can be used to distinguish the products in the mixtures. By sumnariting the spectroscopic data of purine analogs, prepared by us. we are able to present general rules for 1H and 1% isomr
IHR shifts. The signals of H-8 for the W-
shifted upfield relative to the correspondfng H-8 slgnal for the N7-isomer. The
corresponding NH, sfgnals are shifted downfield for the b-isomer sponding NH, sfgnals for the N7-isomer. The 1%
relative to the corre-
NMR signals of C8 and Cl' of the N9-
isomers are shifted upfield relative to the corresponding sfgnals of the Y7-isomers. On the contrary, the signals of C5 are deshielded relative to those of the N7-alkylated compounds. The difference In the shfft is most pronounced for the C5 slgnal, but the shift differences are easily detected for the other signals as well. Similar 13C. shift differences have been reported for adenfne, hypoxanthine and 6-mercaptopurine regio-isomeric derivativesTe and we have recently reported the use of 15N NW
for similar purposesa. The carbon shlfts have been assigned by 13C-lH spfn couplfng
and with deuterilsl induced 13C shift9.
6541
Ltd.
6542
J. Kra~sm~
and
N.
G.
JOHANSSON
Entty
H-8 7.12 7.87 7.a7 a.08 7.87 a.oa 7.93 8.08 7.98
6~ 17
It7
N?
17
Cl
a.25
H
a.07
H
a.07
a.40 a.36 a.51 a.27 a.21
lob
I7
N9
8.10
9b 101
N9
Cl
6b 9J
N9
a.15
7b 0J
II9
Cl 6b
lr
II9
a.32
5b
Y? a9
7.65
11J
llb
Y?
7.7 7.67
12r
19 N7
7.90
12b 7.68
13r
N9 17
7.80
13b
7.91
14J
119 117
8.08
Mb
lb-1Ob
lla,llb
6543
Characterization of N7 and N9 alkylated purine analogues
NH
2
6.49
Cl’ 43.1
6.05 6.37
117.1 46.2
42.45 6.10
6.40 6.11
6.92
49.99
6.63
46.51
6.64
114.99
43.60 123.53 49.43
6.69
147.97
143.47 149.77
40.46 6.21
127.16 42.36
43.3
6
112.4 115.6
46.5 43.10
107.6
46.20
111.46
47.19
6 12
143.54
12
146.56
10
141.67 110.27
6 6
143.6 139.31
116.66
6 6
143.0 137.7
120.60
43.69
6 147.73
138.6
121.6
42.1 6.53
142.92 119.12
47.1
12a,12b
6
6 6
6.19
6.65
6
6
6.50 6.51
6
6 149.60
115.09
11
6
143.&I 114.95
6
6 145.73
143.47
123.70
46.37
145.56
104.66
11
11
139.92
123.63
40.26
6.96
105.69
10 10
6 145.69
140.16
113.67
43.23
6.62
139.92
113.75
Ref.
11 145.32
105.69
46.39
6.14
139.77
113.80
45.95
143.2
105.96
46.66
6.12 6.46
136.0
114.09
42.57
C8
106.3
46.61 42.79
6.45
c5
10
13a,13b
I
J. KBLLBERG
6544
and N. G.
JOHANSWN
The table shows the 6 values, relative to TMS, for some N9 and N7 substituted purfne derivatives. Apart from the compounds 13a,
13b,
14a and 14b where CDCl, was used
the solvent used in all cases was deuterated CMSO. REFERENCES 1.
H. J. Schaeffer. L. H. Beauchamp, P. de Miranda, G. B. Ellon, D. J. Bauer. P. Collins, Nature (London), 272, 583 (1978). A. Larsson, B. iberg, S. Alenfus, C.-E. Hagberg, N. G. Johansson, B. Lfndborg. G.
2.
Stenlng. Antfmfcrob. Agents Chemother., 23, 664 (1983). 3.
K. 0. Smith, K. S. 6allcuay, W. S. Kennel, K. K. Ogflvfe, B. K. Radatus, Antfmfcrob. Agents Chemother., g,
55 (19821.
4.
A. Larsson. Ph. D. Thesis. Biomedical Center, Uppsala University, 1985, and
5.a)
T. A. Krenftsky, Ii.W. Hall, P. de Miranda, L. M. Beauchamp, H. J. Schaeffer, P. 0.
references therein. Whftew.
Proc. Natl. Acad. Scf. USA, fi, 3209 (1984).
b)
J. C. Martin, G. A. Jeffrey, D. P. C. McGee, M. A. Tipple, 0. F. Smee, T. R.
cl
R. Datema, A.-C. Erfcson, N. 6. Johansson, J. Kjellberg, A. Larsson. Manuscript In
Matthews, J. P. H. Verheyden, J. Med. Chef%, a,
358 (1985).
preparation. 6.
J. Kjellberg. N. G. Johansson. Manuscript submitted for publication to Hucleosfdes 6 Nucleotfdes and references therein.
7.a)
B. Singer. Progress In Muclefc Acid Research and Molecular Biology, 2,
Academic
Press, 219 (1975). b)
J. Zemlfcka. Nucleosfdes d Yucleotfdes, 3, 245 (1984).
c)
K.K. OgflVfe, N. Nguyen-Ba. R. G. Hamilton, Can. J. Chem. 62, 1622 (1984).
d)
H. C. Box, K. T. Lflja, J. L. Alderfer, J.B. French, J. Potfenko, J. Carbohydrates Nucleosldes Nucleotfdes, 6, 255 (1979).
e)
M. T. Chenon, R. J. Pupnlre, 0. M. Grant, R. P. Panrfca, L. B. Townsend, J. Am. Chem. SOC.. z,
4636 (1975).
a.
G. Remaud. J. Kjellberg, H. Bazfn, N. G. Johansson, J. Chattopadhyaya. Manuscript
9.
C.-E. Hagberg. Manuscript presented at the 2nd Int. Conf. on Synthetic Olfgonucleo-
accepted for publication In Tetrahedron. tfdes in Molecular Biology, August 18-24, 1985. 10.
J. Kjellberg, C.-E. Hagberg, A. Maim, J. 0. Nor&, e,
N. 6. Johansson, Acta Chem Stand..
310 (1986).
11.
J. Kjellberg, M. Lfljenberg. N. G. Johansson. Tetrahedron Lett., 27, 877 (1986).
12.
J. Kjellberg. N. G. Johansson, J. Heterocyclfc Chew
23, 625 (19861.
Terrahedrm Vol. 42. No. 23. pp. 6541 to 6544, 1986 Pnnkd in Great Britain.
e
co4&4020/86 1986 Pergamon Journals
CHARACTERIZATION OF N7 AND N9 ALKYLATED PURINE ANALOGUES BY lH AND 13C NMR Jonas Kjellberg* and Nils Gunnar Johansson* Department of AntIviral Chefaotherapy, Research 6 Development Laboratories Astra Alab AB, S-151 85 SiidertElje, Sweden (Received in UK 16 September 1986) Abstract: derivatives
The use of ‘H and I3 c NMRfor differentiating is described.
N? and N9 alkylated
guanine
Some acyclfc guanosjne analogues show potent antiviral activity: ac$zlovir (g-(2hydroxyethoxymethyl)guanine)l.
buciclovir ((RI-9-(3,Cdihydroxybutyl)guanlr1e)~
and
g-(1,3-dihydroxy-2-propoxymethyl)guanine 3. They are open-chain analogues to guanoslne and they are phosphorylated by herpes virus thymidine kinase4. Recently it has been shown that some H9 alkylated derivatives of 2-aminopurine are substrates for XafIthlne
oxidases.
The synthesis of N9 substltuted purines usually involves alkylation of the unsubstltuted purines in the presence of a base. We have studied the alkylation of various guanine precursors, and have obtained mixtures of primarily N7 and N9 alkylated products6. The compounds are purified by flash chromatography in combination wlth recrvstallization. The regio-isomers, orlginally synthesized by unambiguous pathways, have been characterlzed by UV and NM
methods 7, but In many cases the ultraviolet spectra are not very
distinct. However, the regfo-isomeric N7 and M9 pairs of alkylated guanine and guanine precursors exhibit characteristic shift differences In their 1H and 13C NW
spectra, that
can be used to distinguish the products in the mixtures. By sumnariting the spectroscopic data of purine analogs, prepared by us. we are able to present general rules for 1H and 1% isomr
IHR shifts. The signals of H-8 for the W-
shifted upfield relative to the correspondfng H-8 slgnal for the N7-isomer. The
corresponding NH, sfgnals are shifted downfield for the b-isomer sponding NH, sfgnals for the N7-isomer. The 1%
relative to the corre-
NMR signals of C8 and Cl' of the N9-
isomers are shifted upfield relative to the corresponding sfgnals of the Y7-isomers. On the contrary, the signals of C5 are deshielded relative to those of the N7-alkylated compounds. The difference In the shfft is most pronounced for the C5 slgnal, but the shift differences are easily detected for the other signals as well. Similar 13C. shift differences have been reported for adenfne, hypoxanthine and 6-mercaptopurine regio-isomeric derivativesTe and we have recently reported the use of 15N NW
for similar purposesa. The carbon shlfts have been assigned by 13C-lH spfn couplfng
and with deuterilsl induced 13C shift9.
6541
Ltd.
6542
J. Kra~sm~
and
N.
G.
JOHANSSON
Entty
H-8 7.12 7.87 7.a7 a.08 7.87 a.oa 7.93 8.08 7.98
6~ 17
It7
N?
17
Cl
a.25
H
a.07
H
a.07
a.40 a.36 a.51 a.27 a.21
lob
I7
N9
8.10
9b 101
N9
Cl
6b 9J
N9
a.15
7b 0J
II9
Cl 6b
lr
II9
a.32
5b
Y? a9
7.65
11J
llb
Y?
7.7 7.67
12r
19 N7
7.90
12b 7.68
13r
N9 17
7.80
13b
7.91
14J
119 117
8.08
Mb
lb-1Ob
lla,llb
6543
Characterization of N7 and N9 alkylated purine analogues
NH
2
6.49
Cl’ 43.1
6.05 6.37
117.1 46.2
42.45 6.10
6.40 6.11
6.92
49.99
6.63
46.51
6.64
114.99
43.60 123.53 49.43
6.69
147.97
143.47 149.77
40.46 6.21
127.16 42.36
43.3
6
112.4 115.6
46.5 43.10
107.6
46.20
111.46
47.19
6 12
143.54
12
146.56
10
141.67 110.27
6 6
143.6 139.31
116.66
6 6
143.0 137.7
120.60
43.69
6 147.73
138.6
121.6
42.1 6.53
142.92 119.12
47.1
12a,12b
6
6 6
6.19
6.65
6
6
6.50 6.51
6
6 149.60
115.09
11
6
143.&I 114.95
6
6 145.73
143.47
123.70
46.37
145.56
104.66
11
11
139.92
123.63
40.26
6.96
105.69
10 10
6 145.69
140.16
113.67
43.23
6.62
139.92
113.75
Ref.
11 145.32
105.69
46.39
6.14
139.77
113.80
45.95
143.2
105.96
46.66
6.12 6.46
136.0
114.09
42.57
C8
106.3
46.61 42.79
6.45
c5
10
13a,13b
I
J. KBLLBERG
6544
and N. G.
JOHANSWN
The table shows the 6 values, relative to TMS, for some N9 and N7 substituted purfne derivatives. Apart from the compounds 13a,
13b,
14a and 14b where CDCl, was used
the solvent used in all cases was deuterated CMSO. REFERENCES 1.
H. J. Schaeffer. L. H. Beauchamp, P. de Miranda, G. B. Ellon, D. J. Bauer. P. Collins, Nature (London), 272, 583 (1978). A. Larsson, B. iberg, S. Alenfus, C.-E. Hagberg, N. G. Johansson, B. Lfndborg. G.
2.
Stenlng. Antfmfcrob. Agents Chemother., 23, 664 (1983). 3.
K. 0. Smith, K. S. 6allcuay, W. S. Kennel, K. K. Ogflvfe, B. K. Radatus, Antfmfcrob. Agents Chemother., g,
55 (19821.
4.
A. Larsson. Ph. D. Thesis. Biomedical Center, Uppsala University, 1985, and
5.a)
T. A. Krenftsky, Ii.W. Hall, P. de Miranda, L. M. Beauchamp, H. J. Schaeffer, P. 0.
references therein. Whftew.
Proc. Natl. Acad. Scf. USA, fi, 3209 (1984).
b)
J. C. Martin, G. A. Jeffrey, D. P. C. McGee, M. A. Tipple, 0. F. Smee, T. R.
cl
R. Datema, A.-C. Erfcson, N. 6. Johansson, J. Kjellberg, A. Larsson. Manuscript In
Matthews, J. P. H. Verheyden, J. Med. Chef%, a,
358 (1985).
preparation. 6.
J. Kjellberg. N. G. Johansson. Manuscript submitted for publication to Hucleosfdes 6 Nucleotfdes and references therein.
7.a)
B. Singer. Progress In Muclefc Acid Research and Molecular Biology, 2,
Academic
Press, 219 (1975). b)
J. Zemlfcka. Nucleosfdes d Yucleotfdes, 3, 245 (1984).
c)
K.K. OgflVfe, N. Nguyen-Ba. R. G. Hamilton, Can. J. Chem. 62, 1622 (1984).
d)
H. C. Box, K. T. Lflja, J. L. Alderfer, J.B. French, J. Potfenko, J. Carbohydrates Nucleosldes Nucleotfdes, 6, 255 (1979).
e)
M. T. Chenon, R. J. Pupnlre, 0. M. Grant, R. P. Panrfca, L. B. Townsend, J. Am. Chem. SOC.. z,
4636 (1975).
a.
G. Remaud. J. Kjellberg, H. Bazfn, N. G. Johansson, J. Chattopadhyaya. Manuscript
9.
C.-E. Hagberg. Manuscript presented at the 2nd Int. Conf. on Synthetic Olfgonucleo-
accepted for publication In Tetrahedron. tfdes in Molecular Biology, August 18-24, 1985. 10.
J. Kjellberg, C.-E. Hagberg, A. Maim, J. 0. Nor&, e,
N. 6. Johansson, Acta Chem Stand..
310 (1986).
11.
J. Kjellberg, M. Lfljenberg. N. G. Johansson. Tetrahedron Lett., 27, 877 (1986).
12.
J. Kjellberg. N. G. Johansson, J. Heterocyclfc Chew
23, 625 (19861.