Synthesis of New 2-Substituted 6-Hydroxy-8-azapurines (8-Azahypoxanthines)
447
TABLE 2. 1H NMR Spectra of 2-({[3-(2-Chlorobenz)yl-7-hydroxy-3H-[1,2,3]triazolo[4,5-d]pyrimidin-5-yl]methyl}sulfanil)-N-arylacetamides
(XXI – XXX)
Proton chemical shift d, ppm
Compound
–CH3
–CH2CH3 (a)–CH2
(b)–CH2
(c)–CH2
Harom
–NH
–OH
12.62 s
XXI
2.18 s (o–CH3)
2.25 s (n-CH3)
–
–
–
3.52 s
3.45 s
3.50 s
3.88 s
3.83 s
3.88 s
5.72 s
5.64 s
5.72 s
7.03 – 7.51 m
7.06 – 7.51 m
6.91 – 7.52 m
9.28 s
9.82 s
9.20 s
XXII
XXIII
12.60 s
12.61 s
2.15 s (o-CH3)
2.23 s (p-CH3)
XXIV
2.10 s (6H, o-CH3)
2.22 s (3H, p-CH3)
–
3.49 s
3.88 s
5.80 s
6.86 – 7.52 m
9.20 s
12.65 s
XXV
1.11 t (o-CH2CH3)
3.78 s (o-OCH3)
3.73 s (p-OCH3)
1.31 t (p-OCH2CH3)
–
2.57 q
3.52 s
3.60 s
3.45 s
3.43 s
3.47 s
3.55 s
3.87 s
3.83 s
3.85 s
3.83 s
3.84 s
3.85 s
5.73 s
5.61 s
5.68 s
5.68 s
5.68 s
5.77 s
7.11 – 7.51 m
6.82 – 7.95 m
6.83 – 7.50 m
6.81 – 7.50 m
7.07 – 7.53 m
7.28 – 7.73 m
9.28 s
9.11 s
9.80 s
9.76 s
9.97 s
9.52 s
12.65 s
12.63 s
12.63 s
12.60 s
12.61 s
12.65
XXVI
XXVII
XXVIII
XXIX
XXX
–
–
3.99 q
–
–
–
sibility of interacting with electrophilic molecules. The max-
imum negative charge (calculated value, –0.355) is concen-
trated at the carbonyl oxygen atom, which agrees with the
electrostatic potential distribution in the compound under
consideration. Apparently, the synthesized 8-azahypoxan-
thines are rather polar compounds, as evidenced by a rela-
tively high calculated dipole moment (m = 3.18 D).
tilled off in vacuum to leave the target ester (oily liquid),
which can be used without additional purification. The esters
are analyzed by TLC on plates eluted with a methylene chlo-
ride – n-hexane (18 : 1) solvent mixture.
General method for the synthesis of 2-({[3-(2-chloro-
benzyl)-7-hydroxy-3H-[1,2,3]triazolo[4, 5-d]pyrimidin-5-
yl]methyl}sulfanil)-N-arylacetamides (XXI – XXX). To a
solution of 10 mmole of metallic sodium in isopropyl alcohol
is added 5 mmole of cyanacetamide and about 7 mmole of
o-chlorobenzyl azide and the reaction mass is boiled for 2 h.
Then 5 mmole of an ester (XI – XX) is added and the mix-
ture is boiled for 4 h. The solvent is distilled off in vacuum,
and the residue is diluted with water and acidified with acetic
acid to pH 7, which leads to the formation of a crystalline
product suspended in an oily medium. The target product is
purified by recrystallization from an acetone – methanol
(9 : 1) mixture.
EXPERIMENTAL PART
o-Chlorobenzyl azide and esters XI – XX were used
without additional purification. The final products XXI –
XXX were purified by recrystallization. The purity of sub-
stances was checked by TLC on Sorbfil plates, with the spots
revealed by exposure to iodine vapor and UV radiation
(l = 254 nm). The melting points are listed in Table 1. The
1H NMR spectra were measured on a Bruker WM-250 spec-
trometer (working frequency, 250 MHz) using DMSO as the
solvent and TMS as the internal standard. The mass spectra
were obtained on a Kratos MS-790 instrument at an electron
impact ionization energy of 70 eV.
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o-chlorobenzyl chloride in 100 ml of acetonitrile was added
60 mmole of sodium azide and the reaction mass was boiled
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