H. Guglielmi et al. • Imidazole Nucleosides, V
1059
flux for 1 h with the exclusion of m oisture. The
cooled m ixture was filtered and evaporated to dry-
ness. The residual sirup was fractionated by silica
gel colum n chrom atography (A).
Hz. The CO SY spectra w ere recorded with a tim e
dom ain of 2 k per F ID and 256 experim ents in F I
dim ension. D ata processing was perform ed with
X W IN N M R
and
ID
W IN N M R
softw are
C om pound
(200 mg).
M.p. 122 °C. R f = 0,63 (A ), [a]578 - 26°, [a]546 -
28°, c 1 in CHC13. U V (A,f): 275 nm (m ax) 10608,
258 nm (m in) 4795 in ethanol.
4
was obtained in 13% yield
(B R U K E R ). Zero-filling to 32 k d ata points and
exponential m ultiplication with a line broadening
of 0.3 H z was applied to the FID prior to F ourier
transform ation in the F2 dim ension.
M elting points w ere determ ined on
a Biichi
m elting point instrum ent and are uncorrected. O p -
tical rotations w ere determ ined in a 5 cm cell with
a light electric Zeiss precision polarim eter L E P
A2 at 22 °C. U ltraviolet absorption spectra w ere
m easured on a C ontron U vicon 930 spectrom eter
using solutions in phosphate buffer (pH 7) unless
otherw ise stated. Thin-layer chrom atography was
perform ed on precoated silica sheets (layer thick-
ness 0,25 mm, IC N B iom edicals) w ith fluorescent
indicator 254/366 nm. C om pounds w ere detected
on t.l.c. plates by U V absorbance and the Pauly
reaction [7]. C olum n chrom atography (45 x 3 cm)
was perform ed on silica gel 60 M erck 7734. The
following solvent system s w ere used (v/v): Light
petroleum (5 0 -7 0 °C) - ethyl acetate 2:1 (A ) and
n-butanol saturated w ith w ater (B).
C24H 20N3O9F (513,45)
Calcd
C 56.14 H 3.90 N 8.19 F 3.69% ,
Found C 56.24 H 3.96 N 8.26 F 3.58% .
C om pound
(350 mg).
5
was obtained in 23% yield
M.p. 125 °C. R f = 0,38 (A ), [a],78 - 25°, [a]546 -
23°, c 1 in CHCI3, U V (A,e): 275 nm (m ax) 8538,
258 nm (m in) 6597 in ethanol.
C24H 20N 3O 9F (513,45)
Calcd
C 56.14 H 3.90 N 8.19 F 3.69% ,
Found C 56.38 H 4.14 N 8.21 F 3.56% .
E lem ental analyses w ere perform ed by M ikroa-
nalytisches L abor Pascher, D-53424 R em agen-
B andorf (G erm any).
4-N itro-l-(3 '-fluoro-3'-deoxy-ß-D -ribofuranosyl) -
im idazole-5-carboxam ide (6)
450 mg (0,88 m m ol) 4 w ere treated with m etha-
nolic am m onia (100 ml) at 0 °C for 50 h. The solu-
tion was evaporated, the residue dissolved in 30 ml
of w ater and extracted two tim es with 30 ml of
ether. The aqueous solution was evaporated. The
residue cristallized from ethanol, yield 220 mg
(87% ). M.p. 225 °C.
M ethyl-4-nitro-l -(2 '-5 '-di-O -benzoyl-3'-fluoro-3'-
deoxy-ß-D -ribofuranosyl)im idazole-5-carboxylate
(4) and m ethyl-5-nitro-1 -(2' -5' -di-O -benzoyl-3' -
flu o ro -3 '-deoxy-ß-D -ribofuranosyl)im idazole-4-
carboxylate (5)
U V (A,f): 294 nm (m ax) 5777, 257 nm (m in)
2854. Rf = 0,55 (B).
1
g (6 m m ol) m ethyl-4(5)-nitroim idazole-5(4)-
carboxylate was dissolved in 150 ml of hot m eth a-
nol and m ixed with the solution of 1 g (6 m m ol)
silver nitrate in 150 m l of hot m ethanol. The sus-
pension was treated w ith 10 ml pyridine, cooled
and centrifugated. The precipitate was stirred w ith
m ethanol, centrifugated again, the precipitate sus-
pended in 400 ml of toluene and dried azeotropi-
cally by distillation of 150 ml of the solvent. 1,2 g
(3 m m ol) l-0-acetyl-2,5-di-0-benzoyl-3-fluoro-3-
deoxy-a,/3-D -ribofuranose (2) w ere dissolved in
100 ml of ether and saturated w ith dry hydrogen
chloride gas at 0 °C. A fter eight days the clear so-
lution was evaporated. The residual sirupy 1-
chloro-2,5-di-0-benzoyl-3-fluoro-3-deoxy-a,/?-D -
ribofuranose (3) was dissolved in toluene and re -
evaporated with toluene (2x50 m l). The resulting
sirup was dissolved in 50 ml anhydrous toluene
and added to the suspension of the silver salt. The
reaction m ixture was stirred and heated under re -
C9H n N40 6F (290,21)
Calcd
C 37.24 H 3.82 N 19.30 F 6.54%
Found C 37.56 H 3.99 N 19.39 F 6.29% .
5-N itro-l-(3 '-fluoro-3'-deoxy-ß-D -ribofuranosyl)-
im idazole-4-carboxam ide (7)
510 m g (1 m m ol) 5 w ere treated w ith m etha-
nolic am m onia (100 ml) at 0 °C for 50 h. The reac-
tion m ixture was processed as described for 6. The
aqueous solution was evaporated to give a gum
which did not crystallize and darkened w ithin a
few days. Yield 250 mg (86% ).
U V (A,e): 298 nm (m ax) 3373, 265 nm (m in)
2752. Rf = 0,51 (B).
C9H „ N 40 6F (290,21)
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