Synthesis of acyclic nucleotide analogues derived from 2-amino-6-C-substituted purines via cross-coupling reactions of 2-amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-halopurines with diverse organometallic reagents

Article abstract of DOI:10.1135/cccc20001357

Cross-coupling reactions of 2-amino-6-chloro-9-{2-[(diisopropoxyphosphoryl)methoxy]-ethyl}purine (1) and 2-amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-iodopurine (2) with diverse types of organometallic reagents have been studied. Arylboronic aci

Full text of DOI:10.1135/cccc20001357

Acyclic Nucleotide Analogues
1357
SYNTHESIS OF ACYCLIC NUCLEOTIDE ANALOGUES DERIVED FROM
2-AMINO-6-C-SUBSTITUTED PURINES via CROSS-COUPLING REACTIONS
OF 2-AMINO-9-{2-[(DIISOPROPOXYPHOSPHORYL)METHOXY]ETHYL}-
6-HALOPURINES WITH DIVERSE ORGANOMETALLIC REAGENTS
1
2,*
3
Michal ČESNEK , Michal HOCEK and Antonín HOLÝ
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic,
1
2
166 10 Prague 6, Czech Republic; e-mail: cesnekm@uochb.cas.cz, hocek@uochb.cas.cz,
holy@uochb.cas.cz
3
Received Jun e 7, 2000
Accepted August 2, 2000
Cross-couplin g reaction s of 2-am in o-6-ch loro-9-{2-[(diisopropoxyph osph oryl)m eth oxy]-
eth yl}purin e (1) an d 2-am in o-9-{2-[(diisopropoxyph osph oryl)m eth oxy]eth yl}-6-iodopurin e
(2) with diverse types of organ om etallic reagen ts h ave been studied. Arylboron ic acids re-
acted with 1 to give th e correspon din g 2-am in o-6-arylpurin es 3a–3d in good yields. An alo-
gously, trialkylalum in ium reagen ts were used for th e preparation of 6-alkyl-2-am in opurin es
3k an d 3l from 1. Hetarylzin c h alides an d h etarylstan n an es required th e use of 2-am in o-
6-iodopurin e 2 to give th e correspon din g 2-am in o-6-h etarylpurin es 3e–3j in fair to good
yields.
A
CuI/KF m ediated couplin g of perfluoroalkylsilan es with
2 afforded th e
2-am in o-6-perfluoroalkylpurin es 3m an d 3n in m oderate yields. Cleavage of th e esters 3
with brom o(trim eth yl)silan e gave th e target free ph osph on ates 4 th at were purified by ion -
exchange chromatography. The title compounds were tested on antiviral and cytostatic activity.
Key words: Purin es; Ph osph on ates; Cross-couplin g reaction s; Nucleosides; Nucleotides; Acyclic
An alogs; Stan n an es; Boron ic acids; Organ ozin c reagen ts; Trialkylalum in um reagen ts;
Perfluoroalkylation s; An tivirals.
N-[(Ph osph on om eth oxy)alkyl] derivatives of purin e bases are poten t
an tivirals1. Th e structure-activity relation sh ip study2 of th ese com poun ds
sh owed th at th e presen ce of an am in o group in th e purin e m oiety is n eces-
sary for th e an tiviral activity. However, recen tly it was foun d3 th at also
6-(alkylam in o)- an d 6-(dialkylam in o)purin e derivatives exh ibit a stron g an -
tiviral, an titum or an d im m un om odulatory activity. To study th e role of th e
un substituted or substituted am in o fun ction in th e biological activity of
th ese com poun ds th e an alogues bearin g stron gly basic 6-(am in om eth yl)4
an d 6-(1-am in oeth yl)5 fun ction s or n itrogen -con tain in g h eterocycles6, as
well as sim ple 6-sec- or 6-tert-alkyl7 or 6-perfluoroalkyl8 groups on th e pu-
rin e rin g were recen tly prepared. An tiviral activity tests of th ese com poun ds
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1358
Česnek, Hocek, Holý:
sh owed th at several 6-(am in om eth yl)purin e derivatives still possess m ar-
gin al activity again st several strain s of DNA viruses wh ile th e oth er com -
poun ds were in active. Sin ce m ost of th ese m odification s were m ade on
2-un substituted purin e system on ly6–8, an d con siderin g th e crucial role of
th e am in o group, a logical con tin uation of th ose studies sh ould be th e
preparation of acyclic n ucleotide an alogues derived from 2-am in o-6-C-sub-
stituted purin es, wh ich is th e subject of th is paper.
Cross-couplin g m eth odology is th e m ost versatile an d efficien t approach
to th e syn th esis of 6-C-substituted purin es. Th us, reaction s of arylm agn esium
h alides9, alkyl(aryl)zin c or tin reagen ts5,6,10, trialkylalum in ium s11 or alkyl-
cuprates12 an d recen tly also arylboron ic acids13,14 with 6-h alopurin es give
th e correspon din g 6-C-substituted purin e derivatives usually in good yields.
In con trast, th e reaction of 6-h alopurin es with Mich ael acceptors un der th e
con dition s of th e Heck reaction leads15 to 1-substituted h ypoxan th in e de-
rivatives. A reverse approach based on th e reaction of purin e-6-zin c iodide
with aryl or vin yl h alides h as also been described16. 6-C-Substituted purin es
display diverse types of biological activity, e.g. 6-m eth ylpurin e derivatives
are cytotoxic17; 6-(trifluorom eth yl)purin e18 an d 6-ph en ylpurin e14 ribon u-
cleosides display cytostatic activity; 6-(arylalkyn yl)- an d 6-(arylalken yl)-
purin es sh ow cytokin in activity19, wh ile 9-ben zyl-6-arylpurin es exh ibit
an tim ycobacterial activity20
.
Cross-couplin g reaction s of 2-am in o-6-h alopurin es with diverse types of
organ om etallic reagen ts was th e m eth odology of ch oice for th e in troduc-
tion of various carbon substituen ts in to th e position 6 of th e 2-am in o-
purin e rin g. Sin ce N-alkylation of purin es usually leads to m ixtures of
regioisom ers, 2-am in o-6-h alopurin es bearin g already th e protected
2-(ph osph on om eth oxy)eth yl m oiety in th e position 9 were ch osen as start-
in g com poun ds for th e couplin g reaction s. Th e kn own 2-am in o-6-
ch loropurin e ph osph on ate2b 1 was easily tran sform ed to th e 6-iodo deriva-
tive 2 by treatm en t with h ydroiodic acid in an alogy to publish ed proce-
dure21
.
Th e Suzuki–Miyaura cross-couplin g reaction s of th e 2-am in o-6-ch loro-
purin e 1 with a series of arylboron ic acids was th e first approach studied
(Sch em e 1, Table I). Th e reaction of 1 with ph en yl-, 2-tolyl- an d 4-fluoro-
ph en ylboron ic acid in toluen e at 100 °C un der Pd(PPh 3)4 catalysis pro-
ceeded sm ooth ly to give th e correspon din g 6-arylpurin es 3a–3c in good
yields (76, 80 an d 84%, respectively). For th e reaction with 2-th ien yl-
boron ic acid th e con dition s h ad to be m odified: usin g water–
1,2-dim eth oxyeth an e (1 : 3) as solven t, th e product 3d was obtain ed in a
good yield of 91%.
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

Acyclic Nucleotide Analogues
1359
Th e Negish i reaction s with h etarylzin c h alides were selected for th e in tro-
duction of h etaryl substituen ts. Th us (pyridin -2-yl)-, (1-m eth ylpyrrol-2-yl)-,
(1-m eth ylim idazol-2-yl)- an d [1-(m eth oxym eth yl)im idazol-2-yl]zin c ch lo-
rides were gen erated in situ an d reacted with th e 2-am in o-6-h alopurin es 1
an d 2 in THF un der con dition s an alogous to th e procedures publish ed for
th e 2-un substituted purin es6. (Pyridin -2-yl)zin c ch loride was gen erated22
from 2-brom opyridin e usin g t-BuLi followed by th e addition of on e equiva-
len t of Zn Cl2. (1-Meth ylpyrrol-2-yl)zin c ch loride was prepared6,23 by
lith iation of 1-m eth ylpyrrole usin g BuLi in presen ce of N,N,N′,N′-
tetram eth yleth ylen ediam in e (TMEDA) followed by tran sm etallation with
Zn Cl2. Both (1-substituted im idazol-2-yl)zin c ch lorides were gen erated6,24
an alogously from th e correspon din g 1-substituted im idazoles usin g BuLi
followed by addition of 3 equivalen ts of Zn Cl2. Th e reaction s of th ese
h etarylzin c h alides with th e 2-am in o-6-iodopurin e 2 proceeded well to give
th e desired 6-h etarylpurin es 3e–3h in good yields (85, 65, 94 an d 76%, re-
spectively), wh ile an alogous reaction s of 2-am in o-6-ch loropurin e 1 gave
very low con version s an d com plex m ixtures of products.
Th e Stille couplin g reaction s with kn own 6,25 (1-m eth ylim idazol-5-yl)- an d
[1-(m eth oxym eth yl)im idazol-5-yl]tributylstan n an es, prepared by successive
double lith iation , stan n ylation an d h ydrolysis of th e correspon din g
im idazoles, were used for th e in troduction of th e im idazol-5-yl m oiety.
Wh ile th e reaction of th ese stan n an es with th e 2-am in o-6-iodopurin e 2 in
DMF at 120 °C gave th e desired 6-(im idazol-5-yl)purin es 3i an d 3j in fair
yields of 61 an d 45%, respectively, an alogous reaction with th e 2-am in o-
6-ch loropurin e 1 led to com plex m ixtures.
Cross-couplin g reaction s of 6-h alopurin es with trialkylalum in ium reagen ts
were described as a good m eth od for th e preparation of 6-alkylpurin es11. In
our study, reaction s of trim eth yl- an d trieth ylalum in ium with th e 2-am in o-
6-ch loropurin e 1 in refluxin g THF catalyzed by Pd(PPh 3)4 gave th e corre-
spon din g 2-am in o-6-alkylpurin es 3k an d 3l in good yields of 67 an d 78%,
respectively. Th is approach to th e kn own com poun d 3k was m ore efficien t
th an th e recen tly described procedure2b based on an alogous m eth ylation of
2-am in o-9-ben zyl-6-ch loropurin e followed by deben zylation an d alkylation
with protected 2-(ph osph on om eth oxy)eth yl ch loride.
Cross-couplin g reaction s of 6-ch loropurin es with alkyl cuprates gen erated
in situ from th e correspon din g Grign ard reagen ts were recen tly used7,12b for
th e in troduction of sec- an d tert-alkyl groups in to th e position 6 of purin e
derivatives. However, an alogous reaction s of a cuprate gen erated from iso-
butylm agn esium brom ide an d CuI with both 2-am in o-6-h alopurin es 1 an d
2 led to com plex m ixtures of products with n o traces of th e desired
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1360
Česnek, Hocek, Holý:
Scheme 1:
X
R
R'
R M, Pd(PPh3)4
O
TMSBr
O
N
N
N
N
N
N
N
N
N
O
H2N
N
H2N
N
H2N
N
O
P
Oi-Pr
O
P
Oi-Pr
O
P
OH
3a-3n
1, X = Cl
2, X = I
4a-4n
Oi-Pr
Oi-Pr
OH
TABLE I
Reactions of the 2-amino-6-halopurines 1 and 2 with organometallics
Starting
halopurine
Entry
R
M
Yield of 3
R'
Yield of 4
a
1
B(OH)2
76 %
84 %
1
1
B(OH)2
B(OH)2
80 %
84 %
92 %
66 %
b
c
CH3
CH3
F
F
S
S
d
e
1
2
2
B(OH)2
ZnCl
91 %
85 %
65 %
95 %
90 %
61 %
N
N
CH3
CH3
CH3
N
N
ZnCl
f
CH3
N
N
g
ZnCl
2
2
94 %
76 %
83 %
55 %
N
N
MOM
H
N
N
h
ZnCl
N
N
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

Acyclic Nucleotide Analogues
1361
TABLE I
(continued)
Starting
halopurine
Entry
R
N
M
Yield of 3
R'
Yield of 4
CH3
CH3
N
i
2
61 %
61 %
SnBu3
N
N
N
N
MOM
H
N
N
j
2
1
45 %
67 %
SnBu3
AlMe2
78 %
89 %
k
CH3
CH3
1
2
2
AlEt2
SiMe3
SiMe3
78 %
28 %
21 %
89 %
65 %
59 %
l
CH2CH3
CF3
CH2CH3
CF3
ma
na
CF2CF2CF3
CF2CF2CF3
a without Pd catalysis - mediated by CuI and KF
2-am in o-6-isobutylpurin e (FAB MS an alysis of th e crude m ixture). Recen tly
we h ave developed a facile syn th esis8 of 6-(perfluoroalkyl)purin es m akin g
use of reaction s of perfluoroalkyl cuprates gen erated from trim eth yl-
(perfluoroalkyl)silan es by th e use of KF an d CuI with 6-iodopurin es.
An alogous reaction s of trim eth yl(trifluorom eth yl)silan e an d (h eptafluoro-
propyl)trim eth ylsilan e with th e 2-am in o-6-iodopurin e 2 in th e presen ce of
KF an d CuI at room tem perature (h eatin g caused decom position of th e
startin g com poun d) was sluggish an d gave th e correspon din g 2-am in o-
6-perfluoroalkylpurin es 3m an d 3n after prolon ged reaction tim es in m od-
erate yields of 28 an d 21%, respectively.
Stan dard tran sesterification protocol was used for th e cleavage of th e
ph osph on ate esters 3a–3n . Th us th e reaction of esters 3a–3n with
brom o(trim eth yl)silan e (TMSBr) in aceton itrile at am bien t tem perature or
at 80 °C followed by th e h ydrolysis of th e in term ediate silyl esters usin g
aqueous am m on ia or trieth ylam in e gave th e free ph osph on ates 4a–4n . In
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1362
Česnek, Hocek, Holý:
th e MOM-protected com poun ds 3h an d 3j, th e MOM-groups were cleaved
sim ultaen ously to give th e 2-am in o-6-(1-un substituted im idazolyl)purin e
ph osph on ates 4h an d 4j. Th e crude products 4a–4n were deion ized an d pu-
rified usin g a com bin ation of cation [Dowex 50X8 (H+ form )] an d an ion
[Dowex 1X2 (acetate form )] exch an ge ch rom atograph y. In som e cases,
wh en dilute acetic acid was in sufficien t for th e elution of th e products from
Dowex 1X2 an d th e use of con cen trated acetic acid led to partial
acetylation of th e com poun ds (MS an alysis of th e im pure products), elution
was accom plish ed by th e use of dilute aqueous form ic acid. In several cases
even th e deion ization on Dowex 50X8 was sufficien t for th e purification of
th e products an d th e an ion exch an ge ch rom atograph y could h ave been
om itted. Gen erally, th e con dition s m ust h ave been m odified case by case
an d th e free ph osph on ates were isolated in th e yields varyin g from 55 to
95%.
All com poun ds were fully ch aracterized by NMR an d MS. Most of th e free
ph osph on ates 4 were also ch aracterized by elem en tal an alysis. Th e assign -
1
m en t of th e H an d 13C NMR sign als of th e com poun ds 3k, 4a an d 4l was
based on COSY, HMBC an d HMQC experim en ts. Assign m en t of sign als of
all oth er com poun ds was m ade in an alogy to th ese com poun ds an d to th e
an alogous 2-un substituted purin e derivatives described previsously6. UV
spectra sh owed stron g substituen t effect depen din g on th e n ature of th e
substituen t in th e position 6: th e m axim a varied from 373 n m
(6-(1-m eth ylpyrrol-2-yl) derivative 4f) to 310 n m (6-m eth yl derivative 4k).
In con clusion , cross-couplin g reaction s of diverse types of organ om etallic
reagen ts with 2-am in o-6-h alopurin es 1 an d 2 were used for th e preparation
of th e correspon din g protected 2-am in o-6-C-substituted purin e derivatives
3a–3n . Each type of organ om etallic reagen t turn ed out to be superior for
th e in troduction of differen t types of C-substituen ts: arylboron ic acids were
used for th e in troduction of aryl groups, h etarylzin c ch lorides or h etaryl-
stan n an es for th e in troduction of h etaryl fun ction s, trialkylalum in ium re-
agen ts for sim ple alkyl groups an d perfluoroalkylsilan es for th e
in troduction of perfluoroalkyl substituen ts. Except for cuprates, all th e
organ om etallic reagen ts used well tolerated th e presen ce of th e un protected
am in o group. Cleavage of th e ph osph on ate esters 3a–3n with TMSBr af-
forded th e target acyclic n ucleotide an alogues 4a–4n . Th e title com poun ds
4a–4n were tested in vitro for cytostatic activity (in h ibition of cell growth in
th e followin g cell cultures: m ouse leukem ia L1210 cells, m urin e L929 cells
an d h um an cervix carcin om a HeLaS3 cells) an d for an tiviral activity (in h ib-
itory effect on DNA viruses: HSV-1, HSV-2, CMV, VZV an d vaccin ia virus,
an d on retroviruses: MSV, HIV-1 an d HIV-2). On ly th e 2-am in o-6-(h epta-
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

Acyclic Nucleotide Analogues
1363
fluoropropyl)purin e 4n sh owed26 an tiviral activity again st HSV-1 (KOS)
(MIC50 21.8 µm ol/l), HSV-2 (F) (MIC50 7.3 µm ol/l) an d HSV-1 TK– (VMW
1837) (MIC50 4.4 µm ol/l) in E6SM cells an d again st CMV (Davis strain )
(MIC50 3.6 µm ol/l) an d VZV (TK– an d TK+ m utan ts) (MIC50 0.6–1.3 µm ol/l)
in HEL cells. Com poun d 4n was cytotoxic for th e h ost cells at con cen tra-
tion s above 45 µm ol/l. Non e of th e oth er com poun ds sh owed an y con sider-
able activity in th ese assays. Th e absen ce of an tiviral an d cytostatic activity
in th is series of com poun ds is in terestin g in com parison with th e h igh ac-
tivity of th e aforem en tion ed acyclic n ucleotide an alogues derived from
2-am in o-6-[(di)alkylam in o]purin es3.
EXPERIMENTAL
Un less oth erwise stated, solven ts were evaporated at 40 °C/2kPa an d com poun ds were dried
at 60 °C/2kPa over P2O5. Meltin g poin ts were determ in ed on a Kofler block an d are un cor-
rected. Paper electroph oresis was perform ed on a paper Wh atm an No.3 MM at 40 V/cm for
1 h in 0.05 M trieth ylam m on ium h ydrogen carbon ate (TEAB) at pH 7.5 an d th e electro-
ph oretical m obilities (EUp) are referen ced to uridin e 3′-ph osph ate. TLC was perform ed on
Silufol UV254 plates (Kavalier Votice, Czech Republic) in th e followin g solven t system s:
MeOH-EtOAc (1 : 9) (A); MeOH-EtOAc (2 : 8) (B); MeOH-CHCl3 (1 : 9) (C); MeOH-CHCl3
(3 : 20) (D); isopropyl alcoh ol-water-35% aqueous NH3 (7 : 2 : 1) (E). NMR spectra (J, Hz; δ,
ppm) were measured on a Bruker AMX-3 400 (400 MHz for 1H, 100.6 MHz for 13C and 376.5 MHz
for 19F n uclei), Bruker DRX 500 (500 MHz for 1H, 125.7 MHz for 13C an d 470.59 MHz for 19F)
an d Varian Gem in i 300HC (300.075 MHz for 1H an d 75.462 MHz for 13C). TMS was used as
in tern al stan dard for 1H an d 13C NMR spectra; CFCl3 was an in tern al stan dard for 19F spec-
tra. Mass spectra were m easured on a ZAB-EQ (VG An alytical) spectrom eter usin g FAB (ion -
ization by Xe, acceleratin g voltage 8 kV, glycerol m atrix) or EI (electron en ergy 70 eV)
tech n iques. UV absorption spectra (λm ax, n m ; ε, l m ol–1 cm –1) were m easured on a Sh im adzu
UVm in i 1240 spectrom eter in aqueous solution s. DMF was distilled from P2O5, degassed in
vacuo an d stored over m olecular sieves un der Ar. THF was refluxed with Na an d ben zoph e-
n on e un der Ar atm osph ere an d fresh ly distilled prior to use. Toluen e was degassed in vacuo
an d stored over m olecular sieves un der Ar. Aceton itrile was refluxed with CaH2 an d distilled.
All n on -h ydrolytic reaction s were perform ed un der argon atm osph ere usin g vacuum -lin e
tech n iques.
2-Am in o-6-iodo-9-{2-[(diisopropoxyph osph oryl)m eth oxy]eth yl}purin e (2)
Com poun d 1 (1.2 g, 3 m m ol) was added to stirred 55% aqueous HI (10 m l) at 0 °C an d th e
resultin g suspen sion was stirred at 0 °C for 2 h . After addition of water (10 m l) th e m ixture
was n eutralized with 1 M aqueous NaOH un til th e suspen sion dissolved. Th e solution was
th en extracted with eth yl acetate (3 × 30 m l). Th e collected organ ic layers were wash ed with
saturated aqueous NaS2O3 (30 m l), dried with MgSO4 an d evaporated in vacuo. Crystalliza-
tion of th e residue from eth yl acetate yielded th e iodo derivative 2 (1.2 g, 81%) as yellowish
crystals; m .p. 116–117 °C, RF (C) 0.48. FAB MS, m/z (rel. %): 484 (100) [M + H]. 1H NMR
(400 MHz, CDCl3): 1.26 an d 1.30 (2 × d, 2 × 6 H, J(CH,CH3) = 6.2, CH3); 3.73 (d, 2 H,
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1364
Česnek, Hocek, Holý:
J(P,CH) = 8.1, PCH2); 3.92 (t, 2 H, J(1′,2′) = 5.0, H-2′); 4.25 (t, 2 H, J(2′,1′) = 5.0, H-1′); 4.69
(sept, 2 H, J(CH3,CH) = 6.2, POCH); 5.35 (s, 2 H, NH2); 7.89 (s, 1 H, H-8). 13C NMR (75 MHz,
CDCl3): 24.60 an d 24.64 (2 × d, J(P,C) = 3.5, CH3); 44.00 (C-1′); 66.69 (d, J(P,C) = 167.3,
PCH2); 71.39 (d, J(P,C) = 9.7, C-2′); 71.86 (d, J(P,C) = 6.3, POCH); 123.19 (C-5); 132.76 (C-6);
143.20 (C-8); 150.46 (C-4); 159.42 (C-2). For C14H23IN5O4P (483.2) calculated: 34.80% C,
4.80% H, 26.26% I, 14.49% N, 6.41% P; foun d: 35.20% C, 4.83% H, 26.15% I, 14.52% N,
6.62% P.
Cross-Coupling Reactions of the 2-Amino-6-chloropurine 1 with Boronic Acids - General Procedure
Method A: Toluen e (10 m l) was added th rough a septum to an Ar purged 50 m l flask with
a m ixture of com poun d 1 (195 m g, 0.5 m m ol), a boron ic acid (1 m m ol), K2CO3 (100 m g,
0.75 m m ol) an d Pd(PPh 3)4 (29 m g, 0.025 m m ol). Th e m ixture was stirred at 100 °C un til th e
startin g com poun d 1 was con sum ed (TLC). Th e solven t was th en evaporated an d th e residue
ch rom atograph ed on a colum n of silica gel (50 g) to get th e products 3a–3d .
Method B: Th e sam e procedure as m eth od A; on ly a m ixture DME–water (3 : 1) (10 m l)
was used as solven t in stead of toluen e.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-phenylpurine (3a). Meth od A; reac-
tion tim e 24 h ; ch rom atograph ed in eth yl acetate/m eth an ol (98 : 2); yield 76%; colourless
oil; RF (A) 0.42. EI MS, m/z (rel. %): 433 (36) [M]; 254 (100). 1H NMR (400 MHz, CDCl3):
1.25 (d, 3 H, J(CH3,CH) = 6.2, CH3); 1.28 (d, 3 H, J(CH3,CH) = 6.2, CH3); 3.73 (d, 2 H,
J(CH2,P) = 8.3, PCH2); 3.93 (t, 2 H, J(2′,1′) = 4.9, CH2-2′); 4.32 (t, 2 H, J(2′,1′) = 4.9, CH2);
4.68 (m , 1 H, POCH); 5.09 (s, 2 H, NH2); 7.46-7.53 (m , 3 H, H-arom .); 7.92 (s, 1 H, H-8);
8.63 (m , 2 H, CH). 13C NMR (75.5 MHz, CDCl3): 23.91 (d, J(P,C) = 4.0, CH3); 42.94 (C-1′);
66.03 (d, J(P,C) = 167.2, PCH2); 70.96 (d, J(P,C) = 9.7, C-2′); 71.13 (d, J(P,C) = 6.9, POCH);
125.40 (C-5); 128.38, 129.51, 130.57 (5 × CH-arom ); 135.70 (C-1′′); 142.60 (C-8); 154.26 a
155.55 (C-6 a C-4); 159.43 (C-2). For C20H28N5O4P (433.4) calculated: 55.42% C, 6.51% H,
16.16% N; foun d: 55.06% C, 6.54% H, 15.82% N.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-(2-tolyl)purine (3b). Meth od A; reac-
tion tim e 5 h ; ch rom atograph ed in CHCl3–m eth an ol (98 : 2); yield 80%; crystallized from
eth an ol–dieth yl eth er; colourless crystals; m .p. 107–110 °C; RF (C) 0.60. FAB MS, m/z (rel. %):
448 (100) [M + H]. 1H NMR (300 MHz, CDCl3): 1.26 (d, 3 H, J(CH3, CH) = 6.1, CH3); 1.29 (d,
3 H, J(CH3,CH) = 6.1, CH3); 2.40 (s, 3 H, CH3); 3.75 (d, 2 H, J(CH2,P) = 8.8, PCH2); 3.96 (t, 2 H,
J(2′,1′) = 5.0, CH2-2′); 4.33 (t, 2 H, J(1′,2′) = 5.0, CH2-1′); 4.70 (m , 1 H, POCH); 5.08 (s, 2 H,
NH2); 7.34 (m , 3 H, H-arom .); 7.58 (m , 1 H, H-arom .); 7.86 (s, 1 H, H-8). 13C NMR (75.5 MHz,
CDCl3): 20.33 (CH3, tolyl); 23.93 (CH3); 42.93 (C-1′); 66.02 (d, J(P,C) = 167.8, PCH2); 70.90
(C-2′); 71.11 (d, J(P,C) = 6.3, POCH); 126.29 (C-5); 125.66, 129.34, 129.92, 130.88 (4 ×
CH-arom ); 135.10, 136.61 (C-1′′,C-2′′); 142.78 (C-8); 153.54 (C-4); 159.33, 159.59 (C-6,C-2).
For C21H30N5O4P (447.5) calculated: 56.37% C, 6.76% H, 15.65% N; foun d: 56.29% C,
6.51% H, 15.43% N.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-(4-fluorophenyl)purine (3c). Meth od A;
reaction tim e 6 h ; ch rom atograph ed in eth yl acetate-m eth an ol (98 : 2); yield 84%; colourless
oil; RF (A) 0.36. FAB MS, m/z (rel. %): 452 (96) [M + H]. 1H NMR (300 MHz, CDCl3 ): 1.26 (d,
3 H, J(CH3, CH) = 6.1, CH3); 1.29 (d, 3 H, J(CH3, CH) = 6.1, CH3); 3.73 (d, 2 H, J(CH2,P) =
8.3, PCH2); 3.94 (t, 2 H, J(2′,1′) = 5.0, CH2-2′); 4.32 (t, 2 H, J(1′,2′) = 5.0, CH2-1′); 4.68 (m , 1 H,
POCH); 5.01 (s, 2 H, NH2); 7.19 (t, 2 H, J(Ho,Hm) = 8.8, H-o-FPh ); 7.92 (s, 1 H, H-8); 8.73
(dd, 2 H, J(Hm,Ho) = 8.8, J(F,Hm ) = 6.0, H-m-FPh ). 13C NMR (75.5 MHz, CDCl3): 23.94 (CH3);
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

Acyclic Nucleotide Analogues
1365
42.99 (C-1′); 66.03 (d, J(P,C) = 167.2, PCH2); 70.92 (d, J(P,C) = 10.3, C-2′); 71.15 (d, J(P,C) =
6.3, POCH); 115.51 (d, J(F,C) = 21.2, C-3′′); 125.04 (C-5); 131.43 (C-1′′); 131.82 d, J(F,C) =
8.6 (C-2′′); 142.99 (C-8); 153.82, 154.43 (C-6, C-4); 159.06 (C-2). 164.49 d, J(F,C) = 252
(C-4′′). For C20H27FN5O4P (451.4) calculated: 53.21% C, 6.03% H, 4.21% F, 15.51% N;
foun d: 53.36% C, 6.20% H, 4.02% F, 14.89% N.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-(2-thienyl)purine (3d ). Meth od B; re-
action tim e 6 h ; ch rom atograph ed in CHCl3–m eth an ol (95 : 5); yield 91%; yellow oil; RF (A)
0.27. FAB MS, m/z (rel. %): 440 (100) [M + H]; 1H NMR (300 MHz, CDCl3): 1.26 (d, 3 H,
J(CH3, CH) = 6.1, CH3); 1.29 (d, 3 H, J(CH3,CH) = 6.1, CH3); 3.72 (d, 2 H, J(CH2,P) = 8.2,
PCH2); 3.93 (t, 2 H, J(2′,1′) = 4.9, CH2-2′); 4.31 (t, 2 H, J(1′,2′) = 5.0, CH2-1′); 4.69 (m , 1 H,
POCH); 4.99 (s, 2 H, NH2); 7.21 (dd, 1 H, J = 5.0, 3.8, H-arom .); 7.54 (dd, 1 H, J = 5.0, 1.1,
H-arom .); 7.90 (s, 1 H, H-8); 8.58 (dd, 1 H, J = 3.8, 1.1, H-arom ). 13C NMR (75.5 MHz,
CDCl3): 23.93 (d, J(P,C) = 4.3, CH3); 42.93 (C-1′); 66.03 (d, J(P,C) = 167.2, PCH2); 70.98 (d,
J(P,C) = 9.7, C-2′); 71.14 (d, J(P,C) = 6.9, POCH); 123.49 (C-5); 128.42, 130.05, 132.21 (3 ×
CH-arom ); 139.96 (C-2′′); 142.64 (C-8); 150.43 (C-6); 153.90 (C-4); 159.27 (C-2). Exact m ass
(FAB HRMS, m/z) foun d 440.1513; calculated for C18H27N5O4PS [M + H] 440.1521.
2-Am in o-9-{2-[(diisopropoxyph osph oryl)m eth oxy]eth yl}-6-(pyridin -2-yl)purin e (3e).
A solution of 2-brom opyridin e (0.38 m l, 8 m m ol) in THF (40 m l) was stirred at –78 °C un der
Ar atm osph ere an d t-BuLi (1.5 M solution in pen tan e, 6.2 m l, 10 m m ol) was added dropwise.
After stirrin g for 1 h at –78 °C, Zn Cl2 (0.5 M solution in THF, 20 m l, 10 m m ol) was added
dropwise an d th e resultin g m ixture was allowed to warm up to am bien t tem perature an d
stirred for addition al 1 h . To th is m ixture, a solution of com poun d 2 (960 m g, 2 m m ol) an d
Pd(PPh 3)4 (110 m g, 0.1 m m ol) in THF (14 m l) was added an d th e m ixture was refluxed for 6 h ,
cooled to am bien t tem perature an d poured in to a saturated aqueous NH4Cl (100 m l). To th is
m ixture, 3% aqueous NH3 (20 m l) an d saturated aqueous Na2EDTA (20 m l) were added an d
th e m ixture was extracted with eth yl acetate (4 × 40 m l). Th e collected organ ic layers were
wash ed with a m ixture of saturated aqueous NH4Cl, 3% aqueous NH3 an d sat aqueous
Na2EDTA (60 m l, 1 : 1 : 1, v/v/v) an d dried with MgSO4. After evaporation of th e solven ts,
th e residue was ch rom atograph ed on
a colum n of silica gel [100 g, eth yl acetate-
m eth an ol–saturated m eth an olic am m on ia (94 : 3 : 3)] to give com poun d 3e (730 m g, 85 %)
as yellowish oil, RF (E) 0.79. FAB MS, m/z (rel. %): 435 (100) [M + H]. 1H NMR (300 MHz,
CDCl3): 1.25 (d, 3 H, J(CH3,CH) = 6.1, CH3); 1.29 (d, 3 H, J(CH3,CH) = 6.1, CH3); 3.73 (d, 2 H,
J(CH2,P) = 8.2, PCH2); 3.95 (t, 2 H, J(2′,1′) = 4.7, CH2-2′); 4.34 (t, 2 H, J(1′,2′) = 4.7, CH2-1′);
4.69 (m , 1 H, POCH); 5.20 (brs, 2 H, NH2); 7.39 (m , 1 H, H-5′′); 7.88 (dt, 1 H, J(4′′,6′′) = 1.1,
J(4′′,3′′) = (4′′,5′′) = 7.7, H-4′′); 7.98 (s, 1 H, H-8); 8.81 (d, 1 H, J(3′′,4′′) = 7.7, H-3′′); 8.91 (m ,
1 H, H-6′′). 13C NMR (75.5 MHz, CDCl3): 23.94 (CH3); 43.01 (C-1′); 66.06 (d, J(P,C) = 167.2,
PCH2); 70.98 (d, J(P,C) = 9.7, C-2′); 71.15 (d, J(P,C) = 6.7, POCH); 124.58 (C-3′′); 125.83
(C-5); 126.07 (C-5′′); 136.60 (C-4′′); 143.46 (C-8); 150.23 (C-6′′); 153.54 (C-6); 154.26 (C-4);
159.73 (C-2). Exact m ass (FAB HRMS, m/z) foun d 435.1938; calculated for C19H28N6O4P
[M + H] 435.1909.
2-Am in o-9-{2-[(diisopropoxyph osph oryl)m eth oxy]eth yl}-6-(1-m eth ylpyrrol-2-yl)purin e (3f).
t-BuLi (1.5 M solution in pen tan e, 2.2 m l, 3.5 m m ol) was dropwise added to a stirred solu-
tion of TMEDA (0.6 m l, 4 m m ol) an d 1-m eth ylpyrrole (0.7 m l, 8 m m ol) in THF (20 m l) at
–70 °C un der Ar atm osph ere an d th e m ixture was allowed to warm up to am bien t tem pera-
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1366
Česnek, Hocek, Holý:
ture. After stirrin g for 1 h at room tem perature, th e m ixture was re-cooled to –70 °C an d
Zn Cl2 (0.5 M solution in THF, 8 m l, 4 m m ol) was added dropwise. Th e m ixture was allowed
to warm up to room tem perature an d after stirrin g for 1 h , a solution of com poun d 2 (340 m g,
0.7 m m ol) an d Pd(PPh 3)4 (58 m g, 0.05 m m ol) in THF (7 m l) was added dropwise. Th e m ix-
ture was th en refluxed for 10 h , cooled to am bien t tem perature an d poured in to saturated
aqueous NH4Cl (50 m l). After addition of 3% aqueous NH3 (10 m l) an d saturated aqueous
EDTA (20 m l), th e m ixture was extracted with CHCl3 (3 × 40 m l). Th e collected organ ic lay-
ers were dried with MgSO4 an d th e solven ts were evaporated in vacuo. Colum n ch rom atogra-
ph y on silica gel [50 g, eth yl acetate–m eth an ol (95 : 5)] afforded com poun d 3f (200 m g,
65%) as brown ish oil, RF (A) 0.30. FAB MS, m/z (rel. %): 437 (100) [M + H]. 1H NMR (300 MHz,
CDCl3): 1.25 (d, 3 H, J(CH3,CH) = 6.1, CH3); 1.29 (d, 3 H, J(CH3,CH) = 6.1, CH3); 3.72 (d, 2 H,
J(CH2,P) = 8.2, PCH2); 3.92 (t, 2 H, J(2′,1′) = 5.0, CH2-2′); 4.12 (s, 3 H, NCH3); 4.28 (t, 2 H,
J(1′,2′) = 5.0, CH2-1′); 4.67 (m , 1 H, POCH); 4.90 (brs, 2 H, NH2); 6.26 (dd, 1 H, J(4′′,5′′) =
2.2, J(4",3′′) = 3.8, H-4′′); 6.81 (t, 1 H, J = 2.2, H-5′′); 7.70 (dd, 1 H, J(3′′,5′′) = 1.7, J(3′′,4′′) =
3.9, H-3′′); 7.83 (s, 1 H, H-8). 13C NMR (75.5 MHz, CDCl3): 23.95 (CH3); 37.96 (NCH3);
42.83 (C-1′); 66.01 (d, J(P,C) = 167.7, PCH2); 71.03 (C-2′); 71.17 (d, J(P,C) = 6.9, POCH);
108.73, 119.04 (2 × CH-arom ); 123.71 (C-5); 127.08 (C-2′′); 128.94 (CH-arom ); 141.52 (C-8);
150.29 (C-6); 152.94 (C-4); 158.64 (C-2). Exact m ass (FAB HRMS, m/z) foun d 437.2096; cal-
culated for C19H30N6O4P [M + H] 437.2066.
2-Am ino-9-{2-(diisopropoxyphosphoryl)m ethoxy]ethyl}-6-(1-m ethylim idazol-2-yl)purine (3g).
BuLi (2.5
M solution in h exan e, 3.2 m l, 8 m m ol) was added to a stirred solution of
1-m eth ylim idazole (660 m g, 8 m m ol) in THF (20 m l) at –78 °C un der Ar. Th e m ixture was
slowly (2 h ) allowed to warm up to –40 °C an d re-cooled to –78 °C. Th en Zn Cl2 (1 M solu-
tion in THF, 22 m l, 22 m m ol) was added an d th e m ixture was allowed to warm up to am bi-
en t tem perature an d stirred for 30 m in . A solution of com poun d 2 (960 m g, 2 m m ol) an d
Pd(PPh 3)4 (110 m g, 0.1 m m ol) in THF (20 m l) was th en added an d th e m ixture was refluxed
for 10 h , cooled to room tem perature an d poured in to saturated aqueous NH4Cl (50 m l). To
th is m ixture, saturated aqueous EDTA (20 m l) was added an d th e m ixture was extracted
with CHCl3 (4 × 40 m l). Th e collected organ ic layers were dried with MgSO4 an d th e sol-
ven ts were evaporated. Th e residue was ch rom atograph ed on a silica gel colum n [100 g,
eth yl acetate–saturated m eth an olic am m on ia (90 : 10)] to give com poun d 3g (820 m g, 94 %)
as yellow oil; RF (D) = 0.51. FAB MS, m/z (rel. %): 438 (100) [M + H]. 1H NMR (300 MHz,
CDCl3): 1.29 (t, 6 H, J(CH3,CH) = 6.6, CH3); 3.73 (d, 2 H, J(CH2,P) = 8.2, PCH2); 3.92 (t, 2 H,
J(2′,1′) = 5.0, CH2-2′); 4.12 (s, 3 H, NCH3); 4.31 (t, 2 H, J(1′,2′) = 5.0, CH2-1′); 4.71 (m , 1 H,
POCH); 4.96 (s, 2 H, NH2); 7.03 an d 7.34 (s, 1 H, H-4′′, H-5′′); 7.95 (s, 1H, H-8). 13C NMR
(75.5 MHz CDCl3): 23.90 (d, J(P,C) = 4.0, CH3); 36.11 (NCH3); 42.86 (C-1′); 66.07 (d, J(P,C) =
167.7, PCH2); 71.05 (C-2′); 71.13 (d, J(P,C) = 6.3, POCH); 124.61 (C-5′′); 125.10 (C-5);
130.246 (C-4′′); 141.83 (C-2′′); 143.29 (C-8); 148.12 (C-6); 154.32 (C-4); 158.82 (C-2). Exact
m ass (FAB HRMS, m/z) foun d 438.2077; calculated for C18H29N7O4P [M + H] 438.2019.
2-Am in o-9-{2-[(diisopropoxyph osph oryl)m eth oxy]eth yl}-6-[1-(m eth oxym eth yl)im idazol-
2-yl]purin e (3h )
Th is com poun d was prepared in
a sim ilar m an n er as described for com poun d 3g.
[1-(Meth oxym eth yl)im idazol-2-yl]zin c ch loride was gen erated from 1-(m eth oxym eth yl)-
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

Acyclic Nucleotide Analogues
1367
im idazole (1.78 g, 16 m m ol), BuLi (2.5 M solution in h exan e, 5.6 m l, 14 m m ol) an d Zn Cl2 (1 M
solution in THF, 32 m l, 32 m m ol) an d reacted with com poun d 2 (960 m g, 2 m m ol) an d
Pd(PPh 3)4 (110 m g, 0.1 m m ol) in THF at reflux for 14 h . After an alogous work up th e
resudie was ch rom atograph ed on a preparative loose layer of silica gel [40 × 17 × 0.4 cm ,
eth yl acetate–m eth an olic am m on ia (85 : 15)] to give com poun d 3h (660 m g, 76%) as yellow
oil; RF (E) 0.76. FAB MS, m/z (rel. %): 468 (100) [M + H]; 1H NMR (300 MHz, CDCl3): 1.26 (t,
6 H, J(CH3,CH) = 6.1, CH3); 1.29 (t, 6 H, J(CH3,CH) = 6.1, CH3); 3.26 (s, 3H, CH3O); 3.72 (d,
2 H, J(CH2,P) = 8.2, PCH2); 3.92 (t, 2 H, J(2′,1′) = 5.0, CH2-2′); 4.30 (t, 2 H, J(1′,2′) = 5.2,
CH2-1′); 4.69 (m , 1 H, POCH); 5.02 (brs, 2 H, NH2); 5.99 (s, 2 H, NCH2O); 7.26 (m , 1 H,
H-4′′); 7.38 (s, 1 H, H-5′′); 7.97 (s, 1 H, H-8). 13C NMR (75.5 MHz CDCl3): 23.91 (CH3); 42.87
(C-1′); 56.32 (CH3O); 66.01 (d, J(P,C) = 167.7, PCH2); 70.99 (C-2′); 71.15 (d, J(P,C) = 6.7,
POCH); 78.58 (NCH2O); 122.73 (C-5′′); 125.05 (C-5); 130.64 (C-4′′); 141.82 (C-2′′); 143.58
(C-8); 147.69 (C-6); 154.48 (C-4); 158.85 (C-2). Exact m ass (FAB HRMS, m/z) foun d
468.2126; calculated for C19H31N7O5P [M + H] 468.2124.
Cross-Couplin g Reaction s of 2-Am in o-6-iodopurin e 2 with Stan n an es. Gen eral Procedure
A
m ixture of com poun d 2 (480 m g, 1 m m ol), 1-m eth yl- or 1-(m eth oxym eth yl)-
5-(tributylstan n yl)im idazole (1.9 m m ol), Pd(PPh 3)4 (58 m g, 0.05 m m ol) an d DMF (10 m l)
was refluxed un der Ar for 8 h . Th e solven t was evaporated in vacuo, th e residue co-distilled
with toluen e an d treated with saturated aqueous Na2EDTA (20 m l) an d 35 % aqueous NH3
(1 m l). Th e m ixture was extracted with CHCl3 (4 × 30 m l). Th e collected organ ic layers were
dried with MgSO4 an d evaporated. Th e residue was ch rom atograph ed on silica gel (50 g) to
give product 3i or 3j.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-(1-methylimidazol-5-yl)purine (3i).
Ch rom atograph ed in CHCl3–m eth an ol (96 : 4); yield 61 %; yellow oil; RF (C) 0.21. FAB MS,
m/z (rel. %): 438 (100) [M + H]. 1H NMR (300 MHz, CDCl3): 1.25 (d, 3 H, J(CH3,CH) = 6.6,
CH3); 1.29 (d, 3 H, J(CH3,CH) = 6.6, CH3); 3.72 (d, 2 H, J(CH2,P) = 8.2, PCH2); 3.92 (t, 2 H,
J(2′,1′) = 5.0, CH2-2′); 4.12 (s, 3 H, NCH3); 4.29 (t, 2 H, J(1′,2′) = 5.0, CH2-1′); 4.68 (m . 1 H,
POCH); 4.92 (s, 2 H, NH2); 7.57 (s, 1 H, CH); 7.87 (s, 1 H, H-8); 8.46 (s, 1 H, CH). 13C NMR
(75.5 MHz, CDCl3): 23.90 (m , J(P,C) = 4.0, CH3); 35.40 (NCH3); 42.80 (C-1′); 65.97 (d, J(P,C) =
167.8, PCH2); 70.98 (d, J(P,C) = 10.3, C-2′); 71.15 (d, J(P,C) = 6.9, POCH); 123.93 (C-5′′);
127.09 (C-5); 137.71 (C-4′′); 141.88 (C-2′′); 142.05 (C-8); 148.59 (C-6); 153.14 (C-4); 158.97
(C-2). Exact m ass (FAB HRMS, m/z) foun d 438.2050; calculated for C18H29N7O4P [M + H]
438.2019.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-[1-(methoxymethyl)imidazol-5-yl]purine
(3j). Ch rom atograph ed in eth yl acetate–m eth an ol (90 : 10); crystallized from m eth an ol-
toluen e–petroleum eth er; yield 45%; m .p. 106–109 °C. RF (B) 0.11. FAB MS, m/z (rel. %): 490
(31) [M+Na]; 468 (100) [M + H]. 1H NMR (300 MHz, CDCl3): 1.26 (d, 3 H, J(CH3,CH) = 6.6,
CH3); 1.29 (d, 3 H, J(CH3,CH) = 6.6, CH3); 3.31 (s, 3 H, CH3O); 3.73 (d, 2 H, J(CH2,P) = 8.2,
PCH2); 3.92 (t, 2 H, J(2′,1′) = 5.0, CH2-2′); 4.30 (t, 2 H, J(1′,2′) = 5.0, CH2-1′); 4.69 (m , 1 H,
POCH); 4.92 (s, 2 H, NH2); 6.03 (s, 2 H, NCH2O); 7.81 (s, 1 H, H-4′′); 7.89 (s, 1 H, H-8); 8.51
(s, 1 H, H-2′′). 13C NMR (75.5 MHz, CDCl3): 23.93 (CH3); 42.85 (C-1′); 56.27 (OCH3); 65.99
(d, J(P,C) = 167.7, PCH2); 70.97 (d, J(P,C) = 9.7, C-2′); 71.17 (d, J(P,C) = 6.3, POCH); 77.92
(NCH2O); 124.05 (C-5′′); 126.51 (C-5); 138.31 (C-4′′); 141.70 (C-2′′); 142.35 (C-8); 148.19
(C-6); 153.30 (C-4); 158.97 (C-2). For C19H30N7O5P (467.5) calculated: 48.82% C, 6.47% H,
20.97% N; foun d: 48.95% C, 6.70% H, 20.90% N.
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1368
Česnek, Hocek, Holý:
Cross-Couplin g Reaction s of 2-Am in o-6-ch loropurin e 1 with Trialkylalum in ium s.
Gen eral Procedure
A trialkylalum in ium solution in toluen e or cycloh exan e (2 m m ol) was dropwise added to a
stirred solution of com poun d 1 (390 m g, 1 m m ol) an d Pd(PPh 3)4 (58 m g, 0.05 m m ol) in
THF (20 m l) at room tem perature un der Ar an d th e m ixture was refluxed for 6 h . Th e sol-
ven t was th en evaporated an d th e residue was treated with m eth an ol (10 m l) an d
evaporated. Th e residue was ch rom atograph ed on a colum n of silica gel [50 g, eth yl acetate–
m eth an ol (93 : 7)] to give product 3k or 3l.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-methylpurine (3k). Yield 67%; colour-
less oil; RF (C) 0.32. FAB MS, m/z (rel. %): 372 (100) [M + H]. 1H NMR (300 MHz, CDCl3):
1.25 (d, 3 H, J(CH3,CH) = 6.6, CH3); 1.28 (d, 3 H J(CH3,CH) = 6.6, CH3); 2.65 (s, 3 H, CH3);
3.71 (d, 2 H, J(CH2,P) = 8.2, PCH2); 3.89 (t, 2 H, J(2′,1′) = 5.0, CH2-2′); 4.26 (t, 2 H, J(1′,2′) =
5.0, CH2-1′); 4.67 (m , 1 H, POCH); 5.13 (s, 2 H, NH2); 7.82 (s, 1 H, H-8). Exact m ass (FAB
HRMS, m/z) foun d 372.1889; calculated for C15H27N5O4P [M + H] 372.1801.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-ethylpurine (3l). Yield 78%; colourless
oil; RF (A) 0.12. FAB MS, m/z (rel. %): 408 (11) [M+Na]; 386 (100) [M + H]. 1H NMR (300 MHz,
CDCl3): 1.25 (d, 3 H, J(CH3,CH) = 6.6, CH3); 1.29 (d, 3 H, J(CH3,CH) = 6.6, CH3); 1.37 (t, 3 H,
J(CH3,CH2) = 7.7, CH3); 3.02 (q, 2 H, J(CH3,CH2) = 7.7, CH2); 3.72 (d, 2 H, J(CH2,P) = 8.3,
PCH2); 3.90 (t, 2 H, J(2′,1′) = 5.3, CH2-2′); 4.28 (t, 2 H, J(1′,2′) = 5.0, CH2-1′); 4.68 (m , 1 H,
POCH); 4.93 (s, 2 H, NH2); 7.80 (s, 1 H, H-8). Exact m ass (FAB HRMS, m/z) foun d 386.1952;
calculated for C16H29N5O4P [M + H] 386.1957.
Perfluoroalkylation of 2-Am in o-6-iodopurin e 2. Gen eral Procedure
A m ixture of com poun d 2 (480 m g, 1 m m ol), RFSiMe3 (2 m m ol), KF (82 m g, 1.4 m m ol), CuI
(304 m g, 1.6 m m ol), DMF (1 m l) an d N-m eth ylpyrrolidon e (1 m l) was stirred at 25 °C for
4 days. To th is solution , saturated aqueous Na2S2O3 (10 m l) was added an d th e m ixture was
extracted with eth yl acetate (3 × 10 m l). Th e collected organ ic layers were dried an d evapo-
rated un der low pressure (ca 100 Pa, bath tem perature ca 40 °C) an d th e residue was
ch rom atograph ed on a colum n of silica gel [50 g, eth yl acetate–m eth an ol (90 : 10)] to give
th e product 3m or 3n .
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-(trifluoromethyl)purine (3m ). Yield
28%; yellowish oil. FAB MS, m/z (rel. %): 426 (100) [M + H], 384 (15) [M – C3H6], 342 (36)
[M – 2C3H6]. 1H NMR (400 MHz, CDCl3): 1.25 an d 1.29 (2 × d, 2 × 6 H, J(CH,CH3) = 6.2,
CH3); 3.73 (d, 2 H, J(P,CH) = 8.1, PCH2); 3.94 (t, 2 H, J(1′,2′) = 4.9, H-2′); 4.33 (t, 2 H, J(2′,1′) =
4.9, H-1′); 4.68 (sept, 2 H, J(CH3,CH) = 6.2, POCH); 5.35 (s, 2 H, NH2); 8.02 (s, 1 H, H-8). 19F NMR
(376.5 MHz, CDCl3): –67.89 (s, CF3). Exact m ass (FAB HRMS, m/z) foun d 426.1530; calcu-
lated for C15H24F3N5O4P [M + H] 426.1518.
2-Amino-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}-6-(heptafluoropropyl)purine (3n ). Yield
21 %; yellowish oil. FAB MS, m/z (rel. %): 526 (100) [M + H], 484 (12) [M – C3H6], 442 (62)
[M – 2C3H6]. 1H NMR (400 MHz, CDCl3): 1.24 an d 1.28 (2 × d, 2 × 6 H, J(CH,CH3) = 6.2,
CH3); 3.74 (d, 2 H, J(P,CH) = 8.2, PCH2); 3.94 (t, 2 H, J(1′,2′) = 4.8, H-2′); 4.34 (t, 2 H, J(2′,1′) =
4.9, H-1′); 4.68 (sept, 2 H, J(CH3,CH) = 6.2, POCH); 5.22 (s, 2 H, NH2); 8.03 (s, 1 H, H-8). 19F NMR
(376.5 MHz, CDCl3): –80.62 (t, J= 9.0, CF2); –115.30 (brd, J= 8.3, CF2), –126.65 (s, CF3). Ex-
act m ass (FAB HRMS, m/z) foun d 526.1542; calculated for C17H24F7N5O4P [M + H] 526.1454.
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Acyclic Nucleotide Analogues
1369
Cleavage of th e Ph osph on ate Esters 3a–3n . Gen eral Procedure
Method A: Ester 3 (0.5 m m ol) was dissolved in aceton itrile (10 m l) an d to th is solution ,
TMSBr (2 m l, 15.2 m m ol) was added dropwise. Th e m ixture was stirred overn igh t at room
tem perature. After evaporation of th e solven t an d reagen t an d co-distillation with aceto-
n itrile (10 m l) an d toluen e (10 m l), th e residue was treated with water (10 m l) an d 35%
aqueous NH3 (1 m l) for 5 m in an d evaporated. Th e residue was dissolved in water, acidified
with on e drop of con c. aqueous HCl an d applied on to a colum n of Dowex 50X8 (H+ form ).
Th e colum n was wash ed with water an d eluted with 3% aqueous NH3. Th e product con tain -
in g UV-absorbin g fraction s were evaporated, th e residue was dissolved in 35% aqueous NH3
an d applied on to a colum n of Dowex 1X2 (acetate form ), wash ed with water an d eluted
with a lin ear gradien t of aqueous acetic or form ic acid (0–1 M). Th e product con tain in g frac-
tion s were evaporated, codistilled with water (5 × 30 m l) an d th e residue was crystallized to
give pure free ph osph on ate 4.
Method B: A m ixture of ester 3 (0.5 m m ol), TMSBr (2 m l, 15.2 m m ol) an d aceton itrile (10 m l)
was stirred at 80 °C for 2 h an d th en allowed to stan d at room tem perature overn igh t. Th e
quen ch in g of th e reaction an d isolation of th e products was perform ed in th e sam e m an n er
as in m eth od A.
Method C: Ester 3 (0.5 m m ol) was dissolved in aceton itrile (10 m l) an d to th is solution ,
TMSBr (2 m l, 15.2 m m ol) was added dropwise. Th e m ixture was stirred overn igh t at room
tem perature. After evaporation of th e solven t an d reagen t an d co-distillation with aceto-
n itrile (10 m l) an d toluen e (10 m l), th e residue was treated with water (10 m l) an d
trieth ylam in e (1 m l) for 5 m in an d evaporated. Th e residue was dissolved in water, acidified
with on e drop of con c. aqueous HCl an d applied on to a colum n of Dowex 50X8 (H+ form ).
Th e product was eluted with water. Th e product-con tain in g fraction s were evaporated an d
th e residue was crystallized from water-eth an ol–dieth yl eth er.
2-Amino-6-phenyl-9-[2-(phosphonomethoxy)ethyl]purine (4a). Meth od A; eluted by a gradien t
of aqueous form ic acid; yield 84%, crystallized from water; m .p. 284–286 °C (dec.); EUp 0.68.
FAB MS, m/z (rel. %): 350 (100) [M + H]. 1H NMR (400 MHz, DMSO-d6): 3.62 (d, 2 H,
J(CH2,P) = 8.7, PCH2); 3.88 (t, 2 H, J(2′,1′) = 5.2, CH2-2′); 4.27 (t, 2 H, J(1′,2′) = 5.2, CH2-1′);
6.51 (brs, 2 H, NH2); 7.52 (m , 3 H, H-arom ); 8.15 (s, 1 H, H-8); 8.71 (m , 2 H, H-arom ). 13C
NMR (100.6 MHz, DMSO-d6): 42.06 (C-1′); 66.35 (d, J(P,C) = 160.0, PCH2); 69.92 (d, J(P,C) =
10.4, C-2′); 123.87 (C-5); 128.24, 129.07, 130.40 (3 × CH-arom ); 135.95 (C-1′′) 142.87 (C-8);
153.34 (C-6); 154.47 (C-4); 160.01 (C-2). For C14H16N5O4P (349.3) calculated: 48.14% C,
4.62% H, 20.05% N, 8.87% P; foun d: 47.81% C, 4.72% H, 19.91% N, 9.03% P. UV spectrum :
(pH 2) λm ax 259 (εm ax 10 700), λm ax 340 (εm ax 11 800).
2-Amino-9-[2-(phosphonomethoxy)ethyl]-6-(2-tolyl)purine (4b). Meth od A, eluted by a gradi-
en t of aqueous form ic acid; yield 92%; crystallized from water–eth an ol; colourless crystals;
m .p. 154–157 °C (dec.); EUp 0.72. FAB MS, m/z (rel. %): 364 (100) [M + H]. 1H NMR (400 MHz,
DMSO-d6): 2.35 (s, 3 H, CH3); 3.62 (d, 2 H, J(CH2,P) = 8.6, PCH2); 3.89 (t, 2 H, J(2′,1′) = 5.3,
CH2-2′); 4.26 (t, 2 H, J(1′,2′) = 5.3, CH2-1′); 6.51 (vbrs, 2 H, NH2); 7.32 (m , 3 H, H-arom .);
7.54 (m ,
1
H, H-arom .); 8.07 (s, 1H, H-8). 13C NMR (100.6 MHz, DMSO-d6): 20.21
(CH3-tolyl); 42.03 (C-1′); 66.35 (d, J(P,C) = 160.2, PCH2); 69.89 (d, J(P,C) = 10.1, C-2′);
124.77 (C-5); 125.19, 128.87, 130.16, 130.33 (4 × CH-arom ); 135.77, 136.28 (C-1′′, C-2′′);
142.80 (C-8); 153.59 (C-6); 157.93 (C-4); 159.88 (C-2). Exact m ass (FAB HRMS, m/z) foun d
364.1222; calculated for C15H18N5O4P [M + H] 364.1175. UV spectrum : (pH 2) λm ax 253
(εm ax 5 700), λm ax 327 (εm ax 9 300).
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1370
Česnek, Hocek, Holý:
2-Amino-6-(4-fluorophenyl)-9-[2-(phosphonomethoxy)ethyl]purine (4c). Meth od A; eluted by a
gradien t of aqueous form ic acid; yield 66%; crystallized from water; colourless crystals; m .p.
145–150 °C. EUp 0.68. FAB MS, m/z (rel. %): 368 (100) [M + H]. 1H NMR (400 MHz,
DMSO-d6): 3.62 (brs, 2 H, PCH2); 3.88 (brs, 2 H, CH2-2′); 4.27 (brs, 2 H, CH2-1′); 6.54 (brs, 2 H,
NH2); 7.32 (t, 2 H, J = 8.9, H-arom .); 8.16 (s, 1 H, H-8); 8.80 (dd, 2 H, J = 6.0, J = 8.5,
H-arom .). 13C NMR (100.6 MHz, DMSO-d6): 42.07 (C-1′); 69.88 (C-2′); 115.23 (d, J(F,C) =
21.4, C-3′′); 123.59 (C-5); 131.37 (d, J(F,C) = 7.7, C-2′′); 132.44 (C-1′′); 142.95 (C-8); 152.10
(C-6); 154.47 (C-4); 159.97 (C-2); 163.47 J(F,C) = 248.5 (C-4′′). For C14H15FN5O4P·H2O
(385.3) calculated: 43.64% C, 4.45% H, 4.93%F, 18.18% N, 8.04% P; found: 43.53% C, 4.16% H,
4.79%F, 18.21% N, 8.44% P. UV spectrum : (pH 2) λm ax 261 (εm ax 9 000), λm ax 341 (εm ax
11 300).
2-Amino-9-[2-(phosphonomethoxy)ethyl]-6-(2-thienyl)purine (4d ). Meth od A; eluted by a gra-
dien t of aqueous form ic acid; yield 95%, crystallized from water; yellowish crystals; m .p.
260–264 °C. EUp 0.67. FAB MS, m/z (rel. %): 356 (95) [M + H]. 1H NMR (400 MHz, DMSO-d6):
3.62 (d, 2 H, J(CH2,P) = 8.6, PCH2); 3.88 (t, 2 H, J(2′,1′) = 5.2, CH2-2′); 4.25 (t, 2 H, J(1′,2′) =
5.2, CH2-1′); 6.50 (vbrs, 2 H, NH2); 7.27 (dd, 1 H, J = 4.8, 3.9, H-arom .); 7.80 (m , 1 H,
H-arom .); 8.14 (s, 1 H, H-8); 8.54 (m , 1 H, H-arom ). 13C NMR (100.6 MHz, DMSO-d6): 42.06
(C-1′); 66.31 (d, J(P,C) = 160.2, PCH2); 69.93 (d, J(P,C) = 10.5, C-2′); 121.93 (C-5); 128.49,
130.28, 131.57 (3 × CH-arom ); 140.50 (C-2′′); 143.01 (C-8); 149.01 (C-6); 153.98 (C-4);
159.90 (C-2). For C12H14N5O4PS (355.3) calculated: 40.57% C, 3.97% H, 19.71% N, 8.72% P;
foun d: 40.18% C, 4.01% H, 19.45% N, 8.81% P. UV spectrum : (pH 2) λm ax 235 (εm ax 17 600),
λm ax 292 (εm ax 6 500), λm ax 369 (εm ax 13 800).
2-Amino-9-[2-(phosphonomethoxy)ethyl]-6-(pyridin-2-yl)purine (4e). Meth od B; eluted by a
gradien t of aqueous acetic acid; yield 90%; crystallized from water; yellow crystals; m .p. 240 °C
(dec). EUp 0.70. FAB MS, m/z (rel. %): 351 (100) [M + H]. 1H NMR (400 MHz, DMSO-d6): 3.61
(d, 2 H, J(CH2,P) = 8.6, PCH2); 3.89 (t, 2 H, J(2′,1′) = 5.1, CH2-2′); 4.28 (t, 2 H, J(1′,2′) = 5.1,
CH2-1′); 6.75 (brs, 2 H, NH2); 7.52 (m , 1 H, H-5′′); 7.99 (m , 1 H, H-4′′); 8.23 (s, 1 H, H-8);
8.58 (d, 1 H, J(3′′,4′′) = 7.9, H-3′′); 8.77 (d, 1 H, J(6′′,5′′) = 4.2, H-6′′). 13C NMR (100.6 MHz,
DMSO-d6): 42.35 (C-1′); 66.64 (d, J(P,C) = 159.9, PCH2); 69.93 (d, J(P,C) = 10.3, C-2′); 124.25
(C-5); 124.92 (C-3′′); 125.52 (C-5′′); 136.78 (C-4′′); 144.04 (C-8); 149.61 (C-6′′); 153.05 (C-6);
153.33 (C-2′′); 155.11 (C-4); 159.98 (C-2). For C13H15N6O4P (350.3) calculated: 44.58% C,
4.32% H, 23.99% N; foun d: 44.24% C, 4.35% H, 23.69% N. UV spectrum : (pH 2) λm ax 276
(εm ax 8 500), λm ax 360 (εm ax 7 900).
2-Amino-6-(1-methylpyrrol-2-yl)-9-[2-(phosphonomethoxy)ethyl]purine (4f). Meth od A; eluted
by a gradien t of aqueous form ic acid; yield 61%; crystallized from water-eth an ol–dieth yl
eth er; green ish crystals; m .p. 141–146 °C. EUp 0.67. FAB MS, m/z (rel. %): 353 (100) [M + H].
1H NMR (400 MHz, DMSO-d6): 3.61 (d, 2 H, J(CH2,P) = 8.6, PCH2); 3.86 (t, 2 H, J(2′,1′) = 5.2,
CH2-2′); 4.12 (s, 3 H, NCH3); 4.22 (t, 2 H, J(1′,2′) = 5.1, CH2-1′); 6.16 (m , 1 H, H-4′′); 6.33
(brs, 2 H, NH2); 7.00 (s, 1 H, H-3′′); 7.63 (m , 1 H, H-5′′); 8.01 (s, 1 H, H-8). 13C NMR (100.6 MHz,
DMSO-d6): 37.81 (NCH3); 41.87 (C-1′); 66.31 (d, J(P,C) = 160.2, PCH2); 70.03 (d, J(P,C) =
10.8, C-2′); 107.83 (C-4′′); 117.92 (C-5′′); 121.89 (C-2′′); 126.87 (C-5); 128.72 (C-3′′); 141.36
(C-8); 149.37 (C-6); 152.99 (C-4); 159.34 (C-2). For C13H17N6O4P·0.5H2O (361.3) calculated:
43.22% C, 5.02% H, 23.26% N, 8.57% P; foun d: 43.52% C, 5.06% H, 23.11% N, 8.95% P.
UV spectrum : (pH 2) λm ax 235 (εm ax 16 000), λm ax 258 sh . (εm ax 4 500), λm ax 310 (εm ax 4 200),
λm ax 373 (εm ax 20 100).
2-Amino-6-(1-methylimidazol-2-yl)-9-[2-(phosphonomethoxy)ethyl]purine (4g). Meth od B;
eluted by a gradien t of aqueous acetic acid; yield 83%; crystallized from water–eth an ol; yel-
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Acyclic Nucleotide Analogues
1371
low crystals; m .p. 252 °C (dec). EUp 0.67. FAB MS, m/z (rel. %): 354 (85) [M + H], 99 (100).
1H NMR (400 MHz, DMSO-d6): 3.59 (d, 2 H, J(CH2,P) = 8.6, PCH2); 3.87 (t, 2 H, J(2′,1′) = 5.1,
CH2-2′); 4.00 (s, 3 H, CH3); 4.26 (t, 2 H, J(1′,2′) = 5.1 CH2-1′); 6.64 (brs, 2 H, NH2); 7.20 an d
7.43 (s, 1 H, H-4′′ an d H-5′′); 8.16 (s, 1 H, H-8). 13C NMR (100.6 MHz, DMSO-d6): 35.42
(CH3); 42.10 (C-1′); 66.57 (d, J(P,C) = 159.8, PCH2); 69.78 (d, J(P,C) = 9.9, C-2′); 123.76
(C-5); 124.91 (C-5′′); 127.43 (C-4′′); 141.15 (C-6); 143.50 (C-8); 146.55 (C-2′′); 154.38 (C-4);
159.66 (C-2). For C12H16N7O4P·0.5H2O (362.3) calculated: 39.78% C, 4.73% H, 27.06% N,
8.55% P; foun d: 39.74% C, 4.78% H, 26.91% N, 8.57% P. UV spectrum : (pH 2) λm ax 229 (εm ax
20 300), λm ax 265 (em ax 10 300), λm ax 351 (εm ax 7 600).
2-Amino-6-(imidazol-2-yl)-9-[2-(phosphonomethoxy)ethyl]purine (4h ). Meth od B; eluted by a
gradien t of aqueous acetic acid; yield 55%; crystallized from water–eth an ol; yellow crystals;
m .p. 234 °C (dec); EUp 0.68. FAB MS, m/z (rel. %): 340 (15) [M + H], 99 (100). 1H NMR (400 MHz,
DMSO-d6): 3.60 (d, 2 H, J(CH2,P) = 8.7, PCH2); 3.88 (t, 2 H, J(2′,1′) = 5.1, CH2-2′); 4.27 (t, 2 H,
J(1′,2′) = 5.2, CH2-1′); 6.53 (brs, 2 H, NH2); 7.35 (m , 2 H, H-4′′ an d H-5′′); 8.23 (s, 1 H, H-8).
13C NMR (100.6 MHz, DMSO-d6): 42.15 (C-1′); 66.53 (d, J(P,C) = 160.0, PCH2); 69.78 (d, J(P,C) =
10.1, C-2′); 122.45 (C-5); 124.75 (CH-arom ); 142.11 (C-6); 143.49 (C-8); 144.74 (C-2′′); 154.22
(C-4); 160.21 (C-2). Exact m ass (FAB HRMS, m/z) foun d 340.0887; calculated for
C
11H14N7O4P [M + H] 340.0923. UV spectrum : (pH 2) λm ax 231 (εm ax 21 100), λm ax 272 (εm ax
13 600), λm ax 360 (εm ax 8 800).
2-Amino-6-(1-methylimidazol-5-yl)-9-[2-(phosphonomethoxy)ethyl]purine (4i). Meth od B;
eluted by a gradien t of aqueous acetic acid; yield 61%; crystallized from water; colourless
crystals; m .p. 325 °C (dec); EUp 0.68. FAB MS, m/z (rel. %): 354 (15) [M + H]. 1H NMR (400
MHz, D2O): 3.70 (d, 2 H, J(CH2,P) = 8.9, PCH2); 3.91 (s, 3 H, NCH3); 3.95 (t, 2H, J(2′,1′) =
4.7, CH2-2′); 4.24 (t, 2 H, J(1′,2′) = 4.8, CH2-1′); 7.75 an d 7.95 (s, 1 H, H-4′′an d H-5′′); 8.16
(s, 1 H, H-8). 13C NMR (100.6 MHz, D2O): 39.20 (NCH3); 45.72 (C-1′); 69.90 (d, J(P,C) =
117.3, PCH2); 73.09 (d, J(P,C) = 8.8, C-2′); 125.22 (C-5); 129.40 (C-5′′); 132.08 (C-4′′); 142.96
(C-8); 146.78 (C-2′′); 148.53 (C-6); 155.42 (C-4); 161.61 (C-2). For C12H16N7O4P·0.5H2O
(362.3) calculated: 39.78% C, 4.73% H, 27.06% N, 8.55% P; foun d: 40.02% C, 4.71% H,
27.02% N, 8.80% P. UV spectrum : (pH 2) λm ax 336 (εm ax 7 500).
2-Amino-6-(imidazol-5-yl)-9-[2-(phosphonomethoxy)ethyl]purine (4j). Meth od B; eluted by a
gradien t of aqueous acetic acid; yield 78%; crystallized from water–eth an ol; yellow crystals;
m .p. 207–212 °C; EUp 0.63. FAB MS, m/z (rel. %): 340 (100) [M + H]. 1H NMR (400 MHz,
D2O): 3.79 (d, 2 H, J(CH2,P) = 8.8, PCH2); 3.95 (m , 2 H, CH2-2′); 4.13 (m , 2 H, CH2-1′); 7.52
an d 7.81 (s, 1 H, H-2′′ an d H-4′′); 8.55 (s, 1 H, H-8). 13C NMR (100.6 MHz, D2O): 37.88
(CH3); 44.16 (C-1′); 68.15 (d, J(P,C) = 157.0, PCH2); 71.27 (d, J(P,C) = 11.9, C-2′); 122.08
(C-5); 122.90 (C-5′′); 128.50 (C-4′′); 136.65 (C-2′′); 142.87 (C-6); 145.98 (C-8); 154.32 (C-4);
159.26 (C-2). Exact m ass (FAB HRMS, m/z) foun d 340.0866; calculated for C11H14N7O4P
[M + H] 340.0923. UV spectrum : (pH 2) λm ax 229 (εm ax 19 400), λm ax 345 (εm ax 7 900).
2-Amino-6-methyl-9-[2-(phosphonomethoxy)ethyl]purine (4k). Meth od A; eluted by a gradien t
of aqueous acetic acid; yield 89%; crystallized from water; colourless crystals; m .p. 287–290 °C
(ref.2b >270 °C); EUp 0.83. FAB MS, m/z (rel. %): 288 (80) [M + H], 57 (100). 1H NMR (300
MHz, D2O): 2.70 (s, 3 H, CH3) 3.61 (d, 2 H, J(CH2,P) = 8.8, PCH2); 3.91 (t, 2 H, J(2′,1′) = 5.0,
CH2-2′); 4.33 (t, 2 H, J(1′,2′) = 5.0, CH2-1′); 8.40 (s, 1 H, H-8). For C9H14N5O4P (287.2) calcu-
lated: 37.64% C, 4.91% H, 24.38% N, 10.78% P; foun d: 37.31% C, 4.94% H, 23.99% N,
10.89% P. UV spectrum : (pH 2) λm ax 248 (εm ax 3 700), λm ax 310 (εm ax 5 000).
2-Amino-6-ethyl-9-[2-(phosphonomethoxy)ethyl]purine (4l). Meth od A; eluted by a gradien t of
aqueous acetic acid; yield 89%; crystallized from water–eth an ol; colourless crystals; m .p.
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1372
Česnek, Hocek, Holý:
139–144 °C; EUp 0.78. FAB MS, m/z (rel. %): 302 (44) [M + H], 115 (100). 1H NMR (400 MHz,
DMSO-d6): 1.26 (t, 3 H, J(CH2,CH3) = 7.6, CH3); 2.84 (q, 2 H, J(CH3,CH2) = 7.6, CH2); 3.48
(d, 2 H, J(P,CH) = 8.5, PCH2); 3.80 (t, 2 H, J(1′,2′) = 5.3, H-2′); 4.18 (t, 2 H, J(2′,1′) = 5.3,
H-1′); 6.37 (brs, 2 H, NH2); 8.02 (s, 1 H, H-8). 13C NMR (100 MHz, DMSO-d6): 12.33 (CH3);
25.66 (CH2CH3); 42.01 (C-1′); 67.49 (d, J(P,CH2) = 157.1 CH2P); 69.67 (C-2′); 124.67 (C-5);
141.80 (C-8); 152.45 (C-4); 160.09 (C-2); 162.86 (C-6). For C10H16N5O4P (301.2) calculated:
39.87% C, 5.35% H, 23.25% N, foun d: 39.66% C, 5.52% H, 22.97 %N. UV spectrum : (pH 2)
λm ax 246 (εm ax 4 100), λm ax 311 (εm ax 5 200).
2-Amino-9-[2-(phosphonomethoxy)ethyl]-6-(trifluoromethyl)purine (4m ). Meth od C; yield 65%;
yellowish crystals; m .p. 138–141 °C; EUp 0.83. FAB MS, m/z (rel. %): 342 (100) [M + H]. 1H NMR
(400 MHz, DMSO-d6): 3.56 (d, 2 H, J(P,CH) = 7.6, PCH2); 3.85 (brs, 2 H, H-2′); 4.26 (brs, 2 H,
H-1′); 7.03 (brs, 2 H, NH2); 8.30 (s, 1 H, H-8). 19F NMR (376.5 MHz, DMSO-d6): –65.06 (s, CF3).
For C9H11F3N5O4P (341.2) calculated: 31.68% C, 3.25% H, 20.53% N; foun d: 31.37% C,
3.32% H, 20.29% N.
2-Amino-6-(heptafluoropropyl)-9-[2-(phosphonomethoxy)ethyl]purine (4n ). Meth od C; yield
59%; yellowish crystals; m .p. 166–168 °C; EUp 0.77. FAB MS, m/z (rel. %): 442 (100) [M + H].
1H NMR (400 MHz, DMSO-d6): 3.56 (d, 2 H, J(P,CH) = 8.5, PCH2); 3.86 (t, 2 H, J(1′,2′) = 5.0,
H-2′); 4.26 (t, 2 H, J(2′,1′) = 5.0, H-1′); 7.03 (brs, 2 H, NH2); 8.30 (s, 1 H, H-8). 19F NMR
(376.5 MHz, DMSO-d6): –79.42 (brs, CF2); -113.09 (brs, CF2), –125.43 (s, CF3). For
C
11H11F7N5O4P (441.2) calculated: 29.95% C, 2.51% H, 15.87% N; foun d: 29.86% C, 2.74% H,
15.83% N.
This work was supported by the Grant Agency of the Czech Republic (grants No. 203/98/P027 and
No. 203/96/K001) and by Gilead Sciences (Foster City, CA, U.S.A.). The authors thanks are due to Dr
H. Dvořáková (Prague Institute of ChemicalTechnoolgy) for measurment and interpretation of some
NMR spectra, to Dr I. Votruba (this Institute) for cytostatic activity tests and to Prof. E. De Clercq and
his group at the Rega Institute for MedicalResearch, Leuven (Beglium) for the antiviralevaul ation of
the compounds.
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