Synthesis of acyclic nucleoside and nucleotide analogs derived from 6-amino-7H-purin-8(9H)-one

Article abstract of DOI:10.1135/cccc20001126

Reaction of 8-bromoadenine derivatives 2 with sodium acetate in acetic acid and cleavage of (S)-7-[(trityloxy)methyl]-7,8-dihydro[1,3]oxazolo[3,2-e]purin-4-amine (12) and diisopropyl (S)-[[(4-amino-8,9-dihydro-7H-[1,3]oxazino[3,2-e]purin-8-yl)oxy]methyl]phosphona te (13a) were used for the synthesis of the corresponding N⁹-substituted derivatives of 6-amino-7H-purin-8(9H)-one 3a-3c and 7. Alkylation of 6-amino-7H-purin-8(9H)-one (3a) with diverse alkylation agents afforded the title N⁹-monosubstituted 3b, 3d and 7a and N⁷,N⁹-disubstituted acyclic nucleoside and nucleotide analogs 6b, 6d and 8a.

Full text of DOI:10.1135/cccc20001126

1126
Janeba, Holý, Masojídková:
SYNTHESIS OF ACYCLIC NUCLEOSIDE AND NUCLEOTIDE ANALOGS
DERIVED FROM 6-AMINO-7H-PURIN-8(9H)-ONE
1,
2
3
Zlatko JANEBA *, Antonín HOLÝ and Milena MASOJÍDKOVÁ
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic,
1
2
166 10 Prague 6, Czech Republic; e-mail: janeba@uochb.cas.cz, holy@uochb.cas.cz,
saman@uochb.cas.cz
3
Received March 27, 2000
Accepted May 3, 2000
Reaction of 8-brom oaden in e derivatives 2 with sodium acetate in acetic acid an d cleavage of
(S)-7-[(trityloxy)m eth yl]-7,8-dih ydro[1,3]oxazolo[3,2-e]purin -4-am in e (12) an d diisopropyl
(S)-{[(4-am in o-8,9-dih ydro-7H-[1,3]oxazin o[3,2-e]purin -8-yl)oxy]m eth yl}ph osph on ate (13a)
were used for th e syn th esis of th e correspon din g N9-substituted derivatives of 6-am in o-
7H-purin -8(9H)-on e 3a –3c an d 7. Alkylation of 6-am in o-7H-purin -8(9H)-on e (3a ) with
diverse alkylation agen ts afforded th e title N9-m on osubstituted 3b, 3d an d 7a an d N7,N9-disub-
stituted acyclic n ucleoside an d n ucleotide an alogs 6b, 6d an d 8a.
Key w ord s: Purin es; Acyclic an alogs; Nucleosides; Nucleotides; Alkylation ; An h ydro deriva-
tives; Ph osph on ates; Brom in ation .
8-Substituted purin e derivatives occupy a prom in en t place in n ucleoside
an d n ucleotide ch em istry. Th e im portan ce of th ese com poun ds as poten tial
an tiviral an d an tican cer agen ts is obvious. Of th em , 8-h ydroxy derivatives
(e.g. 8-h ydroxyguan osin e1) an d 8-am in o derivatives (e.g. 8-am in oguan o-
sin e1 or 8-am in o-9-ben zylguan in e2) sh ould be particularly m en tion ed.
Man y biologically active acyclic n ucleotide an alogs h ave been prepared.
Am on g oth ers, two im portan t groups of com poun ds of th is type h ave been
studied in detail owin g to th eir an tiviral properties in vitro an d in vivo:
N-[2-(ph osph on om eth oxy)eth yl] (PME) an d (S)-N-[3-h ydroxy-2-(ph osph o-
n om eth oxy)propyl] (HPMP) derivatives of h eterocyclic bases3. Exh austive
in form ation was obtain ed on th e in fluen ce of substituen ts in position s 6
an d 2 of th e purin e rin g4. However, th e data on th e effect of th e substitu-
tion in position 8 on th e an tiviral an d/or cytostatic activity in th ese series
are rath er scarce. Such com poun ds derived from 6-am in o-7H-purin -
8(9H)-on e (3a) are n ow of special in terest for us.
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

6-Amino-7H-purin-8(9H)-one Derivatives
1127
RESULTS AND DISCUSSION
Th ere are two prin cipal approach es for th e preparation of 8-substituted pu-
rin e acyclic n ucleoside an d n ucleotide an alogs: (i) m odification of th e cor-
respon din g acyclic n ucleoside or n ucleotide derivative in position 8 of th e
purin e m oiety or (ii) preparation of an 8-substituted purin e base an d its
subsequen t alkylation with a suitable reagen t.
Brom in ation of purin e derivatives is th e first step in m odification of bases
in position 8. 8-Brom oaden in e5 (2a) was prepared by 5 h treatm en t of ade-
n in e (1a) with brom in e (Sch em e 1). Brom in ation of acyclic n ucleotide
an alogs 1b an d 1c with brom in e in a m ixture of dioxan e an d 10% aqueous
solution of disodium h ydrogen ph osph ate afforded th e correspon din g
8-brom opurin e derivatives 2b an d 2c in good yields3g,6
.
NH2
NH2
NH2
H
N
N
N
(ii)
(i)
N
N
N
Br
O
N
R
N
R
N
R
N
N
N
1
2
3
1-3 a, R = H
b, R = CH2CH2OCH2P(O)(OiPr)2
(ia) Br2, 5 h
(i) Br2, dioxane, H2O, Na2HPO4
(ii) AcONa, AcOH, reflux, 8 h
c, R =
H2C
OH
O
P(O)(OiPr)2
SCHEME 1
Syn th esis of com poun ds con tain in g oxo (h ydroxy) group in position 8 of
th e purin e m oiety can be perform ed by th e reaction of appropriate 8-brom o
derivatives with sodium acetate in acetic acid un der reflux7. Th us,
8-brom oaden in e (2a) was con verted to 6-am in o-7H-purin -8(9H)-on e in
94% yield (3a, Sch em e 1) an d, sim ilarly, 8-brom o-9-{2-[(diisopropoxyph os-
ph oryl)m eth oxy]eth yl}aden in e (2b , PMEA derivative) an d (S)-8-brom o-
9-{2-[(diisopropoxyph osph oryl)m eth oxy]-3-h ydroxypropyl}aden in e (2c,
(S)-HPMPA derivative) were con verted to th e correspon din g 8-oxo deriva-
tives 3b an d 3c, respectively. In th e case of HPMP derivative 3c, diester is
partly cleaved to m on oester un der reaction con dition s as con firm ed by
electroph oresis an d TLC. Th is is in accord with th e described cleavage of
ph osph on ate diesters with n ucleoph ilic reagen ts. Th erefore, th e m ixture
was treated with TMSBr with out an y purification to afford ph osph on ate 9
(Sch em e 3).
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1128
Janeba, Holý, Masojídková:
8-Brom oaden in e (2a) gave, in th e alkylation reaction with (S)-trityl-
glycidol in DMF in th e presen ce of Cs2CO3, N9-isom er 4 an d N3-isom er 5a
in yields of 48 an d 20%, respectively (Sch em e 2). Th e form ation an d a sim i-
lar ratio of N9- an d N3-isom ers in 8-brom oaden in e alkylation was recen tly
reported8. Acid treatm en t of com poun d 5a afforded (S)-8-brom o-
3-(2,3-dih ydroxypropyl)aden in e (5b).
NH2
NH2
NH2
N
N
N
N
N
(i)
N
N
N
Br
Br
Br
+
N
H
N
N
N
2a
4
OTr
OR
OH
OH
5
(i) (S)-tritylglycidol, DMF, Cs2CO3, 120 oC, 12 h
a, R = Tr
b, R = H
(ii)
(ii) 80% AcOH, reflux, 1 h
SCHEME 2
An altern ative alkylation approach for th e syn th esis of 8-oxopurin e deriv-
atives is in terestin g because it offers a possibility to obtain diverse
regiom ers as th e alkylation products. In order to obtain in troductory in for-
m ation about th e regiospecificity of th is reaction , alkylation of com poun d
3a was perform ed with diverse alkylation agen ts (Sch em e 3): m eth yl
tosylate, diisopropyl [(2-ch loroeth oxy)m eth yl]ph osph on ate (PME reagen t)
an d (S)-tritylglycidol, in DMF an d with sodium h ydride or cesium carbon -
ate as a base7b. In all cases th e correspon din g N9-alkyl derivatives 3b, 3d
an d 7a were obtain ed, accom pan ied by N7,N9-disubstituted derivatives 6b,
6d an d 8a. Th e PME derivative 3b is iden tical with th e auth en tic com -
poun d prepared by base m odification of th e correspon din g acyclic
n ucleoside an alog (Sch em e 1). Mon oalkyl derivative 7a an d dialkyl deriva-
tive 8a were obtain ed in 33 an d 22% yields, respectively, wh en 1.2
equivalen t of th e (S)-tritylglycidol was used, an d in 15 an d 52% yields, respe-
ctively, wh en 2.4 equivalen ts of th e sam e reagen t was used for alkylation .
No form ation of N7-m on osubstituted product was detected in an y of th ese
alkylation s.
On acid treatm en t, th e dialkyl derivative 8a un derwen t detritylation to
give com poun d 8b (Sch em e 3). N6-[(Dim eth ylam in o)m eth yliden e] deriva-
tive of com poun d 8a was prepared by th e reaction with dim eth yl-
form am ide dim eth ylacetal; it afforded, on treatm en t with diisopropyl
[(tosyloxy)m eth yl]ph osph on ate3d an d sodium h ydride in THF, th e
bis(HPMP) derivative 10a. Sim ilarly, m on oalkyl derivative 7b an d HPMP
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

6-Amino-7H-purin-8(9H)-one Derivatives
1129
derivative 3c (iden tical with th e auth en tic com poun d prepared by base m od-
ification , Sch em e 1) were prepared from m on osubstituted derivative 7a.
Th e alkylation of 6-am in o-7H-purin -8(9H)-on e (3a) with th e used re-
agen ts gives a m ixture of two products: N9-m on osubstituted derivatives an d
N7,N9-disubstituted derivatives bearin g iden tical alkyl groups. Th e ratio of
both products of th e reaction depen ds on th e excess of th e alkylation re-
agen t. Th e origin ally form ed N9-m on osubstituted derivatives can be furth er
substituted in th e N7 position to give N7,N9-disubstituted derivatives con -
tain in g two differen t alkyl groups. Th us, com poun d 11 was prepared by
NH2
NH2
NH2
H
N
H
N
R
N
(i)
N
N
N
O
O
+
O
N
H
N
R
N
R
N
N
N
3a
3
6
3, 6 d, R = CH3
b, CH2CH2OCH2P(O)(OiPr)2
e, CH2CH2OCH2P(O)(OH)2
(viii)
(ii)
OH
OR
NH2
NH2
H
N
N
N
N
O
+
O
N
N
N
N
OR
OR
7
8
OH
OH
a, R = Tr
b, R = H
a, R = Tr
b, R = H
(iii)
(iii)
(iv)-(vii)
(iv)-(vii)
OCH2P(O)(OR)2
OR
NH2
NH2
H
N
N
N
N
N
N
O
O
N
N
OH
OH
10
OCH2P(O)(OR)2
OCH2P(O)(OR)2
a, R = iPr
b, R = H
3c, R = iPr
9, R = H
(viii)
(viii)
(ia) MeOTs, DMF, NaH; (ib) ClCH2CH2OCH2P(O)(OiPr)2, DMF, NaH; (ii) (S)-tritylglycidol, DMF,
Cs2CO3; (iii) 80% AcOH, reflux, 1 h; (iv) Me2NCH(OMe)2, DMF; (v) TsOCH2P(O)(OiPr)2, THF,
NaH; (vi) methanolic NH3; (vii) 80% aq. AcOH; (viii) TMSBr, MeCN
SCHEME 3
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1130
Janeba, Holý, Masojídková:
m eth ylation of com poun d 3b with m eth yl tosylate an d sodium h ydride in
DMF followed by stan dard tran ssilylation cleavage of th e ph osph on ate
diesters (Sch em e 4).
NH2
NH2
H
N
CH3
N
N
N
(i), (ii)
O
O
N
N
N
N
O
P(O)(OiPr)2
O
P(O)(OH)2
3b
11
(i) MeOTs, DMF, NaH; (ii) TMSBr, MeCN
SCHEME 4
Gen erally, 8-h ydroxypurin e n ucleosides are useful key in term ediates of
th e purin e cyclon ucleoside syn th esis9. On th e oth er h an d, purin e cyclo-
n ucleosides an d th eir acyclic an alogs con tain in g O-an h ydro lin kages are
form ed as in term ediates in various tran sform ation s leadin g to th e
8-h ydroxy (8-oxo) purin e derivatives10.
In th e previous study6, we h ave reported on th e preparation of som e
an h ydro derivatives of acyclic n ucleoside an alogs eith er by oxidative
cyclization of 9-(ω-h ydroxyalkyl)aden in e derivatives with lead(IV) acetate
or by reaction of th e correspon din g 8-brom o derivatives with aqueous am -
m on ia, sodium h ydride, potassium tert-butoxide or 1,8-diazabicyclo-
[5.4.0]un dec-7-en e (DBU). As a sim ple m odel of such a cyclic in term ediate
we h ave prepared com poun d 12 by th e in tram olecular cyclization of brom o
derivative 4 with sodium h ydride in THF (Sch em e 5). Acid treatm en t of cy-
clic derivative 12 (Dowex 50) gave com poun d 7b in 66% yield, iden tical
with th e com poun d prepared by alkylation of 8-h ydroxyaden in e with
(S)-tritylglycidol an d subsequen t detritylation (Sch em e 3).
NH2
NH2
NH2
H
N
N
N
N
N
(i)
(ii)
N
N
N
Br
O
O
N
N
N
N
OTr
OTr
OH
4
7b
12
OH
OH
(i) THF, NaH; (ii) Dowex 50 (H+), 50% aq. MeOH
SCHEME 5
Sim ilarly, 8-brom o derivative 2c gave on treatm en t with 2 equivalen ts of
sodium h ydride in DMF an h ydro derivative 13a in 50% yield (Sch em e 6).
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

6-Amino-7H-purin-8(9H)-one Derivatives
1131
Acid treatm en t of com poun d 13a afforded com poun d 3c (iden tical with
th e auth en tic com poun ds prepared by th e base m odification in position 8
(Sch em e 1) an d by an oth er in depen den t syn th esis (Sch em e 3)). Also in th is
case, a partial cleavage of com poun d 3c to th e m on oester was observed.
Partial cleavage of diesters 13a usin g lith ium azide11 gave m on oester 14 in
73% yield.
NH2
NH2
NH2
H
N
N
N
N
N
(i)
(iii)
N
N
N
Br
O
O
N
N
N
OH
OH
N
2c
13
OCH2P(O)(OR)2
OCH2P(O)(OiPr)2
OCH2P(O)(OR)2
a, R = iPr
b, R = H
3c, R = iPr
9, R = H
(ii)
(ii)
(iv)
NH2
N
N
N
(i) NaH, DMF
O
(ii) TMSBr, MeCN
N
(iii) Dowex 50, 50% aq. MeOH
(iv) LiN3, DMF, 100 oC, 5 h
14
OCH2P(O)(OiPr)(OH)
SCHEME 6
Stan dard treatm en t with brom otrim eth ylsilan e (TMSBr) in aceton itrile
followed by h ydrolysis was used for th e ultim ate cleavage of ph osph on ate
diesters3g. Deion isation on Dowex 50 (H+) followed by Dowex 1 (AcO–)
ion -exch an ge ch rom atograph y was used for isolation of th e free ph os-
ph on ates.
1
All n ew com poun ds were fully ch aracterized by H NMR (an d 13C NMR),
MS an d HR-MS or m icroan alysis. Th e structures of th e com poun ds prepared
by alkylation of startin g com poun d 3a were determ in ed on th e basis of pro-
ton -coupled 13C NMR spectra. An exam ple is given for a pair of N9-[2-(ph os-
ph on om eth oxy)eth yl] derivative 3b an d its N7,N9-bis[2-(ph osph on o-
m eth oxy)eth yl] an alog 6b. Th e assign m en t of th e carbon NMR sign als of
C-2 (1J(C-2,H-2) = 200.2), C-6 (3J(C-6,H-2) = 11.7) an d C-5 (splittin g by NH2
proton s to triplet, J = 4.9, th e splittin g disappears after D2O addition ) was
con firm ed for com poun d 3b prepared by two in depen den t procedures. Th e
sign al δ 147.81 of C-4 (3J(C-4,H-2) = 12.7) was splitted to triplet of doublet
by H-1′ proton s. Sim ilarly, th e sign al δ 152.17 of C-8 was splitted by H-1′
proton s to triplet (J = 3.9). Th e N7,N9-disubstitution of com poun d 6b was
con firm ed by th e presen ce of oth er two couplin g con stan ts of C-5
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1132
Janeba, Holý, Masojídková:
(3J(C-5,H-1′′) = 3.9) an d by splittin g of th e sign al δ 152.47 of C-8 to quin tet
by H-1′ an d H-1′′ proton s. Sim ilar results were obtain ed for th e oth er pairs
of N9-m on o- an d N7,N9-disubstituted an alogs.
Sim ilarly, th e structure of N3-substituted 8-brom oaden in e derivative 5b
was determ in ed by th e presen ce of ch aracteristic alkylation effects (upfield
sh ift (–7 ppm ) at C-2 an d down field sh ift (12 ppm ) at C-8) an d by th e sig-
n al m ultiplicity in proton -coupled 13C NMR spectrum : doublet δ 154.09
was assign ed to C-6 (3J(C-6,H-2) = 11.7), doublet of triplets δ 150.46 to C-4
(3J(C-4,H-2) = 5.9, 3J(C-4,H-1′) = 3.5), doublet of triplets δ 145.40 to C-2
3
(1J(C-2,H-2) = 209.0, J(C-2,H-1) = 5.9), sin glet δ 139.42 to C-8 an d sin glet δ
121.67 to C-5.
Th e ch aracter of th e purin e bases an d th eir substitution is un am biguously
reflected in th eir UV spectra. Th ey are addition al eviden ce of th e m on o- or
disubstitution of 6-am in o-7H-purin -8(9H)-on e (3a) an d of th e ch aracter of
substituen t in position 8 of th e purin e m oiety12. Th us, it is easily possible
to distin guish between (average values of λm ax an d εm ax are given , respec-
tively): th e O,8-an h ydro derivatives of aden in e 13b an d 14 (pH 2, 263 n m ,
14 000; pH 12, 263 n m , 14 000)12a, th e N9-m on osubstituted derivatives of
6-am in o-7H-purin -8(9H)-on e 3d , 3e, 7b an d 9 (pH 2, 280 n m , 10 000; pH
12, 280 n m , 10 000)12b,12c an d th eir N7,N9-disubstituted an alogs 6d , 6e, 8b
an d 10b (pH 2, 286 n m , 10 000; pH 12, 273 n m , 11 000)12d. For ch aracter-
ization of 6-am in o-7H-purin -8(9H)-on e derivatives, we h ave used also IR
spectra wh ich support th e occurren ce of th e –N7H–CO– form on C-8 of
N9-m on osubstituted com poun ds 3, 7 an d 9 rath er th an tautom eric 8-OH
fun ction (typical C=O absorption ban ds in th e 1 720–1 700 cm –1). Also pa-
per electroph oresis was used for corroboration of th e structure of th e free
ph osph on ates.
In con clusion , differen t in depen den t m eth ods for preparation of acyclic
n ucleoside an d n ucleotide derivatives derived from 6-am in o-7H-purin -
8(9H)-on e (3a) were used. Th ese are: (i) m odification of 8-brom oaden in e in
position 8 of th e base, (ii) alkylation of 6-am in o-7H-purin -8(9H)-on e with
diverse alkylation agen ts an d (iii) rin g open in g of som e O,8-an h ydro deriva-
tives un der acid con dition s. Th e first m eth od is th e m ost direct an d con ve-
n ien t on e, an d good yields of products can be reach ed out. Th e secon d on e,
th e base alkylation , is suitable for th e syn th esis of oth erwise alkylated de-
rivatives; in th is case of N7,N9-disubstituted derivatives (6, 8 an d 10). Th e
th ird m eth od, rin g open in g, is also con ven ien t for syn th esis of 8-oxoaden in e
derivatives, th ough it con tain s on e m ore reaction step com pared with di-
rect m odification of 8-brom oaden in e derivatives with sodium acetate in
acetic acid. Som e N9-substituted an alogs (3b, 3c an d 7b) were prepared by
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

6-Amino-7H-purin-8(9H)-one Derivatives
1133
differen t in depen den t ways. Biological activities of th e fin al com poun ds
will be exam in ed.
EXPERIMENTAL
Un less oth erwise stated, solven ts were evaporated at 40 °C/2 kPa an d com poun ds were dried
at 2 kPa over P2O5. Meltin g poin ts were determ in ed on a Kofler block an d are un corrected.
An alytical TLC was perform ed on Silufol UV 254 plates (Kavalier Votice, Czech Republic) in
th e system s ch loroform –m eth an ol (9 : 1) (S1), ch loroform –m eth an ol (85 : 15) (S2), ch loro-
form –m eth an ol (8 : 2) (S3), water–eth an ol–aceton e–eth yl acetate (1 : 1 : 1 : 4) (S4). Prepara-
tive TLC was carried out on 40 × 17 × 0.4 cm loose-layer plates of silica gel con tain in g UV
in dicator (m ade in th e Service Laboratory of th e In stitute). Paper electroph oresis was per-
form ed on a Wh atm an No. 3 MM paper 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; th e electroph oretical m obilities are referen ced to
uridin e 3′-ph osph ate. NMR spectra (δ, ppm ; J, Hz) were m easured on a Varian Un ity 500
spectrom eter (500 MHz for 1H an d 125.7 MHz for 13C NMR) in h exadeuteriodim eth yl
sulfoxide (DMSO-d6) referen ced to th e solven t sign als (2.5 ppm for 1H an d 39.7 ppm for 13C
NMR), or in deuterium oxide con tain in g sodium deuteroxide with sodium 3-(trim eth yl-
silyl)propan e-1-sulfon ate as an in tern al stan dard for 1H an d dioxan e as an extern al stan dard
for 13C NMR (δ(dioxan e) 66.86 ppm ). Mass spectra were m easured on a ZAB-EQ (VG An alyti-
cal) 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 were m easured on a Beckm an
DU-65 spectrom etr (λ, n m ), CD spectra on a Jobin Yvon Mark V in strum en t an d IR absorp-
tion spectra on an IFS 88 spectrom eter (CHCl3 or KBr m eth od).
Startin g Materials an d Reagen ts
Brom o(trim eth yl)silan e an d cesium carbon ate were purch ased from Fluka (Switzerlan d).
Dim eth ylform am ide was distilled from P2O5 an d stored over m olecular sieves (4Å).
Aceton itrile was refluxed with CaH2 an d distilled over m olecular sieves (4Å). Tetrah ydro-
furan was distilled before use from sodium m etal.
Brom in ation of Purin e Derivatives6. Gen eral Procedure
Brom in e (0.5 m l, 19.4 m m ol) was added to a suspen sion of com poun d 1b or 1c (7 m m ol) in
a m ixture of dioxan e (130 m l) an d 10% aqueous solution of sodium h ydrogen ph osph ate
(90 m l) an d th e m ixture was stirred at room tem perature for 24 h . A con cen trated solution
of sodium h ydrogen sulfite was added un til th e m ixture becam e colourless an d th e product
was taken up in ch loroform (6 × 30 m l). Th e ch loroform extract was dried over an h ydrous
m agn esium sulfate, filtered, th e solven t was evaporated an d th e product was crystallized.
8-Bromo-9-{2-[(diisopropoxyphosphoryl)methoxy]ethyl}adenine (2b). Wh ite crystals, m .p. 132 °C
(eth an ol); yield 75%, RF = 0.29 (S1). FAB MS, m/z (rel.%): 436/438 (100). 1H NMR (500 MHz,
DMSO-d6): 1.08 (d, 6 H, J(CH3,CH) = 6.1, CH3); 1.13 (d, 6 H, J(CH3,CH) = 6.1, CH3); 3.75 (d,
2 H, J(P,CH) = 8.3, PCH2); 3.91 (t, 2 H, J(2′,1′) = 5.3, H-2′); 4.31 (t, 2 H, J(1′,2′) = 5.3, H-1′);
4.43 (m , 2 H, POCH); 7.38 (brs, 2 H, NH2); 8.12 (s, 1 H, H-2). For C14H23BrN5O4P (436.3)
calculated: 38.55% C, 5.31% H, 18.32% Br, 16.05% N, 7.10% P; foun d: 38.42% C, 5.15% H,
18.53% Br, 15.76% N, 6.98% P.
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1134
Janeba, Holý, Masojídková:
(S)-8-Bromo-9-{2-[(diisopropoxyphosphoryl)methoxy]-3-hydroxypropyl}adenine (2c). Wh ite crys-
tals, m .p. 139 °C (eth yl acetate); yield 64%, RF = 0.32 (S1). FAB MS, m/z (rel.%): 466/468
(100) [M + H]. 1H NMR (500 MHz, DMSO-d6): 1.01 (d, 3 H, J(CH3,CH) = 6.1, CH3); 1.06 (d,
3 H, J(CH3,CH) = 6.1, CH3); 1.11 (d, 3 H, J(CH3,CH) = 6.1, CH3); 1.16 (d, 3 H, J(CH3,CH) =
6.1, CH3); 3.55 (ddd, 1 H, J(3′b,2′) = 4.4, J(3′b,OH) = 5.8, J(gem ) = 12.0, H-3′b); 3.59 (dd,
1 H, J(P,CHb) = 9.3, J(gem ) = 13.9, PCHb); 3.61 (dt, 1 H, J(3′a,2′) = J(3′a,OH) = 5.0, J(gem ) =
12.0, H-3′a); 3.82 (dd, 1 H, J(P,CHa) = 8.3, J(gem ) = 13.9, PCHa); 3.99 (m , 1 H, H-2′); 4.21
(dd, 1 H, J(1′b,2′) = 4.2, J(gem ) = 14.6, H-1′b); 4.27 (dd, 1 H, J(1′a,2′) = 8.5, J(gem ) = 14.6,
H-1′a); 4.34 (d sept, 1 H, J(CH,CH3) = 6.1, J(P,OCH) = 7.6, POCH); 4.44 (d sept, 1 H,
J(CH,CH3) = 6.1, J(P,OCH) = 7.6, POCH); 4.97 (t, 1 H, J(OH,CH2) = 5.6, OH); 7.40 (brs, 2 H,
NH2); 8.12 (s, 1 H, H-2). For C15H25BrN5O5P (466.3) calculated: 38.64% C, 5.40% H, 17.14% Br,
15.02% N, 6.64% P; foun d: 38.64% C, 5.37% H, 17.35% Br, 14.91% N, 6.69% P.
8-Brom oaden in e5
Brom in e (30 m l) was added to aden in e (1a; 10 g, 74 m m ol) in a 250 m l flask, th e flask was
stoppered an d set aside for 5 h . Th e excess of brom in e was rem oved, th e residue was sus-
pen ded in water, alkalized with aqueous am m on ia an d fin ally n eutralized with acetic acid.
Th e precipitated solid was filtered off an d wash ed with water. Th e crude solid was filtered
off from a h ot suspen sion in water an d wash ed successively with water, aceton e an d eth er to
give 9.5 g (60%) of product 2a. Yellowish powder, m .p. >250 °C; RF = 0.30 (S2). FAB MS, m/z
(rel.%): 213/215 (30) [M + H]. 1H NMR (500 MHz, DMSO-d6): 7.44 (brs, 2 H, NH2); 8.10 (s,
1 H, H-2); 13.70 (br, 1 H, NH).
Alkylation of 8-Brom oaden in e (2a)
A m ixture of 8-brom oaden in e (2a; 1 g, 4.7 m m ol), DMF (30 m l), (S)-tritylglycidol (4.7
m m ol), an d cesium carbon ate (0.25 m m ol) was stirred at 120 °C for 12 h . Th e m ixture was
taken down in vacuo, codistilled with toluen e (2 × 20 m l), th e residue was taken up in ch lo-
roform (150 m l) an d extracted with water (3 × 50 m l). Th e organ ic layer was dried with an -
h ydrous m agn esium sulfate, filtered, an d taken down in vacuo. Th e residue afforded, by
colum n ch rom atograph y on silica gel (ch loroform –m eth an ol) followed by crystallization ,
com poun ds 4 (1.2 g, 48%) an d 5a (0.5 g, 20%).
(S)-8-Bromo-9-[(2-hydroxy-3-(trityloxy)propyl]adenine (4): Wh ite crystals, m .p. 176 °C (eth yl
acetate); RF = 0.44 (S2). FAB MS, m/z (rel.%): 530/532 (15) [M + H], 243 (100) [trityl]. 1H NMR
(500 MHz, DMSO-d6): 2.94 (dd, 1 H, J(3′b,2′) = 5.3, J(gem ) = 9.5, H-3′b); 3.18 (dd, 1 H,
J(3′a,2′) = 5.0, J(gem ) = 9.5, H-3′a); 4.08 (dd, 1 H, J(1′b,2′) = 9.4, J(gem ) = 15.1, H-1′b); 4.18
(m , 1 H, H-2′); 4.20 (dd, 1 H, J(1′a,2′) = 4.5, J(gem ) = 15.1, H-1′a); 5.33 (d, 1 H, J(OH,2′) =
5.5, OH); 7.29 (brs, 2 H, NH2); 7.24 (m , 3 H, arom .); 7.30–7.40 (m , 12 H, arom .); 8.10 (s,
1 H, H-2). 13C NMR (125 MHz, DMSO-d6): 48.33 (C-1′); 66.75 (C-3′); 68.02 (C-2′); 86.62
(C-Ph ); 119.48 (C-5); 127.63 (C-8); 127.49 (3 C, arom .); 128.34 (6 C, arom .); 128.76 (6 C,
arom .); 144.18 (3 C, arom .); 151.50 (C-4); 152.97 (C-2); 155.05 (C-6). For C27H24BrN5O2
(530.4) calculated: 61.14% C, 4.56% H, 15.06% Br, 13.20% N; foun d: 61.22% C, 4.65% H,
14.98% Br, 13.20% N.
(S)-8-Bromo-3-[(2-hydroxy-3-(trityloxy)propyl]adenine (5a). Wh ite crystals, m .p. 131 °C (eth yl
acetate); RF = 0.41 (S2). FAB MS spectrum an d elem en tal an alysis are iden tical with th ose of
com poun d 4. 1H NMR (500 MHz, DMSO-d6): 2.98 (dd, 1 H, J(3′b,2′) = 4.0, J(gem ) = 10.5,
H-3′b); 3.03 (dd, 1 H, J(3′a,2′) = 4.0, J(gem ) = 10.5, H-3′a); 4.16 (m , 2 H) an d 4.50 (m , 1 H,
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6-Amino-7H-purin-8(9H)-one Derivatives
1135
H-1′a + H-1′b + H-2′); 5.45 (br, 1 H, OH); 7.26 (brt, 3 H, arom .); 7.34 (brt, 6 H, arom .); 7.41
(brd, 6 H, arom .); 7.40 (br, 1 H, NH2) an d 8.20 (br, 1 H, NH2); 8.29 (s, 1 H, H-2). 13C NMR
(125 MHz, DMSO-d6): 53.08 (C-1′); 66.01 (C-3′); 66.99 (C-2′); 86.21 (C-Ph ); 120.33 (C-5);
127.25 (3 C, arom .); 128.12 an d 128.48 (12 C, arom .); 137.50 (C-8); 143.83 (3 C, arom .);
145.48 (C-2); 149.61 (C-4); 153.68 (C-6).
(S)-8-Brom o-3-(2,3-dih ydroxypropyl)aden in e (5b)
Mixture of th e trityl derivative 5a (1.5 g, 2.8 m m ol) in aqueous acetic acid (80%, 30 m l) was
refluxed for 1 h , th e solven t was evaporated in vacuo, th e residue was codistilled with water
(2 × 20 m l), dissolved in water (100 m l) an d extracted with eth er (3 × 50 m l). Th e aqueous
ph ase was evaporated in vacuo, th e residue was dissolved in m eth an olic am m on ia (60 m l)
an d th e m ixture was h eated to 50 °C for 1 h . It was th en n eutralized with h ydroch loric acid,
taken down an d th e residue was crystallized from water to give 0.42 g (52%) of com poun d
5b. Wh ite crystals, m .p. 243–245 °C (water); RF = 0.26 (S2). FAB MS, m/z (rel.%): 287/289
(100) [M + H]. 1H NMR (500 MHz, DMSO-d6): 3.35 (ddd, 1 H, J(3′b,2′) = 6.0, J(3′b,OH) = 5.0,
J(gem ) = 11.2, H-3′b); 3.46 (dt, 1 H, J(3′a,2′) = J(3′a,OH) = 5.0, J(gem ) = 11.2, H-3′a); 3.95 (m ,
1 H, H-2′); 4.02 (dd, 1 H, J(1′b,2′) = 9.0, J(gem ) = 13.4, H-1′b); 4.45 (dd, 1 H, J(1′a,2′) = 3.0,
J(gem ) = 13.4, H-1′a); 4.90 (t, 1 H, J(OH,3′) = 5.0, OH); 5.15 (d, 1 H, J(OH,2′) = 5.0, OH);
7.98 (brs, 1 H, NH) an d 8.13 (brs, 1 H, NH); 8.18 (s, 1 H, H-2). For C8H10BrN5O2 (288.1) cal-
culated: 33.35% C, 3.50% H, 27.73% Br, 24.31% N; foun d: 33.24% C, 3.66% H, 27.56% Br,
24.08% N.
Reaction of 8-Brom opurin e Derivatives 2 with Sodium Acetate in Acetic Acid.
Gen eral Procedure
A m ixture of th e correspon din g 8-brom o derivative 2 (5 m m ol), acetic acid (30 m l) an d so-
dium acetate (40 m m ol) was refluxed for 8 h , evaporated in vacuo an d codistilled with water
(3 × 30 m l). Th e residue was stirred with sodium m eth oxide (20 m l, 0.25 m ol) at 50 °C for 2 h ,
n eutralized with HCl an d evaporated in vacuo. Th e residue was deion ized on a Dowex 50 X
8 (H+) colum n (150 m l, elution with water followed by 2.5% aqueous am m on ia), th e
UV-absorbin g am m on ia eluate was collected an d evaporated in vacuo an d th e residue was
crystallized from water–eth an ol. In th e case of com poun d 3a , th e crude residue after
deacetylation was n eutralized with HCl, con cen trated in vacuo an d th e precipitated solid was
filtered off an d wash ed with water, aceton e an d eth er.
6-Amino-7H-purin-8(9H)-one (3a). Yellowish powder, m .p. >350 °C; yield 94%, RF = 0.17
(S2). EI MS, m/z (rel.%): 151 (100) [M]. 1H NMR (500 MHz, DMSO-d6): 6.33 (brs, 2 H, NH2);
7.94 (s, 1 H, H-2); 9.90 (brs, 1 H, NH); 11.24 (brs, 1 H, NH). 13C NMR (125 MHz, DMSO-d6):
104.54 (C-5); 146.59 (C-6); 148.20 (C-4); 151.11 (C-2); 152.97 (C-8). IR (KBr): 3 440 (NH2);
3 251, 3 092, 2 990 (NH2, NH); 1 711 (CO); 1 665, 1 644 (NH2); 1 614, 1 600 (rin g). Exact
m ass (FAB HRMS) foun d: 152.0592; calculated for C5H6N5O [M + H]: 152.0572.
6-Amino-9-[2-(diisopropoxyphosphorylmethoxy)ethyl]-7H-purin-8(9H)-one (3b). Wh ite crystals,
m .p. 159 °C (eth an ol); yield 65%, RF = 0.43 (S1). FAB MS, m/z (rel.%): 374 (100) [M + H].
1H NMR (200 MHz, DMSO-d6): 1.10 (d, 6 H, J(CH3,CH) = 6.1, CH3); 1.14 (d, 6 H, J(CH3,CH) =
6.1, CH3); 3.73 (d, 2 H, J(P,CH) = 8.3, PCH2); 3.80 (t, 2 H, J(2′,1′) = 4.9, H-2′); 3.90 (t, 2 H,
J(1′,2′) = 4.9, H-1′); 4.46 (m , 2 H, POCH); 6.40 (brs, 2 H, NH2); 7.99 (s, 1 H, H-2); 10.05 (br,
1 H, NH). 13C NMR (125 MHz, DMSO-d6): 23.70 (d, 2 C, J(P,C) = 4.9, CH3); 23.89 (d, 2 C,
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1136
Janeba, Holý, Masojídková:
J(P,C) = 3.9, CH3); 38.70 (C-1′); 64.56 (d, J(P,C) = 163.1, PC); 69.00 (d, J(P,C) = 11.7, C-2′);
70.31 (d, 2 C, J(P,C) = 6.8, POC); 103.40 (C-5); 146.73 (C-6); 147.81 (C-4); 151.06 (C-2);
152.17 (C-8). Proton -coupled 13C NMR of th e purin e part (125 MHz, DMSO-d6): 103.395 (t,
3J(C-5,NH2) = 4.9 (2 ×), sin glet after D2O addition , C-5); 146.73 (d, J(C-6,H-2) = 11.7, C-6);
147.81 (ddd, 3J(C-4,H-2) = 13.7, 3J(C-4,H-1′) = 2.9 an d 4.9, C-4); 151.06 (d, J(C-2,H-2) =
200.2, C-2); 152.17 (t, 3J(C-8,H-1′) = 3.9 (2 ×), C-8). IR (CHCl3): 3 487 (NH2); 3 340, 3 292,
3 245, 3 199 (NH2, NH); 1 718 (CO); 1 654 (NH2); 1 623, 1 595, 1 497 (rin g); 1 233 (PO);
1 002 (POC). For C14H24N5O5P (373.4) calculated: 45.04% C, 6.48% H, 18.76% N, 8.30% P;
foun d: 45.05% C, 6.45% H, 18.95% N, 8.26% P.
6-Amino-9-[2-(diisopropoxyphosphorylmethoxy)-3-hydroxypropyl]-7H-purin-8(9H)-one (3c). RF = 0.60
(S2). FAB MS, m/z (rel.%): 404 (100) [M + H]. Exact m ass (FAB HRMS) foun d: 404.1706; cal-
culated for C15H27N5O6P [M + H]: 404.1699. By TLC an d electroph oresis a m ixture of
diisopropyl ph osph on ate (RF = 0.60 (S2), EUp = 0.07) an d m on oisopropyl ph osph on ate (RF
=
0.00 (S2), EUp = 0.43) was detected. Th e m ixture was directly treated with TMSBr un der stan -
dard con dition s, see com poun d 9.
Alkylation of 6-Am in o-7H-purin -8(9H)-on e (3a) with Meth yl Tosylate.
Gen eral Procedure
A m ixture of com poun d 3a (0.5 g, 3.3 m m ol), an d sodium h ydride (0.2 g of 60% dispersion ,
5 m m ol) in DMF (30 m l) was stirred at 110 °C for 1 h . Meth yl tosylate (0.6 m l, 4 m m ol) was
added an d th e m ixture was stirred at th is tem perature for an oth er 4 h . Th e solven t was
evaporated an d preparative ch rom atograph y on a silica gel plate in ch loroform –m eth an ol
(S2) followed by crystallization from eth an ol afforded 0.30 g (55%) of com poun ds 3d an d
0.2 g (34%) of com poun d 6d .
6-Amino-9-methyl-7H-purin-8(9H)-one12b,12c (3d ). Yellowish crystals, m .p. 340 °C (eth an ol);
RF = 0.37 (S1). FAB MS, m/z (rel.%): 166 (100) [M + H]. 1H NMR (500 MHz, DMSO-d6): 3.21
(s, 3 H, CH3); 6.44 (brs, 2 H, NH2); 8.02 (s, 1 H, H-2); 9.65 (br, 1 H, NH). 13C NMR (125 MHz,
DMSO-d6): 25.65 (CH3); 103.52 (C-5); 146.69 (C-6); 147.97 (C-4); 151.15 (C-2); 152.51 (C-8).
IR (KBr): 3 406 (NH2); 3 265, 3 135 (NH2, NH); 1 718, 1 669 (CO); 1 648 (NH2); 1 605,
1 596, 1 509 (rin g); 2 958, 1 376 (CH3). Exact m ass (FAB HRMS) foun d: 166.0732; calculated
for C6H8N5O [M + H]: 166.0728. UV, λm ax (εm ax): (pH 2) 278 (10 700); (pH 12) 272 (13 900).
6-Amino-7,9-dimethyl-7H-purin-8(9H)-one12d (6d ). Yellowish crystals, m .p. 275 °C (eth an ol);
RF = 0.31 (S1). FAB MS, m/z (rel.%): 180 (100) [M + H]. 1H NMR (500 MHz, DMSO-d6): 3.22
(s, 3 H, CH3); 3.47 (s, 3 H, CH3); 6.55 (brs, 2 H, NH2); 8.01 (s, 1 H, H-2). 13C NMR (125
MHz, DMSO-d6): 26.08 (CH3); 28.82 (CH3); 105.34 (C-5); 147.30 an d 147.45 (C-4 an d C-6);
150.90 (C-2); 152.84 (C-8). IR (CHCl3): 3 520 (NH2); 1 713, 1 721 (CO); 1 639 (NH2); 1 599,
1 592, 1 512 (rin g); 1 389 (CH3). For C7H9N5O (179.2) calculated: 46.92% C, 5.06% H,
39.09% N; foun d: 46.90% C, 5.03% H, 38,84% N. UV, λm ax (εm ax): (pH 2) 286 (10 600);
(pH 12) 272 (12 400).
Alkylation of 3a with Diisopropyl [(2-Chloroethoxy)m ethyl]phosphonate.
General Procedure
A m ixture of com poun d 3a (1 g, 6.6 m m ol) an d sodium h ydride (0.4 g of 60% dispersion ,
10 m m ol) in DMF (35 m l) was stirred at 110 °C for 1 h . Diisopropyl [(2-ch loroeth oxy)-
m eth yl]ph osph on ate (2.5 m l, 9.7 m m ol) was added an d th e m ixture was stirred for an oth er
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

6-Amino-7H-purin-8(9H)-one Derivatives
1137
18 h . Th e sam e workup as in th e previous section afforded 0.72 g (29%) of com poun d 3b
an d 0.80 g (20%) of com poun d 6b.
6-Amino-9-[2-(diisopropoxyphosphorylmethoxy)ethyl]-7H-purin-8(9H)-one (3b). Wh ite crystals,
m .p. 166–167 °C (eth an ol); RF = 0.43 (S1). FAB MS, 1H NMR an d 13C NMR spectra are iden ti-
cal with th e auth en tic com poun d.
6-Amino-7,9-bis[2-(diisopropoxyphosphorylmethoxy)ethyl]-7H-purin-8(9H)-one (6b ). Oil, RF
=
0.40 (S1). FAB MS, m/z (rel.%): 596 (100) [M + H]. 1H NMR (200 MHz, DMSO-d6): 1.10 (d,
6 H, J(CH3,CH) = 6.1, CH3); 1.11 (d, 6 H, J(CH3,CH) = 6.1, CH3); 1.14 (d, 6 H, J(CH3,CH) =
6.1, CH3); 1.15 (d, 6 H, J(CH3,CH) = 6.1, CH3); 3.71 (t, 2 H, J(CH2,CH2) = 5.0, CH2); 3.73 (d,
4 H, J(P,CH) = 8.3, PCH2); 3.79 (t, 2 H, J(CH2,CH2) = 5.0, CH2); 3.94 (t, 2 H, J(CH2,CH2) =
5.0, CH2); 4.12 (t, 2 H, J(CH2,CH2) = 5.0, CH2); 4.47 (m , 4 H, POCH); 6.46 (brs, 2 H, NH2);
8.01 (s, 1 H, H-2). 13C NMR (125 MHz, DMSO-d6): 23.70 (d, 2 C, J(P,C) = 2.9, CH3); 23.87 (d,
2 C, J(P,C) = 2.9, CH3); 23.89 (d, 4 C, J(P,C) = 2.9, CH3); 39.09 (C-1′); 41.20 (C-1′′); 64.59 (d,
J(P,C) = 164.1, PC); 64.93 (d, J(P,C) = 163.1, PC); 68.95 (d, J(P,C) = 11.7, C-2′); 70.30 (d,
J(P,C) = 6.8, POC); 70.32 (d, J(P,C) = 6.8, POC); 71.40 (d, J(P,C) = 10.7, C-2′′); 105.00 (C-5);
147.33 (C-6); 147.52 (C-4); 150.84 (C-2); 152.47 (C-8). Proton -coupled 13C NMR of th e pu-
rin e part (125 MHz, DMSO-d6): 105.00 (dd, 3J(C-5,H-1′′) = 3.9 an d 4.9, C-5); 147.33 (d,
3J(C-6,H-2) = 10.7, C-6); 147.52 (ddd, 3J(C-4,H-2) = 11.7, 3J(C-4,H-1′) = 3.9 an d 4.9, C-4);
150.84 (d, J(C-2,H-2) = 201.2, C-2); 152.47 (pen t, 3J(C-8,H-1′) = 3J(C-8,H-1′′) = 3.9 (2 ×), C-8).
IR (CHCl3): 3 461, 3 352 (NH2); 1 714 (CO); 1 639 (NH2); 1 603, 1 590, 1 497 (rin g); 1 244
(PO). Exact m ass (FAB HRMS) foun d: 596.2515; calculated for C23H44N5O9P2 [M + H]:
596.2614.
Alkylation of 3a with (S)-Tritylglycidol. Gen eral Procedure
A m ixture of com poun d 3a (1.5 g, 9.9 m m ol), (S)-tritylglycidol (4 g, 12.6 m m ol) an d cesium
carbon ate (0.26 g, 0.8 m m ol) in dim eth ylform am ide (60 m l) was stirred at 110 °C for 25 h .
Th e h ot suspen sion was filtered over Celite an d evaporated. Th e sam e workup as in th e pre-
vious section afforded 1.5 g (33%) of com poun d 7a an d 1.7 g (22%) of com poun d 8a. In an
experim en t with double quan tity of (S)-tritylglycidol (8 g, 25.2 m m ol) an d cesium carbon ate
(0.52 g, 1.6 m m ol) 0.7 g (15%) of com poun d 7a an d 4.0 g (52%) of com poun d 8a were iso-
lated.
(S)-6-Amino-9-[2-hydroxy-3-(trityloxy)propyl]-7H-purin-8(9H)-one (7a). Yellowish crystals,
m .p. 134–135 °C; RF = 0.47 (S2). FAB MS, m/z (rel.%): 468 (10) [M + H]; 243 (100) [trityl].
1H NMR (500 MHz, DMSO-d6): 2.89 (dd, 1 H, J(3′b,2′) = 5.1, J(gem ) = 9.8, H-3′b); 3.02 (dd,
1 H, J(3′a,2′) = 5.6, J(gem ) = 9.8, H-3′a); 3.75 (d, 2 H, J(1′,2′) = 6.6, H-1′); 4.16 (m , 1 H, H-2′);
5.26 (br, 1 H, OH); 6.41 (brs, 2 H, NH2); 7.22 (t, 3 H, arom .) an d 7.29 (t, 6 H, arom .) an d
7.34 (d, 6 H, arom .); 7.99 (s, 1 H, H-2); 10.14 (brs, 1 H, NH). 13C NMR (125 MHz, DMSO-d6):
43.53 (C-1′); 66.64 (C-3′); 67.12 (C-2′); 86.10 (C-Ph ); 103.44 (C-5); 127.06 (3 C, arom .);
127.91 (6 C, arom .); 128.38 (6 C, arom .); 143.91 (3 C, arom .); 146.65 (C-6); 147.86 (C-4);
150.88 (C-2); 152.33 (C-8). IR (KBr): 3 470, 3 370, 3 332, 3 295, 3 205 (OH, NH2, NH);
1 712, 1 698 (CO); 1 651 (NH2); 1 628, 1 595, 1 505 (rin g). For C27H25N5O3 (467.52) calcu-
lated: 69.36% C, 5.39% H, 14.98% N; foun d: 69.20% C, 5.51% H, 14.56% N.
6-Amino-7,9-bis[(2S)-2-hydroxy-3-(trityloxy)propyl]-7H-purin-8(9H)-one (8a). Yellowish crystals,
m .p. 99–101 °C; RF = 0.87 (S2). FAB MS, m/z (rel.%): 784 (100) [M + H]. 1H NMR (500 MHz,
DMSO-d6): 2.88 (dd, 1 H, J(3′b,2′) = 5.4, J(gem ) = 9.5, H-3′b); 2.98 (dd, 1 H, J(3′′b,2′′) = 5.6,
J(gem ) = 9.5, H-3′′b); 3.03 (dd, 1 H, J(3′a,2′) = 5.4, J(gem ) = 9.5, H-3′a); 3.05 (dd, 1 H, J(3′′a,2′′) =
Collect. Czech. Chem. Commun. (Vol. 65) (2000)

1138
Janeba, Holý, Masojídková:
5.1, J(gem ) = 9.5, H-3′′a); 3.73 (dd, 1 H, J(1′′b,2′′) = 8.8, J(gem ) = 14.9, H-1′′b); 3.77 (d, 2 H,
J(1′,2′) = 6.6, H-1′); 3.88 (m , 1 H, H-2′′); 4.01 (brdd, 1 H, J(1′′a,2′′) = 2.0, J(gem ) = 14.9,
H-1′′a); 4.15 (m , 1 H, H-2′); 5.22 (d, 1 H, J(OH,2′) = 5.9, OH); 5.86 (d, 1 H, J(OH,2′′) = 4.4,
OH); 6.58 (brs, 2 H, NH2); 7.20–7.36 (m , 24 H, arom .) an d 7.41 (m , 6 H, arom .); 8.01 (s, 1 H,
H-2). 13C NMR (125 MHz, DMSO-d6): 43.95 (C-1′); 45.81 (C-1′′); 65.87 (C-3′′); 66.70 (C-3′);
67.09 (C-2′); 68.84 (C-2′′); 86.12 (2 C, C-Ph ); 105.98 (C-5); 127.05 (3 C, arom .); 127.17 (3 C,
arom .); 127.92 (6 C, arom .); 128.04 (6 C, arom .); 128.38 (6 C, arom .); 128.42 (6 C, arom .);
143.87 (3 C, arom .); 143.89 (3 C, arom .); 147.40 an d 147.73 (C-4 an d C-6); 150.57 (C-2);
152.77 (C-8). Exact m ass (FAB HRMS) foun d: 784.3513; calculated for C49H46N5O5 [M + H]:
784.3499.
Preparation of Diisopropyl Ph osph on ates from Com poun ds 8a an d 7a.
Gen eral Procedure
A m ixture of com poun d 8a (1.2 m m ol), DMF (20 m l) an d dim eth ylform am ide dim eth yl-
acetal (5 m l) was stirred in a stoppered flask overn igh t at room tem perature. After evapora-
tion in vacuo, th e residue was codistilled with DMF (10 m l), dissolved in THF (20 m l) an d
trace of water an d excess of solid carbon dioxide were gradually added. After 1 h , th e solu-
tion was taken down , th e residue was codistilled with eth an ol (3 × 20 m l) an d dried over
ph osph orus pen toxide. Th e residue, with out furth er purification , was dissolved in THF (20 m l),
th e solution was cooled to 0 °C, sodium h ydride (2.4 m m ol) was added, followed after 0.5 h
with diisopropyl [(tosyloxy)m eth yl]ph osph on ate3d (2.2 m m ol). Th e m ixture was stirred at 0 °C
for 2 h an d at room tem perature for 2 days. Th e m ixture was evaporated, th e residue was
h eated in m eth an olic am m on ia (40 m l) in an autoclave at 80 °C for 5 h , evaporated an d th e
residue was refluxed with aqueous acetic acid (80%, 40 m l) for 0.5 h . Th e m ixture was evap-
orated, codistilled with water (2 × 30 m l) an d eth an ol (2 × 30 m l). Colum n ch rom atograph y
of th e residue on silica gel afforded 0.42 g (54%) of oily product 10a. Th e sam e workup with
com poun d 7a (2 equivalen ts, 1.1 g, 2.4 m m ol), followed by crystallization from eth an ol,
gave 0.5 g (52%) of com poun d 3c.
6-Amino-7,9-bis{(2S)-3-hydroxy-2-[(diisopropoxyphosphoryl)methoxy]propyl}-7H-purin-8(9H)-one
(10a). Oil, RF = 0.56 (S2). FAB MS, m/z (rel.%): 656 (100) [M + H]. 1H NMR (500 MHz,
DMSO-d6): 1.09 (d, 3 H, J(CH3,CH) = 6.1, CH3); 1.12 (d, 3 H, J(CH3,CH) = 6.1, CH3); 1.13 (d,
3 H, J(CH3,CH) = 6.1, CH3); 1.15 (d, 9 H, J(CH3,CH) = 6.1, CH3); 1.17 (d, 3 H, J(CH3,CH) =
6.1, CH3); 1.18 (d, 3 H, J(CH3,CH) = 6.1, CH3); 3.45–4.03 (m , 14 H, OCH, NCH2, OCH2 an d
PCH2); 4.48 (m , 4 H, POCH); 4.81 (t, 1 H, J(OH,CH2) = 5.6, OH); 5.04 (t, 1 H, J(OH, CH2) =
5.2, OH); 6.43 (brs, 2 H, NH2); 8.03 (s, 1 H, H-2). 13C NMR (125 MHz, DMSO-d6): 23.59 (d,
2 C, J(P,C) = 3.9, CH3); 23.65 (d, 2 C, J(P,C) = 3.9, CH3); 23.75 (d, 2 C, J(P,C) = 3.9, CH3);
23.80 (d, 2 C, J(P,C) = 3.9, CH3); 40.61 (C-1′); 43.08 (C-1′′); 59.73 (C-3′); 60.96 (C-3′′); 63.59
(d, J(P,C) = 165.0, PC); 63.72 (d, J(P,C) = 164.1, PC); 70.20 (d, J(P,C) = 5.9, POC); 70.27 (d,
J(P,C) = 5.9, POC); 70.33 (d, J(P,C) = 5.9, POC); 70.35 (d, J(P,C) = 5.9, POC); 79.25 (d, J(P,C) =
11.7, C-2′); 80.59 (d, J(P,C) = 9.8, C-2′′); 105.61 (C-5); 147.53 an d 147.57 (C-4 an d C-6);
150.64 (C-2); 152.84 (C-8). Exact m ass (FAB HRMS) foun d: 656.2819; calculated for
C
25H48N5O11P2 [M + H]: 656.2827.
6-Amino-9-[2-(diisopropoxyphosphorylmethoxy)-3-hydroxypropyl]-7H-purin-8(9H)-one (3c). RF
=
0.60 (S2). FAB MS an d exact m ass (FAB HRMS) are iden tical with th e auth en tic com poun d.
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6-Amino-7H-purin-8(9H)-one Derivatives
1139
Deprotection of th e Trityl Derivatives 8a an d 7a. Gen eral Procedure
A trityl derivative (1 m m ol) in aqueous acetic acid (80%, 20 m l) was refluxed for 1 h , poured
in to water (100 m l) an d extracted with eth er (3 × 50 m l). Th e aqueous ph ase was evaporated
in vacuo an d th e residue was dissolved in aqueous am m on ia (10%, 50 m l). After stan din g
overn igh t at am bien t tem perature, th e solution was evaporated in vacuo an d th e resultin g
solid was crystallized from water–eth an ol m ixture.
6-Amino-7,9-bis[(S)-2,3-dihydroxypropyl]-7H-purin-8(9H)-one (8b ). W h ite crystals, m .p.
125–127 °C; yield 48%, RF = 0.14 (S3). FAB MS, m/z (rel.%): 300 (100) [M + H]. 1H NMR (500
MHz, DMSO-d6): 3.33 (dt, 1 H, J(3′b,2′) = J(3′b,OH) = 5.6, J(gem ) = 11.2, H-3′b); 3.37 (dt,
1 H, J(3′a,2′) = J(3′a,OH) = 5.6, J(gem ) = 11.2, H-3′a); 3.41 (brt, 2 H, J(3′′,2′′) = J(3′′,OH) = 5.4,
H-3′′); 3.71 (m , 1 H, H-2′′); 3.77 (dd, 1 H, J(1′′b,2′′) = 8.3, J(gem ) = 14.4, H-1′′b); 3.78 (d, 2 H,
J(1′,2′) = 6.3, H-1′); 3.91 (br sext, 1 H, J = 5.9, H-2′); 4.03 (dd, 1 H, J(1′′a,2′′) = 2.9, J(gem ) =
14.4, H-1′′a); 4.66 (t, 1 H, J(OH,3′) = 5.8, OH); 4.86 (t, 1 H, J(OH,3′′) = 5.8, OH); 4.88 (d, 1 H,
J(OH,2′) = 5.4, OH); 5.64 (d, 1 H, J(OH,2′′) = 4.4, OH); 6.62 (brs, 2 H, NH2); 8.03 (s, 1 H,
H-2). 13C NMR (125 MHz, DMSO-d6): 43.95 (C-1′); 45.22 (C-1′′); 63.41 (C-3′); 64.10 (C-3′′);
68.92 (C-2′); 70.33 (C-2′′); 106.07 (C-5); 147.85 an d 147.59 (C-4 an d C-6); 150.54 (C-2);
153.21 (C-8). IR (KBr): 3 415, 3 325, 3 162 (OH, NH2); 1 700, 1 688 (CO); 1 662 (NH2);
1 615, 1 584, 1 504, 1 475, 1 443 (rin g); 1 109, 1 097, 1 086, 1 050 (COH). For C11H17N5O5
(299.3) calculated: 44.15% C, 5.73% H, 23.40% N; foun d: 43.96% C, 5.59% H, 23.17% N.
UV, λm ax (εm ax): (pH 2) 284 (9 600); (pH 12) 273 (11 600). CD, λ (∆ε) (0.01 M HCl): 294
(0.52), 225 (–1.08), 204 (1.37).
(S)-6-Amino-9-(2,3-dihydroxypropyl)-7H-purin-8(9H)-one (7b ). Yellowish crystals, m .p.
230–232 °C; yield 54%, RF = 0.22 (S2). FAB MS, m/z (rel.%): 226 (100) [M + H]. 1H NMR (500
MHz, DMSO-d6): 3.33 (dt, 1 H, J(3′b,2′) = J(3′b,OH) = 5.7, J(gem ) = 11.2, H-3′b); 3.37 (ddd,
1 H, J(3′a,2′) = 5.0, J(3′a,OH) = 6.0, J(gem ) = 11.2, H-3′a); 3.73 (d, 2 H, J(1′,2′) = 6.4, H-1′);
3.91 (m , 1 H, H-2′); 4.70 (t, 1 H, J(OH,3′) = 5.9, OH); 4.92 (d, 1 H, J(OH,2′) = 5.4, OH); 6.41
(brs, 2 H, NH2); 8.01 (s, 1 H, H-2); 10.16 (brs, 1 H, NH). 13C NMR (125 MHz, DMSO-d6):
43.31 (C-1′); 64.22 (C-3′); 69.11 (C-2′); 103.55 (C-5); 146.81 (C-6); 148.22 (C-4); 151.08
(C-2); 152.76 (C-8). Exact m ass (FAB HRMS) foun d: 226.1013; calculated for C8H12N5O3 [M +
H]: 226.0940. UV, λm ax (εm ax): (pH 2) 280 (10 400); (pH 12) 280 (10 400). CD, λ (∆ε) (0.01 M
HCl): 283 (–0.20), 255 (0.06), 220 (–1.74), 200 (–1.38).
Meth ylation of Com poun d 3b
A m ixture of com poun d 3b (0.25 g, 0.7 m m ol) an d sodium h ydride (32 m g of 60% disper-
sion , 0.8 m m ol) in DMF (6 m l) was stirred at 110 °C for 1 h . Meth yl tosylate (0.12 m l, 0.75
m m ol) was added an d th e m ixture was stirred for an oth er 2 h . Th e solven t was evaporated
an d th e residue (RF = 0.45 (S1)) was dried an d con verted with out an y purification to th e free
ph osph on ate 11. See un der Deprotection of Ph osph on ates (vide infra). Total yield 95 m g
(45%).
(S)-7-[(Trityloxy)m eth yl]-7,8-dih ydro[1,3]oxazolo[3,2-e]purin -4-am in e (12)
A m ixture of com poun d 4 (1 g, 2 m m ol), THF (20 m l) an d sodium h ydride (2.4 m m ol) was
stirred at room tem perature. After 5 m in , a wh ite solid precipitated wh ich was filtered off
an d th orough ly wash ed with h ot DMF (3 × 20 m l), aceton e (3 × 20 m l) an d eth er. Wh ite pow-
der, m .p. >260 °C; yield 0.73 g (81%), RF = 0.33 (S1). FAB MS, m/z (rel.%): 450 (95) [M + H];
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Janeba, Holý, Masojídková:
243 (100) [trityl]. 1H NMR (500 MHz, DMSO-d6): 3.18 (dd, 1 H, J(3′b,2′) = 3.7, J(gem ) = 11.0,
H-3′b); 3.56 (dd, 1 H, J(3′a,2′) = 2.4, J(gem ) = 11.0, H-3′a); 4.02 (dd, 1 H, J(1′b,2′) = 4.6,
J(gem ) = 9.7, H-1′b); 4.36 (dd, 1 H, J(1′a,2′) = 8.5, J(gem ) = 9.7, H-1′a); 5.63 (m , 1 H, H-2′);
6.80 (brs, 2 H, NH2); 7.24 (m , 15 H, arom .); 8.02 (s, 1 H, H-2). 13C NMR (125 MHz,
DMSO-d6): 42.81 (C-1′); 64.69 (C-3′); 86.07 (3 C, CPh ); 87.13 (C-2′); 120.29 (C-5); 127.42 (3 C,
arom .); 128.17 (6 C, arom .); 128.28 (6 C, arom .); 143.36 (3 C, arom .); 147.28 (C-4); 150.74
(C-2); 154.13 (C-6); 160.65 (C-8). For C27H23N5O2 (449.5) calculated: 72.14% C, 5.16% H,
15.58% N; foun d: 71.88% C, 5.28% H, 15. 37% N.
Diisopropyl (S)-{[(4-Am in o-8,9-dih ydro-7H-[1,3]oxazin o[3,2-e]purin -8-yl)oxy]m eth yl}-
ph osph on ate (13a)
A m ixture of com poun d 2c (0.6 g, 1.3 m m ol), DMF (20 m l) an d sodium h ydride (2.6 m m ol)
was stirred at room tem perature overn igh t. Th e m ixture was n eutralized with acetic acid,
taken down in vacuo, th e residue was codistilled with toluen e (2 × 10 m l) an d purified on a
silica gel plate (see above) in ch loroform –m eth an ol (4 : 1). Th e product was crystallized from
eth yl acetate givin g wh ite crystals, m .p. 195–197 °C; yield 65%, RF = 0.44 (S3). FAB MS, m/z
(rel.%): 386 (40) [M + H]; 302 (100) [M + H – 2 iPr]. 1H NMR (500 MHz, DMSO-d6): 1.10 (d,
3 H, J(CH3,CH) = 6.1, CH3); 1.115 (d, 3 H, J(CH3,CH) = 6.1, CH3); 1.15 (d, 3 H, J(CH3,CH) =
6.1, CH3); 1.17 (d, 3 H, J(CH3,CH) = 6.1, CH3); 3.94 (dd, 1 H, J(P,CHb) = 9.3, J(gem ) = 13.9,
PCHb); 3.97 (dd, 1 H, J(P,CHa) = 8.8, J(gem ) = 13.9, PCHa); 4.13 (dd, 1 H, J(3′b,2′) = 3.4,
J(gem ) = 13.2, H-3′b); 4.27 (dt, 1 H, J(3′a,2′) = J(3′a,P) = 2.2, J(gem ) = 13.2, H-3′a); 4.31 (m ,
1 H, H-2′); 4.515 (brd, 1 H, J(1′b,2′) = 1.0, J(gem ) = 12.2, H-1′b); 4.52 (d sept, 2 H, J(CH,CH3) =
6.1, J(P,OCH) = 7.8, POCH); 4.68 (dt, 1 H, J(1′a,2′) = J(1′a,P) = 2.7, J(gem ) = 12.2, H-1′a); 6.81
(brs, 2 H, NH2); 8.02 (s, 1 H, H-2). 13C NMR (125 MHz, DMSO-d6): 23.66 (d, J(P,C) = 4.9,
CH3); 23.67 (d, J(P,C) = 4.9, CH3); 23.87 (d, J(P,C) = 3.9, CH3); 23.89 (d, J(P,C) = 3.9, CH3);
43.09 (C-1′); 62.81 (d, J(P,C) = 165.1, PC); 67.87 (C-3′); 68.71 (d, J(P,C) = 12.7, C-2′); 70.51
(d, J(P,C) = 5.9, POC); 70.53 (d, J(P,C) = 5.9, POC); 114.89 (C-5); 148.75 (C-4); 150.55 (C-2);
150.80 (C-8); 153.89 (C-6). For C15H24N5O5P (385.4) calculated: 46.75% C, 6.28% H, 18.17% N,
8.04% P; found: 46.65% C, 6.17% H, 17.99% N, 8.35% P. UV, λm ax (εm ax) (MeOH): 262 (15 600).
CD, λ (∆ε) (MeOH): 268 (0.67), 242 (0.40), 213 (–5.80), 202 (4.27).
Cleavage of O,8-An h ydropurin e Derivatives. Gen eral Procedure
A m ixture of an O,8-an h ydropurin e derivative (1 m m ol), Dowex 50 X 8 (H+) (5 m l), m eth a-
n ol (10 m l) an d water (10 m l) was refluxed for 2 h , th en filtered wh ile h ot an d th e resin was
wash ed with a m ixture of 35% aqueous am m on ia an d water (1 : 10). Th e filtrate was evapo-
rated an d th e residue crystallized to afford a 6-am in o-7H-purin -8(9H)-on e derivative.
(S)-6-Amino-9-(2,3-dihydroxypropyl)-7H-purin-8(9H)-one (7b). Yellowish crystals, m .p. 223 °C
(eth an ol); yield 66%. RF (S3), FAB MS, 1H NMR, 13C NMR, UV an d CD spectra are iden tical
with th ose of th e auth en tic com poun d prepared by alkylation of com poun d 3a followed by
deprotection of trityl group.
6-Amino-9-[2-(diisopropoxyphosphorylmethoxy)-3-hydroxypropyl]-7H-purin-8(9H)-one (3c). RF
=
0.60 (S2). FAB MS an d exact m ass (FAB HRMS) are iden tical with th e auth en tic com poun d.
TLC an d paper electroph oresis of th e reaction m ixture in dicated th e presen ce of diisopropyl
ph osph on ate (RF = 0.60 (S2), EUp = 0.07) an d m on oisopropyl ph osph on ate (RF = 0.00 (S2),
EUp = 0.43). Th e m ixture was directly treated with TMSBr un der stan dard con dition s, see
com poun d 9.
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6-Amino-7H-purin-8(9H)-one Derivatives
1141
Deprotection of Ph osph on ates with TMSBr3g. Gen eral Procedure
A m ixture of th e ph osph on ate diester (1 m m ol), TMSBr (1 m l) an d aceton itrile (5 m l) was
stirred overn igh t at am bien t tem perature, th en evaporated an d codistilled with aceton itrile
(10 m l). Th e residue was dissolved in water an d alkalized with aqueous am m on ia. Th e m ix-
ture was evaporated in vacuo an d th e residue was deion ized on a Dowex 50 X 8 (H+) colum n
(50 m l) un der stan dard con dition s. Th e product was purified on a Dowex 1 X 2 (acetate)
colum n by elution with lin ear gradien t of acetic acid (0–0.5 M,
1 liter each ). Th e
UV-absorbin g fraction s were evaporated in vacuo an d th e residue was crystallized from water.
6-Amino-9-[2-(phosphonomethoxy)ethyl]-7H-purin-8(9H)-one (3e). W h ite crystals, m .p.
210–213 °C; yield 54%, EUp = 0.88. FAB MS, m/z (rel.%): 290 (100) [M + H]. 1H NMR (500
MHz, D2O + NaOD): 3.49 (d, 2 H, J(P,CH) = 8.3, PCH2); 3.86 (t, 2 H, J(2′,1′) = 5.6, H-2′); 4.05
(t, 2 H, J(1′,2′) = 5.6, H-1′); 7.97 (s, 1 H, H-2). For C8H12N5O5P (289.2) calculated: 33.23% C,
4.18% H, 24.22% N, 10.71% P; foun d: 32.90% C, 4.34% H, 23.94% N, 10.57% P. UV, λm ax
(εm ax): (pH 2) 281 (8 800); (pH 12) 281 (11 200).
6-Amino-7,9-bis[2-(phosphonomethoxy)ethyl]-7H-purin-8(9H)-one (6e). Oil; yield 75%, EUp
=
0.92. FAB MS, m/z (rel.%): 428 (100) [M + H]. 1H NMR (500 MHz, D2O + NaOD): 3.68 (d,
2 H, J(P,CH) = 8.7, PCH2); 3.71 (d, 2 H, J(P,CH) = 8.9, PCH2); 3.90 (t, 2 H, J(2′′,1′′) = 4.5,
H-2′′); 3.94 (t, 2 H, J(2′,1′) = 5.1, H-2′); 4.22 (t, 2 H, J(1′,2′) = 5.1, H-1′); 4.28 (t, 2 H, J(1′′,2′′) =
4.5, H-1′′); 8.36 (s, 1 H, H-2). 13C NMR (125 MHz, DMSO-d6): 39.67 (C-1′); 41.92 (C-1′′);
66.21 (d, J(P,C) = 160.2, PC); 66.67 (d, J(P,C) = 159.2, PC); 68.67 (d, J(P,C) = 10.7, C-2′);
70.94 (d, J(P,C) = 8.8, C-2′′); 105.28 (C-5); 144.55 (C-6); 147.54 (C-4); 147.66 (C-2); 152.55
(C-8). Proton -coupled 13C NMR of th e purin e part (125 MHz, DMSO-d6 + D2O): 105.28 (t,
3J(C-5,H-1′′) = 3.9 (2 ×), C-5); 144.55 (d, 3J(C-6,H-2) = 9.8, C-6); 147.54 (dt, 3J(C-4,H-2) =
11.7, 3J(C-4,H-1) = 3.9 (2 ×), C-4); 147.66 (d, J(C-2,H-2) = 208.0, C-2); 152.55 (pen t,
3J(C-8,H-1′) = 3J(C-8,H-1′′) = 3.9 (2 ×), C-8). IR (KBr): 3 384, 3 351, 3 203 (NH2); 2 768,
2 650, 2 305 (POH); 1 731 (CO); 1 681 (NH2); 1 630, 1 598, 1 513 (rin g); 1 189 (PO);
996, 935 (POH). Exact m ass (FAB HRMS) fou n d: 428.0720; calcu lated for C11H20N5O9P2
[M + H]: 428.0736. UV, λm ax (εm ax): (pH 2) 286 (9 700); (pH 7) 273 n m (11 000); (pH 12)
273 (11 600).
6-Amino-9-[3-hydroxy-2-(phosphonomethoxy)propyl]-7H-purin-8(9H)-one (9). Wh ite crystals,
m .p. 230 °C; yield 69%, EUp = 0.80. FAB MS, m/z (rel.%): 320 (100) [M + H]. 1H NMR (500
MHz, D2O + NaOD): 3.60 (dd, 1 H, J(P,CHb) = 9.6, J(gem ) = 12.7, PCHb); 3.605 (dd, 1 H,
J(3′b,2′) = 5.6, J(gem ) = 12.6, H-3′b); 3.66 (dd, 1 H, J(P,CHa) = 8.9, J(gem ) = 12.7, PCHa);
3.79 (dd, 1 H, J(3′a,2′) = 3.3, J(gem ) = 12.6, H-3′a); 3.86 (m , 1 H, H-2′); 3.93 (dd, 1 H,
J(1′b,2′) = 5.6, J(gem ) = 14.7, H-1′b); 4.05 (dd, 1 H, J(1′a,2′) = 6.6, J(gem ) = 14.7, H-1′a); 8.04
(s, 1 H, H-2). 13C NMR (125 MHz, D2O): 39.88 (C-1′); 60.40 (C-3′); 66.74 (d, J(P,C) = 153.3,
PC); 79.02 (d, J(P,C) = 10.7, C-2′); 103.53 (C-5); 146.61 an d 146.64 (C-4 an d C-6); 150.54
(C-2); 151.57 (C-8). IR (KBr): 3 424, 3 345 (NH2); 3 280, 3 160, 3 102, 3 055 (OH, NH2, NH);
2 747 (POH); 1 701 (CO); 1 650 (NH2); 1 603, 1 574, 1 512 (rin g); 1 168 (PO); 1 069 (OH);
1 032 (POH). For C9H14N5O6P (319.2) calculated: 33.85% C, 4.42% H, 21.94% N, 9.71% P;
foun d: 33.58% C, 4.55% H, 21.89% N, 9.35% P. UV, λm ax (εm ax): (pH 2) 279 (10 800); (pH 7)
271 (11 600); (pH 12) 279 (12 800). CD, λ (∆ε) (0.01 M HCl): 231 (0.08), 211 (–1.42), 198
(–1.82).
6-Amino-7,9-bis[(S)-3-hydroxy-2-(phosphonomethoxy)propyl]-7H-purin-8(9H)-one (10b ). Oil;
yield 71%, EUp = 1.20. FAB MS, m/z (rel.%): 488 (100) [M + H]. 1H NMR (500 MHz, D2O):
3.57 (dd, 1 H, J = 9.0 an d 12.9, PCH); 3.63 (dd, 1 H, J = 9.0 an d 12.9, PCH); 3.63 (dd, 1 H, J =
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5.1 an d 12.7, OCH); 3.67 (dd, 1 H, J = 9.5 an d 12.9, PCH); 3.72 (dd, 1 H, J = 3.4 an d 12.4,
OCH2); 3.77 (dd, 1 H, J = 9.8 an d 12.9, PCH2); 3.82 (dd, 1 H, J = 3.4 an d 12.4, OCH2); 3.81
(m , 1 H, OCH); 3.89 (m , 1 H, OCH); 3.95 (dd, 1 H, J = 3.9 an d 12.7, OCH); 4.01 (dd, 1 H, J =
5.4 an d 14.7, NCH); 4.12 (dd, 1 H, J = 7.1 an d 14.7, NCH); 4.13 (dd, 1 H, J = 8.3 an d 15.6,
NCH); 4.19 (dd, 1 H, J = 3.6 an d 15.6, NCH); 8.10 (s, 1 H, H-2). 13C NMR (125 MHz, D2O):
40.42 (C-1′); 43.79 (C-1′′); 59.33 an d 60.43 (C-3′ an d C-3′′); 64.30 (d, 2 C, J(P,C) = 156.6, PC);
79.13 (d, J(P,C) = 10.9) an d 79.92 (d, J(P,C) = 10.9) (C-2′ an d C-2′′); 106.27 (C-5); 146.50
(C-4); 147.79 (C-6); 150.41 (C-2); 153.59 (C-8). Proton -coupled 13C NMR of th e purin e part
(125 MHz, D2O): 106.27 (t, 3J(C-5,H-1′′) = 3.9 (2 ×), C-5); 146.50 (dt, 3J(C-4,H-2) = 10.5,
3J(C-4,H-1′) = 3.9 (2 ×), C-4); 147.79 (d, 3J(C-6,H-2) = 10.7, C-6); 150.41 (d, J(C-2,H-2) =
204.1, C-2); 153.59 (pen t, 3J(C-8,H-1′) = 3J(C-8,H-1′′) = 3.9 (2 ×), C-8). Exact m ass (FAB
HRMS) foun d: 488.0845; calculated for C13H24N5O11P2 [M + H]: 488.0947. UV, λm ax (εm ax):
(pH 2) 285 (7 700); (pH 7) 272 (8 900); (pH 12) 272 (9 200). CD, λ (∆ε) (H2O): 260 (0.39),
231 (0.18), 221 (0.40), 208 (–5.3).
6-Amino-7-methyl-9-[2-(phosphonomethoxy)ethyl]-7H-purin-8(9H)-one (11). Wh ite crystals,
m .p. 213–215 °C (H2O); yield 45%, EUp = 0.87. FAB MS, m/z (rel.%): 304 (100) [M + H].
1H NMR (500 MHz, D2O + NaOD): 3.44 (d, 2 H, J(P,CH) = 8.3, PCH2); 3.54 (s, 3 H, NCH3);
3.83 (t, 2 H, J(2′,1′) = 5.4, H-2′); 4.06 (t, 2 H, J(1′,2′) = 5.4, H-1′); 8.00 (s, 1 H, H-2). 13C NMR
(125 MHz, D2O + NaOD): 28.48 (CH3); 39.98 (C-1′); 68.70 (d, J(P,C) = 149.7, PC); 68.90 (d,
J(P,C) = 9.2, C-2′); 105.68 (C-5); 146.20 (C-6); 147.72 (C-4); 150.48 (C-2); 153.52 (C-8). Exact
m ass (FAB HRMS) foun d: 304.0846; calculated for C9H15N5O5P [M + H]: 304.0811. UV, λm ax
(εm ax): (pH 2) 280 (9 300); (pH 12) 273 (11 200).
(S)-{[(4-Amino-8,9-dihydro-7H-[1,3]oxazino[3,2-e]purin-8-yl)oxy]methyl}phosphonic acid (13b).
Wh ite crystals, m .p. >360 °C (H2O); yield 52%, EUp = 0.84. FAB MS, m/z (rel.%): 302 (100)
[M + H]. 1H NMR (500 MHz, D2O + NaOD): 3.62 (dd, 1 H, J(P,CHb) = 8.8, J(gem ) = 12.6,
PCHb); 3.66 (dd, 1 H, J(P,CHa) = 8.6, J(gem ) = 12.6, PCHa); 4.18 (dd, 1 H, J(1′b,2′) = 3.7,
J(gem ) = 13.2, H-1′b); 4.43 (dt, 1 H, J(1′a,2′) = J(1′a,P) = 2.0, J(gem ) = 13.2, H-1′a); 4.49 (m , 1 H,
H-2′); 4.60 (dd, 1 H, J(3′b,2′) = 1.0, J(gem ) = 12.0, H-3′b); 4.88 (dt, 1 H, J(3′a,2′) = J(3′a,P) =
1.5, J(gem ) = 12.0, H-3′a); 8.04 (s, 1 H, H-2). 13C NMR (125 MHz, D2O): 43.03 (C-1′); 66.48
(d, J(P,C) = 149.4, PC); 67.58 (d, J(P,C) = 9.8, C-2′); 68.76 (C-3′); 114.17 (C-5); 147.97 (C-4);
150.20 (C-2); 152.17 (C-8); 152.78 (C-6). Exact m ass (FAB HRMS) foun d: 302.0605; calcu-
lated for C9H13N5O5P [M + H]: 302.0654. UV, λm ax (εm ax): (pH 2) 263 (14 100); (pH 12) 263
(14 600). CD, λ (∆ε) (MeOH): 278 (1.42), 254 (–0.70), 214 (–3.82), 203 (1.64).
Isopropyl Hydrogen (S)-{[(4-Am in o-8,9-dih ydro-7H-[1,3]oxazin o[3,2-e]purin -8-yl)oxy]
m eth yl}ph osph on ate11 (14)
Com poun d 13a (0.4 g, 1 m m ol) an d lith ium azide (0.4 g) in DMF (10 m l) were stirred at 100 °C
for 5 h an d th e solven t was evaporated in vacuo. Th e residue afforded, on preparative TLC
(S4) followed by crystallization from eth an ol, product 14 (0.25 g, 73%). Wh ite crystals, m .p.
>360 °C; RF = 0.12 (S4). FAB MS, m/z (rel.%): 366 (100) [M + Na + H]. 1H NMR (500 MHz,
DMSO-d6): 1.00 (d, 3 H, J(CH3,CH) = 6.2, CH3); 1.01 (d, 3 H, J(CH3,CH) = 6.2, CH3); 3.42
(dd, 1 H, J(P,CHb) = 9.4, J(gem ) = 12.9, PCHb); 3.47 (dd, 1 H, J(P,CHa) = 8.0, J(gem ) = 12.9,
PCHa); 4.09 (dd, 1 H, J(1′b,2′) = 3.3, J(gem ) = 12.7, H-1′b); 4.22 (dt, 1 H, J(1′a,2′) = J(1′a,P) =
1.0, J(gem ) = 12.7, H-1′a); 4.25 (m , 1 H, POCH); 4.45 (m , 1 H, H-2′); 4.47 (brd, 1 H, J(3′b,1′) =
1.0, J(gem ) = 11.7, H-3′b); 4.64 (dt, 1 H, J(3′a,1′) = J(3′a,P) = 2.5, J(gem ) = 11.7, H-3′a); 6.75
(brs, 2 H, NH2); 8.01 (s, 1 H, H-2). 13C NMR: 24.70 (d, 2 C, J(P,C) = 2.9, CH3); 43.23 (C-1′);
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6-Amino-7H-purin-8(9H)-one Derivatives
1143
65.77 (d, J(P,C) = 152.35, PC); 65.80 (d, J(P,C) = 5.9, POC); 66.99 (d, J(P,C) = 7.8, C-2′);
68.27 (C-3′); 114.89 (C-5); 148.78 (C-4); 150.42 (C-2); 151.06 (C-8); 153.77 (C-6). For
C
12H17N5NaO5P (365.3) calculated: 39.46% C, 4.69% H, 19.17% N, 8.48% P; foun d: 39.43% C,
4.97% H, 18.90% N, 8.51% P. UV, λm ax (εm ax): (pH 2) 263 (13 600); (pH 12) 263 (13 600).
CD, λ (∆ε) (0.01 M HCl): 268 (1.57), 243 (0.88), 212 (–7.12), 202 (2.34).
This work was supported by the Grant Agency of the Czech Republic (grant No. 203/96/K001) and
by Gilead Sciences (Foster City (CA), U.S.A.). The authors′ thanks are due to Dr H. Votavová for mea-
surement of CD spectra, Dr P. Fiedler for measurement of IR spectra, and to the staff of the Mass Spec-
trometry and Analytical Departments of this Institute.
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