An approach to the generation of simple analogues of the antitumour agent spicamycin.

Article abstract of DOI:10.1039/b307795k

The one-step glycosylation of arylamines in acidic medium is extended to adenine derivatives for the first time, providing a considerable improvement over existing reactions. This method is used to prepare some rhamnospicamycin analogues containing differ

Full text of DOI:10.1039/b307795k

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An approach to the generation of simple analogues of the
antitumour agent spicamycin†
Stéphane Monsa,b and George W. J. Fleet*a
a Dyson Perrins Laboratory, University of Oxford, South Parks Road, Oxford, UK OX1 3QY.
E-mail: George.Fleet@chem.ox.ac.uk
b Institut de Chimie des Substances Naturelles, CNRS, Avenue de la Terrasse,
91198 Gif sur Yvette cedex, France
Received 9th July 2003, Accepted 22nd August 2003
First published as an Advance Article on the web 4th September 2003
The one-step glycosylation of arylamines in acidic medium is extended to adenine derivatives for the first time,
providing a considerable improvement over existing reactions. This method is used to prepare some
rhamnospicamycin analogues containing different base moieties. Results suggest that this novel approach will be
applicable to a wide range of carbohydrates and arylamines, possibly leading to a combinatorial library of analogues
of spicamycin for the better understanding of the modes of action of this antitumour antibiotic family.
which is currently in Phase 1 clinical trials in the USA,5–7
1. Introduction
exhibits a potent activity against Colo 205 colon carcinoma
Spicamycin 1 (Fig. 1) is an antitumour antibiotic isolated from
xenografts in vivo.8–10 Recent studies suggest that it may be used
cultures of Streptomyces alanosinicus,1 and occurs naturally as
a family of compounds which differ only by the nature and
length of the fatty chain portion of the molecule. The structure
as an anti-leukemic agent11,12 and for combination chemo-
therapy with cisplatin, carboplatin or etoposide against non-
small-cell lung cancer.13 KRN5500 has the ability to potently
of this nucleoside is quite unusual since the adenine moiety
decrease pain which is resistant to other pain relief methods,
is linked through its N 6 amino group, as evidenced by X-ray
such as opioid drugs.14 Incorporation of KRN5500 into poly-
crystallographic studies,2 instead of the common 9-position.
meric micelles has been shown to diminish the pulmonary
Extensive structure–activity relationship (SAR) studies
toxicity.15
directed towards the influence of the amino acid and the fatty
Very little is known about the mechanisms of action of the
chain moieties in spicamycin analogues have led to the dis-
spicamycin family and its metabolites,16 SAN 1 (R = H) and
covery of two potentially antitumour drugs: SPM VIII 1 (R1 =
SAN-Gly 1 (R1 = H), but they seem to involve alteration of the
dodecanoyl),3 which proved to be more potent than the com-
glycoprotein expression and modification of the cellular secre-
monly used mitomycin C against human gastric cancer SC-9,4
tion pathway.17,18 As such, spicamycin would have a completely
and KRN5500 1 (R1 = (2E,4E)-tetradecadienoyl). The latter,
different mode of action compared to conventional antitumour
drugs, which makes its study particularly interesting. No SAR
study has been carried out to elucidate the role of the carbo-
† This is one of a number of contributions from the current members
hydrate or the nucleoside base moieties in the biological activ-
of the Dyson Perrins Laboratory to mark the end of almost 90 years of
ity, except for the rhamnose analogues we have previously
organic chemistry research in that building, as all its current academic
staff move across South Parks Road to a new purpose-built laboratory.
described,19 and some analogues of septacidin 4,20 a natural
Fig. 1
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 3 6 8 5 – 3 6 9 1
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Scheme 1 Reagents: (i) ArNH2, MeOH, H2O, AcOH, reflux, 3 min to 6 days; (ii) see Martín et al.,19 (iii) ArNH2, MeOH, H2O, AcOH, reflux, 1 h to
2 days; (iv) H2, Pd/C, MeOH, rt, 40 min; (v) dodecanoylglycine, EDCI, HOBT, DMF, rt, 12 h.
Table 1 Reaction times and isolated yields in the preparation of com-
pounds 6a–d and 8a–e
isomer of spicamycin. Our results showed that the structure of
1 can be simplified as in 2d without significant loss of activity,
though the pattern of mannose incorporation in HL60 cells was
modified. By contrast, neither the enantiomer of 2d, ent-2d, nor
the compound 3, where the adenine moiety was replaced by a
methoxy group, were active.
Carbohydrate
ArNH2
Product
Reaction time
Yielda (%)
5
5
5
5
7
7
7
7
7
10a
10b
10c
10d
10a
10b
10c
10d
10e
6a
6b
6c
6d
8a
8b
8c
8d
8e
3 min
3 min
4 h
6 days
12 h
95
91
83
10 [15]
86
49 [61]
69 [83]
10 [16]
20 [43]
A general method for preparing 6-(pyranosylamino)purines
is still lacking to allow more in-depth SAR study on the carbo-
hydrate and nucleobase parts of spicamycin. A few methods
are described and use glycosylamines as the starting material
but, because of the poor nucleophilicity of such amines and
their propensity to dimerise,21 it is necessary to use either a very
electrophilic aryl chloride and build the adenine heterocycle, as
we did earlier,19,22 or a palladium-mediated coupling with a
protected 6-chloropurine.23 The former method is a multistep
procedure and affords low to moderate yields of the expected
product, while the latter involves use of expensive catalysts. In
the perspective of extending these methods to the preparation
of analogues of spicamycin containing bases other than
adenine, they are also limited by the availability of the corre-
sponding aryl chlorides. Some solid-state one-step ribosylations
of adenine are described but are of little synthetic interest.24,25
This paper reports a new route to the preparation of rham-
nospicamycin analogues which is much faster than previous
procedures and likely broader in scope. This approach is based
on a one-step glycosylation of adenine, or other arylamines.
1 h
24 h
2 daysb
2 days
a Yields in square brackets are based on recovered starting material.
b Reaction was carried out at 100 ЊC in a sealed tube.
only one synthetic step (Scheme 1, Table 1). Low yield for the
adenine derivative 6d seems to be attributable to a lower stabil-
ity of the compound which decomposes in the course of the
reaction, especially because the poor solubility of adenine in
the solvent makes the reaction much longer than others.
The p-nitrophenyl derivative 6a was unambiguously shown
to be a pyranose ring with the β--rhamnose configuration, as
depicted in Scheme 1. 2D-NMR experiments (COSY, HMQC
3
and HMBC) showed in every case a strong JH,H coupling
between the NH group and the anomeric proton, which ascer-
tained the site of attachment on the amine moiety. Additional
heteronuclear couplings of the NH group with carbons C-2Ј on
the carbohydrate (strong) and C-1 on the base (weak), and for
6a and 6b, between the anomeric proton and the carbon C-1
(strong), were also observed. The assignment of the anomeric
configuration was made on the basis that chemical shifts of the
carbohydrate protons, except H-1Ј, and coupling constants all
around the ring were almost identical to that of 6a, which is
known to have a β configuration (Table 2).
The synthesis of rhamnospicamycin analogues requires the
presence of a primary amino group at position C-4 with the
same configuration as in -rhamnose. The use of an azide as a
masked amine seemed to be particularly convenient here since
it may be reduced in neutral conditions, either by catalytic
hydrogenation or by a Staudinger reaction, accommodating
the reactivity of the base fragment. In order to avoid cross-
2. Synthesis
Glycosylation of amines using a lactol in neutral or acidic
medium is well known. Among the numerous examples avail-
able in the literature, the method described by Honeyman
attracted our attention regarding the yields obtained, the
extremely short reaction time and the high concentrations used,
which should make easier large-scale preparations.26 Also, this
reaction requires no protection of the carbohydrate and was
successfully applied to a wide variety of sugars, unlike solvent-
free methods.24,25
The direct glycosylation of p-nitroaniline 10a, 2-amino-
pyridine 10b, 2-aminopyrimidine 10c and adenine 10d with
-rhamnose afforded the corresponding N-aryl-β--rhamno-
pyranosylamines 6a–d in yields ranging from 15 to 95% in
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 3 6 8 5 – 3 6 9 1
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Table 2 1H Chemical shifts and coupling constants for the carbohydrate fragment of compounds 6a–d, 8a–e and 2b–e
Chemical shifts (ppm) Coupling constants/Hz
H-1
H-2
H-3
H-4
H-5
H-6
1–2
2–3
3–4
5–6
2b
2c
2d
2e
5.19
3.92
3.92
4.01
3.98
3.67
3.67
3.73
3.70
3.89
3.89
3.94
3.91
3.54
3.51
3.61
3.59
1.20
1.19
1.21
1.19
1.2
1.0
1.2
1.2
3.2
3.2
3.2
3.2
10.6
10.5
10.5
10.4
6.0
6.2
6.1
6.0
5.38
5.68a
5.67a
6a
6b
6c
6d
4.87
5.16
5.39
5.72a
3.96
3.72
3.92
4.00
3.56
3.54
3.54
3.59
3.47–3.33b
1.31
1.28
1.29
1.29
1.0
1.1
1.1
1.2
3.4
3.4
3.4
3.4
9.1
9.1
9.2
9.3
5.8
5.7
5.6
5.8
3.48–3.32b
3.48–3.32b
3.52–3.31b
8a
8b
8c
8d
8e
4.93
5.14
5.36
5.69a
5.65a
3.94
3.90
3.89
3.98
3.97
3.70
3.68
3.68
3.74
3.75
3.45–3.28b
3.47–3.34b
3.38–3.27b
3.52–3.45b
3.50–3.30b
1.36
1.30
1.30
1.32
1.33
1.0
1.1
1.2
1.0
1.1
3.3
3.3
3.3
3.3
3.3
9.7
9.7
9.5
9.7
9.7
6.0
6.0
5.8
6.0
5.8
Spectra were recorded in CD3OD at 400 MHz.a Broad singlet. b Individual chemical shifts could not be derived from the spectrum.
reactions of the base during the transformation of compounds
6a–d to 8a–e, and to adopt a more convergent approach, we
introduced the azido group prior to glycosylation. 4-Azido-
4-deoxy--rhamnose 7 was prepared in seven steps from
-rhamnose, as described previously,19 and was used in the
glycosylation of amines 10a–e to afford 4-azido-4-deoxy-N-
aryl-β--rhamnosylamines 8a–e in 16–86% yield (Table 1). In
particular, we obtained the adenine derivative 8d that we had
not been able to prepare previously using lower concentrations
of the reaction medium.19 In the case of 8a, a mixture of ano-
mers was sometimes obtained after short reaction time but
equilibrated to the thermodynamically more stable β-anomer
on prolonged heating. We could otherwise not detect the α
anomer for any of the other compounds, though it has been
observed with another cyclic acetal.27
It is noteworthy that the highest yield reported for
the preparation of a 6-spicaminyl-9H-purine is less than 24%‡
and requires more than seven steps to achieve the conversion of
the lactol into a glycosylamine, the coupling with protected
6-chloropurine and the deprotection.23 In comparison, we
obtained the adenine derivatives 8d and 8e in only one step in
comparable (16%) or much higher (43%) yield, the difference
probably arising from the better solubility of 9-benzyladenine
10e in the reaction medium; 8e may then serve as an indirect
way to prepare 2d, with the additional advantage of providing
easier purification.
with data for 2d unambiguously proved the structure and
β-configuration of these analogues (Table 2). Retrospectively,
it also provided another evidence for the structure of the pre-
cursor azides 8b–e.
3. Summary
One-step glycosylation of adenine derivatives was achieved on
the N 6-amino group, following the general acid-catalysed reac-
tion of lactols with arylamines. The yields for adenine deriv-
atives and other aromatic amines are at least comparable to
those provided by existing methods, and usually much better,
with the advantage of considerably decreasing the number of
synthetic steps as no protection is required. Also, this method
does not require the availability of aromatic chlorides nor the
use of expensive catalysts. Because this glycosylation is quite
broad in scope, it may be anticipated that a large variety of
analogues containing different carbohydrate and base moieties
can be rapidly synthesised for the study of the mechanisms of
action of the spicamycin family. Preliminary results in our
laboratory show that adenine reacts with -glucose in the con-
ditions mentioned in the present paper to afford the corre-
sponding 6-(β--glucosylamino)-9H-purine in 25% yield, based
on recovered starting material, where solvent-free reaction
fails.24,25 This new approach allowed the preparation of several
dodecanoyl--(ϩ)-rhamnospicamycin analogues.
Determination of the structure and anomeric configuration
of 8a–e was achieved as above from 2D-NMR experiments and
comparison of the proton chemical shifts and coupling con-
stants in the carbohydrate fragment with those of 6a. The slight
increase in the average 3J3Ј–4Ј and 3J5Ј–6Ј, when compared to data
for compounds 6a–d, must account for the minor conform-
ational changes accompanying the replacement of the hydroxyl
at C-4 by an azido group in 8a–e (Table 2). Azides 8b–e were
reduced by catalytic hydrogenation using palladium on char-
coal in methanol to give the corresponding amines 9b–e which
were used, without isolation, for the peptide coupling with
dodecanoylglycine in DMF. Rhamnospicamycin analogues 2b,
2c, 2d and 2e were obtained in 72, 71, 60 and 89% yield, respect-
ively, over two steps. Analyses for 2d showed that this com-
pound was identical to the -(ϩ)-rhamnospicamycin obtained
previously in our laboratory by building the adenine moiety.19
Homo- and hetero-nuclear correlations and comparison of
the chemical shifts and coupling constants in 2b, 2c and 2e
4. Experimental
Proton nuclear magnetic resonance spectra (δH) were recorded
on a Bruker DPX 400 (400 MHz) or Bruker AMX 500
(500 MHz) spectrometer, and were calibrated according to the
chemical shift of residual protons in the deuterated solvent. 13
C
Nuclear magnetic resonance spectra (δC) were recorded on a
Bruker DPX 400 (100 MHz) or Bruker AMX 500 (125 MHz)
spectrometer and were calibrated using the chemical shift of the
deuterated solvent. All the compounds were subjected to
1
1
1H,1H-COSY, H,13C-HMQC and H,13C-HMBC experiments
to ascertain assignments. Chemical shifts are quoted in ppm on
the δ-scale. The following abbreviations are used to denote
multiplicities: s, singlet; d, doublet; dd, double-doublet; ddd,
double-double-doublet; t, triplet; q, quartet; dq, double-
quartet; quint, quintuplet; m, multiplet; br, broad; app, appar-
ent. Second order spin systems are described using standard
nomenclature. Infra-red spectra were recorded on a Perkin-
Elmer 1750 FT IR spectrophotometer and peaks are given in
cmϪ1. Mass spectra were recorded on a VG platform (atmos-
pheric pressure chemical ionisation [APCI] in a solvent mixture
‡ From ref. 23. This calculation excludes the protection steps and
anomeric acetylation, whose yields could not be derived from
description of the synthesis.
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 3 6 8 5 – 3 6 9 1
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MeOH/H2O/MeCN, positive or negative ionisation as stated)
or a VG 20–250 spectrometer (chemical ionisation [CI NH3] as
stated). Optical rotations were measured on a Perkin-Elmer 241
polarimeter with a path length of 1 dm. Concentrations (c) are
given in g/100 ml. Microanalyses were performed in dupli-
cate by the microanalysis service of the Inorganic Chemistry
Laboratory (Oxford). Melting points (mp) were measured on
a Leica Galen III apparatus and are uncorrected. Thin
layer chromatography (TLC) was carried out on aluminium
sheets coated with 60F254 silica from Merck, and plates were
developed using a spray of vanillin (8 g lϪ1) in 95% ethanol
containing 1% (v/v) sulfuric acid, and subsequent heating.
Flash chromatography was carried out using Sorbsil C60 40/60
silica. Solvents and commercially available reagents were dried
and purified before use according to standard procedures.
J = 9.9 Hz, NH-pyrimidine), 6.31 (t, 1H, J = 4.8 Hz, H-4), 5.77
(dd, 1H, J = 1.0, 9.9 Hz, H-1Ј), 4.64 (app. q, 1H, J = 9.8 Hz,
H-4Ј), 4.27 (dd, 1H, J = 1.0, 3.2 Hz, H-2Ј), 4.22 (ABX, 1H,
J = 5.6, 16.2 Hz, NHCH2CO), 4.12 (ABX, 1H, J = 5.4, 16.2 Hz,
NHCH2CO), 4.09 (dd, 1H, J = 3.2, 9.8 Hz, H-3Ј), 3.72 (qd, 1H,
J = 6.0, 9.8 Hz, H-5Ј), 2.40 (t, 2H, J = 7.5 Hz, CH2CH2CO),
1.56 (app quint, 2H, J = 7.5 Hz, CH2CH2CO), 1.29 (d, 3H,
J = 6.0 Hz, H-6Ј), 1.13–0.94 (m, 16H, CH2 fatty chain), 0.67–
0.61 (m, 3H, CH3 fatty chain); δC (pyridine d5, 100 MHz) 174.2
(CONHCH2CONH), 171.4 (CONHCH2CONH), 162.8 (C-1),
158.9 (br s, C-3), 112.7 (C-4), 81.0 (C-1Ј), 74.01, 73.95 (C-3Ј,
C-5Ј), 72.3 (C-2Ј), 54.9 (C-4Ј), 44.2 (CONHCH2CONH), 36.8
(CH2CH2CONH), 32.48, 30.27, 30.23, 30.17, 30.11, 30.04
(6s, CH2 fatty chain), 26.5 (CH2CH2CONH), 23.3 (CH2 fatty
chain), 19.2 (C-6Ј), 14.7 (CH3 fatty chain); IR (KBr) 3430 (free
νOH), 3410, 3305 (br, bonded νOH), 2922, 2850, 1657, 1639, 1594,
1576, 1539, 1525, 1457, 1261, 1190, 1093, 1064, 1015, 976, 893,
800, 627; m/z (APCIϩ) 138 [2-aminopyrimidine ϩ Ac]ϩ (100%),
480 [M ϩ H]ϩ (97%); m/z (APCIϪ) 514 : 516 [M ϩ Cl]Ϫ (3 : 1,
100%); HRMS (CI NH3) m/z 480.3183 [M ϩ H]ϩ (calcd. for
C24H42N5O5 m/z 480.3186).
4.1 2-[4Ј-Deoxy-4Ј-(dodecanoylglycyl)amino-ꢀ-L-rhamno-
pyranosylamino)pyridine 2b
Azide 8b (20 mg, 0.075 mmol) was dissolved in 5 ml methanol
and 1 ml water. 10 mg 10% palladium on charcoal was added
and the mixture was stirred at room temperature under an
atmosphere of hydrogen. After 40 min, TLC showed no start-
ing material. Reaction mixture was filtered through Celite and
evaporated to dryness. The residue was dissolved in 1.5 ml dry
DMF with N-hydroxybenzotriazole monohydrate (HOBT)
(17 mg, 0.111 mmol), dodecanoylglycine (21 mg, 0.082 mmol)
and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydro-
chloride (EDCI) (29 mg, 0.151 mmol). The mixture was stirred
overnight and evaporated in vacuo. The residue was purified by
flash chromatography on silica (CH2Cl2/MeOH 9 : 1 to 8 : 2)
then a preparative TLC (CH2Cl2/MeOH 3 : 1) to afford the title
compound (26 mg, 72%) as a white solid. Rf 0.15 (CH2Cl2/
MeOH 9 : 1); mp (MeOH) 182–184 ЊC; [α]D22 ϩ39.2 (c = 0.475,
pyridine); δH (pyridine d5, 400 MHz) 8.78 (d, 1H, J = 9.8 Hz,
CONHCH2CONH ), 8.69 (t, 1H, J = 5.4 Hz, CONHCH2-
CONH), 8.06 (dd, 1H, J = 1.9, 5.1 Hz, H-5), 7.20 (ddd, 1H,
J = 1.9, 7.1, 8.4 Hz, H-3), 7.05 (d, 1H, J = 9.9 Hz, NH-pyridyl),
6.61 (d, 1H, J = 8.4 Hz, H-2), 6.40 (ddd, 1H, J = 0.7, 5.1,
7.1 Hz, H-4), 5.61 (d, 1H, J = 9.9 Hz, H-1Ј), 4.63 (app. q, 1H,
J = 9.8 Hz, H-4Ј), 4.26 (d, 1H, J = 3.2 Hz, H-2Ј), 4.22 (ABX,
1H, J = 5.6, 16.1 Hz, CONHCH2CONH), 4.12 (ABX, 1H,
J = 5.4, 16.1 Hz, CONHCH2CONH), 4.08 (dd, 1H, J = 3.2,
9.8 Hz, H-3Ј), 3.71 (qd, 1H, J = 6.1, 9.8 Hz, H-5Ј), 2.18 (t, 2H,
J = 7.5 Hz, CH2CH2CONH), 1.56 (app quint, 2H, J = 7.5 Hz,
CH2CH2CONH), 1.29 (d, 3H, J = 6.1 Hz, H-6Ј), 1.14–0.92
(m, 16H, CH2 fatty chain), 0.66–0.61 (m, 3H, CH3 fatty chain);
δC (pyridine d5, 100 MHz) 174.1 (CONHCH2CONH), 171.3
(CONHCH2CONH), 158.7 (C-1), 148.8 (C-5), 137.9 (C-3),
114.5 (C-4), 109.4 (C-2), 81.1 (C-1Ј), 74.0 (C-3Ј), 73.7 (C-5Ј),
72.4 (C-2Ј), 55.0 (C-4Ј), 44.2 (CONHCH2CONH), 36.7 (CH2-
CH2CONH), 32.4, 30.20, 30.16, 30.10, 30.04, 29.97 (6s, CH2
fatty chain), 26.5 (CH2CH2CONH), 23.3 (CH2 fatty chain),
19.2 (C-6Ј), 14.6 (CH3 fatty chain); IR (KBr) 3421 (free νOH),
3309 (br, νNH, νOH), 2923, 2851, 1651, 1639 (νCO amide), 1606,
1575, 1524, 1445, 1398, 1323, 1264, 1194, 1155, 1087, 1064,
1015, 971, 770; m/z (APCIϩ) 137 [2-aminopyridine ϩ Ac]ϩ
(100%), 479 [M ϩ H]ϩ (31%); m/z (APCIϪ) 297 (100%), 477
[M Ϫ H]Ϫ (66%); HRMS (CI NH3) m/z 479.3227 [M ϩ H]ϩ
(calcd. for C25H43N4O5 m/z 479.3233).
4.3 6-[4Ј-Deoxy-4Ј-(dodecanoylglycyl)amino-ꢀ-L-rhamno-
pyranosylamino)-9H-purine 2d
Following the same procedure as described above for 2b, the
title compound was obtained in 60% yield (47 mg, 0.090 mmol)
as a white solid starting from 8d (41 mg, 0.147 mmol). The
hydrogenation step was carried out in 12 ml methanol and 2 ml
water. Analyses were fully consistent with data previously
reported.19,22
4.4 9-Benzyl-6-[4Ј-deoxy-4Ј-(dodecanoylglycyl)amino-ꢀ-L-
rhamnopyranosylamino)-9H-purine 2e
Following the same procedure as described above for 2b, the
title compound was obtained in 89% yield (27 mg, 0.044 mmol)
as a white solid starting from 8e (20 mg, 0.050 mmol). The
hydrogenation step was carried out in 8 ml methanol and 2 ml
water and the product was purified by crystallisation in meth-
anol. Rf 0.10 (CH2Cl2/MeOH 9 : 1); mp (MeOH) 214–216 ЊC
24
(dec.); [α]D ϩ10.3 (c = 0.29, pyridine); δH (pyridine d5, 400
MHz) 8.83 (d, 1H, J = 9.3 Hz, CONHCH2CONH ), 8.71 (app t,
1H, J = 5.6 Hz, CONHCH2CONH), 8.52 (s, 1H, H-2), 8.08 (s,
1H, H-8), 7.85 (d, 1H, J = 7.8 Hz, NH-purine), 7.21–7.02 (m,
5H, Ph), 6.10 (d, 1H, J = 7.8 Hz, H-1Ј), 5.21 (s, 2H, CH2Ph),
4.70 (app q, 1H, J = 9.3 Hz, H-4Ј), 4.37 (br s, 1H, H-2Ј), 4.24
(ABX, 1H, J = 5.6, 16.1 Hz, NHCH2CO), 4.19–4.11 (m, 2H,
NHCH2CO, H-3Ј), 3.80 (br s, 1H, H-5Ј), 2.19 (t, 2H, J = 7.5 Hz,
CH2CH2CONH), 1.57 (app quint, 2H, J = 7.5 Hz, CH2CH2-
CONH), 1.33 (d, 3H, J = 5.7 Hz, H-6Ј), 1.18–0.91 (m, 16H,
CH2 fatty chain), 0.67–0.61 (m, 3H, CH3 fatty chain); δC (pyrid-
ine d5, 100 MHz) 174.6 (CONHCH2CONH), 171.9 (CONH-
CH2CONH), 155.2 (br s, C-6), 154.1 (C-2), 151.4 (C-4), 142.4
(br s, C-8), 138.1 (Ph C-1), 130.0 (Ph C-2 or C-3), 129.2 (Ph
C-4), 129.0 (Ph C-2 or C-3), 121.5 (br s, C-5), 80.0 (br s, C-1Ј),
74.7 (C-5Ј), 74.3 (C-3Ј), 72.6 (C-2Ј), 55.3 (C-4Ј), 47.9 (CH2Ph),
44.7 (NHCH2CO), 37.3 (CH2CH2CONH), 33.0, 30.75, 30.71,
30.64, 30.58, 30.51, 30.43 (7s, CH2 fatty chain), 27.0 (CH2CH2-
CONH), 23.8 (CH2 fatty chain), 19.7 (C-6Ј), 15.1 (CH3 fatty
chain); IR (KBr) 3392, 3310 (br, νOH, νNH), 2924, 2852, 1647,
1624 (νCO amide), 1588, 1534, 1483, 1458, 1408, 1337, 1292,
1230, 1130, 1091, 1067, 1022, 970, 862, 798, 731, 697, 647; m/z
(APCIϩ) 268 [9-benzyladenine ϩ Ac ϩ H]ϩ (100%), 610 [M ϩ
H]ϩ (9%); m/z (APCIϪ) 255 [dodecanoylglycinamide]Ϫ (33%),
297 (100%), 608 [M Ϫ H]Ϫ (37%); HRMS (CI NH3) m/z
610.3690 [M ϩ H]ϩ (calcd. for C32H48N7O5 m/z 610.3717).
4.2 2-[4Ј-Deoxy-4Ј-(dodecanoylglycyl)amino-ꢀ-L-rhamno-
pyranosylamino)pyrimidine 2c
Following the same procedure as described above for 2b, the
title compound was obtained in 71% yield (29 mg, 0.060 mmol)
as a white solid starting from 8c (22.5 mg, 0.085 mmol). Rf 0.10
24
(CH2Cl2/MeOH 9 : 1); mp (MeOH) 187–189 ЊC; [α]D ϩ24.7
4.5 1-Nitro-4-(ꢀ-L-rhamnopyranosylamino)benzene hydrate 6a
(c = 0.15, pyridine); δH (pyridine d5, 400 MHz) 8.79 (d, 1H,
J = 9.8 Hz, CONHCH2CONH ), 8.69 (t, 1H, J = 5.4 Hz,
CONHCH2CONH), 8.16 (d, 2H, J = 4.8 Hz, H-3), 7.57 (d, 1H,
-Rhamnose monohydrate (2.052 g, 11.26 mmol) and p-nitro-
aniline (1.954 g, 14.15 mmol) were suspended in a mixture of
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 3 6 8 5 – 3 6 9 1
3688

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MeOH/H2O/AcOH 8 : 1 : 4 (6.5 ml). The suspension was heated
to reflux for 3 min and allowed to cool to room temperature.
Filtration and washing of the solid with absolute ethanol, then
ether, afforded the title compound 6a (3.183 g, 95%) as a bright
yellow powder which can be used without purification (micro-
analysis found C 48.75%, H 5.66%, N 9.30%; C12H16N2O6ؒ
¾H2O requires C 48.40%, H 5.92%, N 9.41%). Recrystallisation
from methanol/water afforded an analytically pure sample. Rf
0.75 (AcOEt/MeOH 3 : 1); mp (MeOH/H2O) 214–216 ЊC (dec.)
1H, J = 4.7 Hz, H-4), 6.55 (d, 1H, J = 9.8 Hz, NH), 5.25 (d, 1H,
J = 9.8 Hz, H-1Ј), 5.09 (s, 1H, OH-2Ј), 4.79 (s, 1H, OH-4Ј), 4.76
(s, 1H, OH-3Ј), 3.72 (s, 1H, H-2Ј), 3.40–3.32 (m, 1H, H-3Ј),
3.20–3.10 (m, 2H, H-4Ј, H-5Ј), 1.11 (d, 3H, J = 5.2 Hz, H-6Ј);
δC (DMSO d6, 125 MHz, 80 ЊC) 162.0 (C-1), 159.0 (C-3), 113.0
(C-4), 80.2 (C-1Ј), 75.1 (C-3Ј), 74.0 (C-5Ј), 73.0 (C-4Ј), 71.9
(C-2Ј), 18.8 (C-6Ј); IR (KBr) 3446 (br, νOH, νNH), 3272 (br, νOH
,
νNH), 2987, 2906, 1588, 1574, 1521, 1456, 1419, 1362, 1320,
1256, 1225, 1190, 1083, 1062, 1020, 967, 906, 858, 804, 789, 700,
652, 630, 525; m/z (APCIϩ) 137 [2-aminopyrimidine ϩ MeCN
ϩ H]ϩ (100%), 206 [M Ϫ 2H2O ϩ H]ϩ (47%), 224 [M Ϫ H2O ϩ
H]ϩ (40%), 242 [M ϩ H]ϩ (29%); m/z (APCIϪ) 136 [2-amino-
pyrimidine ϩ MeCN]Ϫ (100%), 240 [M Ϫ H]Ϫ (82%); HRMS
(CI NH3) m/z 242.1129 [M ϩ H]ϩ (calcd. for C10H16N3O4 m/z
242.1141).
22
{lit. 232 ЊC28 (MeOH) 208 ЊC29}; [α]D ϩ304 (c = 1, pyridine)
{lit.28 ϩ319 in pyridine}; δH (DMSO d6, 400 MHz) 8.01
(AAЈXXЈ, 2H, J = 0.3, 2.5, 9.6 Hz, H-3), 7.29 (d, 1H, J = 8.4 Hz,
NH), 6.89 (AAЈXXЈ, 2H, J = 0.3, 2.5, 9.6 Hz, H-2), 4.97 (d, 1H,
J = 5.2 Hz, OH-2Ј), 4.83–4.80 (m, 3H, H-1Ј, OH-3Ј, OH-4Ј),
3.77–3.74 (m, 1H, H-2Ј), 3.42–3.35 (m, 1H, H-3Ј), 3.32–3.25 (m,
1H, H-5Ј), 3.22–3.15 (m, 1H, H-4Ј), 1.13 (d, 3H, J = 6.0 Hz,
H-6Ј); δC (DMSO d6, 100 MHz) 153.1 (C-1), 137.3 (C-4), 125.8
(C-3), 112.7 (C-2), 80.6 (C-1Ј), 73.8 (C-3Ј), 72.8, 71.8 (C-4Ј,
C-5Ј), 70.7 (C-2Ј), 18.0 (C-6Ј); IR (film) 3325 (br, νOH, νNH),
1601, 1535, 1503, 1342, 1274, 1082, 1001, 834, 790, 752; m/z
(APCIϩ) 138 [aniline]ϩ (33%), 148 [rhamnosyl ϩ H]ϩ (100%),
284 [M]ϩ (10%); m/z (APCIϪ) 179 [aniline ϩ MeCN]Ϫ (100%),
283 [M Ϫ H]Ϫ (23%); Microanalysis found C 48.48%, H 5.70%,
N 9.40% (C12H16N2O6ؒ¾H2O requires C 48.40%, H 5.92%, N
9.41%).
4.8 6-(ꢀ-L-Rhamnopyranosylamino)-9H-purine 6d
-Rhamnose monohydrate (1.044 g, 5.73 mmol) and adenine
(1.262 g, 9.34 mmol) were suspended in a mixture of MeOH/
H2O/AcOH 10 : 0.6 : 4 (14 ml). The suspension was heated to
reflux for 6 days, then evaporated to dryness. Purification by
repeated flash chromatography on silica (AcOEt/MeOH 1 : 0 to
1 : 1) afforded -rhamnose (295 mg, 1.80 mmol) and the title
compound (161 mg, 15% based on recovered starting material)
as a white powder. A sample was recrystallised from iso-
propanol for analytical purposes. Rf 0.15 (AcOEt/MeOH 3 : 1);
4.6 2-(ꢀ-L-Rhamnopyranosylamino)pyridine 6b
23
mp (iPrOH) 178–180 ЊC; [α]D ϩ45.3 (c = 0.258, pyridine);
-Rhamnose monohydrate (1.498 g, 8.22 mmol) and 2-amino-
pyridine (868 mg, 9.22 mmol) were suspended in a mixture of
MeOH/H2O/AcOH 8 : 1 : 4 (4 ml). The suspension was heated
to reflux for 3 min during which solution occurred. A hard gel
formed on cooling which was ground in a mortar and washed
with absolute ethanol. Recrystallisation from a mixture of
acetonitrile/ethanol 1 : 2 afforded the title compound (792 mg,
40%) as white needles. Evaporation of the filtrates and purifi-
cation of the residue by column chromatography (CH2Cl2/
MeOH 95 : 5 to 70 : 30) gave an additional amount of 6b (1.009
g, 51%) as a white solid with a total yield of 91%. Rf 0.30
δH (DMSO d6, 500 MHz, 80 ЊC) 8.28 (s, 1H, H-2), 8.13 (s, 1H,
H-8), 6.86 (d, 1H, J = 8.5 Hz, C6-NH), 5.72 (d, 1H, J = 8.5 Hz,
H-1Ј), 3.83 (d, 1H, J = 3.0 Hz, H-2Ј), 3.46 (dd, 1H, J = 3.0,
9.5 Hz, H-3Ј), 3.32–3.21 (m, 2H, H-4Ј, H-5Ј), 1.16 (d, 3H,
J = 6.0 Hz, H-6Ј); δC (DMSO d6, 125 MHz, 80 ЊC) 153.4, 153.3
(C-4, C-6), 152.9 (C-2), 141.5 (C-8), 118.7 (C-5), 79.3 (C-1Ј),
75.1 (C-3Ј), 74.1 (C-5Ј), 72.9 (C-4Ј), 71.8 (C-2Ј), 18.8 (C-6Ј);
IR (KBr) 3368 (br, νOH, νNH), 2989, 2921, 2852, 1617 (br),
1521, 1457, 1401, 1327, 1244, 1146, 1082, 1062, 1013, 969,
945, 900, 797, 758, 694, 640, 621; m/z (APCIϩ) 136 [adenine ϩ
H]ϩ (39%), 178 (100%), 282 [M ϩ H]ϩ (87%); m/z (APCIϪ)
134 [adenyl]Ϫ (23%), 176 [adenine ϩ MeCN]Ϫ (100%), 280
[M Ϫ H]Ϫ (16%); HRMS (CI NH3) m/z found 282.1206
[M ϩ H]ϩ (calcd. for C11H16N5O4 m/z 282.1202).
22
(CH2Cl2/MeOH 85 : 15); mp (EtOH) 201–203 ЊC (dec.); [α]D
ϩ132 (c = 1, pyridine); δH (DMSO d6, 400 MHz) 8.01 (dd, 1H,
J = 2.0, 5.0 Hz, H-5), 7.44 (ddd, 1H, J = 2.0, 6.8, 8.4 Hz, H-3),
6.67 (dd, 1H, J = 0.4, 8.4 Hz, H-2), 6.60 (ddd, 1H, J = 0.4,
5.0, 6.8 Hz, H-4), 6.39 (d, 1H, J = 8.8 Hz, NH), 5.19 (d, 1H,
J = 8.8 Hz, H-1Ј), 4.93 (d, 1H, J = 4.8 Hz, OH-2Ј), 4.74 (d, 1H,
J = 5.2 Hz, OH-4Ј), 4.71 (d, 1H, J = 5.6 Hz, OH-3Ј), 3.71–3.67
(m, 1H, H-2Ј), 3.39–3.30 (m, 1H, H-3Ј), 3.22–3.11 (m, 2H,
H-4Ј, H-5Ј), 1.10 (d, 3H, J = 5.6 Hz, H-6Ј); δC (DMSO d6, 100
MHz) 157.2 (C-1), 147.5 (C-5), 137.2 (C-3), 113.5 (C-4), 108.6
(C-2), 79.2 (C-1Ј), 74.2 (C-3Ј), 72.8, 72.0 (C-4Ј, C-5Ј), 71.2
(C-2Ј), 18.1 (C-6Ј); IR (KBr) 3398, 3150 (br, νOH, νNH), 2974,
2911, 1608, 1572, 1522, 1459, 1445, 1362, 1322, 1284, 1261,
1138, 1086, 1074, 1005, 971, 899, 770, 668; m/z (APCIϩ) 222
[M Ϫ H2O]ϩ (30%), 240 [M]ϩ (100%), 241 [M ϩ H]ϩ (82%);
m/z (APCIϪ) 135 [2-aminopyridine ϩ MeCN]Ϫ (100%), 239
[M Ϫ H]Ϫ (12%); Microanalysis found C 54.92%, H 6.76%, N
11.71% (C11H16N2O4 requires C 54.99%, H 6.71%, N 11.66%).
4.9 1-(4Ј-Deoxy-4Ј-azido-ꢀ-L-rhamnopyranosylamino)-4-
nitrobenzene 8a
4-Azido-4-deoxy--rhamnose19 7 (298 mg, 1.58 mmol) and
p-nitroaniline (322 mg, 2.33 mmol) were dissolved in a mixture
of MeOH/H2O/AcOH 8 : 1 : 4 (1 ml). The solution was heated
to reflux for 12 hours. The reaction mixture was evaporated to
dryness and purified by flash chromatography on silica (hexane/
AcOEt 1 : 1) to afford the title compound (421 mg, 86%) as
a bright yellow solid. A sample was recrystallised from iso-
propanol for analytical purposes. Rf 0.25 (hexane/AcOEt 1 : 1);
22
mp (iPrOH) 191–192 ЊC (dec.); [α]D ϩ246 (c = 1, pyridine);
δH (DMSO d6, 400 MHz) 8.01 (AAЈXXЈ, 2H, J = 0.3, 2.5,
9.6 Hz, H-3), 7.33 (d, 1H, J = 8.8 Hz, NH), 6.90 (AAЈXXЈ, 2H,
J = 0.3, 2.5, 9.6 Hz, H-2), 5.51 (d, 1H, J = 6.6 Hz, OH-3Ј), 5.27
(d, 1H, 5.7 Hz, OH-2Ј), 4.91 (d, 1H, J = 8.8 Hz, H-1Ј), 3.77 (dd,
1H, J = 3.2, 5.7 Hz, H-2Ј), 3.65 (ddd, 1H, J = 3.2, 6.6, 9.8 Hz,
H-3Ј), 3.42–3.33 (m, 1H, H-5Ј), 3.28 (app t, J = 9.8 Hz, H-4Ј),
1.17 (d, 3H, J = 6.0 Hz, H-6Ј); δC (DMSO d6, 100 MHz) 153.7
(C-1), 138.4 (C-4), 126.6 (C-3), 113.6 (C-2), 81.3 (C-1Ј), 73.7
(C-3Ј), 71.4 (C-2Ј), 71.1 (C-5Ј), 65.7 (C-4Ј), 19.4 (C-6Ј); IR
(film) 3332 (br, νOH, νNH), 2912, 2465, 2114 (N3), 1604, 1534,
1502, 1489, 1348, 1330, 1298, 1277, 1182, 1115, 1057, 1002, 912,
832, 785, 751; m/z (APCIϩ) 139 [p-nitroaniline ϩ H]ϩ (100%),
310 [M ϩ H]ϩ (42%); m/z (APCIϪ) 137 [p-nitroaniline Ϫ H]Ϫ
(23%), 179 [p-nitroaniline ϩ MeCN]Ϫ (100%), 308 [M Ϫ H]Ϫ
(38%); HRMS (CI NH3 Ϫve) m/z found 308.0995 [M Ϫ H]Ϫ
(calcd. for C12H15N5O5 m/z 308.0995).
4.7 2-(ꢀ-L-Rhamnopyranosylamino)pyrimidine 6c
-Rhamnose monohydrate (1.016 g, 5.577 mmol) and 2-amino-
pyrimidine (599 mg, 6.30 mmol) were suspended in a mixture of
MeOH/H2O/AcOH 8 : 1 : 4 (3.25 ml). The suspension was
heated to reflux for 3.5 hours during which solution occurred. A
hard gel formed on cooling which was dissolved in 200 ml hot
absolute ethanol and left overnight at 6 ЊC. The gel was ground
in a mortar, filtered and dried in vacuo to afford the title com-
1
pound (1.112 g, 83%) as an amorphous colourless solid. H
NMR showed no impurity. Rf 0.25 (CH2Cl2/MeOH 85 : 15);
23
mp (EtOH) 194–196 ЊC; [α]D ϩ79.1 (c = 1.05, pyridine);
δH (DMSO d6, 400 MHz) 8.37 (d, 2H, J = 4.7 Hz, H-3), 6.75 (t,
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 3 6 8 5 – 3 6 9 1
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1
4.10 2-(4Ј-Deoxy-4Ј-azido-ꢀ-L-rhamnopyranosylamino)-
of the starting lactol. H NMR showed the presence of 5% of
adenine as a contaminant. Rf 0.30 (AcOEt/MeOH 3 : 1); mp
(EtOH) 262–263 ЊC (dec.); δH (DMSO d6, 500 MHz, 80 ЊC) 8.29
(s, 1H, H-2), 8.15 (s, 1H, H-8), 6.92 (d, 1H, J = 8.5 Hz, C6-NH),
5.73 (d, 1H, J = 8.5 Hz, H-1Ј), 3.85 (dd, 1H, J = 1.0, 3.5 Hz,
H-2Ј), 3.72 (dd, 1H, J = 3.5, 9.5 Hz, H-3Ј), 3.38–3.27 (m, 2H,
H-4Ј, H-5Ј), 1.20 (d, 3H, J = 6.0 Hz, H-6Ј); δC (DMSO d6, 125
MHz, 80 ЊC) 153.3, 153.2 (C-4, C-6), 152.9 (C-2), 141.5 (C-8),
118.6 (C-5), 79.4 (brs, C-1Ј), 73.7 (C-3Ј), 72.0 (C-5Ј), 71.3
(C-2Ј), 66.0 (C-4Ј), 19.3 (C-6Ј); m/z (APCIϩ) 178 [adenyl ϩ Ac
ϩ H]ϩ (100%), 307 [M ϩ H]ϩ (47%); m/z (APCIϪ) 176 [adenyl
ϩ Ac Ϫ H]Ϫ (100%), 305 [M Ϫ H]Ϫ (38%); HRMS (CI NH3)
m/z 307.1259 [M ϩ H]ϩ (calcd. for C11H15N8O3 m/z 307.1267).
pyridine 8b
Following the same procedure as for 8a with 7 (303 mg, 1.60
mmol) and 2-aminopyridine (239 mg, 2.54 mmol) the title com-
pound was obtained (208 mg, 61% based on recovered starting
material) as a white solid along with 61 mg (0.32 mmol) of the
starting carbohydrate after flash chromatography on silica
(AcOEt). A sample was recrystallised from isopropanol for
analytical purposes. Rf 0.30 (AcOEt); mp (iPrOH) 178–180 ЊC;
22
[α]D ϩ60.8 (c = 1.01, pyridine); δH (DMSO d6, 500 MHz,
80 ЊC) 8.01 (ddd, 1H, J = 0.5, 1.5, 6.0 Hz, H-5), 7.46 (ddd, 1H,
J = 1.5, 7.5, 8.5 Hz, H-3), 6.70 (ddd, 1H, J = 0.5, 1.0, 8.5 Hz,
H-2), 6.62 (ddd, 1H, J = 1.0, 6.0, 7.5 Hz, H-4), 6.25 (d, 1H,
J = 9.5 Hz, NH), 5.22 (dd, 1H, J = 1.0, 9.5 Hz, H-1Ј), 5.05 (d,
1H, J = 6.5 Hz, OH-3Ј), 4.94 (d, 1H, J = 5.0 Hz, OH-2Ј), 3.79–
3.77 (m, 1H, H-2Ј), 3.66 (ddd, 1H, J = 3.0, 6.5, 9.5 Hz, H-3Ј),
3.32–3.23 (m, 2H, H-4Ј, H-5Ј), 1.19 (d, 3H, J = 6.0 Hz, H-6Ј);
δC (DMSO d6, 100 MHz) 157.1 (C-1), 147.5 (C-5), 137.3 (C-3),
113.7 (C-4), 108.8 (C-2), 79.1 (C-1Ј), 73.1 (C-3Ј), 0.7 (C-2Ј), 70.6
(C-5Ј), 65.1 (C-4Ј), 18.6 (C-6Ј); IR (KBr) 3476 (br, νOH, νNH),
4.13 9-Benzyl-6-(4Ј-deoxy-4Ј-azido-ꢀ-L-rhamnopyranosyl-
amino)-9H-purine 8e
Following the same procedure as for 8a with 7 (304 mg, 1.61
mmol) and 9-benzyladenine 10e (500 mg, 2.22 mmol) the title
compound was obtained (125 mg, 43% based on recovered
starting material) as a white solid along with 167 mg (0.88
mmol) of the starting carbohydrate after flash chromatography
on silica (AcOEt/MeOH 100 : 0 to 93 : 7). A sample was
recrystallised from ethanol for analytical purposes. Rf 0.55
2418, 3081, 2940, 2907, 2875, 2715, 2126 (νN᎐N᎐N), 1610, 1574,
᎐
1516, 1444, 1386, 1317, 1301, 1279, 1226, 1196, 1159, 1100,
1083, 1066, 1014, 968, 911, 878, 845, 774, 739, 646, 620, 593,
555, 510; m/z (APCIϩ) 137 (100%), 266 [M ϩ H]ϩ (48%);
m/z (APCIϪ) 135 [2-aminopyridine ϩ MeCN]Ϫ (100%), 264
[M Ϫ H]Ϫ (67%); HRMS (CI NH3) m/z 266.1254 [M ϩ H]ϩ
(calcd. for C11H16N5O3 m/z 266.1253).
22
(AcOEt/MeOH 9 : 1); mp (EtOH) 225–226 ЊC; [α]D ϩ8.02
(c = 1.035, pyridine); δH (DMSO d6, 500 MHz, 80 ЊC) 8.35
(s, 1H, H-8), 8.30 (s, 1H, H-2), 7.36–7.27 (m, 5H, Ph), 6.91
(d, 1H, J = 9.5 Hz, NH), 5.75 (brd, 1H, J = 9.5 Hz, H-1Ј), 5.43
(s, 2H, CH2Ph), 5.31 (d, 1H, J = 4.5 Hz, OH-2Ј), 5.15 (d, 1H,
J = 7.0 Hz, OH-3Ј), 3.88–3.86 (m, 1H, H-2Ј), 3.73 (ddd, 1H,
J = 3.0, 7.0, 9.5 Hz, H-3Ј), 3.39–3.28 (m, 2H, H-4Ј, H-5Ј), 1.20
(d, 3H, J = 6.0 Hz, H-6Ј); δC (DMSO d6, 125 MHz, 80 ЊC) 154.2
(C-6), 153.2 (C-2), 151.1 (C-4), 142.9 (C-8), 137.7 (Ph C-1),
129.5 (Ph C-2 or C-3), 128.6 (Ph C-4), 128.4 (Ph C-2 or C-3),
120.2 (C-5), 79.4 (C-1Ј), 73.7 (C-3Ј), 72.0 (C-5Ј), 71.3 (C-2Ј),
66.0 (C-4Ј), 47.3 (CH2Ph), 19.3 (C-6Ј); IR (KBr) 3430, 3320 (br,
4.11 2-(4Ј-Azido-4Ј-deoxy-ꢀ-L-rhamnopyranosylamino)-
pyrimidine 8c
4-Azido-4-deoxy--rhamnose19 7 (297 mg, 1.57 mmol) and
2-aminopyrimidine (234 mg, 2.46 mmol) were dissolved in a
mixture of MeOH/H2O/AcOH 9.8 : 0.2 : 4 (1 ml). The solution
was heated at reflux for 24 hours. The reaction mixture was
evaporated to dryness and purified by flash chromatography on
silica (hexane/AcOEt 1 : 1 to 0 : 1) to afford the title compound
(287 mg, 83% based on recovered starting material) as a white
solid along with 50.5 mg (0.27 mmol) of the starting lactol.
A sample was recrystallised from methanol for analytical
νOH, νNH), 2993, 2900, 2109 (νN᎐N᎐N), 1616, 1588, 1480, 1456,
᎐
1432, 1407, 1350, 1287, 1268, 1229, 1128, 1077, 1017, 963, 908,
866, 798, 732, 695, 644, 554, 512; m/z (APCIϩ) 226 [9-benzyl-
adenine ϩ H]ϩ (58%), 268 [9-benzyladenine ϩ Ac ϩ H]ϩ
(100%), 397 [M ϩ H]ϩ (49%); m/z (APCIϪ) 266 [9-benzyl-
adenine ϩ Ac Ϫ H]Ϫ (100%), 395 [M Ϫ H]Ϫ (6%); HRMS
(CI NH3) m/z 397.1740 [M ϩ H]ϩ (calcd. for C18H20N8O3 m/z
397.1737).
24
purposes. Rf 0.50 (AcOEt); mp (MeOH) 162 ЊC; [α]D ϩ14.2
(c = 1.165, pyridine); δH (DMSO d6, 500 MHz) 8.38 (d, 2H,
J = 5.0 Hz, H-3), 6.77 (t, 1H, J = 5.0 Hz, H-4), 6.60 (d, 1H,
J = 9.5 Hz, NH), 5.40 (d, 1H, J = 7.0 Hz, OH-3Ј), 5.36 (d, 1H,
J = 5.5 Hz, OH-2Ј), 5.30 (dd, 1H, J = 1.0, 9.5 Hz, H-1Ј), 3.76–
3.73 (m, 1H, H-2Ј), 3.66 (ddd, 1H, J = 3.5, 7.0, 10.0 Hz, H-3Ј),
3.28–3.19 (m, 2H, H-4Ј, H-5Ј), 1.15 (d, 3H, J = 5.5 Hz, H-6Ј);
δC (DMSO d6, 100 MHz) 160.8 (C-1), 158.3 (C-3), 112.4 (C-4),
79.0 (C-1Ј), 72.8 (C-3Ј), 70.8 (C-2Ј), 70.4 (C-5Ј), 64.9 (C-4Ј),
18.6 (C-6Ј); IR (KBr) 3419 (free νOH), 3346 (br, νOH, νNH), 3206
4.14 Benzyladenine 10e
This compound was prepared according to a literature pro-
cedure.30 In our hands however, the ratio of 3-/9-isomer was
never better than 2 : 1 and only 14% of 9-benzyladenine 10e
could be crystallized as fine white needles. Analyses were
consistent with data from the literature.30,31
(br, νOH, νNH), 2908, 2877, 2115 (νN᎐N᎐N), 1673, 1595, 1573, 1516,
1450, 1390, 1363, 1337, 1280, 12᎐50, 1192, 1148, 1090, 1079,
1063, 1015, 969, 906, 857, 803, 790, 722, 609, 564; m/z (APCIϩ)
138 [2-aminopyridyl ϩ Ac ϩ H]ϩ (100%), 267 [M ϩ H]ϩ (61%);
m/z (APCIϪ) 136 [2-aminopyridyl ϩ Ac Ϫ H]Ϫ (100%), 265
[M Ϫ H]Ϫ (100%); HRMS (CI NH3) m/z 267.1199 [M ϩ H]ϩ
(calcd. for C10H15N6O3 m/z 267.1206).
᎐
5. Acknowledgements
This work was supported by a grant from Association pour la
Recherche sur le Cancer (ARC).
6. References
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