Synthesis of gluco-configured tetrahydroimidazopyridine-2-phosphonate- derived lipids, potential glucosyl transferase inhibitors

Article abstract of DOI:10.1002/(SICI)1522-2675(19990804)82:8<1137::AID-HLCA1137>3.0.CO;2-N

The analogues 1-3 of dolichol monophosphatidyl β-D-glucose have been prepared as potential inhibitors of the glucosyl transferase Alg10p, Pd(PPh₃)₄-catalysed phosphonylation of the iodoimidazole 4 with diethyl, dimethyl, and diphenyl

Full text of DOI:10.1002/(SICI)1522-2675(19990804)82:8<1137::AID-HLCA1137>3.0.CO;2-N

Helvetica Chimica Acta ± Vol. 82 (1999)
1137
Synthesis of gluco-Configured Tetrahydroimidazopyridine-2-
phosphonate-Derived Lipids, Potential Glucosyl Transferase Inhibitors
by Isabelle Billault and Andrea Vasella*
Laboratorium für Organische Chemie, ETH-Zentrum, Universitätstrasse 16, CH-8092 Zürich
The analogues 1 ± 3 of dolichol monophosphatidyl b-d-glucose have been prepared as potential inhibitors of
the glucosyl transferase Alg10p. Pd(PPh3)4-catalysed phosphonylation of the iodoimidazole 4 with diethyl,
dimethyl, and diphenyl phosphite led to the corresponding phosphonic acid diesters, which were transformed
into deprotected and silyl-protected diesters, deprotected monoesters, and protected and unprotected
phosphonic acids (Scheme). A N-methyl imidazolium salt was obtained as a by-product of the dimethyl-
phosphonylation of the iodoimidazole, and prepared in high yields by methylation of the imidazole 8 with MeI;
the corresponding deprotected salt 11 inhibits sweet almond b-glucosidases (IC50 ˆ 308 mm). Trichloroacetoni-
trile-promoted monoesterification of the acetylated mono-triethylammonium salt 19 with oleyl alcohol,
phytanol, and dolichol-19, followed by deacetylation, gave the desired glycophospholipids.
Introduction. ± Glycosyl transferases catalyse the regio- and stereoselective
formation of a glycosidic bond between the reducing end of a mono- or oligosaccharide
and a defined heteroatom (O or N) of their acceptor substrate1). The glycosyl donor is
either a monosaccharide activated as a nucleoside diphosphate, a nucleoside mono-
phosphate, or a dolichyl monophosphate, or then an oligosaccharide activated as a
dolichyl monophosphate. Most glycosyl transferases transfer the glycosyl moiety with
inversion of configuration at the anomeric centre of the transferred sugar residue [1].
There is a great amount of amino-acid sequence data, available on the internet2), that
have been classified into sequence-related families [1]. However, crystal-structure
details of glycosyl transferases are very scarce [2][3], and information about the active
site and the amino-acid residues directly involved in the catalysis is limited [4 ± 6].
Analysis of the isotope effects [7][8] and inhibition studies [9][10] strongly suggest that
the reactive intermediate resembles a glycosyl cation similar to the reactive
intermediate of the enzymic glycoside hydrolysis. It is, however, not clear whether
the phosphate leaving group is protonated at one of its O-centres (by a functional
equivalent of the catalytic acid in glycosidases) or activated by coordination to a metal
ion (Mg2‡, Mn2‡), or whether a basic amino-acid residue, accepting a proton from the
hydroxy or amido function of the acceptor is implied in catalysis. fuco-Configured
ꢀazonia sugarsꢁ, mimicking the positive charge of the putative cationic intermediate,
inhibit fucosidases strongly, but fucosyl transferases only weakly. Addition of GDP
1
)
The acceptor of a monosaccharide is either a mono- or oligosaccharide or a phospholipid, and the acceptor
of an oligosaccharide is either a peptide or a protein.
B. Henrissat and P. Coutinho at URL http://afmb.cnrs-mrs.fr/ ꢀ pedro/CAZY/db.html.
2
)

1138
Helvetica Chimica Acta ± Vol. 82 (1999)
(guanosine 5'-diphosphate) improves the inhibition of fucosyl transferases by ꢀazonia
sugarsꢁ3) [9][11][12], and the nucleotide part of the fucosyl donor, viz. GDP, acts itself
as inhibitor of fucosyl transferases. Analogues of UDP-Gal and GDP-Fuc with a
nucleotide moiety bound to an unsaturated glycosyl or carba-glycosyl residue derived
from glycosidase inhibitors mimic the shape of the hypothetical intermediate, and also
inhibit galactosyl and fucosyl transferases, respectively [13][14]. Thus, potential
inhibitors of glycosyl transferases may be obtained by appropriate modifications of
glycosidase inhibitors [11 ± 14], in spite of the obvious differences between glycosidases
and glycosyl transferases.
We became interested in the inhibition of the glucosyl transferase Alg10p involved
in the N-glycosylation process [15]. Alg10p is a transmembrane enzyme localized in the
endoplasmic reticulum (ER). It uses b-d-Glc dolichyl-monophosphate [16][17] as
glucosyl donor and catalyses the formation of a Glca(1,2)Glc bond [18]. Neither the
exact role of the dolichyl monophosphate moiety, nor the specificity of Alg10p are
known. Inhibitors of Alg10p have not yet been reported.
The strong inhibition of retaining b-glycosidases by gluco-, manno-, and galacto-
configured tetrahydroimidazopyridines [19 ± 21] has been attributed mainly to the
combined effect of a (partial) protonation of the imidazole moiety by the catalytic acid
and an electrostatic interaction between the imidazolium cation and the catalytic base
[22]. As Alg10p uses a b-d-configured glucosyl donor, it may interact similarly with a
gluco-configured tetrahydroimidazopyridine. We planned to prepare the glucophos-
pholipid analogues 1 ± 3 from the known benzyl-protected imidazole 8 [19] via the
phosphonates 5 ± 7 (Scheme), introducing oleyl, phytanyl, and dolichyl substituents to
evaluate the selectivity of Alg10p for the lipid moiety.
Synthesis. ± The required imidazolylphosphonates 5 ± 7 were obtained via the
mono-iodoimidazole 4 that was prepared [23] similarly to the known bromo analogue
[21][24] (Scheme). The phosphonate group was introduced by Pd(PPh3)4-catalysed
cross-coupling with dialkyl or diphenyl hydrogen phosphites [25 ± 29]. Treatment of 4
with diethyl hydrogen phosphite in the presence of Et3N and Pd(PPh3)4 led to a mixture
of the diethyl phosphonate 5 and the unsubstituted imidazole 8. A 5/8 ratio of ca. 7 :3
1
was determined from the integrals of the benzyl H-NMR signals at 5.10 (5) and
3
)
The synergism of the inhibition of GDP and ꢀazonia sugarsꢁ is expressed by a 22 ± 77-fold decrease of the
IC50 for the piperidinium salts upon addition of GDP [11].

Helvetica Chimica Acta ± Vol. 82 (1999)
1139
5.19 ppm (8); the phosphonate 5 was isolated in 62% yield4). The ratio 5/8 depends
strongly on the concentration of the iodoimidazole 4 and the amount of the catalyst. In
the presence of 0.3 equiv. of [Pd(PPh3)4], the ratio 5/8 ranged from 1:1 (0.15m 4) to 7 :3
(0.3m 4), and reached 9 :1 in the presence of 1 equiv. [Pd(PPh3)4] (0.3m 4). To suppress
the formation of 8, we tested a range of amines and phosphites (Table 1). The bulkiest
base, 1,2,2,6,6-pentamethylpiperidine (PMP), led to the highest 5/8 ratio and improved
the yield of 5 to 71% (Entry 3).
Scheme
a) [Pd(PPh3)4], Et3N, toluene, HPO(OR)2; 5 (62%); 6 (30%); 7 (84%). b) MeI, toluene, 958; 98%. c) 20%
Pd(OH)2/C, AcOH, AcOEt/MeOH/H2O, H2; 89%. d) tBuMe2SiCl, 1H-imidazole, 258, 48 h. e) aq. NaOH soln.,
‡
708, Amberlite IRC 50 (H form); 58%. f) 1m aq. HCl soln., Bio-Rad AG 2-X8 resin (Cl form). g) 20%
Pd(OH)2/C, AcOH, MeOH/H2O, H2; 90%. h) Me3SiBr, CH2Cl2. i) Pd(OH)2, MeOH/AcOEt/H2O 3:1:1, H2;
‡
‡
81% (from 5). j) Ac2O, pyridine. k) Dowex 50W8 (Na form), Dowex CCR-2 (Na form). l) CCl3CN, pyridine,
oleyl alcohol for 20 (50% from oleyl alcohol), phytanol for 21 (61% from phytanol), or dolichol-19 for 22 (65%
‡
from dolichol-19). m) MeONa, MeOH, Dowex IRC 50 (H form); 1 (95%); 2 (66%); 3 (75%).
4
)
Excess diethyl hydrogen phosphite led to increased amounts of triphenylphosphine oxide that had to be
removed by repeated chromatography.

1140
Helvetica Chimica Acta ± Vol. 82 (1999)
Table 1. Phosphonylation of 4 (0.4m 4 in toluene at 958 with 5 equiv. of HPO(OR)2, 7 equiv. of base, and
0.3 equiv. of [Pd(PPh3)4])
Entry
Phosphite
Basea)
Time
(h)
Ratiob)
5/8
Yield [%]
5
6/8
7/8
6
7
1
2
3
HPO(OEt)2
HPO(OEt)2
HPO(OEt)2
HPO(OEt)2
HPO(OMe)2
HPO(OMe)2
HPO(OMe)2
HPO(OPh)2
HPO(OPh)2
HPO(OPh)2
HPO(OPh)2
Et3N
26
18
19.5
21
19
20
19.5
19
18
19.5
17
70 : 30
83 : 17
95 : 05
50 : 50
62
60
71
±
(iPr)2EtN
PMP
4 c)
5
Et3N
Et3N
(iPr)2EtN
PMP
Et3N
(iPr)2EtN
PMP
74 : 26
30
20
10
d
6
7
8
9
10
11 c)
)
d
)
100 : 0
100 : 0
100 : 0
85 : 15
84
83
78
74
Et3N
a) PMP: 1,2,2,6,6 pentamethylpiperidine. b) The ratio was determined on the basis of integrals of the benzyl
1H-NMR signals. c) Reaction performed in the presence of CuI (0.36 equiv.). d) The ratio could not be
determined, because of the insufficient amount of the expected products (6/8).
While the Pd0-catalysed phosphonylation of a bromoimidazole with dimethyl
hydrogen phosphite failed [29], dimethyl-phosphonylation of the iodoimidazole 4 in
the presence of [Pd(PPh3)4] and Et3N yielded 30% of 6 (Entry 5). Using (iPr)2EtN
instead of Et3N (Entry 6) proved detrimental. The major by-product of this coupling
was an N-methylimidazolium salt that was isolated by flash chromatography (silica
gel). Its NMR spectra are very similar to those of the iodide 10, obtained by treating 8
with MeI in toluene (4 h at 958). Presumably, 10 and the by-product differ only by the
nature of the counterion. The unprotected N-methylimidazolium salt 11 was prepared
in almost quantitative yields by methylation of 9. With an IC50 value of 308 mm (378,
pH 6.8, phosphate buffer), 11 is a rather weak inhibitor of sweet-almond b-glucosidases
[30].
Coupling of the iodide 4 with diphenyl hydrogen phosphite yielded 78 ± 84% of 7
(Entries 8 ± 10) without forming any of the dehalogenated imidazole 8. To the best of
our knowledge, this is the first example of a [Pd(PPh3)4]-catalysed coupling of diphenyl
hydrogen phosphite with a halo(het)arene. Coupling 4 with either diethyl or diphenyl
hydrogen phosphite in the presence of both [Pd(PPh3)4] and CuI, as in the Sonogashira
reaction [31][32], lowered the ratio 5/8 and 7/8 (Entries 4 and 11, resp.).
We briefly studied the deprotection of the phosphonates and the introduction
of alternative protecting groups. Catalytic hydrogenolysis of the diethyl phosphonate 5
led cleanly to the tetrol 12. Silylation of 12 yielded 87% of 13. Saponification of 12
gave the monoester 14, which was transformed into its hydrochloride, characterized by
a pKHA of 5.15. Hydrogenolysis of 7 provided the monophenyl ester 15 in excellent
yields.
The synthesis of 1 ± 3 was continued by dealkylating the diethyl phosphonate 5 with
Me3SiBr [33] to the phosphonic acid 16 which was subjected to hydrogenolytic
debenzylation. The product was purified by chromatography on DEAE-cellulose
‡
(elution with aq. HEt3N HCO3 ) to afford a mixture of mostly the mono(triethylam-
monium) salt 17 and varying amounts of the corresponding acid (81%; 0.70± 0.95 equiv.

Helvetica Chimica Acta ± Vol. 82 (1999)
1141
1
of Et3N by H-NMR). Alternatively, 17 was obtained by treating the hydrogenolysis
product with Et3N, followed by lyophilization; this preparation also contained between
‡
0.70 and 0.95 equiv. of Et3N. Treatment of 17 with Dowex 50W8 (Na form) and then
‡
Dowex CCR-2 (Na form) led to the disodium salt 18. The pKHA values of 18 (7.69 and
4.84) were determined by titration of an aqueous solution with 0.1n HCl at 258. The
higher pKHA, corresponding to the dissociation constant of the phosphonate group, is
close to the pKHA value of pyridin-2-ylphosphonic acid (pKa ˆ 7.71) [34]. The second
pKHA of 18 is slightly lower than that of the gluco-tetrahydroimidazopyridine 9
(pKHA ˆ 6.10). The third pKHA value was not determined. Acetylation of 17 (Ac2O,
pyridine) gave the tetraacetate 19. As chromatography of 19 (DEAE-cellulose) led to
partial deacetylation, it was used without further purification and esterified with
0.87 equiv. of oleyl alcohol (ˆ(Z)-octadec-9-en-1-ol) using trichloroacetonitrile in
pyridine as coupling agent [35][36] to yield 50% of the oleyl phosphonate 20. Other
coupling agents, such as bromotris(dimethylamino) phosphonium hexafluorophos-
phate (BroP) [37][38], 2,4,6-triisopropylbenzensulfonyl chloride [39], oxalyl chloride,
DMF (cat.) [40], and diethyl diazenedicarboxylate (DEAD)/PPh3 [41][42] either
led to incomplete transformation of the alcohol or to byproducts. Esterification of
19 with 0.80 equiv. of phytanol yielded 61% of the phytanyl phosphonate 21. Similarly,
esterification with dolichol-19 (ˆ 3,7,11,15,19,23,27,31,35,39,43,47,51,55,59,63,67,71,75-
nonadecamethylhexaheptaconta-6,10,14,18,22,26,30,34,38,42,46,50,54,58,62,66,70,74-octa-
decaen-1-ol), but using 5 equiv. of the phosphonate 195), provided 65% of the dolichyl
phosphonate 22. Deacetylation of 20 ± 22 (NaOMe in MeOH followed by Amberlite
‡
IRC 50 (H form)) led to 1, 2, and 3 in 95%, 66%, and 75% yield, respectively.
This synthesis provides the gluco-configured tetrahydroimidazopyridine-2-phos-
phonates 1 ± 3 in six steps from the iodoimidazole 4 and in overall yields of 24, 20 and
24%, respectively. The iodoimidazole 4 is available in five steps and 65% overall yield
from the readily available 2,3,4,6-tetra-O-benzyl-d-gluconolactam [19][43]. The inhibi-
tory effect of 1 ± 3 on the (a1 ! 2) glucosyl transferase Alg10p is under investigation.
1
Formation of the C(2) P bond in 5 ± 7 is evidenced by J(C(2),P) of 247.4 and 256.4 Hz in the 13C-NMR
spectra of 6 and 7, respectively. Signal overlap did not allow the determination of 1J(C(2),P) of 5. However, the
13C-NMR spectra of 17 and 18, derived from 5 show a 1J(C(2),P) of 190.4 and 202.6 Hz, respectively. The
conformation of the phosphonate 17 in D2O (7H6) is very similar to the one of the imidazole 9 [19] (Table 2).
The FAB-MS of 20 ± 22 evidence the formation of a monoester in each case. This is further corroborated by the
shift of the 31P-NMR signal from 1.12 ppm (CD3OD) for 19 to 3.98 ppm (CD3OD) for 20, 3.78 ppm (CD3OD)
for 21, and 3.87 ppm (CD3OD/CDCl3 4 : 2) for 22. The CH2O signal of the alkoxy moiety of 20 ± 22 is also shifted
to characteristically lower field. The phosphonates 1 and 2, but not 3, are sufficiently well soluble in CD3OD to
lead to sharp 1H-, 13C-, and 31P-NMR signals, while the spectra of 3 (CDCl3/CD3OD/D2O 10 : 7: 1) showed only
broad signals. The conformation of the saccharide moiety of 1 ± 3 should be similar to that of 9 and 17
(7H6). This is fully evidenced only for 1 for which all coupling constants could be determined. The signals of
H
C(5) or H C(6) of 2 are hidden, but J(7,8) and J(6,7) are in agreement with the expected conformation
(Table 2).
5
)
The phosphonate 19 was used in excess, considering the price of dolichol-19.

1142
Helvetica Chimica Acta ± Vol. 82 (1999)
Table 2. Coupling Constants J [Hz] of Tetrahydroimidazopyridine 9 and Tetrahydroimidazopyridine-2-phos-
phonates 1, 2, 17, and 18
9
17
18
1
2
Solvent
J(8,7)
D2O
8.7
D2O
9.7
D2O
9.0
CD3OD
8.0
CD3OD
8.1
J(7,8)
J(6,5)
J(5,CH C(5))
J(5,CH' C(5))
2J(CH2 C(5))
9.7
9.7
2.5
2.2
9.7
8.8
3.1
2.2
10.0
10.0
2.5
2.5
13.0
9.5
8.0
4.0
2.0
8.8
)
a
4.1
a
)
12.8
13.2
11.8
13.5
a) Coupling constant not determined due to overlap of the signals.
We thank T. Mäder for the HPLC purifications, Dr. B. Bernet for checking the experimental part,
M. Schneider and D. Manser for the determination of the pKHA values, and the Swiss National Science
Foundation and F. Hoffmann-La Roche AG, Basel, for generous support.
Experimental Part
General. Solvents were distilled before use, toluene was degassed, and reactions were run under Ar.
[Pd(PPh3)4] (Aldrich) and CuI (Fluka) were used without purification. Oleyl alcohol (tech. 85%, Aldrich) was
purified by FC (hexane/AcOEt 9 :1) followed by FC (RP-18 silica gel; MeOH/H2O 9 :1 ! 85 : 15). Phytanol was
obtained in 64% yield (following the procedure of Sakata et al. [44]) by catalytic hydrogenation of phytol
(Fluka) in the presence of Pd/C (10%) for 2 h. Dolichol-19 was purchased from the Polish Academy of Sciences
(Institute of Biochemistry and Biophysics) and purified by FC (toluene) before use. TLC: Merck silica gel
60F254 plates; detection by heating with ꢀmostainꢁ (400 ml of 10% H2SO4 soln., 20 g of (NH4)6Mo7O24 ´ 6 H2O,
0.4 g of Ce(SO4)2). Flash chromatography (FC): silica gel 60 (Fluka; 0.04 ± 0.063 mm), unless indicated
otherwise. M.p.: uncorrected. 1H-, 13C-, and 31P-NMR Spectra: chemical shifts d in ppm rel. to TMS (1H and 13C)
or H3PO4 (31P) as external standard, and coupling constants J in Hz. FAB-MS: 3-nitrobenzyl alcohol as matrix,
unless indicated otherwise.
Diethyl (5R,6R,7S,8S)-6,7,8-Tris(benzyloxy)-5-[(benzyloxy)methyl]-5,6,7,8-tetrahydroimidazo[1,2-a]pyri-
dine-2-phosphonate (5). A mixture of 4 (1.0 g, 1.45 mmol) and [Pd(PPh3)4] (505 mg, 0.44 mmol) in toluene
(3.6 ml) was treated with Et3N (1.4 ml, 10 mmol) and HPO(OEt)2 (0.94 ml, 7.28 mmol), warmed to 958, and
stirred for 19 h. After the addition of AcOEt (10 ml), the suspension was filtered through Celite and the residue
washed with AcOEt (300 ml). The filtrate was concentrated to 150 ml, washed (H2O), dried (MgSO4), filtered,
and evaporated. 1H-NMR of the crude showed a mixture 5/8 ca. 70 :30, besides P(O)Ph3 and HPO(OEt)2. FC
(hexane/AcOEt/Et3N 7:3 :0.03 ! 0 : 1 : 1 : 0.03) gave 8 [19] (242 mg, 30%) and a brown mixture containing
principally 5 and P(O)Ph3 (717 mg). FC of this mixture (CH2Cl2/i-PrOH 10 : 0.05 ! 10 : 0.5) gave a colourless
oil 5/P(O)Ph3 ca. 80 : 20. PO(Ph)3 was removed by FC (RP-C18 silica gel; MeOH/H2O 8 : 2 ! 9 : 1): 5 (624 mg,
62%) as a colourless oil. Rf (hexane/AcOEt/Et3N 1 : 0.03) 0.2. UV (CHCl3): 269 (2.81). IR (CCl4): 3065w,
3032w, 2980w, 2929w, 2906w, 2867w, 1497w, 1454m, 1438w, 1362w, 1264m, 1235m, 1203m, 1117s, 1098s, 1062s,
1030s, 968m. 1H-NMR (CDCl3, 300 MHz): 1.35 (br. q, J ˆ 6.4, 2 Me); 3.76 (dd, J ˆ 5.2, 10.2, CH C(5)); 3.81 ±
3.90 (m, irrad. at 4.11 ! change, CH' C(5), H C(6)); 4.12 (dd, J ˆ 5.1, 6.7, irrad. at 3.84 ! change, H C(7));
4.06 ± 4.30 (m, 5 H, irrad. at 1.35 ! change, 2 MeCH2O, irrad. at 3.84 ! change, H C(5)); 4.46 (br. s, PhCH2);
4.47 (d, J ˆ 11.8, PhCH); 4.64 (d, J ˆ 11.3, PhCH); 4.77 (d, J ˆ 5.1, irrad. at 4.12 ! change, H C(8)); 4.78
(d, J ˆ 11.8, PhCH); 4.80 (d, J ˆ 11.7, PhCH); 4.82 (d, J 11.3, PhCH); 5.10 (d, J ˆ 11.7, PhCH); 7.12 ± 7.22
(m, 2 arom. H); 7.23 ± 7.42 (m, 18 arom. H); 7.71 (s, H C(3)). 13C-NMR (CDCl3, 75 MHz): 16.11
(dq, 3J(C,P) ˆ 5.9, Me); 16.15 (dq, 3J(C,P) ˆ 5.9, Me); 58.15 (d, C(5)); 62.23 (t, 2J(C,P) ˆ 4.9, 2 CH2O); 67.71
(t, CH2 C(5)); 72.23, 73.26, 73.57, 73.88 (4t, 4 PhCH2); 73.26, 75.88, 81.46 (3d, C(6), C(7), C(8)); 127.42
(dd, 2J(C,P) ˆ 40.3, C(3)); 127.68 ± 128.54 (several d); ca. 131.87 (d, 1J(C,P) ꢁ 250, C(2)); 137.08, 137.41, 137.60,
137.97 (4s); 146.55 (d, 3J(C,P) ˆ 22.0, C(8a)). 31P-NMR (CDCl3, 121 MHz): 12.21. FAB-MS: 697 (100, [M ‡
‡
‡
1] ), 1393 (20, [2M ‡ 1] ). Anal. calc. for C40H45N2O7P (696.78): C 68.95, H 6.51, N 4.02; found: C 68.98, H 6.66,
N 4.21.

Helvetica Chimica Acta ± Vol. 82 (1999)
1143
Dimethyl (5R,6R,7S,8S)-6,7,8-Tris(benzyloxy)-5-[(benzyloxy)methyl]-5,6,7,8-tetrahydroimidazo[1,2-a]pyri-
dine-2-phosphonate (6). A mixture of 4 (20 mg, 29.15 mmol) and [Pd(PPh3)4] (10 mg, 8.74 mmol) in toluene
(73 ml) was treated with Et3N (28 ml, 0.2 mmol) and HPO(OMe)2 (13 ml, 0.14 mmol), warmed to 958, and stirred
1
for 19 h. The mixture was concentrated and co-evaporated with toluene. The H-NMR spectrum of the crude
showed a mixture 6/8 ca. 70 :30, besides P(O)Ph3 and HPO(OMe)2. FC (hexane/AcOEt 5 :5 ! 0 : 1) gave 8
(3 mg, 18%) and 6 as coloured oils. FC on RP-C18 silica gel (MeOH/H2O 8 : 2) gave 6 (6 mg, 31%). Colourless
oil. Rf (AcOEt) 0.26. IR (CCl4) 3089w, 3065w, 3032w, 2950w, 2929w, 2854w, 1515w, 1497w, 1454m, 1361w, 1334w,
1268m, 1239m, 1207w, 1185w, 1098s, 1064s, 1039s. 1H-NMR (CDCl3, 300 MHz): 3.75 (dd, J ˆ 5.3, 10.3,
CH C(5)); 3.78 ± 3.89 (m, irrad. at 4.11 or 4.23 ! change, CH' C(5), H C(6)); 3.80 (d, 3J(H,P) ˆ 7.0, Me);
3.84 (d, 3J(H,P) ˆ 7.0, Me); 4.11 (dd, J ˆ 4.8, 6.9, irrad. at 4.76 ! d, J ꢁ 6.8, H C(7)); 4.23 (ddd, J ˆ 2.7, 4.8, 7.6,
H
C(5)); 4.46 (d, J ˆ 11.4, PhCH); 4.46 (t, J ˆ 13.0, PhCH2); 4.62 (d, J ˆ 11.5, PhCH); 4.76 (d, J ˆ 4.9, irrad. at
4.11 ! s, H C(8)); 4.77 (d, J ˆ 11.4, PhCH); 4.78 (d, J ˆ 11.5, PhCH); 4.80 (d, J ˆ 11.8, PhCH); 5.08 (d,
J ˆ 11.5, PhCH); 7.12 ± 7.20 (m, 2 arom. H); 7.22 ± 7.42 (m, 18 arom. H); 7.72 (s, H C(3)). 13C-NMR (CDCl3,
75 MHz): 52.87 (dq, 2J(C,P) ˆ 6.4, Me); 53.00 (dq, 2J(C,P) ˆ 6.4, Me); 58.33 (d, C(5)); 67.83 (t, CH2 C(5));
72.40, 73.35, 73.63, 73.92 (4t, PhCH2); 73.35, 75.92, 81.38 (3d, C(6), C(7), C(8)); 127.79 ± 128.64 (several d);
129.01 (d, 1J(C,P) ˆ 247.4, C(2)); 137.12, 137.44, 137.63, 138.01 (4s); 146.77 (d, 3J(C,P) ˆ 22.3, C(8a)). 31P-NMR
‡
‡
(CDCl3, 121 MHz): 14.84. FAB-MS: 669 (100, [M ‡ 1] ), 1338 (10, [2 (M ‡ 1)] ).
Diphenyl (5R,6R,7S,8S)-6,7,8-Tris(benzyloxy)-5-[(benzyloxy)methyl]-5,6,7,8-tetrahydroimidazo[1,2-a]pyri-
dine-2-phosphonate (7). A mixture of 4 (20 mg, 29.15 mmol) and [Pd(PPh3)4] (10 mg, 8.74 mmol) in toluene
(73 ml) was treated with Et3N (28 ml, 0.20 mmol) and HPO(OPh)2 (28 ml, 0.14 mmol), warmed to 958, and stirred
1
for 19 h. The mixture was concentrated and co-evaporated with toluene. The H-NMR spectrum of the crude
showed 7, besides P(O)Ph3 and HPO(OPh)2. FC (hexane/AcOEt 8 :2 ! 7: 3 ! 6 : 4) followed by FC (CH2Cl2/i-
PrOH 10 : 0.05) gave 7 (19.4 mg, 84%). Colourless oil. Rf (hexane/AcOEt 4 : 6) 0.47. IR (CCl4): 3066w, 3032w,
2923w, 2865w, 1593m, 1490s, 1454m, 1361w, 1280m, 1243w, 1216m, 1193s, 1162m, 1099m, 1070m, 1006w, 986w,
941s. 1H-NMR (CDCl3, 300 MHz): 3.71 (dd, J ˆ 5.4, 10.7, irrad. at 4.19 ! d, J ꢁ 10.5, CH C(5)); 3.81 (dd,
J ˆ 2.5, 10.7, irrad. at 4.19 ! change, CH' C(5)); 3.83 (t, J ˆ 7.5, irrad. at 4.12 ! change, H C(6)); 4.12
(dd, J ˆ 5.0, 7.2, irrad. at 3.83 ! change, H C(7)); 4.19 (ddd, J ˆ 2.5, 5.4, 7.5, irrad. at 3.83 ! change, H C(5));
4.39 (d, J ˆ 11.7, PhCH); 4.44 (d, J ˆ 11.7, PhCH); 4.46 (d, J ˆ 11.2, PhCH); 4.64 (d, J ˆ 11.2, PhCH); 4.78
(d, J ˆ 10.7, PhCH); 4.79 (d, J ˆ 11.3, 2 PhCH); 4.79 (d, J ˆ 5.1, irrad. at 4.12 ! change, H C(8)); 5.06 (d,
J ˆ 11.7, PhCH); 7.06 ± 7.44 (m, 30 arom. H); 7.76 (s, H C(3)). 13C-NMR (CDCl3, 75 MHz): 58.31 (d, C(5));
67.51 (t, CH2 C(5)); 72.11, 73.27, 73.61, 73.95 (4t, 4 PhCH2); 73.10, 75.96, 81.44 (3d, C(6), C(7), C(8));
120.93 ± 121.03, 124.91, 125.25 (several d of P(OPh)2); 128.49 (d, 1J(C,P) ˆ 256.4, C(2)); 127.71 ± 129.49 (several
d); 136.88, 137.29, 137.50, 137.90 (4s); 146.85 (d, 3J(C,P) ˆ 22.0, C(8a)); 150.44 (d, 2J(C,P) ˆ 7.3); 150.49
‡
(d, 2J(C,P) ˆ 7.3). 31P-NMR (CDCl3, 121 MHz): 5.24. FAB-MS: 793 (100, [M ‡ 1] ).
(5R,6R,7S,8S)-6,7,8-Tris(benzyloxy)-5-[(benzyloxy)methyl]-5,6,7,8-tetrahydro-5-methylimidazo[1,2-a]pyr-
idinium Iodide (10). A soln. of 8 [19] (50 mg, 89.3 mmol) in toluene (0.5 ml) was treated with MeI (30 ml,
0.45 mmol) and kept at 958 for 4 h. Evaporation of the mixture followed by co-evaporation with toluene gave
64 mg of 10 (quant.). Coloured gel. Rf (AcOEt/iPrOH/H2O 10 :3 :0.5) 0.57. UV (CHCl3) 259 (3.6). IR (CHCl3):
3405w, 3155w, 3089w, 3067w, 3010w, 2946s, 2871m, 1602m, 1536m, 1497m, 1455s, 1364m, 1088s, 1001m, 909m.
1H-NMR (CD3Cl, 300 MHz): 3.78 (dd, J ˆ 2.9, 10.6, irrad. at 4.50 ! d, J ꢁ 10.6, CH C(5)); 3.97 (dd, J ˆ 8.8,
10.6, irrad. at 4.50 ! d, J ˆ 10.3, CH' C(5)); 4.10 (s, Me); 4.14 (dd, J ˆ 4.1, 5.3, irrad. at 4.50 ! d, J ꢁ 5,
H
C(6)); 4.20 (dd, J ˆ 3.5, 5.3, irrad. at 5.94 ! d, J ꢁ 5.6, H C(7)); 4.41 (d, J ˆ 11.8, PhCH); 4.46 (d, J ˆ 11.8,
PhCH); 4.48 ± 4.52 (m, H C(5)); 4.57 (d, J ˆ 11.8, PhCH); 4.64 (d, J ˆ 11.1, PhCH); 4.82 (d, J ˆ 11.8, PhCH);
4.94 (2d, J ˆ 11.8, J ˆ 11.1, 2 PhCH); 5.08 (d, J ˆ 11.1, PhCH); 5.94 (d, J ˆ 3.3,
H C(8)); 7.08 ± 7.41
(m, 20 arom. H); 7.44 (d, J ˆ 2.1, H C(3)); 7.49 (d, J ˆ 2.1, H C(2)). 13C-NMR (CDCl3, 75 MHz): 37.40
(q, Me); 61.94 (d, C(5)); 69.80 (t, CH2 C(5)); 70.37, 72.75, 74.33 (3d, C(6), C(7), C(8)); 73.20, 73.56, 73.65,
73.70 (4t); 121.35 (d, C(3)); 124.42 (d, C(2)); 128.10 ± 128.78 (several d, arom. C); 136.31, 136.36, 136.69, 136.88
‡
‡
(4s); 141.12 (s, C(8a)). FAB-MS: 575 (100, M ), 1277 (8, [2M ‡ I] .
(5R,6R,7S,8S)-5,6,7,8-Tetrahydro-6,7,6-trihydroxy-5-(hydroxymethyl)-5-methylimidazo[1,2-a]pyridinium
Iodide (11). A soln. of 9 (10 mg, 0.05 mmol) and MeI (4 ml, 0.064 mmol) in DMSO (0.25 ml) was kept at 238
for 5 h. Evaporation gave 11 (17 mg, quant.). Colourless resin. Rf (AcOEt/MeOH 5 :1) 0.04. 1H-NMR
(300 MHz, (D6)DMSO): 3.69 ± 3.79 (m, irrad at 4.79 ! change, H C(6), H C(7)); 3.87 (s, Me); 3.82
(dd, J ˆ 12.0, 4.2, CH C(5)); 4.04 ± 4.08 (m, H C(5)); 4.79 (d, J ˆ 6.0, H C(8)); 7.75, 7.77 (2d, J ˆ 3.0,
H
H
C(2), H C(3)). 1H-NMR (300 MHz, D2O): 3.96 (s, Me); 3.99 ± 4.02 (m, irrad. at 4.99 ! change,
C(6), H C(7)); 4.12 (dd, J ˆ 12.8, 3.1, CH C(5)); 4.24 ± 4.27 (m, H C(5)); 4.30 (dd, J ˆ 12.8, 2.5,
CH C(5)); 4.98 (m, H C(8)); 7.49, 7.65 (2d, J ˆ 2.1, H C(2), H C(3)). 13C-NMR (75 MHz, (D6)DMSO)

1144
Helvetica Chimica Acta ± Vol. 82 (1999)
35.56 (q, Me); 58.29 (t, CH2C(5)); 62.79 (d, C(5)); 66.19, 66.40 (2d, C(6), C(7)); 74.10 (d, C(8)); 119.51
‡
(d, C(2)); 124.52 (d, C(3)); 143.97 (s, C(8a)). FAB-MS: 215 (100, M ).
Diethyl
(5R,6R,7S,8S)-5,6,7,8-Tetrahydro-6,7,8-trihydroxy-5-(hydroxymethyl)imidazo[1,2-a]pyridine-2-
phosphonate (12). A mixture of 5 (250 mg; 0.36 mmol), AcOEt/MeOH/H2O 0.5 :3 :0.5 (1 ml), AcOH
(0.5 ml), and 20% Pd(OH)2 was hydrogenated at atmospheric pressure for 20 h. The suspension was
filtered through Celite, washed with MeOH (20 ml) and chromatographed (AcOEt/iPrOH/H2O 8 :4 :1)
to give 12 as white powder after lyophilization (107 mg, 89%). Rf (AcOEt/iPrOH/H2O 8 :4 :1) 0.3. IR (KBr):
3386s (br.), 3000s, 2985s, 1644m, 1528s, 1394s, 1221s, 1024s (br.), 860m, 797s, 697m, 662s, 603s. 1H-NMR
(D2O, 300 MHz): 1.30 (t, J ˆ 7.2, 2 Me); 3.81 (dd, J ˆ 9.2, 9.9, irrad. at 4.63 ! d, irrad. at 3.94 ! change,
H
H
C(7)); 3.94 (t, J ˆ 9.2,
H
C(6)); 4.04 ± 4.13 (m, irrad. at 3.94 ! change, irrad. at 4.26 ! change,
C(5)); CH C(5)); 4.14 (q, J ˆ 7.2, irrad. at 1.30 ! change, 2 MeCH2); 4.26 (dd, J ˆ 3.3, 13.8, CH' C(5));
4.63 (d, J ˆ 9.9, H C(8)); 7.93 (s, H C(3)). 13C-NMR (D2O, 75 MHz): 15.49 (dq, 3J(C,P) ˆ 6.4, 2 MeCH2);
58.85 (t, CH2 C(5)); 64.19 (dt, 2J(C,P) ˆ 4.8, 2 MeCH2); 60.97 (d, C(5)); 67.23, 67.96, 74.53 (3d, C(6), C(7),
C(8)); 127.52 (d, 1J(C,P) ˆ 247.4, C(2)); 128.47 (dd, 2J(C,P) ˆ 36.7, C(3)); 150.32 (d, 3J(C,P) ˆ 22.3, C(8a)).
31P-NMR (D2O, 121 MHz): 14.62. FAB-MS: 337 (100, [M ‡ 1] ), 359 (61, [M ‡ Na] ), 695 (13,
‡
‡
‡
[2M ‡ Na] ).
Diethyl (5R,6R,7S,8S)-6,7,8-Tris{[(tert-Butyl)dimethylsilyl]oxy}-5-({[(tert-Butyl)dimethylsilyl]oxy}meth-
yl)-5,6,7.8-tetrahydroimidazo[1,2-a]pyridine-2-phosphonate (13). A soln. of 12 (30 mg, 89.3 mmol) in DMF
(0.15 ml) was treated with tBuMe2SiCl (188 mg, 1.25 mmol) and 1H-imidazole (170 mg, 2.5 mmol) and stirred at
258 for 48 h. The mixture was diluted with Et2O, washed by H2O. Combined org. phase was dried (MgSO4),
filtered, and evaporated. FC (hexane/AcOEt 7:3) gave 13 (61 mg, 87%). White solid. Rf (hexane/AcOEt 3 :7)
0.75. IR (CCl4): 2955s, 2930s, 2897m, 2858s, 1515w, 1472m, 1463w, 1442w, 1390w, 1362w, 1259s, 1236m, 1188w,
1099s, 1034m, 1006w, 970w, 940m, 838s, 668w, 594w. 1H-NMR (C6D6, 500 MHz): 0.01, 0.03, 0.08, 0.10, 0.13, 0.15,
0.25, 0.40 (8s, 8 Me); 0.85, 0.92, 0.93; 1.03 (4s, Me3CSi); 1.16 (dt, J ˆ 0.5, 7.0, Me); 1.18 (dt, J ˆ 0.5, 7.0, 2 Me);
3.82 (dd, J ˆ 7.0, 11.0, CH C(5)); 3.87 (dd, J ˆ 4.5, 11.0, CH' C(5)); 4.10 ± 4.28 (m, 2 MeCH2, H C(5),
H
C(6)); 4.29 (t, J ˆ 2.2, irrad. at 5.0 ! d, H C(7)); 5.00 (dd, J ˆ 0.7, 2.2, H C(8)); 7.87 (s, H C(3)).
13C-NMR (C6D6, 125 MHz): 5.53, 5.33, 4.88, 4.84, 4.55, 4.51, 4.22, 4.03, 3.99 (8t, 8 Me); 16.53
(dq, 3J(C,P) ˆ 5.2, Me); 16.56 (dq, 3J(C,P) ˆ 5.0, Me); 18.1, 18.19, 18.35, 18.54 (4s, 4 Me3CSi); 25.85, 25.95, 26.01,
26.29 (4q, 4 Me3CSi); 61.83 (t, 2J(C,P) ˆ 5.1, MeCH2); 61.93 (t, 2J(C,P) ˆ 5.3, MeCH2); 63.43 (t, CH2 C(5));
63.73 (d, C(5)); 69.64, 71.63, 77.54 (3d, C(6), C(7), C(8)); 129.12 (dd, 2J(C,P) ˆ 36.9, C(3)); 130.99
(d, 1J(C,P) ˆ 241.2, C(2)); 146.92 (d, 3J(C,P) ˆ 22.0, C(8a)). 31P-NMR (C6D6, 202 MHz): 11.56. FAB-MS: 735
(84, [M ‡ 1 tBu] ), 793 (100, [M ‡ 1] ). Anal. calc. for C36H77N2O7Si4P (793.34): C 54.50, H 9.78, N 3.53,
‡
‡
P 3.90; found: C 54.54, H 9.66, N 3.54, P 3.84.
Ethyl Hydrogen (5R,6R,7S,8S)-5,6,7,8-Tetrahydro-6,7,8-trihydroxy-5-(hydroxymethyl)imidazo[1,2-a]pyri-
dine-2-phosphonate (14). A soln. of 12 (14 mg, 41.6 mmol) in 1m aq. NaOH (200 ml) was stirred at 708 for 14 h,
‡
neutralized with Amberlite IRC 50 (H form), filtered, and evaporated. A soln. of the residue in MeOH (5 ml)
was adsorbed on silica gel. FC (iPrOH/H2O 8 :2) gave 14 as white powder after lyophilization (7.5 mg, 58%). Rf
(iPrOH/H2O 7:3) 0.5. 1H-NMR (D2O, 300 MHz): 1.96 (t, J ˆ 7.3, irrad. at 3.85 ! s, Me); 3.80 (t, J ˆ 9.6, irrad. at
4.26 ! change, irrad. at 3.94 ! change, H C(7)); 3.85 (q, J ˆ 7.3, MeCH2); 3.94 (t, J ˆ 9.6, H C(6)); 4.00 ± 4.08
(m, irrad. at 4.26 ! change, irrad. at 3.94 ! change, H C(5)); 4.07 (dd, J ˆ 2.8, 13.0, irrad. at 4.26 ! change,
CH C(5)); 4.26 (dd, J ˆ 2.3, 13.0, CH' C(5)); 4.62 (d, J ˆ 9.6, H C(8)); 7.57 (s, H C(3)). 13C-NMR (D2O,
75 MHz): 15.77 (dq, 3J(C,P) ˆ 6.4, Me); 58.75 (t, CH2 (5)); 64.37 (dt, 2J(C,P) ˆ 4.8, MeCH2); 60.56 (d, C(5));
67.32, 68.11, 74.78 (3d, C(6), C(7), C(8)); 124.55 (dd, 2J(C,P) ˆ 31.9, C(3)); 134.77 (d, 1J(C,P) ˆ 226.7, C(2));
‡
148.64 (d, 3J(C,P) ˆ 19.1, C(8a)). 31P-NMR (D2O, 121 MHz): 8.30. FAB-MS (glycerol): 309 (9.40, [M ‡ 1] ),
‡
331 (5.72, [M ‡ Na] ).
Ethyl Hydrogen (5R,6R,7S,8S)-5,6,7,8-Tetrahydro-6,7,8-trihydroxy-5-(hydroxymethyl)imidazo[1,2-a]pyri-
dine-2-phosphonate Hydrochloride (14 ´ HCl). A soln. of 14 (10 mg, 32 mmol) in D2O (0.7 ml) was treated with
1m aq. HCl (20 ml), evaporated, co-evaporated with H2O, and lyophilized. The residue was taken up in H2O
(1 ml), treated with Bio-Rad AG 2-X8 resin (Cl form), filtered, and lyophilized to give 8 mg of 14 ´ HCl.
1H-NMR (D2O, 300 MHz): 1.23 (t, J ˆ 7.0, MeCH2); 3.92 (q, J ˆ 7.2, MeCH2); 3.93 (br. t, J ˆ 9.6, irrad. at
4.89 ! d, J ꢁ 10, H C(7)); 4.03 (t, J ˆ 9.2, irrad. at 4.26 ! d, J ꢁ 10, H C(6)); 4.11 (dd, J ˆ 3.2, 12.8, irrad. at
4.26 ! d, J ꢁ 10, CH C(5)); 4.22 ± 4.29 (m, H C(5)); 4.32 (dd, J ˆ 2.4, 12.8, irrad. at 4.26 ! change,
CH' C(5)); 4.89 (d, J ˆ 8.4, H C(8)); 7.84 (s, H C(3)). 13C-NMR (D2O, 75 MHz): 18.45 (dq, 3J(C,P) ˆ 6.1,
Me); 61.15 (t, CH2 C(5)); 65.19 (dt, 2J(C,P) ˆ 6.1, MeCH2); 65.28 (d, C(5)); 69.31, 69.68, 75.99 (3d, C(6),
C(7), C(8)); 127.89 (dd, 2J(C,P) ˆ 20.7, C(3)); 131.59 (d, 1J(C,P) ˆ 202.6, C(2)); 150.99 (d, 3J(C,P) ˆ 7.3,
C(8a)). 31P-NMR (D2O, 121 MHz): 1.78.

Helvetica Chimica Acta ± Vol. 82 (1999)
1145
Phenyl Hydrogen (5R,6R,7S,8S)-5,6,7,8-Tetrahydro-6,7,8-trihydroxy-5-(hydroxymethyl)imidazo[1,2-a]pyr-
idine-2-phosphonate (15). A soln. of 7 (17 mg, 21.4 mmol) in MeOH/H2O/AcOH 2 :0.5 :1 (1.75 ml) was treated
with 20% Pd(OH)2/C (17 mg) and hydrogenated at atmospheric pressure for 34 h. The suspension was filtered
through Celite, and the residue washed with MeOH/H2O 9 :1. Evaporation of the filtrate gave 10 mg of crude
‡
which was taken up in H2O (1 ml) treated with Dowex 50W8 (H form), filtered, and lyophilized. The residue
was taken up in MeOH/H2O 1:1 (1.5 ml), treated with activated charcoal, filtered, and lyophilized to give 10 mg
of white solid 15. Rf (iPrOH/H2O 8 :2) 0.32. 1H-NMR (D2O, 300 MHz): 3.81 (t, J ˆ 8.8, irrad. at 4.65 ! d, J ꢁ 9.3,
H
C(7)); 3.94 (t, J ˆ 8.8, H C(6)); 3.98 ± 4.11 (m, H C(5), CH C(5)); 4.21 (br. d, J ˆ 12.8, CH' C(5)); 4.65
(d, J ˆ 8.8, H C(8)); 7.03 (br. d, J ˆ 7.8, 2 arom. H); 7.16 (br. t, J ˆ 7.8, arom. CH); 7.32 (br. t, J ˆ 7.8,
2 arom. H); 7.52 (s, H C(3)). 13C-NMR (D2O, 75 MHz): 61.53 (t, CH2 C(5)); 63.32 (d, C(5)); 70.12, 70.89,
77.52 (3d, C(6), C(7), C(8)); 124.18, 124.23, 127.34 (3d, arom. CH); 128.03 (dd, 2J(C,P) ˆ 34.2, C(3)); 132.58
(d, arom. CH); 137.18 (d, 1J(C,P) ˆ 233.17, C(2)); 151.66 (d, 3J(C,P) ˆ 20.7, C(8a)); 154.5 (d, 2J(C,P) ˆ 7.3).
31P-NMR (D2O, 121 MHz): 6.05, ESI-MS (negative mode): 355 (100, [M 1] ).
Triethylammonium Hydrogen (5R,6R,7S,8S)-6,7,8-Trihydroxy-5-(hydroxymethyl)imidazo[1,2-a]pyridine-
2-phosphonate (17). A soln. of 5 (260 mg, 0.373 mmol) in CH2Cl2 (3.5 ml) at 08 was treated with Me3SiBr
(0.29 ml, 2.24 mmol), warmed to 258, and stirred for 16 h. The mixture was concentrated and co-evaporated with
toluene (4 Â 5 ml). The residue was taken up in MeOH/H2O 9 : 1 (2 ml), evaporated, and co-evaporated with
toluene until crude 16 became a foam (241 mg). A soln. of crude 16 in MeOH/AcOEt/H2O 3 : 1 : 1 (4 ml) was
treated with 20% Pd(OH)2/C (180 mg) and hydrogenated at atmospheric pressure for 19 h. The suspension was
filtered through Celite, and the residue washed with MeOH/H2O 95 : 5 (75 ml). Evaporation of the filtrate gave
116.5 mg of crude 17, which was taken up in 1 ml of H2O and applied to a DEAE-cellulose column (Cellex-D,
Bio-rad, 18 Â 1.5 cm; UV detection). The column was washed with H2O (30 ml), and 17 was eluted with a
triethylammonium hydrogen carbonate buffer (pH ꢁ 7; 5 mm, 30 ml; 10 mm, 40 ml; 20 mm, 40 ml). The
‡
fractions containing 17 were combined and lyophilized (3Â) to give 17 (110 mg, 81%, 0.83 equiv. of Et3NH ).
Triethylammonium salt 17 was also obtained after treatment of an aq. soln. of crude deproteced free acid
with Et3N (3 equiv.). The soln. was evaporated, concentrated, and co-evaporated with toluene. The residue was
taken up in H2O/MeOH ca. 1:1, treated with activated charcoal, and filtered. Evaporation and lyophilization
‡
(3Â) gave 17 (0.87 equiv. of Et3NH ).
Data of (5R,6R,7S,8S)-6,7,8-Tris(benzyloxy)-5-[(benzyloxy)methyl]-5,6,7,8-tetrahydroimidazo[1,2-a]pyri-
dine-2-phosphonic Acid (16): Rf (RP C18, MeOH/H2O 9 :1) 0.6. IR (CHCl3): 3500 ± 2233w (br.), 3028m, 2971m,
1602w, 1496m, 1454m, 1363m, 1230m, 1094s, 996s. 1H-NMR (CD3OD, 300 MHz): 3.78 (dd, J ˆ 6.5, 10.6,
CH C(5)); 3.90 (dd, J ˆ 3.2, 10.6, CH' C(5)); 4.20 (dd, J ˆ 5.7, 9.7, H C(6)); 4.22 (br. t, J ˆ 4.9, irrad. at
5.01 ! d, J ꢁ 5.4, H C(7)); 4.42 (d, J ˆ 11.8, PhCH); 4.50 (d, J ˆ 11.8, PhCH); 4.52 (d, J ˆ 11.4, PhCH); 4.60 ±
4.72 (m, irrad. at 3.90 ! change, H C(5), 3 PhCH); 4.80 (d, J ˆ 11.4, PhCH); 4.91 (d, J ˆ 11.4, PhCH); 5.01
(d, J ˆ 4.1, irrad. at 4.22 ! s, H C(8)); 7.12 ± 7.39 (m, 20 arom. H); 7.70 (d, J ˆ 2.5, H C(3)). 13C-NMR
(CD3OD, 75 MHz): 62.18 (d, C(5)); 69.06 (t, CH2 C(5)); 72.86, 74.77, 78.43 (3d, C(6), C(7), C(8)); 74.20,
74.28, 74.64, 75.03 (4t, 4 PhCH2); 127.86 (dd, 2J(C,P) ˆ 22.0, C(3)); 130.03 (d, 1J(C,P) ˆ 214.0, C(2)); 129.21 ±
129.73 (several d)); 138.43 ± 138.71 (4s); 146.52 (d, 3J(C,P) ˆ 8.5, C(8a)). 31P-NMR (CD3OD, 121 MHz): 1.63.
‡
‡
‡
FAB-MS: 663 (32, [M ‡ Na] ); 685 (100, [M 1 ‡ 2 Na] ); 707 (43, [M 2 ‡ 3 Na] ; 1347 (16, [2 (M 1) ‡ 3
‡
Na] ).
Data of 17: Rf (MeOH/NH3/H2O 4 :3 :1) 0.57. UV (H2O): 232 (2.78). IR (KBr): 3386s (br.), 2361m, 1654w,
1476m, 1398m, 1109s (br.), 903m, 667m, 592s, 492m. 1H-NMR (D2O, 300 MHz): 1.27 (t, J ˆ 7.6, 3 MeCH2); 3.19
(q, J ˆ 7.6, 3 MeCH2); 3.90 (t, J ˆ 9.7, irrad. at 4.83 ! change, H C(7)); 4.02 (dd, J ˆ 8.8, 9.7, irrad. at 3.90 !
change, H C(6)); 4.09 (dd, J ˆ 3.1, 13.2, CH C(5)); 4.19 (br. d, J ˆ 8.8, H C(5)); 4.30 (dd, J ˆ 2.2, 13.2,
CH' C(5); 4.83 (d, J ˆ 9.7, irrad. at 3.90 ! change, H C(8)); 7.60 (s, H C(3)). 13C-NMR (D2O, 75 MHz):
10.99 (q, 3 Me); 49.46 (t, 3 MeCH2); 61.01 (t, CH2 C(5)); 64.66 (d, C(5)); 69.52, 69.69, 76.29 (3d, C(6), C(7),
C(8)); 125.02 (dd, 2J(C,P) ˆ 22.0, C(3)); 137.40 (d, 1J(C,P) ˆ 190.4, C(2)); 149.59 (d, 3J(C,P) ˆ 8.8, C(8a)). 31P-
NMR (D2O, 121 MHz): 1.97. ESI-MS (MeOH/H2O 1 : 1, 1% AcOH, negative mode): 279 ([M 1] ), 339
([M ‡ AcO] ), 559 ([2M 1] ), 839 ([3 M 1] ).
Disodium (5R,6R,7S,8S)-6,7,8-Trihydroxy-5-(hydroxymethyl)imidazo[1,2-a]pyridine-2-phosphonate (18).
‡
‡
A soln. of 17 (60 mg, 0.164 mmol, 0.75 equiv. of Et3NH ) in H2O (5 ml) was treated with Dowex 50W8 (Na
‡
form) then with Dowex CCR-2 (Na form), filtered, and lyophilized to give 18 (38 mg) as a white solid, of which
25 mg were taken up in a minimum of H2O (ca. 0.2 ml) and treated with MeOH (1.5 ml) until a white precipitate
was formed. The mixture was kept for 12 h at 48. The precipitate was isolated by centrifugation to give, after
washing with MeOH and drying under vacuum, 20 mg of 18. White powder. UV (H2O): 230 (3.10). IR (KBr):
3384s (br.), 1648m, 1523m, 1438m, 1334m, 1069s (br.), 996s, 952s, 906m, 667s, 602s, 498s. 1H-NMR (D2O,

1146
Helvetica Chimica Acta ± Vol. 82 (1999)
500 MHz): 3.76 (dd, J ˆ 9.0, 10.0, irrad. at 4.61 ! change, H C(7)); 3.90 (t, J ˆ 10.0, H C(6)); 3.96 ± 4.01
(m, H C(5)); 4.01 (dd, J ˆ 2.5, 13.0, CH C(5)); 4.21 (dd, J ˆ 2.5, 13.0, CH' C(5)); 4.61 (d, J ˆ 9.0, H C(8));
7.31 (s, H C(3)). 13C-NMR (D2O, 125 MHz): 61.08 (t, CH2 C(5)); 63.26 (d, C(5)); 69.82, 70.38, 77.13 (3d,
C(6), C(7), C(8)); 123.69 (dd, 2J(C,P) ˆ 26.8, C(3)); 142.41 (d, 1J(C,P) ˆ 202.6, C(2)); 149.29 (d, 3J(C,P) ˆ
14.6, C(8a)). 31P-NMR (D2O, 202 MHz): 2.64. FAB-MS (glycerine, negative mode): 279 (100, [M 2 Na] ),
301 (59, [M Na] ). Anal. calc. for C8H11N2Na2O7P ´ 0.75 H2O (337.64): C 28.46, H 3.73, N 8.29; found:
C 28.64, H 3.67, N 8.14.
Triethylammonium Hydrogen (5R,6R,7S,8S)-6,7,8-Triacetoxy-5-[(acetoxy)methyl]-5,6,7,8-tetrahydroimida-
‡
zo[1,2-a]pyridine-2-phophonate (19). A soln. of 17 (0.70 equiv. of Et3NH ; 15 mg, 40 mmol) in pyridine (0.5 ml)
was treated with Ac2O (195 ml) and stirred at 258 overnight. The soln. was evaporated and co-evaporated with
‡
toluene. The phosphonate 19 (23 mg, 0.72 equiv. of Et3NH ) was used for the next step without further
purification. Rf (AcOEt/MeOH/H2O 8 :4 :1) 0.5. UV (H2O): 289 (2.28), 234 (2.89). IR (KBr): 3444m, 2677w,
2360w, 1748s, 1652w, 1435w, 1373m, 1229s, 1036s, 920w, 838w. 1H-NMR (CD3OD, 300 MHz): 1.29 (t, J ˆ 7.9,
3 MeCH2); 2.06, 2.08, 2.09, 2.11 (4s, 4 AcO); 3.19 (q, J ˆ 7.9, 3 MeCH2); 4.42 (dd, J ˆ 5.4, 12.6, CH C(5)); 4.59
(dd, J ˆ 3.8, 12.6, CH' C(5)); 4.67 ± 4.76 (m, H C(5)); 5.54 (br. t, J ꢁ 6.5, irrad. at 4.7 ! d, J ꢁ 9.0, H C(6));
5.56 (br. t, J ꢁ 6.0, irrad. at 6.16 ! d, J ꢁ 7.5, H C(7)); 6.16 (dd, J ˆ 5.1, 0.7, H C(8)); 7.74 (d, J ˆ 1.2,
H
C(3)). 13C-NMR (D2O, 75 MHz): 8.25 (q, 3 MeCH2); 20.29, 20.28, 21.96, 22.06 (4q, 4 Me); 46.75
(t, 3 MeCH2); 56.53 (d, C(5)); 62.15 (t, CH2 C(5)); 66.11, 66.69, 70.43 (3d, C(6), C(7), C(8)); 126.60
(dd, 2J(C,P) ˆ 36.7, C(3)); 135.12 (d, 1J(C,P) ˆ 236.2, C(2)); 142.62 (d, 3J(C,P) ˆ 20.6, C(8a)); 172.51 ± 173.66
‡
‡
(several s, 4 CˆO). 31P-NMR (CD3OD, 121 MHz): 1.12. FAB-MS: 102 (72, Et3NH ), 449 (29, [M ‡ 1] ), 550
‡
‡
‡
(15, [(M ‡ Et3NH] ), 592 (100, [M 3 ‡ Et3N ‡ 2 Na] ), 693 (12, [M 3 ‡ 2 Et3N ‡ 2 Na] ).
6
Oleyl ) Hydrogen (5R,6R,7S,8S)-6,7,8-Triacetoxy-5-[(acetoxy)methyl]-5,6,7,8-tetrahydroimidazo[1,2-
a]pyridine-2-phosphonate (20). A soln. of 19 (39 mg, 0.068 mmol) and oleyl alcohol (16 mg, 0.059 mmol) in
pyridine (1 ml) was treated at 258 with CCl3CN (0.1 ml, 1 mmol) and warmed to 708. After 13 h, the resulting
brown soln. was evaporated and co-evaporated with toluene, dissolved in AcOEt (10 ml), and washed (H2O).
The aq. phase was extracted with AcOEt (4 Â 10 ml). The combined org. phases were dried (MgSO4), filtered,
and evaporated. FC (silica gel 60; AcOEt/iPrOH/H2O 10 : 1 : 0.1 ! 10 : 4 : 1) followed by RP 18 (MeOH/H2O
8 : 2 ! 95 : 5) gave 20 (27 mg) as a brown gel. A soln. of 20 in MeOH (2 ml) was treated with activated charcoal
and gave, after filtration and evaporation, 20 (20 mg, 50% from oleyl alcohol). Solid. Rf (AcOEt/MeOH/H2O
8 : 4 : 1) 0.6. UV (CHCl3): 273 (2.24), 245 (2.64). IR (CCl4): 3341w, 3135w, 2927s, 2855m, 1763s, 1512w, 1466w,
1433w, 1369w, 1260m, 1222s, 1065s, 946w, 904w. 1H-NMR (CD3OD, 300 MHz): 0.89 (t, J ˆ 6.4, Me); 1.29 ± 1.40
(m, 22 H); 1.46 ± 1.58 (m, CH2CH2O); 1.92 ± 2.25 (m, CH2CHˆCHCH2); 2.06, 2.07, 2.09, 2.10 (4s, 4 AcO); 3.76
(q, J ˆ 6.4, irrad. at 1.53 ! d, CH2CH2O); 4.43 (dd, J ˆ 5.4, 12.7, CH C(5)); 4.57 (dd, J ˆ 3.6, 12.7, CH' C(5));
4.54 (br. q, J ꢁ 4.5, H C(5)); 5.28 ± 5.42 (m, irrad. at 2.20 ! change, CH2CHˆCHCH2); 5.51 (t, J ˆ 7.0,
H
H
C(6)); 5.55 (dd, J ˆ 5.5, 7.5, irrad. at 6.09 ! d, J ꢁ 8.0, H C(7)); 6.09 (d, J ˆ 5.5, H C(8)); 7.59 (d, J ˆ 0.9,
C(3)). 13C-NMR (CD3OD, 75 MHz): 14.38 (q, Me); 20.49 ± 20.82 (several q); 23.68 ± 30.86 (several t); 31.87
(t, 3J(C,P) ˆ 7.3, CH2CH2O); 30.03 (t, CH2) 58.14 (d, C(5)); 63.17 (t, CH2 C(5)); 67.52, 67.76, 71.76 (C(6),
C(7), C(8)); 65.88 (dt, 2J(C,P) ˆ 6.1, CH2CH2O); 125.99 (dd, 2J(C,P) ˆ 30.5, C(3)); 131.00 (d, CHˆCH);
139.00 (d, 1J(C,P) ˆ 225.8, C(2)); 143.47 (d, 3J(C,P) ˆ 18.0, C(8a)); 171.01, 171.22, 171.61, 172.00 (4s, 4 CˆO).
‡
31P-NMR (CD3OD): 3.98. FAB-MS: 721 (100, [M ‡ Na] ).
6
Phytanyl ) Hydrogen (5R,6R,7S,8S)-6,7,8-Triacetoxy-5-[(acetoxy)methyl]-5,6,7,8-tetrahydroimidazo[1,2-
a]pyridine-2-phosphonate (21). A soln. of 19 (22 mg, 42.7 mmol) in pyridine (0.5 ml) was treated with phytanol
(10.2 mg, 34 mmol) and CCl3CN (8.6 ml, 85.4 mmol), and stirred at 608 for 18 h. After workup as described for 20,
FC (CHCl3 ! CHCl3/MeOH/H2O 10 : 1.2 : 0.1 ! 10 : 1.5 : 0.1 ! 10 : 2 : 0.2) gave 21 containing ca. 15% of the
deacetylated product at C(8) (determined by 1H-NMR). Acetylation of the mixture (1.2 ml of pyridine/Ac2O
5 : 1, 258, overnight) gave 21 (15 mg, 61% from phytanol). Solid. Rf (CHCl3/MeOH/H2O 10 : 2 : 0.25) 0.24. IR
(CCl4): 3353w, 3138w, 2956s, 2927s, 2868m, 1763s, 1512w, 1463m, 1432w, 1369m, 1222s, 1065s, 946s, 903w. UV
1
(CDCl3): 274 (1.96), 243 (2.49). H-NMR (CD3OD, 300 MHz): 0.80 (d, J ˆ 6.4, irrad. at 1.54 ! change, Me);
0.82 (d, J ˆ 6.4, irrad. at 1.54 ! change, Me); 0.86, 0.87, 0.88 (3d, J ˆ 6.4, 3 Me); 1.00 ± 1.45 (m, 21 H); 1.53
(sept., J ˆ 6.5, 1 H); 1.47 ± 1.66 (m, 2 H); 2.06, 2.07, 2.09, 2.10 (4s, 4 AcO); 3.72 ± 3.90 (m, CH2OP); 4.43
(dd, J ˆ 5.1, 12.1, irrad. at 4.90 ! d, J ꢁ 12.5, CH C(5)); 4.58 (dd, J ˆ 3.3, 12.1, irrad. at 4.90 ! d, J ꢁ 12.5,
6
)
Oleyl ˆ (Z)-octadec-9-enyl; phytanyl ˆ 3,7,11,15-tetramethylhexadecyl; dolichyl-19 ˆ 3,7,11,15,19,23,27,31,
35,39,43,47,51,55,59,63,67,71,75-nonadecamethylhexaheptaconta-6,10,14,18,22,26,30,34,38,42,46,50,54,58,62,
66,70,74-octadecaenyl.

Helvetica Chimica Acta ± Vol. 82 (1999)
1147
CH' C(5)); 4.90 (br. q, J ꢁ 4.6, H C(5)); 5.51 (t, J ˆ 6.5, irrad. at 4.90 ! d, J ꢁ 8.0, H C(6)); 5.56 (dd, J ˆ 4.7,
6.5, irrad. at 6.09 ! d, J ꢁ 8, H C(7)); 6.09 (dd, J ˆ 0.9, 4.7, H C(8)); 7.60 (s, H C(3)). 13C-NMR (CD3OD,
75 MHz): 19.69 ± 23.07 (several q, 9 Me); 25.47, 25.85 (2t); 29.10 ± 33.95 (several d); 38.37 ± 40.52 (several t);
63.17 (t, CH2 C(5)); 64.19 (m, CH2OP); 58.20 (d, C(5)); 67.46, 67.65, 71.57 (3d, C(6), C(7), C(8)); 126.09
(dd, 2J(C,P) ˆ 30.5, C(3)); 138.68 (d, 1J(C,P) ˆ 225.8, C(2)); 143.48 (d, 3J(C,P) ˆ 19.5, C(8a)); 170.93, 171.16,
‡
171.58, 171.92 (4s, 4 CˆO). 31P-NMR (CD3OD, 121 MHz): 3.78. FAB-MS: 751 (100, [M ‡ Na] ). Anal. calc.
for C36H61N2O11P ´ 2 H2O (764.12): C 56.53, H 8.56, N 3.66; found: C 56.36, H 8.44, N 3.65.
6
Dolichyl-19 ) Hydrogen (5R,6R,7S,8S)-6,7,8-Triacetoxy-5-[(acetoxy)methyl]-5,6,7,8-tetrahydroimida-
zo[1,2-a]pyridine-2-phosphonate (22). A soln. of 19 (22 mg, 42.7 mmol) in pyridine (0.4 ml) was treated with
dolichol-19 (10 mg, 7.6 mmol) and CCl3CN (9 ml, 90 mmol) and stirred at 608 for 18 h. The mixture was
evaporated and co-evaporated with toluene, diluted with CHCl3, washed with H2O, dried (MgSO4), and filtered.
Evaporation and FC (CHCl3 ! CHCl3/MeOH/H2O 10 : 0.6 : 0.05 ! 10 : 0.8 : 0.05 ! 10 : 1.0 : 0.05) followed by
acetylation (0.6 ml pyridine/Ac2O 5 : 1, 258, overnight) gave 22 (10 mg, 65% from dolichol-19). Coloured gel. Rf
(CHCl3/MeOH/H2O 10 : 2 : 0.25) 0.31. IR (CCl4): 3317w, 2962s, 2928s, 2955m, 1762s, 1664w, 1449m, 1376m,
1261s, 1222s, 1088s, 1031s. 1H-NMR (CD3OD/CDCl3 4 : 2, 500 MHz): 0.84 (d, J ˆ 6.5, Me); 1.10 ± 1.45 (m, 15 H
instead of the expected 5 H); 1.62, 1.60 (2s, 4 Me); 1.68 (s, 15 Me); 1.93 ± 2.08 (m, 70 H); 2.09, 2.10, 2.11, 2.12 (4s,
4 AcO); 3.66 ± 3.84 (m, CH2OP); 4.43 (dd, J ˆ 5.5, 12.5, irrad. at 4.63 ! d, J ꢁ 12.8, CH C(5)); 4.56 (dd, J ˆ 3.5,
12.5, irrad. at 4.63 ! d, J ꢁ 12.8, CH' C(5)); 4.63 (br. q, J ꢁ 5.0, H C(5)); 5.46 (dd, J ˆ 6.5, 7.5, irrad. at 4.63 !
d, J ꢁ 7.8, H C(6)); 5.54 (dd, J ˆ 5.7, 7.5, irrad. at 6.07 ! d, J ꢁ 7.5, H C(7)); 6.07 (d, J ˆ 5.5, H C(8)); 7.57
(s, H C(3)). 13C-NMR (CD3OD/CDCl3 4 : 2, 125 MHz): 16.26 ± 20.86 (several q); 23.74, 23.85 (2q); 25.93 ±
27.44 (several t); 29.89 (d); 32.59 ± 40.43 (several t); 57.56 (d, C(5)); 62.64 (t, CH2 C(5)); 63.71 (t, CH2OP);
66.85, 67.12, 71.12 (3d, C(6), C(7), C(8)); 124.97 ± 126.55 (several d); 131.65 ± 135.87 (several s); 138.29
(d, 1J(C,P) ˆ 224.0, C(2)); 142.50 (d, 3J(C,P) ˆ 18.7, C(8a)); 170.23, 170.42, 170.79, 171.29 (4s, 4 CˆO). 31P-
‡
NMR (CD3OD/CDCl3 4 : 2, 202 MHz): 3.87. FAB-MS: 1766 (19, [M ‡ Na] ).
6
Oleyl ) Hydrogen (5R,6R,7S,8S)-5,6,7,8-Tetrahydro-6,7,8-trihydroxy-5-(hydroxymethyl)imidazo[1,2-a]pyri-
dine-2-phosphonate (1). A soln. of 20 (12 mg, 17.5 mmol) in MeOH (1 ml) was treated at 258 with a 0.5m soln. of
MeONa in MeOH (41 ml), and stirred for 45 min. MeOH (3 ml) was added, and the mixture was neutralized
‡
with Amberlite IRC50 (H form). The resin was filtered and the filtrate evaporated. The residue (10 mg) was
taken up in hot MeOH (ca. 0.25 ml), and 1 was precipitated at 08 by the addition of cold MeCN, separated by
filtration, and dried under vacuum, affording 1 (8.5 mg, 95%). White solid. Rf (AcOEt/MeOH/H2O 10 :4 :1) 0.2.
IR (KBr): 3356s (br.), 2924s, 2853s, 1522m, 1466m, 1184m, 1066s, 828w. 1H-NMR (CD3OD, 500 MHz): 0.89
(t, J ˆ 6.9, Me); 1.20 ± 1.40 (m, 22 H); 1.53 ± 1.61 (m, CH2CH2O); 1.98 ± 2.07 (m, CH2CHˆCHCH2); 3.70
(dd, J ˆ 8.1, 9.5, irrad. at 4.54 ! change, H C(7)); 3.79 (q, J ˆ 6.5, CH2CH2O); 3.84 (dd, J ˆ 8.0, 9.5, irrad. at
3.70 ! change, H C(6)); 3.89 ± 3.94 (m, H C(5)); 3.96 (dd, J ˆ 4.0, 11.8, CH C(5)); 4.18 (dd, J ˆ 2.0, 11.8,
CH' C(5)); 4.54 (d, J ˆ 8.0, H C(8)); 5.29 ± 5.37 (m, CH2CHˆCHCH2); 7.60 (d, J ˆ 0.9, H C(3)). 13C-NMR
(CD3OD, 125 MHz): 14.47 (q, Me); 23.77 ± 30.94 (several d); 32.04 (dt, 3J(C,P) ˆ 7.3, CH2CH2O); 33.09
(t, CH2); 61.19 (t, CH2 C(5)); 63.24 (dt, 2J(C,P) ˆ 5.5, CH2CH2O); 65.88 (d, C(5)); 69.27, 69.59, 71.28
(3d, C(6), C(7), C(8)); 125.10 (dd, 2J(C,P) ˆ 29.1, C(3)); 130.86, 130.92 (2d, CHˆCH); 136.78 (d, 1J(C,P) ˆ
197.5, C(2)); 149.44 (d, 3J(C,P) ˆ 16.8, C(8a)). 31P-NMR (CD3OD, 121 MHz): 5.89. FAB-MS: 553 (69, [M ‡
‡
‡
Na] ), 575 (100, [M 1 ‡ Na] ).
6
Phytanyl ) Hydrogen (5R,6R,7S,8S)-5,6,7,8-Tetrahydro-6,7,8-trihydroxy-5-(hydroxymethyl)imidazo[1,2-
a]pyridine-2-phosphonate (2). A soln. of 21 (15 mg, 20.6 mmol) in MeOH (1.2 ml) was treated with 0.5m
MeONa in MeOH (49 ml) and stirred for 90 min. After dilution with MeOH (4 ml), the mixture was
‡
neutralized with Amberlite IRC50 (H form). The resin was filtered and the filtrate evaporated. The residue
(13 mg) was taken up in hot MeOH (ca. 0.2 ml), and 2 was precipitated at 08 by the addition of cold MeCN.
Filtration and drying under vacuum gave 2 (7 mg, 61%). White solid. Rf (CHCl3/MeOH/H2O 3 :1:0.1) 0.16. IR
(KBr): 3382s (br), 2953s, 2912s, 2839s, 1522w, 1460m, 1375w, 1262w, 1189m, 1138m, 1065s, 901w, 856w, 805w.
1H-NMR (CD3OD, 300 MHz): 0.85 (m, Me); 0.89 (br. d, J ˆ 7.2, irrad. at 1.53 ! change, 4 Me); 1.0 ± 1.44
(m, 21 H); 1.53 (sept., J ˆ 8.8, irrad. at 0.87 ! change, 1 H); 1.50 ± 1.70 (m, 3 H); 3.72 (t, J ˆ 8.8, irrad. at 4.19 !
d, J ꢁ 9.3, H C(7)); 3.84 (m, irrad. at 3.96 ! change, H C(6), CH2O); 3.96 (m, CH C(5), H C(5)); 4.19
(dd, J ˆ 4.1, 13.5, irrad. at 3.96 ! br. s, CH' C(5)); 4.58 (d, J ˆ 8.1, H C(8)); 7.66 (d, J ˆ 1.2, H C(3)).
13C-NMR (CD3OD, 75 MHz): 19.73 ± 23.05 (several q); 25.46, 25.85 (2t); 29.12 ± 33.95 (several d); 38.37 ± 40.52
(several t); 61.04 (t, CH2 C(5)); 64.30 (dt, 3J(C,P) ˆ 6.1, CH2O); 61.04 (d, C(5)); 69.15, 69.25, 76.05 (3d, C(6),
C(7), C(8)); 125.47 (dd, 2J(C,P) ˆ 26.8, C(3)); 135.54 (d, 1J(C,P) ˆ 216.1, C(2)); 149.6 (d, 3J(C,P) ˆ 13.4,
‡
‡
C(8a)). 31P-NMR (CD3OD): 4.30. FAB-MS: 281 (43, [(M phytanyloxy ‡ 1] ), (561 (43, [(M ‡ 1] ), 583

1148
Helvetica Chimica Acta ± Vol. 82 (1999)
‡
‡
‡
‡
(100, [M ‡ Na] ), 605 (60, [M 1 ‡ 2 Na] ), 1188 (4, [2 M 1 ‡ 3 Na] ). HR-FAB-MS: 561.3676, (MH ; calc.
561.3668).
6
Dolichyl ) Hydrogen (5R,6R,7S,8S)-5,6,7,8-Tetrahydro-6,7,8-trihydroxy-5-(hydroxymethyl)imidazo[1,2-
a]pyridine-2-phosphonate (3). A soln. of 22 (14 mg, 8.02 mmol) in THF/MeOH 1 :2 (0.75 ml) was treated
with 0.4m of MeONa in MeOH (24 ml) at 258 and stirred for 105 min. The soln. was diluted with THF (ca. 2 ml),
‡
neutralized with Amberlite IRC50 (H form). The resin was filtered off and the filtrate evaporated. FC (CHCl3/
MeOH/H2O 10 :1:0.15 ! 10 : 2 : 0.25 ! 10 : 3.5 : 0.5), evaporation, washing with MeOH, and drying in vacuo
gave 3 (9.3 mg, 75%). Rf (CHCl3/MeOH/H2O 10 : 2 : 0.25) 0.28. IR (CCl4): 3286m (br.), 2960s, 2926s, 2855s,
1736w, 1598w, 1451m, 1376m, 1260w, 1194w, 1072m. 1H-NMR (CDCl3/CD3OD/D2O 10 : 7 : 1, 500 MHz): 0.59
(d, J ˆ 6.5, Me); 0.75 ± 1.20 (m, 15 H instead of the expected 5 H); 1.40, 1.36, 1.34 (3s, 4 Me); 1.42 (s, 15 Me);
1.86 ± 1.69 (m, 70 H); 3.48 (br. t, J ꢁ 8.5, 1 H); 3.51 ± 3.68 (m, 4 H); 3.74 (br. d, J ꢁ 12, CH C(5)); 3.91
(br. d, J ꢁ 12, CH' C(5)); 4.80 ± 4.95 (m, 18 H); 7.23 (br. s, H C(3)). 13C-NMR (CDCl3/CD3OD/D2O 10 : 7: 1,
125 MHz): some signals are hidden by the noise; 15.36 ± 18.36 (several q); 22.74, 22.86 (2q, 2 Me) 24.64 ± 26.26
(several t); 28.82 (d, CH); 29.11 ± 39.58 (several t); 60.78 (t, C(5)); 63.0 (t, CH2 C(5)); 64.5 (t, CH2O); 67.06,
67.5, 74.21 (3d, C(6), C(7), C(8)); 123.75 ± 125.34 (several d); 130.71 ± 134.84 (several s). 31P-NMR (CDCl3/
‡
CD3OD/D2O 10 : 7: 1, 202 MHz) 7.4. FAB-MS: 1577 (100, [M ‡ 1] ). MALDI-MS (THA (1,2,3,4-tetrahy-
‡
‡
droacridin-9-amine hydrochloride)/citrate 2 : 1): 1576.7 (M ), 1599.0 ([M ‡ Na] ). ESI-FT/MS/MS: 281 (100,
‡
‡
‡
[M dolichyloxy ‡ 2] ), 1577 (84, [M ‡ 1] ). HR-ESI-FT/MS: 1576.2602 (MH ; calc. 1576.2588).
REFERENCES
[1] J. A. Campbell, G. J. Davies, V. Bulone, B. Henrissat, Biochem. J. 1997, 326, 929.
[2] S. Charnok, G. J. Davies, Biochemistry 1999, 38, 6369.
[3] A. Vrielink, W. Rüger, H. P. C. Driessen, P. S. Freemont, EMBO 1994, 13, 3413.
[4] E. H. Holmes, Z. Xu, A. L. Sherwood, B. A. Macher, J. Biol. Chem. 1995, 270, 8145.
[5] B. W. Murray, S. Takayama, J. Schultz, C.-W. Wong, Biochemistry 1996, 35, 11183.
[6] C. J. Britten, M. Bird, Biochim. Biophys. Acta 1997, 1334, 57.
[7] S. C. Kim, A. N. Singh, F. M. Raushel, Arch. Biochem. Biophys. 1988, 267, 54.
[8] B. W. Murray, V. Wittmann, M. D. Burkart, S.-C. Hung, C.-H. Wong, Biochemistry 1997, 36, 823.
[9] Y. Ichikawa, Y.-C. Lin, D. Dumas, G.-J. Shen, E. Garcia-Juncade, M. A. Williams, R. Bayer, C. Ketcham,
L. E. Walker, J. C. Paulson, C.-H. Wong, J. Am. Chem. Soc. 1992, 114, 9283.
[10] T. Hayashi, B. W. Murray, R. Wang, C.-H. Wong, Bioorg. Med. Chem. 1997, 5, 497.
[11] L. Qiao, B. W. Murray, M. Shimazaki, J. Schultz, C. H. Wong, J. Am. Chem. Soc. 1996, 118, 7653.
[12] I. Jefferies, B. R. Bowen, Bioorg. Med. Chem. Lett. 1997, 7, 1171.
[13] S. Cai, M. R. Stroud, S. Hakomori, T. Toyokuni, J. Org. Chem. 1992, 57, 6693.
[14] R. R. Schmidt, K. Frische, Bioorg. Med. Chem. Lett. 1993, 3, 1747.
[15] R. D. Cumming, in ꢀGlycoconjugates, Composition, Structure, and Functionꢁ, Eds. H. J. Allen and E. C.
Kisailus, Marcel Dekker, New York, 1992, p. 333.
[16] N. H. Behrens, L. F. Leloir, Proc. Natl. Acad. Sci. U.S.A. 1970, 66, 153.
[17] C. J. Waechter, Ann. Rev. Biochem. 1976, 45, 95.
[18] P. Burda, M. Aebi, Glycobiology 1998, 8, 455.
[19] T. Granier, N. Panday, A. Vasella, Helv. Chim. Acta 1997, 80, 979.
[20] K. Tatsuta, S. Miura, S. Ohta, H. Gunji, Tetrahedron Lett. 1995, 36, 1085.
[21] K. Tatsuta, S. Miura, H. Gunji, Bull. Chem. Soc. Jpn. 1997, 70, 427.
[22] T. D. Heightman, M. Locatelli, A. Vasella, Helv. Chim. Acta 1996, 79, 2190.
[23] N. Panday, A. Vasella, in preparation.
[24] K. Tatsuta, S. Miura, Tetrahedron Lett. 1995, 36, 6721.
[25] T. Hirao, T. Masunaga, Y. Ohshiro, T. Agawa, Synthesis 1981, 56.
[26] T. Hirao, T. Masunaga, N. Yamada, Y. Ohshiro, T. Agawa, Bull. Chem. Soc. Jpn. 1982, 55, 909.
[27] Y. Xu, J. Zhang, Synthesis 1984, 778.
[28] H. Lei, M. S. Stoakes, A. W. Schwabacher, Synthesis 1992, 1255.
[29] J. Lin, C. M. Thompson, J. Heterocycl. Chem. 1994, 31, 1701.
[30] N. Panday, Ph. D. Thesis, in preparation.
[31] K. Sonogashira, Y. Tohda, N. Hagihara, Tetrahedron Lett. 1975, 50, 4467.
[32] C. Cai, A. Vasella, Helv. Chim. Acta 1995, 78, 2053.

Helvetica Chimica Acta ± Vol. 82 (1999)
1149
[33] T. Morita, Y. Okamoto, H. Sakurai, Bull. Chem. Soc. Jpn. 1978, 51, 2169.
[34] D. Redmore, J. Org. Chem. 1973, 38, 1306.
[35] L. A. Vargas, L. X. Miao, A. F. Rosenthal, Biochim. Biophys. Acta 1984, 796, 123.
[36] L. Qiao, J. C. Vederas, J. Org. Chem. 1993, 58, 3480.
[37] J. Coste, M.-N. Dufour, A. Pantaloni, B. Castro, Tetrahedron Lett. 1990, 31, 669.
[38] N. Galeotti, J. Coste, P. Bedos, P. Jouin, Tetrahedron Lett. 1996, 37, 3997.
[39] K. Yamauchi, F. Une, S. Tabata, M. Kinoshita, J. Chem. Soc., Perkin Trans. 1 1986, 765.
[40] D. V. Patel, K. Rielly-Gauvin, D. E. Ryono, Tetrahedron Lett. 1990, 31, 5591.
[41] O. Mitsunobu, M. Eguchi, Bull. Chem. Soc. Jpn. 1971, 44, 3427.
[42] O. Mitsunobu, Synthesis 1981, 1.
[43] R. Hoos, A. B. Naughton, A. Vasella, Helv. Chim. Acta 1992, 75, 1802.
[44] Y. Sakata, Y. Hirano, H. Tatemitsu, S. Misumi, H. Ochiai, H. Shibata, Tetrahedron 1989, 45, 4717.
Received April 30, 1999