The synthesis of a new class of potential inhibitors for glycoside hydrolases

Article abstract of DOI:10.1081/CAR-200067125

Some attempts toward the synthesis of novel inhibitors of glycosyl transferases are described. More successfully, the synthesis of an activated cyclopropacyclohexene and an amide and an amine of a cyclopropa-fused pyranose are described. None of these three novel compounds proved to be a significant inhibitor of a retaining α-glucosidase from barley. Copyright Taylor & Francis, Inc.

Full text of DOI:10.1081/CAR-200067125

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The Synthesis of a New Class of Potential
Inhibitors for Glycoside Hydrolases
Robert V. Stick a & Keith A. Stubbs a
a Chemistry M313, School of Biomedical and Chemical Sciences ,
University of Western Australia , Crawley, WA, Australia
Published online: 16 Aug 2006.
To cite this article: Robert V. Stick & Keith A. Stubbs (2005) The Synthesis of a New Class of Potential
Inhibitors for Glycoside Hydrolases , Journal of Carbohydrate Chemistry, 24:4-6, 529-547
To link to this article: http://dx.doi.org/10.1081/CAR-200067125
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Journal of Carbohydrate Chemistry, 24:529–547, 2005
Copyright # Taylor & Francis, Inc.
ISSN: 0732-8303 print 1532-2327 online
DOI: 10.1081/CAR-200067125
The Synthesis of a New Class
of Potential Inhibitors for
Glycoside Hydrolases
Robert V. Stick and Keith A. Stubbs
Chemistry M313, School of Biomedical and Chemical Sciences, University of Western
Australia, Crawley, WA, Australia
Some attempts toward the synthesis of novel inhibitors of glycosyl transferases are
described. More successfully, the synthesis of an activated cyclopropacyclohexene and
an amide and an amine of a cyclopropa-fused pyranose are described. None of these
three novel compounds proved to be a significant inhibitor of a retaining a-glucosidase
from barley.
Keywords Glycoside hydrolases, Glycosyl transferases, Cyclopropanes, Inhibitors
The design and subsequent synthesis of inhibitors for the major carbohydrate-
processing enzymes, namely the glycosyl transferases and the glycoside hydro-
lases, have attracted much attention over the past few decades. Although great
strides have been made toward the successful inhibition of the glycoside hydro-
lases,[1] things have not progressed nearly as well with the glycosyl
transferases.[2]
It occurred to us that a molecule such as 1 (Fig. 1) could offer the potential
to label a glycosyl transferase covalently at the active site; related to this design
would be the cyclopropane 2 (Fig. 2). This paper, then, describes our efforts
toward the synthesis of 1 and 2 and the carbocyclic counterpart 3. Along the
way we diverted to syntheses of the dinitrophenyl ether 4, the amide 5, and
the amine 6. Whereas the amine 6 (in its protonated form) could only ever
act as a reversible inhibitor of a glycoside hydrolase, there was some hope
Received February 7, 2005; accepted April 6, 2005.
This paper is dedicated to the memory of Jacques H. van Boom.
Address correspondence to Robert V. Stick, Chemistry M313, School of Biomedical and
Chemical Sciences, University of Western Australia, Crawley, WA 6009, Australia.
E-mail: rvs@chem.uwa.edu.au
529

R. V. Stick and K. A. Stubbs
530
Figure 1: The alkene 1 as a potential inhibitor of a glycosyl transferase; ‘OUDP’ is uridine
diphosphate.
that the molecules 4 and 5 could provide a covalent label for such an enzyme
(Figs. 3 and 4). We were well aware that Vasella and coworkers had prepared
a range of spirocyclic cyclopropylamines that were found to be very weak
inhibitors of several glycoside hydrolases.[3]
Toward a synthesis of the alkene 1, we treated the readily available alkene
7
[4–6] with diphenyl chlorophosphonate and pyridine; not too surprisingly, only
the diene 8 was isolated, and in good yield (Sch. 1). Presumably, the desired
phosphate 9 is formed but rapidly decomposes through a favored carbenium
ion intermediate.
We immediately turned our attention to the cyclopropane derivative 2.
Penta-O-acetyl-b-D-glucopyranose was converted into the trisilyl D-glucal 10
(Sch. 2).[7] Cyclopropanation of 10 then gave the ester 11,[8] and a subsequent
reduction gave the primary alcohol 12.[9] Treatment of 12 with diphenyl chlor-
ophosphonate and pyridine again failed to give the desired phosphate 13—the
activated cyclopropane ring caused immediate formation of the diene 14
(Sch. 3). The instability of both the purported phosphates 9 and 13 undoubtedly
resided in the endocyclic oxygen atom; we therefore turned to a synthesis of the
carbocyclic analog of 2, namely the cyclopropacyclohexene 3. The obvious pre-
cursor to 3 is the phosphate 15.
Methyl a-D-glucopyranoside was easily converted into the alkene 16
(Sch. 4).[10–12] Acetolysis of 16 then gave the tetraacetate 17 that was the
direct precursor, using our VO(salen)-catalyzed procedure,[13] of the glycals
Figure 2: The cyclopropane 2 as a potential inhibitor of glycosyl transferase.

New Class of Potential Inhibitors for Glycoside Hydrolases
531
Figure 3: The cyclopropane 4 as a potential inhibitor of a glycoside hydrolase.
18, 19, and 20. A Claisen rearrangement on the glycal 19 in 1,2-dichloroben-
zene heated to 2408C in a sealed tube is reported to give the aldehyde 21 in
84% yield[14]; we found it simpler to heat the glycal 19 in boiling diphenyl
ether (2108C) (Sch. 5). After a subsequent reduction, the unsaturated alcohol
was obtained in good yield; a similar rearrangement was performed on the
glycal 20, with both the unsaturated alcohols being protected as the appropri-
ate ether (22 and 23).
Cyclopropanation of the tribenzyl ether 22 gave the ethyl ester 24 in a
modest yield (Sch. 6); however, a similar treatment of the trisilyl ether 23
gave the ethyl ester 25 in good yield (71%). The stereochemical assignment
of the three new stereogenic centers in 24 and 25 was based on an ana-
lysis of their 1H NMR NOESY spectra—interactions between H1 and H3
confirmed the orientation of the cyclopropane rings, and interactions
between H4 and H7 defined the configuration in both molecules as 7R.
With the ready availability of the ester 25, subsequent transformations
gave the alcohol 26 and the phosphate 27 (Sch. 7). Unfortunately, we were
unable to deprotect 27 successfully to form the triol 15, the precursor of 3;
the treatment of 27 with tetrabutylammonium fluoride gave a complex

R. V. Stick and K. A. Stubbs
532
Figure 4: The cyclopropane 5 as a potential inhibitor of a glycoside hydrolase.
mixture, with some apparent loss of the phenyl groups,[15] and treatment of 27
with hydrogen and platinum(IV) oxide again gave a complex mixture.
We next considered the preparation of the dibenzyl phosphate 28 but
encountered problems with the preparation and use of dibenzyl chlorophospho-
nate.[16] Instead, we prepared the diethyl phosphate 29; however, treatment of
Scheme 1: a) ClPO(OPh)2, pyridine, CH2Cl2.

New Class of Potential Inhibitors for Glycoside Hydrolases
533
Scheme 2: a) i. HBr, AcOH; ii. Zn, NH4Cl, VO(salen), MeOH; iii. NaOMe, MeOH; iv. BMSCl,
imidazole, DMF; b) Rh2(OAc)4, N2CHCO2Et, CH2Cl2; c) LiAlH4, THF.
29 with tetrabutylammonium fluoride or hydrochloric acid in ethanol[17] again
gave complex mixtures. Finally, we prepared the bis(trichloroethyl) phosphate
30; again, treatment of 30 with tetrabutylammonium fluoride[18] gave a
complex mixture. However, hydrochloric acid in ethanol did cause a poor con-
version of 30 into the triol 31, along with what appeared to be a mixture of
the ethyl ethers 32, 33, and 34. At this stage we curtailed our investigations
into the synthesis of 3, but not the prospect of using the cyclopropane moiety
in inhibitor design. Treatment of the alcohol 26 with 2,4-dinitrofluorobenzene
Scheme 3: a) ClPO(OPh)2, pyridine, CH2Cl2.

R. V. Stick and K. A. Stubbs
534
Scheme 4: a) TMSOTf, Ac2O; b) i. HBr, HOAc; ii. Zn, VO(salen), with NH4Cl, MeOH or HOAc,
MeCN; c) i. NaOMe, MeOH; ii. NaH, BnBr, DMF for 19; BMSCl, imidazole, DMF for 20.
gave the ether 35, and deprotection the desired putative inhibitor (of glycoside
hydrolases) 4 (Sch. 8).
Our final efforts were toward a synthesis of 5 and 6. Thus, the ester 11 was
converted into the amide 36 (Sch. 9), but a subsequent treatment with ethanol
under acidic conditions gave only the ethyl glycoside 37 (perhaps a good sign
for potential inhibition of a glycoside hydrolase). However, 36 was efficiently
converted into the triol 5 under basic conditions. It was gratifying to observe
a successful Hofmann reaction[19] on the amide 5, to yield the amine 6.
None of the compounds 4, 5, and 6 was found to be a significant inhibitor of
the retaining a-glucosidase from barley (family 31). Only the amine 6 showed
Scheme 5: a) Ph2O, 2108C; b) i. NaBH4, THF; NaH, BnBr, DMF for 22; BMSCl, imidazole, DMF for 23.

New Class of Potential Inhibitors for Glycoside Hydrolases
535
Scheme 6: a) Rh2(OAc)4, N2CHCO2Et, CH2Cl2.
any (competitive) inhibition (Ki 18 mM), with maltose (KM 1.5 mM) as
substrate.
EXPERIMENTAL
General experimental procedures have been given previously.[20]
1,5-Anhydro-tetra-O-benzyl-1-C-vinyl-D-gluc-1-enitol 8. Diphenyl chloro-
phosphonate (0.2 mL, 0.8 mmol) was added to the alkene 7[6] (160 mg, 0.30 mmol)
and pyridine (0.03 mL, 0.4 mmol) in CH2Cl2 (5 mL) and the solution was stirred
(rt, 12 hr). Concentration of the mixture followed by flash chromatography
1
(EtOAc/petrol 1:19) gave the diene 8 as a colorless oil (100 mg, 80%). H NMR
Scheme 7: a) LiAlH4, THF; b) ClPO(OPh)2, pyridine, CH2Cl2.

R. V. Stick and K. A. Stubbs
536
Scheme 8: a) 2,4-dinitrofluorobenzene, Et3N, ClCH2CH2Cl; b) conc. HCl, EtOH.
Scheme 9: a) NaCN, NH3, MeOH; b) conc. HCl, EtOH; c) i. TBAF, THF; ii. Ac2O, pyridine; iii.
NaOMe, MeOH; (d) NaOCl, NaOH, H2O.

New Class of Potential Inhibitors for Glycoside Hydrolases
537
(500 MHz) d3.80, dd, J5,6 3.9, J6,6 10.9 Hz, H6; 3.84, dd, J5,6 5.4 Hz, H6; 4.03, dd, J3,4
4.7, J4,5 6.8 Hz, H4; 4.15, ddd, H5; 4.44, d, H3; 4.57–4.80, m, 8H, CH2Ph; 5.17, dd, J
1.9, 11.0 Hz, 1H,55CH2; 5.63, dd, J 17.4 Hz, 1H,55CH2; 6.66, dd,55CH; 7.28–7.36,
m, 20H, Ph. 13C NMR (125.7 MHz) d 68.16, C6; 70.54, 72.74, 73.43, 74.32, 4C,
CH2Ph; 73.50, 75.29, 76.32, C3,4,5; 115.03, 55CH2; 125.82–138.22,
C1,2,55CH,Ph. HRMS (FAB) m/z 548.2577 [C36H36O5 (M)þ. requires 548.2563].
1,5-Anhydro-tri-O-(t-butyldimethylsilyl)-2-deoxy-2-C-vinyl-D-gluc-1-enitol
14. Diphenyl chlorophosphonate (0.2 mL, 0.8 mmol) was added to the alcohol 12[9]
(140 mg, 0.30 mmol) and pyridine (0.03 mL, 0.4 mmol) in CH2Cl2 (5 mL) and the
solution was stirred (rt, 1 hr). Concentration of the mixture followed by flash
chromatography (EtOAc/petrol 1:19) gave the diene 14 as a colorless oil (92 mg,
1
83%). H NMR (200 MHz) d 0.05, 0.07, 0.09, 0.11, 4s, 18H, CH3; 0.89, 0.91, 2s,
27H, C(CH3)3; 3.72, dd, J5,6 3.5, J6,6 7.6 Hz, H6; 3.89–4.11, m, H3,4,5,6; 4.79,
dd, J1.1, 11.0 Hz, 1H, 55CH2; 4.99, dd, J16.9 Hz, 1H,55CH2; 6.18, dd, 55CH;
6.49, s, H1. HRMS (FAB) m/z 515.3411 [C26H55O4Si3 (M þ H)þ requires
515.3408].
Tetra-O-acetyl-6,7-dideoxy-a-D-gluco-hept-6-enopyranose 17. Trimethyl-
silyl trifluoromethanesulfonate (1 mL, 5 mmol) was added to the alkene 16
(8.0 g, 19 mmol) in Ac2O (40 mL) and the solution was stirred (rt, 24 hr). The
mixture was quenched by the addition of saturated NaHCO3 solution (5 mL).
Concentration of the mixture followed by a standard work-up (EtOAc) and
flash chromatography (EtOAc/petrol 1:4) gave the alkene 17 as colorless
needles (2.5 g, 83%), m.p. 98–1008C (Et2O/petrol), [a]D þ 7.88 (Found: C,
1
52.6; H, 5.6. C15H20O9 requires C, 52.5; H, 5.6%). H NMR (500 MHz) d 1.97,
1.98, 2.13, 3s, 12H, CH3; 4.27–4.31, m, J4,5 10.0 Hz, H5; 4.91, dd, J3,4
10.0 Hz, H4; 5.05, dd, J1,2 3.7, J2,3 10.0 Hz, H2; 5.24, ddd, J5,7 1.3, J6,7 10.4,
J7,7 1.2 Hz, H7; 5.32, ddd, J6,7 17.2 Hz, H7; 5.44, dd, H3; 5.65–5.70, m, H6;
6.30, d, H1. 13C NMR (125.7 MHz) d 20.33, 20.50, 20.55, 20.77, 4C, CH3;
69.36, 69.42, 71.04, C2,3,4; 72.95, C5; 88.87, C1; 120.11, C7; 132.59, C6;
168.74, 169.29, 169.58, 170.06, 4C, C55O. HRMS (FAB) m/z 344.1107
[C15H20O9 (M)þ. requires 344.1107].
Di-O-acetyl-1,5-anhydro-2,6,7-trideoxy-D-arabino-hept-1,6-dienitol 18.
(i) 30% HBr in AcOH (3.0 mL, 15 mmol) was added to the tetraacetate 17
(5.0 g, 14 mmol) and the solution was stirred (rt, 1 hr). Standard work-up
(EtOAc) gave a light yellow oil that crystallized upon standing to give tri-O-
acetyl-6,7-dideoxy-a-D-gluco-hept-6-enopyranosyl bromide as needles (4.8 g,
90%), m.p. 93–998C (Et2O/petrol), [a]D þ 1758. 1H NMR (500 MHz) d 2.01,
2.02, 2.09, 3s, 9H, CH3; 4.48, ddd, J4,5 10.1, J5,6 7.1, J5,7 0.7 Hz, H5; 4.81, dd,
J1,2 4.0, J2,3 9.8 Hz, H2; 4.98, dd, J3,4 9.8 Hz, H4; 5.32, ddd, J6,7 10.4, J7,7
1.0 Hz, H7; 5.40, ddd, J6,7 17.1 Hz, H7; 5.57, dd, H3; 5.75, ddd, H6; 6.61, d,

R. V. Stick and K. A. Stubbs
538
H1. 13C NMR (125.7 MHz) d 20.60, 20.62, CH3; 69.83, 70.47, 70.85, C2,3,4;
75.19, C5; 86.52, C1; 121.07, C7; 131.67, C6; 169.45, 169.75, 169.78, 3C,
C55O. HRMS (FAB) m/z 365.0236 [C13H BrO7 (M þ H)þ requires 365.0204].
81
18
(ii) (a) Powdered Zn (2.0 g, 30 mmol), NH4Cl (1.8 g, 6 mmol), and VO(salen)
(10 mg) were added to the bromide from (i) (2.2 g, 6.0 mmol) in MeOH (30 mL)
and the mixture was stirred (10 min). Filtration, followed by concentration of
the filtrate, standard work-up (EtOAc), and flash chromatography (EtOAc/
1
petrol 1:4), gave the diene 18 as a colorless oil (1.2 g, 92%), [a]D 2 81.78. H
NMR (500 MHz) d 2.03, 2.05, 2s, 6H, CH3; 4.41, dd, J4,5 7.9, J5,6 7.3 Hz, H5;
4.82, dd, J1,2 6.2, J2,3 3.1 Hz, H2; 5.11, dd, J3,4 6.0 Hz, H4; 5.30, ddd,
J5,7 ꢀ J7,7 2.3, J6,7 10.3 Hz, H7; 5.36–5.39, m, H3; 5.39, ddd, J6,7 17.2 Hz, H7;
5.87, ddd, H6; 6.48, dd, J1,3 1.4 Hz, H1. 13C NMR (125.7 MHz) d 20.91, 21.03,
2C, CH3; 67.63, 70.03, C3,4; 77.44, C5; 98.92, 119.88, C2,7; 132.50, C6;
145.82, C1; 169.73, 170.52, 2C, C55O. HRMS (FAB) m/z 227.0910 [C11H15O5
(M þ H)þ requires 227.0919].
(b) Powdered Zn (4.0 g, 60 mmol), AcOH (35 mg, 0.60 mmol), and VO(salen)
(10 mg) were added to the bromide from (i) (2.2 g, 6 mmol) in MeCN (30 mL) and
the mixture was stirred (80 min). Filtration, followed by neutralization with
resin (Amberlite IRA 400, OH2) and another filtration, gave a green residue.
Flash chromatography (EtOAc/petrol 1:4) then gave the diene 18 as a colorless
oil (1.1 g, 90%). The 1H and 13C NMR spectra were consistent with those
reported in (a).
1,5-Anhydro-di-O-benzyl-2,6,7-trideoxy-D-arabino-hept-1,6-dienitol 19.
10% NaOMe in MeOH was added to the diene 18 (1.0 g, 4.4 mmol) in MeOH
(10 mL) and the solution was stirred (rt, 30 min). Concentration of the
solution gave a yellow residue that was dissolved in DMF (20 mL), and NaH
(60% dispersion in mineral oil, 220 mg, 9.0 mmol) and BnBr (1.0 mL,
9.0 mmol) were added and the mixture stirred (rt, 1 hr). The mixture was
quenched with MeOH (5 mL) and concentration followed by a standard work-
up (EtOAc) and flash chromatography (EtOAc/petrol 1:19) gave the diene 19
1
as a colorless oil (1.3 g, 95%), [a]D 232.98. H NMR (600 MHz) d 3.69, dd, J3,4
6.1, J4,5 8.5 Hz, H4; 4.28–4.30, m, H3; 4.40–4.43, m, H5; 4.65, 4.71, AB, J
11.8 Hz, CH2Ph; 4.77, 4.85, AB, J 11.3 Hz, CH2Ph; 4.96, dd, J1,2 2.7, J2,3
6.1 Hz, H2; 5.38, ddd, J5,7 ꢀ J7,7 1.3, J6,7 10.6 Hz, H7; 5.51, ddd, J6,7 17.2 Hz,
H7; 6.14, ddd, J5,6 6.5 Hz, H6; 6.49, d, H1; 7.33–7.41, m, 10H, Ph. 13C NMR
(150.8 MHz) d 70.54, 73.68, 2C, CH2Ph; 75.32, 77.88, 78.18, C3,4,5; 100.23, C2;
118.14, C7; 127.52, 127.61, 127.66, 128.27, 137.99, 138.31, Ph; 134.26, C6;
144.42, C1. HRMS (FAB) m/z 321.1491 [C21H21O3 (M–H)þ requires 321.1514].
1,5-Anhydro-di-O-(t-butyldimethylsilyl)-2,6,7-trideoxy-D-arabino-hept-
1,6-dienitol 20. 10% NaOMe in MeOH was added to the diene 18
(1.0 g, 4.4 mmol) in MeOH (10 mL) and the solution was stirred (rt, 30 min.).

New Class of Potential Inhibitors for Glycoside Hydrolases
539
Concentration of the mixture gave a yellow residue that was dissolved in DMF
(20 mL), ButMe2SiCl (2.0 g, 9.0 mmol) and imidazole (3.1 g, 44 mmol) were
added, and the solution was stirred (608C, 24hr). Concentration of the mixture
followed by a standard work-up (EtOAc) and flash chromatography (PhMe/
petrol 1:4) gave the diene 20 as a colorless oil (1.5 g, 92%), [a]D 247.68. 1H NMR
(600 MHz) d 0.08, 0.09, 0.10, 0.11, 4s, 12H, CH3; 0.90, s, 18H, C(CH3)3; 3.69, dd,
J3,4 ꢀ J4,5 4.6 Hz, H4; 4.06, dd, J1,3 1.0, J2,3 4.5 Hz, H3; 4.26–4.29, m, H5; 4.71,
dd, J1,2 6.2 Hz, H2; 5.17, ddd, J5,7 ꢀ J7,7 1.6, J6,7 10.7 Hz, H7; 5.28, ddd, J6,7
18.8 Hz, H7; 6.08, ddd, J5,6 7.2 Hz, H6; 6.35, dd, H1. 13C NMR (150.8 MHz) d
24.21, 24.16, 24.13, 23.91, 4C, CH3; 18.04, C(CH3)3; 25.91, C(CH3)3; 68.29,
C3; 73.62, C4; 80.07, C5; 102.75, C2; 117.02, C7; 134.94, C6; 143.06, C1. HRMS
(FAB) m/z 369.2283 [C19H37O3Si2 (M–H)þ requires 369.2281].
(3R,4R,5R)-3,4-Dibenzyloxy-5-(benzyloxymethyl)cyclohexene 22. (i) The
diene 19 (1.0 g, 3.2 mmol) in Ph2O (15 mL) was heated (2108C, 2 hr). Concen-
tration of the solution gave a colorless residue, presumably the aldehyde 21.
This residue was dissolved in THF (5 mL), NaBH4 (450 mg, 12 mmol) was
added and the mixture was stirred (rt, 1 hr). The mixture was quenched by
the addition of AcOH (5 mL). Concentration of the mixture followed by a
standard work-up (EtOAc) and flash chromatography (EtOAc/petrol 1:19)
gave (3R,4R,5R)-3,4-dibenzyloxy-5-(hydroxymethyl)cyclohexene as a colorless
oil (850 mg, 84%), [a]D 223.48 (Found: C, 77.5; H, 7.7. C21H24O3 requires C,
1
77.7; H, 7.5%). H NMR (600 MHz) d 1.89–1.95, m, H6; 2.03–2.08, m, H5;
2.13–2.17, m, H6; 2.69, s, OH; 3.62, dd, J3,4 10.7, J4,5 2.8 Hz, H4; 3.67–3.69,
m, CH2OH; 4.25, m, J1,3 1.3, J2,3 3.8 Hz, H3; 4.66, 4.75, AB, J 11.6 Hz,
CH2Ph; 4.66, 4.75, AB, J 11.3 Hz, CH2Ph; 5.73, m, J1,2 10.3 Hz, H1; 5.78–
5.79, m, H2; 7.30–7.40, m, 10H, Ph. 13C NMR (150.8 MHz) d 27.95, C6;
40.48, C5; 65.43, CH2OH; 71.18, 74.22, 2C, CH2Ph; 81.06, C3; 81.93, C4;
125.81, C1; 128.16, C2; 127.39–138.33, Ph. HRMS (FAB) m/z 325.1804
[C21H25O3 (M þ H)þ requires 325.1811].
(ii) Sodium hydride (60% dispersion in mineral oil, 80 mg, 3.0 mmol) was
added to (3R,4R,5R)-3,4-dibenzyloxy-5-(hydroxymethyl)cyclohexene (800 mg,
2.6 mmol) in DMF (10 mL) at 08C and the mixture was stirred (10 min).
Benzyl bromide (0.3 mL, 3 mmol) was then added and the mixture was
stirred (rt, 1 hr). The mixture was quenched with MeOH (5 mL), followed by
concentration, standard work-up (EtOAc), and flash chromatography
(EtOAc/petrol 1:19) to give the alkene 22 as a colorless oil (900 mg, 89%),
[a]Dþ3.48. 1H NMR (500 MHz) d 2.13–2.18, m, H5; 2.30–2.35, m, 2H, H6;
3.65, dd, J5,H 3.2, J 9.0 Hz, 1H, CH2O; 3.73, dd, J5,H 5.8 Hz, 1H, CH2O; 3.77,
dd, J3,4 10.8, J4,5 7.2 Hz, H4; 4.25–4.26, m, H3; 4.55, s, CH2Ph; 4.69, 4.95,
AB, J 11.1 Hz, CH2Ph; 4.73, 4.75, AB, J 11.2 Hz, CH2Ph; 5.75–5.78, m, H1;
5.83–5.84, m, H2; 7.30–7.43, m, 15H, Ph. 13C NMR (125.7 MHz) d 28.72, C6;
39.30, C5; 70.39, CH2O; 71.34, 73.01, 74.31, 3C, CH2Ph; 79.46, C4; 81.01, C3;

R. V. Stick and K. A. Stubbs
540
126.00, C1; 127.38–138.91, Ph; 128.45, C2. HRMS (FAB) m/z 415.2273
[C28H31O3 (M þ H)þ requires 415.2308].
(3R,4R,5R)-3,4-Di-(t-butyldimethylsilyloxy)-5-(t-butyldimethylsilylox-
ymethyl)cyclohexene 23. (i) According to the procedure described for
the preparation of (3R,4R,5R)-3,4-dibenzyloxy-5-(hydroxymethyl)cyclohexene,
the diene 20 (1.4 g) gave (3R,4R,5R)-3,4-di-(t-butyldimethylsilyloxy)-5-(hydro-
xymethyl)cyclohexene as colorless crystals (1.2 g, 86%), m.p. 74–778C
1
(CH2Cl2/petrol), [a]D290.28. H NMR (600 MHz) d 0.06, 0.07, 0.11, 0.12, 4s,
12H, CH3; 0.86, 0.89, 2s, 18H, C(CH3)3; 1.85–1.88, m, H6; 2.00–2.03, m, H5;
2.35–2.38, m, H6; 2.90, s, OH; 3.66–3.68, m, CH2OH; 3.86–3.88, m, H3,4;
5.56–5.59, m, H2; 5.84–5.86, m, H1. 13C NMR (150.8 MHz) d 24.78, 24.71,
24.58, 24.56, 4C, CH3; 17.95, C(CH3)3; 23.76, C6; 25.74, C(CH3)3; 39.60, C5;
64.5, CH2OH; 69.21, 73.00, C3,4; 125.11, C1; 130.14, C2. HRMS (FAB) m/z
373.2580 [C19H41O3Si2 (M þ H)þ requires 373.2594].
(ii) Imidazole (400 mg, 5.4 mmol) and ButMe2SiCl (760 mg, 5.4 mmol) were
added to the alkene from (i) (1.0 g, 2.7 mmol) in DMF (10 mL) and the solution
was stirred (rt, 30 min). The mixture was quenched with MeOH (5 mL) and con-
centration followed by a standard work-up (EtOAc) and flash chromatography
(PhMe/petrol 1:19) gave the alkene 23 as a colorless oil (1.2 g, 91%), [a]D 240.48.
1H NMR (600 MHz) d 0.03, 0.04, 0.06, 0.07, 0.08, 0.09, 6s, 18H, CH3; 0.87, 0.88,
0.89, 3s, 27H, C(CH3)3; 1.95–2.01, m, H5,6; 2.25–2.30, m, H6; 3.63, dd, J5,H ꢀ J
9.7 Hz, 1H, CH2O; 3.68, m, H4,CH2O; 3.86–3.89, m, H3; 5.53–5.55, m, H2;
5.68–5.71, m, H1. 13C NMR (150.8 MHz) d 25.31, 24.63, 24.37, 24.29,
24.20, CH3; 18.02, 18.07, 18.39, 3C, C(CH3)3; 24.14, C6; 25.91, 26.03,
C(CH3)3; 41.73, C5; 63.33, CH2O; 70.76, C3; 73.12, C4; 127.00, C2; 127.27, C1.
HRMS (FAB) m/z 487.3436 [C25H55O3Si3 (M þ H)þ requires 487.3459].
(1R,2R,3R,4R,6S,7R)-2,3-Dibenzyloxy-4-(benzyloxymethyl)bicyclo[4.1.0]
heptane-7-carboxylic acid, ethyl ester 24. Ethyl diazoacetate (0.7 mL,
4.4 mmol) in CH2Cl2 (1 mL) was added dropwise to the alkene 22 (900 mg,
2.2 mmol) and Rh2(OAc)4 (5 mg) in CH2Cl2 (3 mL) and the mixture was
stirred (rt, 10 hr). A further amount of N2CHCO2Et (0.7 mL) in CH2Cl2
(1 mL) was then added dropwise and the solution was stirred (rt, 10 hr). The
mixture was concentrated and flash chromatography (EtOAc/petrol 1:9) gave
the ester 24 as a colorless oil (450 mg, 40%), [a]Dþ14.48 (Found: C, 76.6; H,
7.3. C32H36O5 requires C, 76.8; H, 7.2%). 1H NMR (600 MHz) d 1.27, t,
J 7.1 Hz, CH2CH3; 1.45–1.47, m, H4,6; 1.71–1.77, m, H1,7; 2.01–2.12, m,
2H, H5; 3.40, dd, J2,3 7.5, J3,4 10.8 Hz, H3; 3.49, dd, J4,8 3.1, J8,8 8.9 Hz, H8ꢁ;
*
The designation H8/C8 has been arbitrarily assigned to the hydrogen and carbon
atoms of the substituent at C-4 of the cyclohexane.

New Class of Potential Inhibitors for Glycoside Hydrolases
541
3.58, dd, J4,8 5.8 Hz, H8; 3.69, d, H2; 4.14, dq, CH2CH3; 4.46, s, CH2Ph; 4.54,
4.84, AB, J 11.0 Hz, CH2Ph; 4.61, 4.77, AB, J 11.5 Hz, CH2Ph; 7.23–7.38, m,
15H, Ph. 13C NMR (150.8 MHz) d 14.25, CH2CH3; 22.58, 26.17, C1,7; 22.88,
35.48, C4,6; 25.65, C5; 60.58, CH2CH3; 70.54, C8; 71.75, 73.09, 74.45, 3C,
CH2Ph; 80.32, C3; 81.59, C2; 127.44–138.81, Ph; 173.71, C55O. HRMS (FAB)
m/z 501.2649 [C32H37O5 (M þ H)þ requires 501.2641].
(1R,2R,3R,4R,6S,7R)-2,3-Di-(t-butyldimethylsilyloxy)-4-(t-butyldimethyl-
silyloxy)methylbicyclo[4.1.0]heptane-7-carboxylic acid, ethyl ester 25.
According to the procedure described for the preparation of 24, the alkene 23
1
(1.0g) gave the ester 25 as a colorless oil (830 mg, 71%), [a]Dþ11.98. H NMR
(500 MHz) d 0.03, 0.04, 0.05, 0.06, 0.07, 0.09, 6s, 18H, CH3; 0.88, 0.89, 0.91, 3s,
27H, C(CH3)3; 1.24, t, J 7.0 Hz, CH2CH3; 1.53–1.57, m, H1,4,6; 1.83, dd,
J1,7 ꢀ J6,7 4.5 Hz, H7; 1.86, ddd, J4,5 2.4, J5,5 14.6, J5,6 5.5 Hz, H5; 1.99, ddd,
J4,5 4.8, J5,6 7.6 Hz, H5; 3.44, dd, J2,3 ꢀ J3,4 4.3 Hz, H3; 3.58, dd, J4,8 4.2, J8,8
9.7 Hz, H8; 3.59, dd, J4,8 9.7 Hz, H8; 3.80, d, H2; 4.10, dq, CH2CH3. 13C NMR
(125.7 MHz) d 25.31, 25.29, 24.81, 24.77, 24.55, 24.43, 6C, CH3; 14.32,
CH2CH3; 17.91, 17.92, C(CH3)3; 18.40, 27.54, 40.66, C1,4,6; 19.42, C5; 24.59,
CH2CH3; 25.84, 26.02, C(CH3)3; 26.25, C7; 60.25, CH2CH3; 63.77, C8; 70.01,
C2; 73.05, C3; 174.41, C55O. HRMS (FAB) m/z 573.3804 [C29H61O5Si3
(M þ H) þ requires 573.3827].
[(1R,2R,3R,4R,6S,7R)-2,3-Di-(t-butyldimethylsilyloxy)-4-(t-butyldimethyl-
silyloxy)methylbicyclo[4.1.0]hept-7-yl]methanol 26. Lithium aluminium
hydride (220 mg, 6.0 mmol) was added to the ester 25 (700 mg, 1.2 mmol) in
THF (5mL) at 08C and the solution was stirred (5 min). The mixture was
quenched with EtOAc (5mL) and preadsorption onto silica gel followed by flash
chromatography (EtOAc/petrol 1:19) furnished the alcohol 26 as a colorless oil
(560 mg, 87%), [a]Dþ12.38 (Found: C, 61.0; H, 11.1. C27H58O4Si3 requires C,
61.1; H, 11.0%). 1H NMR (600 MHz) d 0.02, 0.04, 0.05, 0.07, 0.09, 5s, 18H, CH3;
0.70, dd, J1,6 8.8, J1,7 4.9 Hz, H1; 0.79–0.84, m, H6; 0.88, 0.89, 0.91, 3s, 27H,
C(CH3)3; 1.21–1.24, m, H7; 1.57–1.59, m, H4; 1.81, ddd, J4,5 5.3, J5,5 14.2, J5,6
2.9 Hz, H5; 1.94, ddd, J4,5 8.2, J5,6 3.9 Hz, H5; 3.30, dd, J7,H 7.6, J 11.1 Hz, 1H,
CH2OH; 3.39, dd, J2,3 ꢀ J3,4 4.3 Hz, H3; 3.54, dd, J7,H 6.4 Hz, 1H, CH2OH;
3.60–3.63, m, 2H, H8; 3.78, d, H2. 13C NMR (150.8 MHz) d 25.30, 25.21,
24.79, –4.55, 24.41, 24.39, 6C, CH3; 13.34, C6; 17.93, 17.96, 18.43, 3C,
C(CH3)3; 21.28, C5; 22.28, C1; 25.32, C7; 25.90, 26.04, C(CH3)3; 40.91, C4;
64.00, C8; 67.24, CH2OH; 71.19, C2; 73.51, C3. HRMS (FAB) m/z 531.3674
[C27H59O4Si3 (M þ H)þ requires 531.3721].
[(1R,2R,3R,4R,6S,7R)-2,3-Di-(t-butyldimethylsilyloxy)-4-(t-butyldimethyl-
silyloxy)methylbicyclo[4.1.0]hept-7-yl]methyl
Diphenyl
Phosphate
27. Diphenyl chlorophosphonate (0.1 mL, 0.4 mmol) was added to the alcohol

R. V. Stick and K. A. Stubbs
542
26 (100 mg, 0.2 mmol) and pyridine (0.03 mL, 0.4 mmol) in CH2Cl2 (5 mL) and
the solution was stirred (rt, 10 min). Concentration of the mixture followed
by flash chromatography (EtOAc/petrol 1:19) gave the phosphate 27 as a
1
colorless oil (130 mg, 90%), [a]Dþ11.18. H NMR (500 MHz) d 0.01, 0.03, 0.04,
0.05, 0.07, 5s, 18H, CH3; 0.85–0.90, m, 29H, H1,6,C(CH3)3; 1.38–1.42, m,
H7; 1.54–1.56, m, H4; 1.75, ddd, J4,5 5.3, J5,5 11.7, J5,6 2.9 Hz, H5; 1.93, ddd,
J4,5 4.6, J5,6 8.8 Hz, H5; 3.41, dd, J2,3 ꢀ J3,4 3.8 Hz, H3; 3.55, dd, J4,8 4.1, J8,8
11.0 Hz, H8; 3.63, dd, J4,8 10.0 Hz, H8; 3.78, d, H2; 4.00, ddd, J7,H ꢀ JH,P 8.0,
J 10.0 Hz, 1H, CH2O; 4.15, J7,H 6.4, JH,P 8.6 Hz, 1H, CH2O; 7.15–7.23, 7.30–
7.34, 2 m, 10H, Ph. 13C NMR (125.7 MHz) d 25.28, 24.84, 24.68, 24.57,
24.42, CH3; 13.81, C6; 17.86, 17.90, 18.41, 3C, C(CH3)3; 20.41, C5; 22.46, C1;
22.71, C7; 25.83, 26.04, C(CH3)3; 40.75, C4; 63.73, C8; 70.23, C2; 73.18, C3;
73.75, JC,P 25 Hz, CH2O; 120.04, 125.18, 129.70, 150.62, Ph. HRMS (FAB)
m/z 763.4005 [C39H68O7PSi3 (M þ H)þ requires 763.4010].
[(1R,2R,3R,4R,6S,7R)-2,3-Di-(t-butyldimethylsilyloxy)-4-(t-butyldimethyl-
silyloxy)methylbicyclo[4.1.0]hept-7-yl]methyl
Diethyl
Phosphate
29. According to the procedure described for the preparation of 27, the
alcohol 26 (100 mg, 0.2 mmol) and diethyl chlorophosphonate (70 mg,
0.4 mmol) yielded the phosphate 29 as a colorless oil (100 mg, 85%),
1
[a]Dþ26.38. H NMR (500 MHz) d 0.02, 0.04, 0.05, 0.06, 0.09, 5s, 18H, CH3;
0.80–0.87, m, 29H, H1,6,C(CH3)3; 1.32–1.34, m, 7H, H7,CH2CH3; 1.57–1.58,
m, H4; 1.79, ddd, J4,5 5.3, J5,5 11.9, J5,6 2.7 Hz, H5; 1.95, ddd, J4,5 4.9, J5,6
8.6 Hz, H5; 3.40, dd, J2,3 ꢀ J3,4 4.0 Hz, H3; 3.56, dd, J4,8 3.9, J8,8 10.6 Hz, H8;
3.63, dd, J4,8 9.9 Hz, H8; 3.76–3.79, m, 2H, H2,CH2O; 3.94, ddd, J7,H ꢀ JH,P
8.0, J 10.0 Hz, 1H, CH2O; 4.06–4.12, m, 4H, CH2CH3. 13C NMR (125.7 MHz)
d 25.31, 25.29, 24.80, 24.66, 24.50, 24.38, 6C, CH3; 13.71, C6; 16.13, d,
JC,P 26 Hz, CH2CH3; 17.89, 17.92, 18.42, 3C, C(CH3)3; 20.72, C5; 22.52, C1;
22.63, C7; 25.85, 26.03, C(CH3)3; 40.80, C4; 63.53, d, JC,P 28 Hz, CH2CH3;
63.83, C8; 70.56, C2; 71.89, JC,P 20 Hz, CH2O; 73.34, C3. HRMS (FAB) m/z
667.4015 [C31H68O7PSi3 (M þ H)þ requires 667.4010].
[(1R,2R,3R,4R,6S,7R)-2,3-Di-(t-butyldimethylsilyloxy)-4-(t-butyldimethyl-
silyloxy)methylbicyclo[4.1.0]hept-7-yl]methyl Bis(trichloroethyl) Phos-
phate 30. According to the procedure described for the preparation of 27,
the alcohol 26 (100 mg, 0.2 mmol) and bis(trichloroethyl) chlorophosphonate
(130 mg, 0.40 mmol) yielded the phosphate 30 as a colorless oil (140 mg,
1
88%), [a]Dþ42.38 H NMR (600 MHz) d 0.02, 0.03, 0.04, 0.05, 0.06, 0.09, 6s,
18H, CH3; 0.87, m, 10H, H1,C(CH3)3; 0.88, 0.89, 2s, 18H, C(CH3)3; 0.98–
1.00, m, H6; 1.39–1.43, m, H7; 1.56–1.61, m, H4; 1.79, ddd, J4,5 5.3, J5,5
14.3, J5,6 2.7 Hz, H5; 2.03, ddd, J4,5 8.1, J5,6 4.8 Hz, H5; 3.42, dd, J2,3 ꢀ J3,4
3.9 Hz, H3; 3.56, dd, J4,8 4.0, J8,8 10.0 Hz, H8; 3.63, dd, J4,8 9.9 Hz, H8; 3.83,

New Class of Potential Inhibitors for Glycoside Hydrolases
543
d, H2; 4.00–4.04, m, CH2O; 4.61, dd, JH,P ꢀ JH,H 1.9 Hz, CH2CCl3; 4.62, dd,
CH2CCl3. 13C NMR (150.8 MHz) d 25.30, 25.28, 24.78, 24.60, 24.49,
24.38, 6C, CH3; 13.91, C6; 17.88, 17.94, 18.41, 3C, C(CH3)3; 20.55, C5; 22.33,
d, JC,P 7.5 Hz, C7; 22.84, C1; 25.84, 25.87, 26.03, 3C, C(CH3)3; 40.76, C4;
63.75, C8; 70.30, C2; 73.16, C3; 73.94, d, JC,P 6.2 Hz, CH2O; 77.10, d, JC,P
4.5 Hz, CH2CCl3; 94.70, d, JC,P 10.5 Hz, CCl3. HRMS (FAB) m/z 873.1594 [C31-
H Cl357ClO7PSi3 (M þ H)þ requires 873.1642].
35
62
[(1R,2R,3R,4R,6S,7R)-2,3-Dihydroxy-4-(hydroxymethyl)bicyclo[4.1.0]hept-
7-yl]methyl Bis(trichloroethyl) Phosphate 31. Conc. HCl (1 drop) was
added to the phosphate 30 (50 mg) in EtOH (5 mL) and the solution kept
(12 hr). Concentration of the mixture gave a yellow residue that was subjected
to flash chromatography (MeOH/CHCl3 1:19), yielding the triol 31 as an
1
unstable, colorless solid (3 mg, 11%). H NMR (600 MHz, CD3OD) d 1.06, dd,
J1,6 8.6, J1,7 4.4 Hz, H1; 1.15–1.24, m, H4,6,7; 1.70, ddd, J4,5 10.4, J5,5 13.6,
J5,6 5.0 Hz, H5; 2.03, ddd, J4,5 1.2, J5,6 4.4 Hz, H5; 3.10, dd, J2,3 8.2, J3,4
10.1 Hz, H3; 3.50–3.55, m, 2H, H2,8; 3.64, dd, J4,8 4.6, J8,8 12.1 Hz, H8;
4.11–4.15, m, CH2O; 4.75, dd, JH,P ꢀ JH,H 1.3 Hz, CH2CCl3; 4.76, dd,
CH2CCl3. 13C NMR (150.8 MHz, CD3OD) d 18.90, 38.46, C4,6; 22.33, d, JC,P
6.0 Hz, C7; 25.04, C1; 26.94, C5; 64.87, C8; 75.00, d, JC,P 6.2 Hz, CH2O;
75.68, C2; 77.24, C3; 78.38, d, JC,P 4.5 Hz, CH2CCl3; 96.14, d, JC,P 10.5 Hz,
CCl3. Next to elute was what appeared to be a mixture (1H NMR) of the
ethyl ethers 32, 33, and 34 as a colorless oil (7 mg, 56%).
[(1R,2R,3R,4R,6S,7R)-2,3-Di-(t-butyldimethylsilyloxy)-4-(t-butyldimethyl-
silyloxy)methylbicyclo[4.1.0]hept-7-yl]methyl 2,4-Dinitrophenyl Ether
35. 2,4-Dinitrofluorobenzene (0.2 mL, 2 mmol) was added to the alcohol 26
(100 mg, 0.2 mmol) in ClCH2CH2Cl (5 mL) and Et3N (0.3 mL, 2 mmol) and the
solution was stirred (408C, 24 hr). Concentration of the mixture followed by
standard work-up (CH2Cl2) and flash chromatography (EtOAc/petrol 1:19)
1
furnished the ether 35 as a colorless oil (130 mg, 91%), [a]Dþ25.78. H NMR
(600 MHz) d 0.01, 0.03, 0.04, 0.06, 0.07, 0.08, 6s, 18H, CH3; 0.84, 0.89, 0.90,
3s, 27H, C(CH3)3; 0.95, dd, J1,6 8.9, J6,7 4.7 Hz, H1; 0.99–1.04, m, H6; 1.50–
1.53, m, H7; 1.61–1.64, m, H4; 1.79, ddd, J4,5 5.5, J5,5 14.3, J5,6 2.6 Hz, H5;
2.03, ddd, J4,5 8.5, J5,6 3.7 Hz, H5; 3.44, dd, J2,3 ꢀ J3,4 3.3 Hz, H3; 3.56, dd, J4,8
3.9, J8,8 10.3 Hz, H8; 3.67, dd, J4,8 10.2, H8; 3.83, d, H2; 3.94, dd, J7,H 7.7, J
10.3 Hz, 1H, CH2O; 4.29, dd, J7,H 6.3 Hz, 1H, CH2O; 7.15, 8.37, 8.72, 3 m, 3H,
Ar. 13C NMR (150.8 MHz) d 25.30, 25.27, 24.85, 24.83, 24.65, 24.55, 6C,
CH3; 13.62, C6; 17.86, 17.88, 18.42, 3C, C(CH3)3; 20.13, C5; 20.92, C7;
22.95, C1; 25.78, 25.80, 26.04, 3C, C(CH3)3; 40.81, C4; 63.67, C8; 69.73,
C2; 72.95, C3; 74.83, CH2O; 114.55, 121.86, 128.78, 139.22, 139.83, 156.75,
6C, Ar. HRMS (FAB) m/z 697.3702 [C33H61N2O8Si3 (M þ H)þ requires
697.3735].

R. V. Stick and K. A. Stubbs
544
[(1R,2R,3R,4R,6S,7R)-2,3-Dihydroxy-4-(hydroxymethyl)bicyclo[4.1.0]hept-
7-yl]methyl 2,4-Dinitrophenyl Ether 4. Conc. HCl (1 drop) was added to the
ether 35 (120 mg) in EtOH (5 mL) and the solution kept (rt, 6 hr). Concentration
of the mixture followed by coevaporation with PhMe left a colorless solid that
was subjected to flash chromatography (MeOH/CHCl3 1:19), yielding the
triol 4 as colorless needles (58 mg, 94%), m.p. 125–1298C (CH2Cl2/petrol),
[a]Dþ43.98 (CH3OH) (Found: C, 50.9; H, 5.0. C15H18N2O8 requires C, 50.8; H,
1
5.1%). H NMR (500 MHz, CD3OD) d 1.06, dd, J1,6 8.6, J1,7 4.6 Hz, H1; 1.15–
1.23, m, H4,6,7; 1.71, ddd, J4,5 12.4, J5,5 12.9, J5,6 5.1 Hz, H5; 2.03, ddd, J4,5
1.2, J5,6 4.4 Hz, H5; 3.10, dd, J2,3 8.0, J3,4 10.0 Hz, H3; 3.54–3.59, m, H2,8;
1
3.66, dd, J4,8 4.5, J8,8 11.1 Hz, H8; 4.16, dd, J7,H 6.7, J 10.3 Hz, H, CH2O;
4.28, dd, J7,H 6.7, 1H, CH2O; 7.45, 8.45, 8.70, 3 m, 3H, Ar. 13C NMR
(125.7 MHz, CD3OD) d 18.54, 21.04, 38.40, C4,6,7; 24.91, C1; 26.85, C5;
64.94, C8; 75.32, CH2O; 75.82, C2; 77.34, C3; 116.51, 122.32, 130.01, 140.57,
141.37, 157.82, 6C, Ar. HRMS (FAB) m/z 355.1120 [C15H19N2O8 (M þ H)þ
requires 355.1141].
(1S,3R,4R,5R,6S,7R)-4,5-Di-(t-butyldimethylsilyloxy)-3-(t-butyldimethylsi-
lyloxy)methyl-2-oxabicyclo[4.1.0]heptane-7-carboxylic acid, amide
36. Sodium cyanide (2 mg) was added to the ester 11[8] (600 mg) in 9 M NH3/
MeOH (10 mL) and the solution was stirred at 508C in a pressure bottle (4
d). The ammonia was then allowed to evaporate and concentration of the
mixture followed by flash chromatography (EtOAc/petrol 1:4) gave the amide
1
36 as a colorless oil (470 mg, 82%), [a]Dþ43.18. H NMR (500 MHz) d 0.05,
0.06, 0.07, 0.08, 0.09, 0.11, 6s, 18H, CH3; 0.88, 0.89, 2s, 27H, C(CH3)3; 1.74,
ddd, J1,6 7.1, J5,6 1.3, J6,7 6.1 Hz, H6; 2.06, dd, J1,7 1.7 Hz, H7; 3.54–3.56, m,
H3,5; 3.64, dd, J3,8 4.0, J8,8 11.4 Hz, H8; 3.75, dd, H1; 3.88–3.92, m, H4,8;
6.14, 6.20, 2s, NH2. 13C NMR (125.7 MHz) d 25.31, 25.23, 24.87, 24.81,
24.73, CH3; 17.80, 17.90, 18.33, 3C, C(CH3)3; 25.69, 25.76, 25.93, 3C,
C(CH3)3; 26.08, 26.25, C6,7; 55.07, C1; 62.34, C8; 66.27, 71.17, 78.91, C3,4,5;
173.35, C55O. HRMS (FAB) m/z 545.3401 [C26H55NO5Si3 (M)þ. requires
545.3388].
Ethyl 2-C-Carbamoylmethyl-2-deoxy-D-glucopyranoside 37. Conc. HCl
(1 drop) was added to the amide 36 (200 mg) in EtOH (5 mL) and the solution
kept (rt, 8 hr). Concentration of the mixture followed by coevaporation with
PhMe left a colorless solid that was subjected to flash chromatography
1
(MeOH/CHCl3 1:3), yielding the triol 37 as a colorless solid (60 mg, 90%). H
NMR (600 MHz, CD3OD) d 1.16–1.19, m, CH3; 1.85–1.94, m, H2b; 2.05–
2.09, m, H2a; 2.31, dd, J2,H 9.7, J 15.0 Hz, 1H, CH2COa; 2.36, dd, J2,H 5.8,
J 14.7 Hz, 1H, CH2COb; 2.51, dd, J2,H 4.2 Hz, 1H, CH2COb; 2.61, dd, J2,H
4.5 Hz, 1H, CH2COa; 3.24–3.33, m, H3b,4,5a; 3.40–3.42, 3.53–3.57,
3.71–3.73, 3.91–3.95, 4 m, CH2CH3,5b; 3.48, dd, J2,3 ꢀ J3,4 9.3 Hz, H3a;

New Class of Potential Inhibitors for Glycoside Hydrolases
3.66–3.85, 2 m, 2H, H6; 4.35, d, J1,2 8.7 Hz, H1b; 4.79, d, J1,2 3.1 Hz, H1a. 13
545
C
NMR (150.8 MHz, CD3OD) d 15.23, 15.29, CH3; 34.82, CH2COa; 34.86,
CH2COb; 44.53, C2a; 46.39, C2b; 62.91, 62.93, C6; 64.04, 66.15, CH2CH3;
72.89, 73.04, 76.34, 77.82, C3b,4,5a; 73.80, 73.82, C3a,5b; 99.56, C1a;
104.24, C1b; 173.28, 173.45, C55O. HRMS (FAB) m/z 250.1291 [C10H20NO6
(M þ H)þ requires 250.1290].
(1S,3R,4R,5R,6R,7S)-4,5-Dihydroxy-3-hydroxymethyl-2-oxabicyclo[4.1.0]-
heptane-7-carboxylic acid, amide 5. (i) Tetrabutylammonium fluoride
trihydrate (340 mg, 1.1 mmol) was added to the amide 36 (160 mg, 0.3 mmol)
in THF (5 mL) and the solution was stirred (rt, 1 hr). The solution was
concentrated and the residue was dissolved in pyridine (5 mL), and then
Ac2O (2 mL) was added and the solution stirred (rt, 1 hr). The mixture was
quenched with MeOH (5 mL), and concentration of the mixture followed by
standard work-up (CH2Cl2) and flash chromatography (EtOAc/petrol 7:3)
gave (1S,3R,4R,5R,6S,7S)-4,5-diacetoxy-3-acetoxymethyl-2-oxabicyclo[4.1.0]
heptane-7-carboxylic acid amide as a colorless oil (90 mg, 94%), [a]Dþ43.78.
1H NMR (500 MHz) d 1.68, ddd, J1,6 6.8, J5,6 2.3, J6,7 4.6 Hz, H6; 1.91, dd,
J1,7 1.9 Hz, H7; 2.00, 2.03, 2.05, 3s, 9H, CH3; 3.79, ddd, J3,4 5.4, J3,8 3.9,
7.5 Hz, H3; 3.83, dd, H1; 4.09, dd, J8,8 12.1 Hz, H8; 4.37, dd, H8; 4.80, dd, J4,5
5.4 Hz, H4; 4.94, dd, H5; 6.16, 6.24, 2s, NH2. 13C NMR (125.7 MHz) d 20.57,
20.60, 20.71, 3C, CH3; 22.30, 25.91, C6,7; 55.32, C1; 61.86, C8; 67.65, 68.55,
72.77, C3,4,5; 169.37, 169.67, 170.47, 171.92, 4C, C55O. HRMS (FAB) m/z
330.1178 [C14H20NO8 (M þ H)þ requires 330.1188].
(ii) 10% NaOMe in MeOH (5 mL) was added to the diacetate from (i) (80 mg)
in MeOH (5 mL) and the solution was stirred (rt, 30 min). The solution was
quenched by the addition of resin (Amberlite IR-120, Hþ). Concentration of
the mixture followed by flash chromatography (MeOH/EtOAc 1:4) gave the
triol 5 as a colorless solid (45 mg, 92%), [a]D þ 78.18 (H2O) (Found: C, 47.4;
1
H, 6.6. C8H13NO5 requires C, 47.3; H, 6.4%). H NMR (500 MHz, D2O) d 1.49,
ddd, J1,6 7.4, J5,6 2.4, J6,7 5.8 Hz, H6; 1.98, dd, J1,7 2.3 Hz, H7; 3.33–3.37, m,
H4,8; 3.58, dd, J3,8 1.1, J8,8 12.4 Hz, H8; 3.68–3.73, m, H3,5; 3.80, dd, H1.
13C NMR (125.7 MHz, D2O) d 24.72, 25.21, C6,7; 56.85, C1; 60.82, C8; 69.58,
69.96, 76.66, C3,4,5; 176.01, C55O. HRMS (FAB) m/z 204.0881 [C8H14NO5
(M þ H)þ requires 204.0871].
(1S,3R,4R,5R,6R,7S)-7-Amino-3-hydroxymethyl-2-oxabicyclo[4.1.0]heptane-
4,5-diol 6. Sodium hypochlorite (1.6 M, 5 mL, 8 mmol) was added to the amide
5 (100 mg, 0.5 mmol) in 2 M NaOH solution (2 mL) and the solution was stirred
at 508C (1 hr). Concentration of the mixture left a yellow residue that was dis-
solved in water and applied to a column of resin (Amberlite IR-120, Hþ).
Elution with water followed by 1 M NH3 solution gave the amine 6 as a colorless
oil (69 mg, 81%), [a]Dþ46.88 (H2O) (Found: C, 47.7; H, 7.3. C7H13NO4 requires

R. V. Stick and K. A. Stubbs
546
1
C, 47.9; H, 7.5%). H NMR (300 MHz, D2O) d 0.88, ddd, J1,6 7.2, J5,6 4.2, J6,7
5.6 Hz, H6; 2.39–2.41, m, H7; 3.24, dd, J3,4 6.7, J4,5 8.2 Hz, H4; 3.35–3.40,
m, H1,3; 3.49, dd, H5; 3.53, dd, J3,8 2.9, J8,8 12.4 Hz, H8; 3.71, dd, J3,8 7.6 Hz,
H8. 13C NMR (75.5 MHz, D2O) d 27.34, C6; 37.05, C7; 57.95, C1; 63.40, C8;
72.39, 72.69, 82.06, C3,4,5. HRMS (FAB) m/z 176.0921 [C7H14NO4 (M þ H)þ
requires 176.0921].
ACKNOWLEDGMENTS
K.A.S. would like to thank The University of Western Australia for a Hackett
Postgraduate Scholarship. We thank Andrew Watts for helpful discussions,
and Birte Svensson and Henrik Naested (Technical University of Denmark)
for performing some of the inhibition studies.
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