From lianas to glycobiology tools: Twenty-five years of 2,5-dideoxy-2,5-imino-D-mannitol

Article abstract of DOI:10.1007/s007060200018

2,5-Dideoxy-2,5-imino-D-mannitol (DMDP) has been isolated from several natural sources. Many synthetic approaches are available, and many derivatives have been synthesized and their biological activities have been investigated. An overview on isolation, s

Full text of DOI:10.1007/s007060200018

Monatshefte fur Chemie 133, 393±426 ꢀ2002)
Invited Review
From Lianas to Glycobiology Tools:
Twenty-Five Years of 2,5-Dideoxy-
2,5-imino-D-mannitol
Ã
Tanja M. Wrodnigg


Glycogroup, Institut fur Organische Chemie, Technische Universitat Graz,
A-8010 Graz, Austria
Summary. 2,5-Dideoxy-2,5-imino-D-mannitol ꢀDMDP) has been isolated from several natural sources.
Many synthetic approaches are available, and many derivatives have been synthesized and their
biological activities have been investigated. An overview on isolation, syntheses, and biological data
of DMDP as well as some closely related compounds will be given in this review.
Keywords. 2,5-Dideoxy-2,5-imino-D-mannitol; Glycosidase inhibitors; Iminosugars; Iminoalditols;
Glycosidase inhibitory activities.
Introduction
In 1976, Welter and coworkers isolated a new alkaloid from the leaves of Derris
eliptica ꢀLeguminosae) ꢀFig. 1) with the molecular formula of C6H13NO. Giving
a positive nihydrine reaction, IR and NMR data as well as the obtained optical
rotation led to the conclusion that the structure must be 2,5-dihydroxymethyl-3,4-
dihydroxypyrrolidine ꢀDMDP) having either a ꢀ2R,3R,4R,5R) or an all-S con®g-
uration [1]. Soon the crystal structure of this compound was determinated, and the
all-R con®guration was con®rmed [2].
Ten years before the isolation of this alkaloid and its examination as a glyco-
sidase inhibitor, important synthetic and structural studies on sugar analogues with
nitrogen instead of oxygen in the ring had been conducted by Paulsen and co-
workers [3]. Studies of glycosidases date back as early as the eighteen-forties
when Liebig and Wohler made their ®rst contributions to this emerging area [4].
Recently, these important enzymes have been investigated comprehensively by
Ã
1Z1 Canada. E-mail: wrodnigg@chem.ubc.ca
Present Address: Department of Chemistry, University of British Columbia, Vancouver, B. C., V6T

394
T. M. Wrodnigg
Fig. 1. Derris elliptica
Legler [5], Sinnot [6], and the Withers group [7] and are believed to be well
understood today.
Glycosidase inhibitors [8] are known as compounds which inhibit these carbohy-
drate processing enzymes. This class of compounds can mainly be divided into high
and low molecular mass structures. The most important subgroup in the low molec-
ular class is formed by polyhydroxylated derivatives of piperidines, pyrrolidines,
indolizidines, pyrrolizidines, and nortropane alkaloids. Such compounds can be re-
garded as mimetics of the corresponding sugar with nitrogen instead of oxygen in the
ring. Some of the most investigated compounds in this class are 2,5-dideoxy-2,5-
imino-D-mannitol ꢀ1), 1-deoxynojirimycin ꢀDNJ, 2), castanospermine ꢀ3), and autra-
line ꢀ4), all being excellent reversible inhibitors of D-glucosidases ꢀFig. 2).
1-Deoxynojirimycin ꢀ2), which had been synthesized by Paulsen and his group
in 1966 [9], was later found in the fermentation broths of a Bacillus species [10] as
well as in that of Streptomyces lavandulae [11]. Castanospermine ꢀ3), which can be
regarded as a bicyclic version of 1-deoxynojirimycin ꢀ2) also exhibiting a D-gluco
Fig. 2. DMDP ꢀ1), DNJ ꢀ2), castatonspermine ꢀ3), australine ꢀ4)

2,5-Dideoxy-2,5-imino-D-mannitol
395
Fig. 3. Superposition ꢀmiddle) of DNM ꢀleft) and DMDP ꢀright)
Fig. 4. Comparison of DNJ and DMDP with the carboxonium ion transition state
con®guration pattern, was isolated from the Australian legume Castanospermum
australae [12]. Australine ꢀ4) was also found in the fruit of this tree [13] and is
related to DMDP in the same way as is 2 to 3. Whereas in the case of 2 and 3 the
D-gluco con®guration is quite obvious, 1 and 4 are apparently rather ꢀ-D-fructo-
furanose analogues. Nevertheless, 1 is in some cases even more active against D-
glucosidases than 2 or 3. From the superposition of 2 and 1 ꢀFig. 3) it can be seen
that all hydroxyl groups as well as the ring nitrogen match very well.
1 features a C2 axis of symmetry in contrast to 4 in which one of the hydroxy-
methyl groups is locked in the bicyclic system which abolishes the symmetry and
changes inhibitory properties relative to 1. When compared to 1-deoxynoirimycin
and castanospermine, the more ¯at ®ve-membered ring in 1 is closer mimicking the
half-chair conformation found in the oxocarbonium ion transition state of ꢀenzy-
matic) glycoside hydrolysis [14] ꢀFig. 4).
The ®ve-carbon-containing natural product 1,4-dideoxy-1,4-imino-D-arabinitol
5 ꢀFig. 5) is structurally closely related to DMDP and was isolated from two types
of leguminose plants in 1985 [15]. Several synthetic approaches have been devised
for this compound [16] which is an inhibitor of ꢀ-glucosidases, mammalian gly-
coprotein trimming glucosidases such as ER ꢀ-glucosidase II, plant ꢀ-mannosidase
and Golgi located ꢀ-mannosidases I and II, and intestinal isomaltase and trehalase
[22] ꢀsee Table 1).
Another closely related natural product is 2-hydroxymethyl-3,4-dihydroxy-6-
methylpyrrolidine ꢀ6-deoxy-DMDP, 6; Fig. 5). This compound was isolated from

396
T. M. Wrodnigg
Table 1. Biological activities of 1, 2, 3, 4, and 6 ꢀD and L are indicated at the values); Ki and IC50 values in mM; NI: no inhibition,
ng: not given, nd: not determined
Enzyme
pH
Ref.
ꢀ-Glucosidase
Yeast
6.5 Ki ˆ 0.73
Ki ˆ 7
ng
ng
Ki ˆ 25
Ki51500
ng
[37]
ng
ng
ng
ng
ng
ng
Ki ˆ 54
[24b]
[16a], [20]
[27]
6.8 IC50 ˆ 3.3
IC50 ˆ 0.18 IC50 ˆ 190
ng
Brewer's yeast
Baker's yeast
opt IC50 ˆ 0.0599 ng
IC50 ˆ 9.57
ng
IC50 ˆ 15
IC50 ˆ 3.6
IC50 ˆ 7.0
ng
ng
IC50 ˆ 85 ꢀDL)
[24a]
[18]
ng
ng
IC50 ˆ 270 ꢀDL)
ꢀ-Glucosidase
Rice
opt IC50 ˆ 300
ng
ng
ng
IC50 ˆ 130 ꢀDL)
ng
[18], [25]
[27]
NIng
IC50 ˆ 1.44
IC50 ˆ 200
7.0 Ki ˆ 330
ng
ng
IC50 ˆ 130 ꢀDL)
Ki ˆ 28 ꢀD)
[24b], [24c]
ꢀ-Glucosidase
ꢀsaccharomyces sp)
ꢀ-Glucosidase
ꢀrabbit gut)
ng
ng
ng
[48]
opt NI
IC50 ˆ 85
ng
NI[24a]
ꢀ-Glucosidase
Rat intestinal
maltase
opt
6.8 IC50 ˆ 290
IC50 ˆ 55
IC50 ˆ 0.36
ng
ng
IC50 ˆ 400 ꢀDL)
[18], [22],
[24b], [24c]
isomaltase
6.8 IC50 ˆ 91
IC50 ˆ 5.8
IC50 ˆ 0.3
NI[24b], [22]
sucrase
NIng
ng
ng
IC50 ˆ 300 ꢀDL)
[24b]
ꢀ-Glucosidase
Rat liver
opt
6.8 IC50 ˆ 92
IC50 ˆ 100 IC50 ˆ 0.4
ng
ng
NI[24b], [22]
ng
lysosome
ER glucosidase II
NI
IC50 ˆ 20
IC50 ˆ 4.6
[22]
[27]
ꢀ-Glucosidase
Porcine small
intestine
6.8
Starch
IC50 ˆ 307
IC50 ˆ 9.57
IC50 ˆ 20.1
ng
ng
ng
IC50 ˆ 0.479
ng
ng
ng
ng
Maltose
IC50 ˆ 0.00957 ng
Sucrose
IC50 ˆ 0.144
ng
ꢀ-Glucosidase
Bovine liver
4.0 IC50 ˆ 170
5.0 Ki ˆ 57
IC50 ˆ 89
IC50 ˆ 0.4
Ki ˆ 2.0
ng
ng
[22]
lysosome
ꢁ-Glucosidase
ꢀAsp. wentii)
ꢁ-Glucosidase
ꢀbovine kidney)
ꢁ-Glucosidase
ꢀbitter almonds)
ꢁ-Glucosidase
ng
Ki ˆ 0.9
Ki ˆ 25
ng
ng
[37]
5.0 Ki ˆ 44
ng
Ki ˆ 250
ng
[37]
6.8 IC50 ˆ 7.8
opt IC50 ˆ 11
IC50 ˆ 200 IC50 ˆ 81
ng ng
ng
[16a], [20]
ng
IC50 ˆ 3.8 ꢀDL)
[24b]
ꢀcontinued)

2,5-Dideoxy-2,5-imino-D-mannitol
Table 1 ꢀcontinued)
397
Enzyme
pH
Ref.
ꢀCaldocellum
IC50 ˆ 3.8 ꢀDL)
[24c]
saccharolyticum)
ꢁ-Glucosidase
ꢀalmonds)
5.0 Ki ˆ 1.7
IC50 ˆ 13
ng
Ki ˆ 300
Ki ˆ 1.5
ng
ng
[37]
ng
ng
IC50 ˆ 23
ng
[18]
IC50 ˆ 2.40
Ki ˆ 10
ng
IC50 ˆ 153
ng
[27]
ng
ng
ng
ng
ng
Ki ˆ 1.5
[24b]
[47]
5.0 ng
ng
ng
Ki ˆ 24.5 ꢀD)
Ki ˆ 1.5 ꢀDL)
IC50 ˆ 4 ꢀDL)
Ki ˆ 2.6 ꢀD)
IC50 ˆ 23 ꢀDL)
ng
opt Ki ˆ 10
opt IC50 ˆ 9
5.0 Ki ˆ 50
4.8 Ki ˆ 5.2
IC50 ˆ 7.3
Ki ˆ 280
ng
[24a]
[24a]
[48]
IC50 ˆ 965 ng
ng
ng
ng
ng
ng
ng
ng
ng
ng
[24c]
[68]
ng
ꢁ-Glucosidase
ꢀrat intestine
cellobiase)
4.0 IC50 ˆ 34
NI
IC50 ˆ 520
ng
ng
[22]
ꢁ-Galactosidase opt IC50 ˆ 2.5
ng
ng
ng
ng
ng
ng
IC50 ˆ 4.4 ꢀDL)
IC50 ˆ 4.4 ꢀDL)
IC50 ˆ 4.4 ꢀDL)
[24b], [24c]
[18], [25]
[22]
ꢀbovine liver)
cytosolic
opt IC50 ˆ 2.2
6.8 IC50 ˆ 3.3
IC50 ˆ 1000 NIng
ꢁ-Galactosidase
ꢀrat intestinal
lactase)
opt IC50 ˆ 3.6
IC50 ˆ 260 IC50 ˆ 26
ng
IC50 ˆ 4.0 ꢀDL)
[24b], [22],
[24c]
ꢀ-Mannosidase
ꢀjack beans)
opt NI
IC50 ˆ 750
IC50 ˆ 100
ng
IC50 ˆ 695 ꢀDL) [24a]
NI
[16a]
ꢁ-Mannosidase
ꢀsnail)
opt NIng
ng
IC50 ˆ 400 ꢀDL) [24c]
ꢀ-Mannosidase
rat liver
ng
ng
ng
ng
ng
ng
ng
[22]
Golgi I5.5 NI
Golgi II
IC50 ˆ 53
IC50 ˆ 46
NIng
NIng
5.5 NI
4.5 NI
6.5 IC50 ˆ 260
NI
lysosomal
IC50 ˆ 110 IC50 ˆ 1000
ng
ng
soluble
IC50 ˆ NINI
IC50 ˆ 84
ng
ng
rat epididymis
IC50 ˆ 320
ng
ꢀ,ꢀ-Trehalase
rat instestine
porcine kidney
ng
ng
ng
ng
ng
opt IC50 ˆ 360
IC50 ˆ 200
IC50 ˆ 500
Ki ˆ 150
IC50 ˆ 25
IC50 ˆ 4.8
ng
IC50 ˆ 42
IC50 ˆ 41
ng
IC50 ˆ 2.0 ꢀDL)
IC50 ˆ 5.0 ꢀDL)
NI[25], [24b]
ng
[22], [24b], [24b]
[22], [24c], [18]
ng
ng
[25]
ꢀcontinued)

398
T. M. Wrodnigg
Table 1 ꢀcontinued)
Enzyme
pH
Ref.
Trehalase
ng IC50 ˆ 0.35
ng IC50 ˆ 10
ng
ng
ng
ng
ng
ng
ng
[30]
[30]
ꢀCorynebacterium sp.)
Trehalase
ng
ng
ꢀPlutella xylostella)
Sucrase
ng IC50 ˆ 0.957
NIng
ng
ng
[27]
[20]
ꢀbaker's yeast)
ꢁ-Fructofuranosidase
Yeast
4.6 IC50 ˆ 52.5
5.0 Ki ˆ 6.8
6.0 Ki ˆ 3.5
7.0 Ki ˆ 1.1
ng
ng
ng
ng
NInd
Ki55000
nd
nd
nd
nd
ng
ng
ng
[37]
[37]
[37]
nd
Invertase
5.5 Ki ˆ 78
Ki ˆ 1070 ng
ng
Ki ˆ 77 ꢀDL)
[24a]
ꢀPleum pratense)
ꢁ-Xylosidase
ꢀAsp. niger)
5
IC50 ˆ 250
NI
IC50 ˆ 400
ng
ng
[16a], [20]
ꢀ-L-Fucosidase
ꢀbovine epidermis)
opt IC50 ˆ 110
ng IC50 ˆ 38.3
ng
ng
ng
ng
ng
ng
ng
[24c]
[27]
Amyloglucosidase
ꢀRhizophus)
IC50 ˆ 613
Amyloglucosidase
ꢀA. niger)
opt IC50 ˆ 19
ng
ng
ng
IC50 ˆ 180
[18], [24c]
[62]
Thioglucosidase
ꢀmustard myrosinase):
singrin acetate
phosphate
5
7
5
5
7
IC50 ˆ 9.3
IC50 ˆ 33
IC50 ˆ 35
IC50 ˆ 150
IC50 ˆ 51
NINI
NINI
NINI
NINI
NINI
IC50 ˆ 10
IC50 ˆ 180
IC50 ˆ 36
IC50 ˆ 76
IC50 ˆ 340
ng
ng
ng
ng
ng
progoitin acetate
citrate
phosphate
Thioglucosidase
ꢀBrevicoryne
brassicae)
[62]
singrin acetate
phosphate
5
7
5
5
7
IC50 ˆ 240
IC50 ˆ 100
IC50 ˆ 140
IC50 ˆ 400
IC50 ˆ 87
NINI
IC50 ˆ 90
IC50 ˆ 43
IC50 ˆ 58
IC50 ˆ 6.0
IC50 ˆ 34
ng
ng
ng
ng
ng
IC50 ˆ 280 IC50 ˆ 970
NINI
progoitin acetate
citrate
IC50 ˆ 570 IC50 ˆ 230
phosphate
IC50 ˆ 340 IC50 ˆ 850
Glucosidase I6.5
ꢀmung bean
seedlings)
IC50 ˆ 40
ng
IC50 ˆ 5±7
IC50 ˆ 2±3
[68]
ꢀcontinued)

2,5-Dideoxy-2,5-imino-D-mannitol
Table 1 ꢀcontinued)
399
Enzyme
pH
Ref.
[61]
Activity of
mouse small
intestinal mucosal
homogenates:
p-nitrophenyl-ꢀ-D-
glucoside
6
IC50 ˆ 300
IC50 ˆ 47
IC50 ˆ 0.83
IC50 ˆ 2.8
ng
maltose
6.4
6
IC50 ˆ 200
IC50 ˆ 320
IC50 ˆ 42
IC50 ˆ 23
IC50 ˆ 71
IC50 ˆ 56
IC50 ˆ 10
IC50 ˆ 35
IC50 ˆ 22
IC50 ˆ 23
IC50 ˆ 4.0
IC50 ˆ 28
IC50 ˆ 13
NINI
IC50 ˆ 0.37
IC50 ˆ 67
IC50 ˆ 0.83
IC50 ˆ 9.8
IC50 ˆ 0.042
IC50 ˆ 3.1
IC50 ˆ 0.23
IC50 ˆ 43
ng
ng
ng
ng
ng
ng
ng
trehalose
sucrose
6
IC50 ˆ 0.06
IC50 ˆ 0.12
IC50 ˆ 0.14
IC50 ˆ 0.25
isomaltose
6.4
6
turanose
palatinose
6
p-nitrophenyl-ꢁ-D-
glucoside
6
IC50 ˆ 17
cellobiose
6
6
6
IC50 ˆ 26
IC50 ˆ 2.2
IC50 ˆ 2.0
NINI
IC50 ˆ 8.5
IC50 ˆ 0.73
IC50 ˆ 5.5
ng
ng
ng
gentiobiose
p-Nitrophenyl-ꢁ-D-
galactoside
Lactose
IC50 ˆ 100
IC50 ˆ 210
IC50 ˆ 44
IC50 ˆ 220
6
IC50 ˆ 2.1
NI
IC50 ˆ 57
IC50 ˆ 0.58
ng
Fig. 5. Structures of DMDP-related natural compounds
seeds of the African legume Angylocalyx pynaerii. Its con®guration was proved by
stereospeci®c synthesis, and it could be shown to be a selective inhibitor of
ꢁ-mannosidase from Aspergillus niger with an IC50 of 380 ꢂM without any effect
on ꢀ-mannosidase from jack beans and several other glycosidases [17].
A homologue of DMDP containing seven carbons, 2,5-dideoxy-2,5-imino-D-
glycero-D-manno-heptitol ꢀ7, Fig. 5), synthesized by Wong and coworkers [47]
prior to its discovery in nature, was isolated from Hyacinthoides nonscripta
together with 1 and 5. The absolute con®guration at C-6 in compound 7 could

400
T. M. Wrodnigg
not be determinated at this time, so all biological studies were referred to
2,5-dideoxy-2,5-imino-DL-glycero-D-manno-heptitol ꢀ7) [24a]. This inhibitor could
be shown to be more potent against almond ꢁ-glucosidase ꢀsee Table 1) and to be
more active against sucrase, maltase, and lactase than the parent compound.
Recently, the 6-C-butyl derivative of DMDP ꢀ8, Fig. 5) was found in Adenophora
triphylla var. japonica ꢀCampanilacae) and showed interesting inhibitory activity
against ꢁ-glucosidase and amyloglucosidase [18] ꢀTable 2).
Broussonetines ꢀFig. 6) were discovered as a family of compounds hav-
ing DMDP-type structures and could be shown to be ꢁ-galactosidase and
ꢁ-mannosidase inhibitors. These compounds contain the same ®ve-membered ring
structure as DMDP with diversely modi®ed lipophilic side chains at position C-1
such as in, for example, 9 and 10 [19].
Table 2. IC50 values of different derivatives ꢀmM)
Enzyme
pH
Ref.
ꢀ-Glucosidase
ꢀrice)
opt NI
IC50 ˆ 2.2 NININI [24b]
ꢀ-Glucosidase
rat intestinal
maltase
opt NI
NI
IC50 ˆ 2.5 NININI [24b]
IC50 ˆ 11 NININI [24b]
sucrase
ꢀ-Glucosidase
rat liver lysosomal opt ng
IC50 ˆ 7.2 ng
ng
ng
[24b]
ꢁ-Glucosidase
ꢀalmond)
opt NIng
NI
IC50 ˆ 4.6
[18],
IC50 ˆ 68
[24c]
ꢁ-Glucosidase C. opt NI
saccharolyticum
IC50 ˆ 380 NIng
IC50 ˆ 0.34
IC50 ˆ 24
[24b], [24c]
ꢁ-Galactosidase opt NI
ꢀbovine liver)
IC50 ˆ 60 IC50 ˆ 40
[24c], [24b]
[18]
IC50 ˆ 390
ꢁ-Galactosidase
ꢀrat intestinal
lactase)
opt NI
IC50 ˆ 320 IC50 ˆ 1.6
ng
IC50 ˆ 0.18
IC50 ˆ 140
[24b],
[24c]
ꢁ-Mannosiase
ꢀsnail)
opt NIng
opt NI
ng NI
[24c]
ꢀ,ꢀ-Trehalase
ꢀrat instestine)
IC50 ˆ 380 NIng
NI [24b]
NI [24c]
ꢀ-L-Fucosidase
ꢀbovine epidermis) opt IC50 ˆ 110
ng
ng
NIng
Amyloglucosidase opt IC50 ˆ 40
IC50 ˆ 60
IC50 ˆ 100
[24c]
[18]
ꢀA. niger)
IC50 ˆ 40

2,5-Dideoxy-2,5-imino-D-mannitol
401
Fig. 6. Structures of two broussonetines
Natural Sources and Isolation
After the ®rst isolation and recognition of the biological activities of DMDP and
related compounds and the understanding of the potential biological importance of
these structures, further screening of all kinds of sources became a research topic in
the nineteen-eighties. The compound could be found in plants, animals, and micro-
organisms, demonstrating to be a fairly common metabolite.
Plant sources
Because of its ®rst discovery in a leguminose plant, many others were screened
for the presence of DMDP. The seeds of Lonchocarpus sericeus ꢀLeguminosae)
[20] and the leaves of the large liana Omphalea diandra L. [21] as well as the
leaves of Derris malaccensis [22] were found to contain DMDP and other al-
kaloids such as deoxynojirimycin and derivatives. More recently, DMDP was
found, besides other iminoalditols such as six-membered homologues with D-
gluco, D-manno, or D-galacto con®gurations, in extracts of the plant Aglaonema
treubii Engl. ꢀAraceae) [23].
Since livestock have been poisoned by grazing the leaves of bluebells,
Hyacinthoides nonscripta was screened for alkaloids, and DMDP as well as 5 and
the homo-derivative 7 could be isolated from the British plant. Other species of
Hyacinthaceae such as Hyacinthus orientalis and the bulbs of Scilla campanulata,
were also investigated and found to be rich in alkaloids such as DMDP and related
compounds, for example the 6-deoxy-homo-DMDP which had not been found in
nature before [24]. Furthermore, DMDP and many other iminosugar derivatives
were found in the plant Lobelia sessilifolia and the roots of Adenophora spp.
ꢀCampanulaceae) [25].
Kite and coworkers have screened many species of Nephthytis Schott, Ancho-
manes Schott, Pseudohydrosme Engl., Aglaonema Schott, and Aglaodorum Engl.
where they found reasonable amounts of DMDP together with six-membered ring
iminoalditols [26]. In their search for ꢀ-glucosidase inhibitors, Kim and his group
became interested in Commelina communis L., the dried aerial parts of which have
been used in traditional medicine as an antipyretic for noninfectious fever and to
treat ascites, edema, and hordeolum. This herb was also very popular in Korea for
the treatment of diabetes. Consequently, the extract was screened for glycosidase
inhibitory activity, and DMDP together with four piperidine-related alkaloids were
found [27].

402
T. M. Wrodnigg
Animal and microbial sources
The larvae of the day-¯ying moth Urania fulgens, which was found to feed exclu-
sively on the liana O. diandra, was consequently thought to accumulate DMDP, and
it could be shown that the adult form contains DMDP and other alkaloids in all body
parts including their wings [28]. This was the ®rst example of the occurrence of such
a compound in animals. Several other moths were found to contain this alkaloid,
such as adults of Alcides metaurus, Lyssa macleayi, and Urapteroides astheniata
[29]. DMDP was also isolated from the fermentation broth of Steptomyces sp. KSC-
5791 when it was screened for trehalase inhibitor activity, showing the general
presence of DMDP not only in plants and animals but also in microorganisms [30].
Syntheses
Because of the biological importance of DMDP, great interest in synthetic ap-
proaches arose. The ®rst synthesis was reported by Fleet who employed D-glucose
as the starting material in 1985 [31] ꢀScheme 1). Protection with acetone followed
by O-3 benzylation gave the protected sugar 11. The 5,6-O-isopropylidene group
was exchanged by a carbonate residue to yield 12. Acidic cleavage of the 1,2-O-
isopropylidene acetal in methanol furnished the ꢀ,ꢁ-glucosides. The ꢀ-isomer with
O-2 available for tri¯ate formation and subsequent SN2 substitution at C-2 with
Scheme 1

2,5-Dideoxy-2,5-imino-D-mannitol
403
Scheme 2
sodium azide gave key intermediate 13. The azidodeoxymannofuranoside can
undergo subsequent cyclization via C-5 during an intramolecular nucleophilic attack
with overall retention of con®guration at this center by a nitrogen nucleophile gen-
erated from the azide yielding the bicyclic amine 16. This approach was carried out
with the epoxide 15 which subsequently suffered attack of the nitrogen to the
desired bicyclic compound 16. Subsequent deprotection converted 16 into DMDP.
13 can also undergo cyclization via C-6 leading to 1-deoxymannojirimycin.
At about the same time, Card and Hitz [32] who were interested in sucrose
transport and inhibitors of invertase ꢀꢁ-D-fructofuranosidase) reported a different
approach ꢀScheme 2). Starting from tosylate 17, readily available from L-sorbose in
three steps, they introduced the azide by substitution of the tosylate to obtain 18.
Deprotection under acidic conditions gave 5-azido-5-deoxy-D-fructose 19a which
underwent cyclization during hydrogenation to form DMDP in an overall yield of
68% for these three steps.
A double reductive amination of suitable dicarbonyl sugars, such as 5-keto-D-
fructose, was introduced by Reitz and Baxter. With benzylamine as the amino
compound the reaction gave DMDP only as a side product ꢀ6%), the correspond-
ing D-gluco-epimer being the main product [33]. This unnatural isomer was also
synthesized by an aldolase catalyzed carbon±carbon bond formation by Wong and
coworkers [34].
The ®rst chemoenzymatic synthesis had been conducted by Whitesides and
coworkers in 1991 [35] who used RAMA ꢀrabbit muscle aldolase, EC 4.1.2.13) to
synthesize polyhydroxylated amines from C3 fragments ꢀScheme 3). The synthesis
of the key intermediate 23, an azidoaldehyde, started with the methylenation of
cinnamaldehyde 20 to epoxide 21, followed by nucleophilic opening with sodium
azide to 22. Subsequent ozonolysis provided 23 for the RAMA-catalyzed reaction
with dihydroxy acetone phosphate ꢀDHAP) from which a 1:1-mixture of C-5 epi-
mers 19a and 19b was obtained. Separation of the isopropylidene protected ketoses
by silica gel chromatography and subsequent hydrogenation of the 5-azidodeoxy-
D-fructose 19a cleanly afforded the C2-symmetric pyrrolidine 1 in approximate-
ly 10% overall yield.

404
T. M. Wrodnigg: 2,5-Dideoxy-2,5-imino-D-mannitol
Scheme 3
Durꢀeault and coworkers [36] employed D-mannitol ꢀ24) as the starting material
ꢀScheme 4). Regioselective opening of the easily available L-ido-bisepoxide 25 with
benzyl alcohol gave 1,6-di-O-benzyl-L-iditol derivative 26. Ditosylation of the sec-
ondary alcohols to furnish 27 followed by cleavage of the 3,4-O-isopropylidene
group to 28 and subsequent dibenzylation employing benzyltrichloroacetamidate
gave the key indermediate 29. The pyrrolidine ring 30 was obtained by heating of
29 in benzylamine for 12 h at 140ꢀC. Hydrogenolysis of the benzyl groups gave 1
in an overall yield of 20%.
Another chemoenzymatic approach has been reported by Stutz and coworkers
ꢀScheme 5) who exploited glucose isomerase ꢀE.C. 5.3.1.5) in the key step [37]. 5-
Azido-glucose 32, easily available in six steps from D-glucurono-6,3-lactone 31,
was isomerized quantitatively to the 5-azidodeoxyfructose 19a employing this
enzyme. Conventional hydrogenation with concomitant intramolecular reductive
amination furnished 1. The N-ꢀ5-carboxypentyl) derivative 34 was prepared by
reductive alkylation with adipic methyl ester hemialdehyde and subsequent sapon-
i®cation of the ester. Coupling to aminohexylsepharose with water-soluble carbo-
diimide and N-hydroxysuccinimide for activation led to an immobilized inhibitor
which could be used as af®nity ligand for the puri®cation of glycosidases as pre-
viously demonstrated with the corresponding 1-deoxynojirimycin derivative
attached to sepharose. The 2-2H-derivative of DMDP 33 was prepared employing
deuterium gas in methanol-d1 as the solvent [38].
The N-methyl derivative 139 was made available by reductive amination of 1
with formaldehyde [39], and the iodide of the N,N-dimethyl derivative 140 by N-
methylation with iodomethane [40] ꢀFig. 7).
Liu and coworkers reported a synthesis starting from arabinofuranose derivative
35 [41] ꢀScheme 6). Wittig methenylation to 36 and subsequent Swern oxidation
gave an unstable unsaturated ketone which was immediately converted to oxime 37.
Reduction and protection of the nitrogen with benzyloxycarbonyl chloride ꢀCbz)

Scheme 4
Scheme 5

406
T. M. Wrodnigg
Fig. 7. Structures of compounds 139 and 140
Scheme 6
gave a mixture of C-5 epimers 38 in a ratio of 7:1 for the desired Cram product
which was separated by HPLC. Cyclization gave the correctly con®gured product
39 which was converted to 41 via 40. Subsequent deprotection yielded 1.
Lee and coworkers [42] developed a synthetic approach starting from D-glu-
cono-ꢃ-lactone 42 ꢀScheme 7) which was transformed to mannonate 43. The depro-
tection of the terminal 5,6-O-isopropylidene group was carried out with Dowex
‡
50W-X8 H to yield 96% 44. The primary hydroxyl group was silylated, followed
by O-mesylation to afford 45. Reduction of the methyl ester gave alcohol 46. The
remaining acid-labile protecting groups were cleaved with Dowex 50W-X8 H ,
‡

2,5-Dideoxy-2,5-imino-D-mannitol
407
Scheme 7
and removal of the carbamate gave 1 in 67% yield from the di-O-isopropyl deri-
vative 43.
Ikota [43] used a dihydroxylation protocol for the functionalization of 47
ꢀScheme 8). The dihydroxylation was carried out with potassium osmate employ-
ing hydroquinidine-9-phenanthryl ether as a chiral ligand in the presence of
K3FeꢀCN)6 and K2CO3 in tert-BuOH-H2O to give precursor 48 as the main product
which could be separated from its isomer after O-methoxymethylation of the
hydroxyl groups. Reduction to alcohol 50 followed by Swern oxidation and sub-
sequent reaction of the resulting aldehyde with vinylmagnesium bromide gave a
mixture of isomers in a ratio of 9:1 in favour of the desired intermediate 51. This
was, after separation by column chromatography, mesylated and cyclized with
potassium tert-butoxide to furnish intermediate 52. Ozonolysis and reduction to
53 followed by acidic removal of the protecting groups gave 1.
Merrer and coworkers ꢀScheme 9) found that isomerization of partially pro-
tected polyhydroxypiperidines such as 1-deoxynojirimycin derivative 54 can be
achieved by activating C-2 to give 55 which can undergo various transformations
[44]. Activation of derivative 54 was carried out either by mesylation of the free
hydroxyl groups or under Mitsunobu conditions ꢀPh3P-DEAD-PhCO2H, THF) at
0ꢀC. In both cases a mixture of starting material and ring-contracted compound
was obtained in favour of the pyrrolidine 56 in ratios of 31%:51% and 29%:64%,
respectively. This has been explained by the ease of neighbouring nitrogen parti-
cipation, since the leaving group is in equatorial position, and subsequent ring
opening of the aziridinium ring occurs at the less substituted side.
Efforts were also made to trap the cyclic imine resulting from the reduction and
ring closure of the corresponding azidodeoxyfructose derivative 19a ꢀScheme 10),

408
T. M. Wrodnigg
Scheme 8
Scheme 9
Scheme 10
whose shape and charge were assumed to mimic the transition state stabilized by
glycoprocessing enzymes [45]. Thus, the aminosugar intermediate was trapped as
the corresponding hydrochloride 57. When the salt was transferred into basic solu-
tion, the compound immediately formed an equilibrium in which the cyclic imine
58 was the major species present.

2,5-Dideoxy-2,5-imino-D-mannitol
409
Scheme 11
Following the work of Whitesides and his group, the 1-acetamidodeoxy deriva-
tive of DMDP 65 was synthesized by Wong and coworkers employing a chemoenzy-
matic approach [46] ꢀScheme 11). The synthesis of the azidoaldehyde 63, the key
intermediate for the enzymatic step, started from azidoalcohol 22 whose mesylation
gave 59 which by treatment with hexamethylenetetramine afforded ammonium salt
60. The primary amine 61 was obtained by hydrolysis of 60 in concentrated hydro-
cloric acid. Enzymatic resolution exploiting Pseudomonas lipase in ethyl acetate
gave the desired stereomer 62 in a yield of 34% based on a mixture of the primary
amines 61. Ozonolysis in methanol followed by reductive work-up employing
dimethyl sul®de produced the azidoaldehyde derivative 63 required for the FDP-
aldolase catalyzed condensation with DHAP. The phosphates were removed with
acid phosphatase, and subsequent hydrogenation led to the desired 1-acetamido
derivative 65.
The DMDP homologue 7 was also synthesized by Wong et al. [47] who started
from 2,3,5-tri-O-benzylarabinose 35 ꢀScheme 12). Wittig reaction gave the E-
con®gured 66 in good yield. Reduction of the ester to the corresponding alcohol
and subsequent protection of the latter as silylether furnished 67 bearing a free
hydroxy group at position C-6. This was activated with chloromethylsulfonyl chlor-
ide, and a SN2 reaction gave 68 in 60% yield. Zemplen deprotection gave 69 and
was followed by chloromethylsulfonation and subsequent removal of the silyl pro-
tecting group to obtain 70. Sharpless epoxidation employing D-ꢀ±)-diethyl tartrate
led to the epoxide 71 in a highly stereoselective reaction. Replacement of the

410
T. M. Wrodnigg
Scheme 12
chloromethylsulfonate with azide allowed the desired introduction of the azido
group at this carbon under formal overall retention of con®guration at this center
to yield 72. Reduction of the azide to the amine, ring closure to 73, and removal of
the protecting groups furnished 7.
The same group has reported the synthesis of several N-alkylated derivatives
[48] of 7 as well as of the 1-acetamidodeoxy derivative 65 ꢀScheme 13). Starting
from the precursor 73, straightforward derivatization, N-Boc protection to 74, and
introduction of the acetamido group at C-1 led to derivative 77 which was either
converted to the known compound 65 or, by deprotection of the nitrogen with TFA,

2,5-Dideoxy-2,5-imino-D-mannitol
411
Scheme 13
to 78. N-Alkylation employing two different aldehydes followed by deprotection of
the hydroxyl groups led to N-alkylated derivatives 79 and 80. These three prod-
ucts exhibited Ki values with ꢁ-N-acetylglucosaminidase in the low micromolar
range.
The acetamidodeoxy homologues were synthesized in a similar manner
ꢀScheme 14). Tosylation of the primary hydroxyl group of 74, followed by sub-
stitution employing sodium azide and protection with benzyl bromide, furnished
81. Reduction of the azide and acetylation of the resulting amine gave acetamide
82 which underwent hydrogenolysis yielding derivative 85. On the other hand,
deprotection of the nitrogen, reductive alkylation employing aldehydes, and hydro-
genolysis gave the two N-alkylated compounds 83 and 84.
A dimeric form of DMDP featuring a nitrogen bridge between the to rings was
prepared by coupling aldehyde 75 under reductive amination conditions employing
ammonium acetate and sodium cyanoborhydride to yield 86.ꢀScheme 15)
The synthesis of ꢀdi¯uoromethyl)-phosphonate iminosugars was investigated
by Guillerm and coworkers [49] when they became interested in using such
compounds as glycosyl transferase inhibitors ꢀScheme 16). 2,3,5-Tri-O-benzyl-L-
xylose 87 was reacted with benzylamine to yield furanosylamine 88 which was
exposed to ꢀdiethylphosphinoyl)-di¯uoromethyllithium furnishing a separable
mixture of the two possible diastereomers 89a and 89b with moderate diastereos-
electivity. For the ®nal cyclization step, the hydroxyl group was activated as the
methanesulfonate which underwent intramolecular nucleophilic displacement by
the amino group leading to 90.

412
T. M. Wrodnigg
Scheme 14
Scheme 15
Eustache and his group [50] were also interested in such 1-phosphonate
derivatives in the context of glycosyltransferases. Starting from 2,3,5-tri-O-ben-
zyl-D-arabinofuranose ꢀ35, Scheme 17) which underwent Wittig ole®nation and
subsequent Mitsunobu reaction employing p-nitrobenzoic acid followed by phthal-
imide protection of the nitrogen, 91 was obtained. The nitrogen protecting group
was then exchanged to N-Cbz protected 92. Ring closure was achieved by treat-
ment with NBI, and reaction of iododeoxy compound 93 with triethylphosphite
followed by deprotection yielded the desired 1-phosphonate 94.
A C-1 aryl derivative was synthesized recently by Correia and coworkers [51]
during their synthetic studies of codonopsine and codonopsinine, two pyrrolidine
alkaloids ꢀScheme 18). The key step was the Heck reaction on endocyclic ene-
carbamates 95 and 96, which was carried out in the presence of a diazonium salt

2,5-Dideoxy-2,5-imino-D-mannitol
413
Scheme 16
Scheme 17
and 2,6-di-t-butylpyridine to yield the C-1-arylated compounds 97 and 98 in a
highly regio- and stereoselective manner. The silyl and trityl groups in 97 and 98,
respectively, were removed to yield intermediate 99 which was converted to a
single epoxide 100 employing m-CPBA. Subsequent acidic hydrolysis led to 101.
Fleet and coworkers synthesized the achiral aliphatic version of DMDP start-
ing from dimeric dihydroxyacetone 102 by reductive amination employing ammo-
nium chloride. 103 showed no biological activities with the common glycosidases
[52] ꢀScheme 19).
The ®rst O-glycosylated derivative of DMDP was synthesized by Stutz and co-
workers [53] ꢀScheme 20) by reacting intermediate 5-azidodeoxyfructose 19a with

414
T. M. Wrodnigg
Scheme 18
Scheme 19
Scheme 20
ꢀ-glucosidase from yeast in the presence of maltose as the donor. Glycosylation
took place at positions O-1 and O-4; the isomers could be separated by chromato-
graphy on charcoal. Conventional hydrogenation of disaccharide 104 over Pd=C
led to the O-4 glucosylated derivative 105.
In the mid-nineteen-nineties, C-1 substituted derivatives of DMDP aroused in-
terest. The ®rst compounds prepared were the 1-deoxy¯uoro-, 1-O-methyl, and
1-aminodeoxy derivatives of DMDP ꢀ108, 116, and 118). The 1-deoxy¯uoro com-
pound was easily accessible in two steps from known 5-azido-5,6-dideoxy-
6-¯uoro-D-glucofuranose ꢀ106, Scheme 21) by enzymatic isomerization to the

2,5-Dideoxy-2,5-imino-D-mannitol
415
Scheme 21
Scheme 22
open-chain ketose 107 employing glucose isomerase, followed by conventional
intramolecular reductive amination leading to the 1-¯uoro derivative 108 [54].
The 1-O-methyl derivative 116 [54] was prepared from 5-azido-5-deoxy-
1,2-O-isopropylidene-ꢀ-D-glucofuranose ꢀ109, Scheme 22). Reaction with
chlorodimethyl-ꢀ1,1,2-trimethylpropyl)-silane gave O-6 silyl ether 110. O-Me-
thoxymethylation afforded the fully protected sugar 111. Subsequent desilylation
of O-6 using tetrabutylammonium ¯uoride to obtain 112 and O-methylation
with iodomethane in the presence of sodium hydride gave intermediate 113.
Acidic deprotection to 114 and enzymatic isomerization to the corresponding
open-chain D-fructose derivative 115 followed by hydrogenation yielded 116.
The 1-aminodeoxy compound 118 was obtained following a different approach
[55] ꢀScheme 23). Bearing in mind that the release of ring strain in the 5-membered

416
T. M. Wrodnigg
Scheme 23
Scheme 24
ring 32 is a strong driving force for the quantitative isomerization into the corre-
sponding D-fructopyranose isomer [56], it could be expected that an Amadori
rearrangement reaction would introduce the desired amino group under concomi-
tant formation of the D-fructopyranose derivative. Thus, employing dibenzylamine
in an Amadori rearrangement [57] on 5-azidodeoxy-D-glucose 32 gave the rear-
rangement product 117 in almost quantitative yield. Hydrogenolysis and concomi-
tant intramolecular reductive amination afforded 118.
The Amadori rearrangement of 5-azidodeoxyglucose 32 was also performed
employing 6-aminohexanol as well as 3-ꢀN-phenyl)-amino propionitile to furnish
the rearrangement products 119 and 121, respectively ꢀScheme 24). Catalytic
hydrogenation gave the 6-hydroxyhexyl derivative 120 and the triamine 122 [58].
118 was subsequently shown to react highly chemo- and regioselectively with
acylating agents at the primary amine ꢀScheme 25); the 1-acetamido derivative 65
could easily be obtained by reaction of 118 with acetic anhydride in methanol, and
the hydroxyhexanoyl, hexanoyl, and dodecanoyl derivatives 123, 124, and 125
resulted from the reaction with caprolactone, hexanoic anhydride, and dodecanoic
anhydride, respectively [59].
To extend the series of hydroxyhexyl derivatives, the corresponding 1-O-hy-
droxyhexyl ether 127 was synthesized taking advantage of the same synthetic ap-
proach as reported for the methyl ether 116, employing methoxymethyl-protected
6-hydroxybromohexane for the ether formation to obtain precursor 126 ꢀScheme 26).

2,5-Dideoxy-2,5-imino-D-mannitol
417
Scheme 25
Scheme 26
Scheme 27
This was converted to the desired inhibitor 127 following the conventional route
[58]. Introduction of aromatic substituents at position 1 of 118 gave, for example,
the phenylpropanoyl and naphthoyl derivatives 128 and 129 [59] ꢀScheme 27).
Other examples in this series are the phenyl ꢀ130), the 4- and the 3-ꢀdimethyl-
amino)-phenyl ꢀ131 and 132, respectively), and the coumarin derivative 134
ꢀScheme 28). These compounds were synthesized by coupling the primary amino
group in 118 with the corresponding carboxylic acid moieties employing HBTU as
the coupling reagent. Reaction of 118 with naphthylsulfonic chloride gave the
corresponding sulfonamide derivative 133 [59].
Interestingly, all compounds bearing an aromatic substituent exhibited very good
to excellent inhibitory activities with the ꢁ-glucosidase from Agrobacterium sp.

418
T. M. Wrodnigg
Scheme 28
Scheme 29
with Ki values in the low micromolar to nanomolar range ꢀTable 4). Thus, it was
envisaged that derivatives of DMDP labelled with aromatic ¯uorescent tags might
also be good inhibitors and, consequently, might be useful potential diagnostic
compounds for monitoring enzyme±inhibitor interactions exploiting ¯uorescence

2,5-Dideoxy-2,5-imino-D-mannitol
419
spectrometry methods. N-Dansyl derivative 135 as well as a related compound
featuring a C6 spacer arm between the dye and the inhibitor ꢀ136) were synthesized
[60] ꢀScheme 29). Their excellent inhibitory activities in the single-®gure nanomolar
range prompted the subsequent preparation of the diethylaminocoumarin and acry-
lodan derivatives 137 and 138.
Biological Activities and Applications
DMDP has been shown to be a very interesting compound concerning its biological
activities such as interaction with glycoprotein processing glucosidase I, anti-retro-
viral activity ꢀincluding HIV), antifeedant properties against important pest insects,
and trehalase, invertase, and D-fructofuranosidase inhibition. It also exhibits plant
growth regulatory activity as well as anti-cancer properties.
Activity of DMDP and related compounds against various glycosidases
DMDP has been screened against a wide variety of glycosidases from several dif-
ferent sources as shown in Table 1. Compared to closely related compounds such
as 2, 3, 5, and 7, DMDP shows to be a universal inhibitor of such enzymes.
A very interesting study was performed by Fleet and coworkers who investi-
gated the inhibitory properties of DMDP, 2, 3, and 5 against mouse gut dissacchar-
idases. Inhibitors of such enzymes bear potential for the treatment of diabetes,
obesity, and related metabolic disorders. Although these compounds failed to inhib-
it ꢀ-amylase, which to date is only inhibited by the pseudotetrasaccharide acarbose,
these compounds have potential as research tools and can help to understand many
aspects of carbohydrate metabolism [61].
A structural basis of inhibition of mammalian glycosidases has been deduced
by Asano and coworkers when testing 1, 2, and 5 amongst other iminoalditols
against several of these enzymes. DMDP was shown not to be an inhibitor of
ER ꢀ-glucosidase II [22], whereas it is known to inhibit ꢀ-glucosidase Iin cell
cultures causing the accumulation of glycoproteins with high-mannose oligosac-
charide structures and, thus, is a speci®c inhibitor of this enzyme [66].
The ability of DMDP and related iminoalditols to inhibit the hydrolysis of the
glucoinolates sinigrin and progitin, which are thioglucosides present in the cruci-
ferae having a variety of biological properties such as insect antifeedant activity, by
inhibition of thioglucosidase has been shown by Sco®eld et al. [62]. Additionally,
the protein processing glucosidase Ifrom mung bean seedings was also shown to
be inhibited by DMDP ꢀIC50 ˆ 40 ꢂM), 2 ꢀIC50 ˆ 5±7 ꢂM) and 3 ꢀIC50 ˆ 2±3 ꢂM)
exhibited stronger activities [63].
Early investigations have shown that DMDP is an inhibitor of invertase ꢀꢁ-D-
fructofuranosidase), an enzyme which is known to act by a mechanism analogous
to that of glucosidases and that hydrolyses sucrose. DMDP showed 50% inhibition
at about 1.5 ꢂM for the invertase at a pH above 6.5 [32]. DMDP also inhibits
PFP ꢀpyrophosphate-D-fructose-6-phosphate-1-phosphotransferase), an enzyme in
plants, which is activated by fructose 2,6-diphosphate and catalyzes a reversible
reaction at a crucial point in the synthesis of sucrose in young tissues and the uti-
lization of this sugar in meristems. Because DMDP inhibits PFP to an extent of

420
T. M. Wrodnigg
48% in the forward direction and 52% in the reverse direction, it was expected to
be useful in the bio-rational design of herbicides [41].
Anti-viral activity
Anti-HIV activity of DMDP is caused by inhibition of ꢀ-glucosidase I, an enzyme
involved in the processing of N-linked olidosaccharides on glycoproteins. The
inhibitory effect is weak when compared to the value of 2 and interestingly, con-
trasting 2, N-alkylation does not lead to any increase in its potency [64]. Tested on
in¯uenza-infected MDCK cells, DMDP inhibited the processing of the viral hem-
agglutin by inhibiting ꢀ-glucosidase I[65] and inhibited at a concentrations
of 250 ꢂM ꢀ-glucosidase Ito accumulate glycopeptides exhibiting Glc3-Man9-
ꢀGlacNAc)2 as the major oligosaccharide [66].
Effects on insects
Very early, DMDP has been found to be toxic to insects. The potential role as a
plant protective chemical against a range of phytophagous insects was investigated
by examining the effects on development, feeding behaviour, and functioning of
taste receptors, and it could be shown that DMDP is an effective anti-feedant [67].
Furthermore, DMDP was found to be active against digestive enzymes from larvae
of Callosobruchus maculatus, making it an interesting lead substance in the search
for new insecticidal compounds [68]. IC50-values with these enzymes were 0.6
micromolar against ꢀ-glucosidase and 340 micromolar against ꢁ-glucosidase,
showing its lethal activity to the larvae of the bruchid beetle. The antifeedant
activities against other insects such as the larvae of the lepidopterans Spodoptera
littoralis, Spodoptera frugiperda, Heliothis virescens, and Helicoverpa armigera
turned out to be consistently effective [69].
Several other insect species such as the orders Orthoptera, Phasmida, Dicty-
optera, Diptera, and Cleoptera were screened for their inhibition of glycosidase
activity by DMDP as well as other polyhydroxylated alkaloids. DMDP inhibited
both ꢀ-glucosidase, including trehalase, and ꢁ-glucosidase activity strongly in
these insects [70a]. Differentiation of glycosidase activity in some Hemiptera
and Lepidoptera was also examined. The data obtained suggest that several
separate enzymes or active sites are responsible for maltose and sucrose hydro-
lysis in aphids and H. melpomone, a species of larval Lepidoptera [70b]. Addi-
tionally, DMDP shows also potent antifeedant activity against important pest
insects [71].
Activities of derivatives of DMDP
Related natural products bearing modi®cations at position 6 such as compounds 7
and 8 were found in various Hyacinthaceae and were tested against several glyco-
sidases ꢀTable 2). These studies were used for the explanation of the symptoms of
poisoning live stock by bluebells [24].
Iminosugars 58 and its O-1-butyrate were believed to mimic the transition state
stabilized by glycoprocessing enzymes and were tested against a few glycosidases

2,5-Dideoxy-2,5-imino-D-mannitol
421
Table 3. Activities of 58 and 140
Enzyme
pH
DMDP
Ref.
ꢁ-Glucosidase ꢀalmonds)
6.8
Ki ˆ 7.8
Ki ˆ 13 Æ 0.7
NI[45]
ꢀ-Glucosidase
ꢀbrewer's yeast)
6.8
6.8
Ki ˆ 3.3
NI
Ki ˆ 2.6 Æ 0.2
Ki ˆ 276 Æ 51
Ki ˆ 167 Æ 29
Ki ˆ 253 Æ 44
[45]
[45]
ꢁ-Galactosidase ꢀE. coli)
ꢀ-Mannosidase
ꢀjack beans)
6.8
6.8
NI
NI
Ki ˆ 17 Æ 1
NI[45]
ꢀ-Fucosidase
ꢀbovine epidimysis)
Ki ˆ 381 Æ 71
Ki ˆ 336 Æ 54
[45]
ꢀTable 3). Most notable was the inhibition of 58 against ꢀ-mannosidase, as DMDP
itself does not show any activity against this enzyme at all [45].
Information about the active site of invertase ꢀꢁ-fructofuranosidase), the plant
enzyme that splits sucrose into D-glucose and D-fructose, was obtained from the N-
methyl and N,N-dimethyl derivatives 139 and 140 ꢀFig. 7) as well as with the N-
ꢀcarboxypentyl) derivative 34 ꢀKi values of 139, 140, and 34 were 20, 130, and
50 ꢂM, respectively, at pH ˆ 6). The reduced biological activities of the N-alkyl
derivatives as compared to parent compound 1 indicate steric clashes of the N-
substituents with the active site. The pH dependence of the Ki values as well as the
moderate impairment of inhibitory potency places yeast invertase among the small
group of glycosidases which are strongly inhibited by cationic rather than basic
glycon analogues [37]. Interestingly, DMDP had virtually no effect on the enzyme
from the mammalian gut which catalyzes the same reaction [72].
The 1-acetamido derivative 65 was found to be a potent inhibitor of N-acetyl-
glucosaminidases with Ki values of 9.8 and 1.9 ꢂM for ꢁ-N-acetylglucosaminidase
from bovine kidney and jack beans, respectively, at pH 6.5 [46] but exhibited only
weak activity against ꢀ-glucosidase from Saccharomyces sp. ꢀKi ˆ 380 ꢂM at pH
7) [48] as would have been predictable from its structure.
Recently, 65 and its N-methyl derivative 79 were suggested as new drug leads
for the therapy of osteroarthritis. This disease is characterized by a decreased
concentration of glycosaminoglycans in articular cartilage, the degradation being
mainly caused by hexosaminidases. This ®ndings might open new applications of
DMDP and its derivatives as drugs with chondroprotective activity [73].
Interestingly, the homologous N-acetamido compound 85 as well as the corre-
sponding N-alkylated derivatives 83 and 84 showed activities against ꢁ-glucosi-
dase from sweet almonds ꢀKi values of 2.2, 45, and 120 ꢂM, respectively, at pH 5)
[48]. The dimeric form of DMDP ꢀ86) exhibited Ki values of 53 ꢂM against ꢀ-
glucosidase from Saccaromyces sp. ꢀpH 7) and 37 ꢂM against ꢁ-glucosidase from
sweet almonds ꢀpH 5) [48].
Good glucosidase inhibitory activities were found for C-1 modi®ed analogues
of DMDP. The 1-deoxy¯uoro, 1-O-methyl, and 1-aminodeoxy derivatives 108,

422
T. M. Wrodnigg
Table 4. Activities of C-1 derivatives of DMDP against ꢁ-glucosidase Agrobacterium sp., pH ˆ 7.0
116, and 118 exhibited moderate activities against ꢁ-glucosidase from Argobacter-
ium sp. in the ꢂM range ꢀTable 4). Triamine 122 and the 1-N-hydroxyhexyl deriv-
ative 120 were similarly active. Surprisingly, all 1-N-acylamino derivatives such as
123, 124, and 125 showed Ki values comparable to that of 1. Improved activities
were detected with analogues bearing aromatic amides such as 128, the corre-
sponding sulfonamide 133, and 129. Fluorescently tagged compounds 135, 136,
and 137 were found to be active in the low nanomolar range. This is noteworthy as
only a few examples of related natural products and analogues, such as, for
example, 1-deoxygalactonojirimycin ꢀ141, Ki ˆ 2 nM with ꢀ-D-galactosidase from
human placenta), 2-acetamido-1,2-dideoxygalactonijirimycin ꢀ142, Ki ˆ 1.2 nM
with N-Ac-ꢁ-D-glucosaminidase from jack beans), and 1-deoxyfuconojirimycin
ꢀ143 Ki ˆ 40 pM with canine ꢀ-L-fucosidase) have been reported to show similar
activities [8] ꢀFig. 8).
Exploitation of the ¯uorescence properties of compound 135 has shown that
this inhibitor is bound as a 1:1-complex with the enzyme. The experiment was
conducted by quenching the intrinsic tryptophane ¯uorescence of a de®ned amount