From Spanish fly to room-temperature ionic liquids (RTILs): Synthesis, thermal stability and inhibition of dynamin 1 GTPase by a novel class of RTILs

Article abstract of DOI:10.1039/b707092f

In a series of simple synthetic manipulations the active component of the aphrodisiac Spanish fly has resulted in the generation of a new family of room-temperature ionic liquids (RTILs). These RTILs are synthesized in high yield from readily attainable starting materials and can be generated in either meso or chiral forms dependant on the starting furan analogue. Substituted furans (2-methyl and 2-ethyl) afford chiral RTILs, furan affords a family of meso RTILs. In all cases the counterion was crucial, with CH₃SO ₃^- consistently displaying the lowest melting points. Of the RTILs synthesized, TGA plots showed most to be stable up to at least 250°C. We had sought to use these RTILs in a series of dynamic combinatorial chemistry (DCC) assembly reactions via solubulisation of dynamin GTPases pleckstrin homology (PH) domain, as such all analogues were screened as potential inhibitors. Screening reveals that these RTILs display varying levels of dynamin GTPase inhibition with a number amongst the most potent inhibitors of dynamin GTPase yet discovered, e.g.13 IC₅₀ = 2.3 ± 0.3 μM (4-(N,N-dimethyl-N-octadecyl-N-ethyl)-4-aza-10-oxatricyclo[5.2.1]decane-3, 5-dione bromide. Accordingly these RTILs have limited utility for DCC assembly with dynamin GTPase, but may be of use with other proteins or in other fields of study. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Full text of DOI:10.1039/b707092f

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New Journal of Chemistry
An international journal of the chemical sciences
Volume 32 | Number 1 | January 2008 | Pages 1–180
www.rsc.org/njc
ISSN 1144-0546
PAPER
Adam McCluskey et al.
From Spanish fly to room-temperature
ionic liquids (RTILs): synthesis, thermal
stability and inhibition of dynamin 1
1144-0546(2008)32:1;1-6
GTPase by a novel class of RTILs

PAPER
www.rsc.org/njc | New Journal of Chemistry
From Spanish fly to room-temperature ionic liquids (RTILs): synthesis,
thermal stability and inhibition of dynamin 1 GTPase by a novel class
of RTILsw
Jie Zhang,a Geoffrey A. Lawrance,a Ngoc Chau,b Phillip J. Robinsonb and
Adam McCluskey*a
Received (in Durham, UK) 10th May 2007, Accepted 21st August 2007
First published as an Advance Article on the web 10th September 2007
DOI: 10.1039/b707092f
In a series of simple synthetic manipulations the active component of the aphrodisiac Spanish fly
has resulted in the generation of a new family of room-temperature ionic liquids (RTILs). These
RTILs are synthesized in high yield from readily attainable starting materials and can be
generated in either meso or chiral forms dependant on the starting furan analogue. Substituted
furans (2-methyl and 2-ethyl) afford chiral RTIꢀLs, furan affords a family of meso RTILs. In all
cases the counterion was crucial, with CH3SO3 consistently displaying the lowest melting points.
Of the RTILs synthesized, TGA plots showed most to be stable up to at least 250 1C. We had
sought to use these RTILs in a series of dynamic combinatorial chemistry (DCC) assembly
reactions via solubulisation of dynamin GTPases pleckstrin homology (PH) domain, as such all
analogues were screened as potential inhibitors. Screening reveals that these RTILs display
varying levels of dynamin GTPase inhibition with a number amongst the most potent inhibitors
of dynamin GTPase yet discovered, e.g. 13 IC50 = 2.3 ꢁ 0.3 mM (4-(N,N-dimethyl-N-octadecyl-
N-ethyl)-4-aza-10-oxatricyclo[5.2.1]decane-3,5-dione bromide. Accordingly these RTILs have
limited utility for DCC assembly with dynamin GTPase, but may be of use with other proteins or
in other fields of study.
We have developed an interest in the utility of RTILs across
Introduction
a wide variety of fields from precious metals recovery to sensor
development with molecularly imprinted polymers.5–9 Over
Over the past decade there has been an almost exponential
growth in the synthesis and utility of room-temperature ionic
the past decade our group has explored three main areas,
liquids (RTILs). RTILs are defined as salts with a melting
firstly the development of small molecule inhibitors of proteins
point r150 1C. The archetypal RTILs are the imidazolium
(1), pyridinium (2) and alkyl ammonium (3) based salts
such as protein phosphatase 1 (PP1) and protein phosphatase
2A (PP2A);10–15 secondly the design and synthesis of small
(Fig. 1).1,2 They are widely regarded as viable replacements
molecule inhibitors for the inhibition of dynamin GTPase;16,17
for volatile organic solvents (VOCs) due to their perceived
and thirdly the synthesis and potential utility of room-tem-
non-toxicity, low volatility (zero), high thermal stability, tun-
perature ionic liquids in attaining the first goal.18–21
able nature and ease of recycling, and RTILs have been
Our recent discoveries of novel dynamin GTPase inhibitors
studied and used in a wide variety of reactions.3,4 In a number
have led us to evaluate dynamic combinatorial chemistry
of cases synthetic transformations occur faster, and cleaner,
(DCC) approaches as a methodology to develop new classes
thus their ‘greenness’ is not limited to their own physicochem-
of drugs. Pivotal to DCC approaches is access to large
ical properties but also intricately linked to their reduction in
quantities of protein; in this case we have access to mg
waste from cleaner reactions and lower energy consumption.
quantities of dynamin’s pleckstrin homology (PH) domain.
To date a lack of predictably of RTIL properties is perhaps the
The PH domain of dynamin presents a significant challenge to
a DCC approach as it is a lipid binding domain.22–25 Muta-
greatest issue still to be resolved. The resultant inability to
predict reaction outcomes when replacing traditional VOCs
tions in this domain have been implicated in Charcot–Marie–
Tooth disease, a common heriditary disorder.26 The PH
with RTILs has limited their integration into mainstream
chemistry.
domain’s lipid binding role and its requirement for lipid-like
compounds ensures that they are essentially mutually
a Chemistry, School of Environmental & Life Sciences, The University
of Newcastle, Callaghan, NSW 2308, Australia. E-mail:
Adam.McCluskey@newcastle.edu.au; Fax: 612 49215472;
Tel: 612 9216486
b Cell Signalling Unit, Children’s Medical Research Institute, 214
Hawkesbury Road, Westmead, NSW 2145, Australia
w Electronic supplementary information (ESI) available: TGA plots
for RTILs. See DOI: 10.1039/b707092f
Fig. 1 The archetypal room-temperature ionic liquids.
ꢂc
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28 | New J. Chem., 2008, 32, 28–36

Table 1 Melting point data for norcantharimide alkylammonium
salts 11–20
Fig. 2 Structures of cantharidin (4) and norcantharidin (5).
incompatible with the former requiring an aqueous environ-
ment to maintain protein function and the latter requiring
organic solvent to ensure a homogeneous reaction mixture.
We rationalised that the reported solvating powers associated
with RTILs would facilitate a homogeneous, compatible en-
vironment suitable for dynamic combinatorial library assem-
bly. We were also interested in developing new RTILs and
designed such a series building on our experience with the
design and synthesis of PP1 and PP2A inhibitors. In targeting
PP1 and PP2A our lead compound is a modified version of the
purported aphrodisiac Spanish fly, cantharidin (4) (Fig. 2).
Structurally simpler norcantharidin (5) (Fig. 2) offers a rapid
and green route to a number of analogues possessing note-
worthy biological activity.14,15,27–29 In this instance we were
more concerned with the ease of access into a rigid, stereo-
defined backbone that had promise for further modification
and development of a series of novel ionic liquids. Further-
more, we have previously developed a number of cantharimide
analogues with pendant nitrogens suitable for quaternisation,
and ultimately metathesis via the addition of a variety of
anions in order to develop a novel series of RTILs. The facility
of our chemistry tied to the availability of substituted furans
also held promise for developing chiral RTILs based on the
natural product, cantharidin (4).
Compound
R1
R2
X
Mp/1C
11
12
13
14
15
16
17
18
19
20
–C2H4
–C2H4
–C2H4
–C3H6
–C3H6
–C2H4
–C2H4
–C2H4
–C3H6
–C3H6
–C4H9
Br
Br
Br
Br
Br
BF4
CH3SO3
CH3SO3
CH3SO3
CH3SO3
216–220
172–175
168–172
199–202
148–151
192–195
93–95
46–50
80–83
28–30
–C12H25
–C18H37
–C4H9
–C12H25
–C4H9
–C4H9
–C12H25
–C4H9
–C12H25
of this investigation. Regardless anion metathesis was exam-
ined, firstly Brꢀ to BF4 (11 ) 16). However this only
ꢀ
resulted in a B20 1C melting point decrease, insufficient to
translate our bromine salts into RTILs and as such this
metathesis route was discontinued. The corresponding
ꢀ
CH3SO3 salts resulted in a significant depression of melting
points such that the three products 17–20 are all clearly
RTILs. Analogues 17 and 19 differ only by virtue of a
methylene linker, with the propyl analogue 19 melting 13 1C
lower than the ethyl linked 17, again suggesting that the
corresponding butyl linker would be a better candidate
(although we ruled out this synthesis above). Introduction of
a dodecyl chain results in a B50 1C depression of mp, with
both 18 and 20 clearly RTILs. The ethyl to propyl elongation
associated with 17 and 19, respectively, also affords two novel
RTILs as anticipated.
Results and discussion
Given the positive results achieved above, we also investi-
gated the effect of encapsulation of the terminal N,N-dimethyl-
amino substituent within a piperidine ring. To improve the
likelihood of attaining an RTIL, we limited our efforts to the
generation of the CH3SO3ꢀ salt (21) (Fig. 3). Concurrently, we
also explored disruption of the symmetry (chiral analogues)
associated with the norcantharidin skeleton by synthesis of
two 1-alkyl analogues (22 and 23) (Fig. 3). These cases limited
our evaluations to the propyl linker dodecyl analogues as we
have shown herein that analogues of this nature display the
lowest melting points (18, 46–50 1C and 20, liquid).
Synthesis of 21 was accomplished as described in Scheme 1
commencing with 5, via treatment under standard conditions
with 1-(2-aminoethyl)piperidine. Somewhat surprisingly we
were unable to alkylate the piperidine nitrogen with bromo-
butane even with prolonged reaction times, elevated tempera-
tures and use of excess bromobutane. Alkylation was
Commencing from readily available furan (6) and maleic
anhydride (7), norcantharidin (8) was generated in excellent
yield (two steps: Diels–Alder followed by hydrogenation).
Treatment with N,N-dimethylethylenediamine or N,N-di-
methylpropylenediamine afforded 9 and 10, respectively as
solids. Quaternisation of 9 and 10 was achieved by alkylation
with an appropriate alkyl bromide, yielding the ammonium
salts 11–15. Metathesis of the bromide anion was by treatment
with HBF4 (16) or CH3SO3H (17–19). All compounds were
recovered in high purity in modest to good yields.
Whereas the parent material norcantharidin is crystalline,
we had anticipated that the introduction of a flexible side
chain would permit a reduction in melting point (mp), poten-
tially into the range associated with RTILs. This was simply
and rapidly evaluated via mp determinations; this data is
shown in Table 1.
Not surprisingly the simple bromine salts (11–15) display
the highest melting points and are not RTILs, though 15 is on
the cusp (assuming we adhere to the o150 1C mp definition).
Insertion of a methylene bridge results in a B20 1C decrease in
mp, cf. 11 vs. 14; 12 vs. 15. Further elongation would un-
doubtedly result in a further melting point decrease; however
the required N,N-dimethylbutane-1,4-diamine is not commer-
cially available, a design limitation we considered at the outset
Fig. 3
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New J. Chem., 2008, 32, 28–36 | 29

ionic liquids from percent mass loss. Microanalysis confirms
the presence of both water and residual ulfonic acid in these
latter 17–23. The second and major decomposition step is the
actual decomposition of the ionic liquid itself, which is around
300 1C.
Given our desire to utilise these RTILs in the solubilisation
of dynamin’s PH domain, we felt it prudent to evaluate their
effect, if any, on dynamin’s GTPase activity. The interaction of
these new RTILs with dynamin was assessed via a modified
Malachite Green colorimetric assay.30 The results of this
screening are presented in Table 2.
As can be clearly seen, the majority of the novel RTILs,
inhibit dynamin GTPase activity. Analogues 14 and 16 are
inactive. Increasing the alkyl chain length from C4 to C12 and
C18 greatly enhances inhibition, as noted with 11–13 (15%
inhibition at 300 mM drug concentration; IC50 = 8.5 ꢁ 1.5,
IC50 = 2.3 ꢁ 0.3 mM, respectively) with the latter being
equipotent with the most potent analogue that we have
reported in this field thus far.16,17 Notwithstanding the chain
length effect noted, it also appears that the incorporation of a
more sterically demanding piperidine core is beneficial to the
Scheme 1 Reagents and conditions: (i) diethyl ether, RT, 24 h; (ii)
10% Pd–C, H2 (50 psi), acetone; (iii) N,N-dimethylethane-1,2-diamine
or N,N-dimethylpropane-1,3-diamine–THF, reflux; (iv) RBr–EtOH,
reflux; (v) HBF4 or CH3SO3H.
successful in the case of the more active methyl iodide and
finally metathesis with methanesulfonic acid afforded 21 as a
RTIL. Analogues 22 and 23 were synthesized as per 20
commencing with 2-methyl and 2-ethylfuran, respectively.
Our melting point determinations for 21–23 demonstrate
our approach to the development of novel RTILs to be
successful with the simpler meso 21 returning a mp = 89 1C,
within the range associated with RTILs. Whilst the chiral 22
and 23 deviate from our original intent, these data (both are
liquids) clearly demonstrates that the ability to disrupt the
crystalline matrix has a pronounced effect on melting points
and in these cases returns RTILs with sub-ambient melting
points.
inhibition of dynamin GTPase activity (21, IC50 = 43.0 ꢁ 12
mM). Manipulation of the counter anion (Brꢀ ) BF4
)
ꢀ
Table 2 Inhibition of dynamin GTPase by norcantharidin alkyl-
ammonium based RTILs
Compound R1
R2
X
IC50 (mM)
After having a novel series of RTILs established, we next
sought to investigate their working temperature range. Each
new RTIL was evaluated via thermogravimetric analysis
(TGA); a representative example is shown in Fig. 4.
11
12
13
14
15
16
17
18
19
20
–C2H4
–C4H9
Br
Br
Br
Br
Br
BF4
15%a
–C2H4
–C2H4
–C3H6
–C3H6
–C2H4
–C2H4
–C2H4
–C3H6
–C3H6
–C12H25
–C18H37
–C4H9
–C12H25
–C4H9
–C4H9
–C12H25
–C4H9
–C12H25
8.5 ꢁ 1.5
2.3 ꢁ 0.3
b
—
8.4 ꢁ 1.1
According to the TGA plot (Fig. 4), we can see the onset
temperature of decomposition for bromide salt (11) are higher
than 250 1C, and proceed in one major step. This is typical of
all bromide salts examined. The decomposition of methane-
sulfonate RTILs has one more step than those above (ESIw).
The first minor step occurs near 130 1C may be attributed to
some water or residual acid closely associated with the ionic
liquids; loss of hydrogen-bonded or structural water invari-
ably occurs at over 100 1C. One can estimate the amount in the
b
—
CH3SO3 404
CH3SO3 8.9 ꢁ 0.9
CH3SO3 18%a
CH3SO3 11.2 ꢁ 1.8
21
22
23
CH3SO3 43.0 ꢁ 12
CH3SO3 11.8 ꢁ 1.6
CH3SO3 6.8 ꢁ 0.5
a
Percentage inhibition at 300 mM compound concentration.
No observable activity at 700 mM drug concentration.
b
Fig. 4 TGA plot of bromide salt (11).
ꢂc
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30 | New J. Chem., 2008, 32, 28–36

CH3SO3ꢀ) had little effect in the analogues inhibitory poten-
tial, but as mentioned previously has a pronounced effect on
analogue melting points. Introduction of bridgehead substi-
tuents to the bicyclo[2.2.1]heptane core has no effect on
inhibitory potential.
1H NMR (DMSO-d6):
d
(ppm): 6.54 (2H, s,
CH(–O)–CHQCH), 5.31 (2H, s, CH–CH(–O)–CH), 3.27
(2H, s, CH(–O)–CH(–CH)–CQO).
13C NMR (DMSO-d6): d (ppm): 171.5 (2 ꢃ CH–C(QO)–O),
136.8 (CH(–O)–CHQCH), 81.5 (CH–CH(–O)–CH), 49.0
(CH(–O)–CH(–CH)–CQO).
It had been our belief, based on modelling data (not shown)
that the introduction of the bulky norcantharidin subunit
would remove any dynamin inhibition previously noted for
long chain alkyl ammonium salts.16 These data suggest that
inhibition is independent of the norcantharimide subunit.
4,10-Dioxatricyclo[5.2.1]decane-3,5-dione (5) (norcanthari-
din). 4,10-Dioxa-5,6-dehydrotricyclo[5.2.1]decane-3,5-dione
(8) (6.657 g, 0.04 mol) was dissolved in acetone (125 cm3)
and degassed by using an ultrasonic bath for 20 min, then was
cooled to B0 1C. To this, palladium catalyst (0.673 g, 10%-
Pd/C) was added and the mixture hydrogenated at 50 psi
overnight at room temperature. After this time, the catalyst
was filtered off through a Celite pad, the pad washed with ice-
cold acetone (3 ꢃ 30 cm3), and the solvent was removed by
rotary evaporation. Recrystallisation from ethyl acetate
afforded an off-white solid (3.867 g, 58%).
1H NMR (DMSO-d6): d (ppm): 4.82 (2H, d, J = 2.0 Hz,
CH2–CH(–O)–CH), 3.36 (2H, s, CH(–O)–CH(–CH)–CQO),
1.61 (4H, d, J = 1.4 Hz, CH(–O)–CH2–CH2).
13C NMR (DMSO-d6): d (ppm): 172.8 (2 ꢃ CH–C(QO)–O),
79.5 (CH2–CH(–O)–CH), 50.6 (CH(–O)–CH(–CH)–CQO),
27.4 (CH(–O)–CH2–CH2).
Conclusions
We have generated a new family of RTILs in which to suspend
the pleckstrin homology domain of dynamin 1 and found they
are also dynamin inhibitors. Significantly, these data indicate
that where RTILs are to be utilised in the presence of proteins
that a pre-screen should be conducted to ensure that they do
not interfere with the proteins intrinsic function. Whilst we
have shown that these RTILs inhibit dynamin GTPase activ-
ity, it does not directly follow that they will adversely interact
with other proteins. Therefore these RTILs are potentially
important for the study of other proteins or domains thereof.
The varying levels of dynamin inhibition noted indicate that
we have serendipitously generated a new series of dynamin
inhibitors. The data clearly highlights a rarely conceded
fact—that in certain limited cases RTILs may adversely affect
certain protein functions.
4-(N,N-Dimethyl-N-ethyl)-4-aza-10-oxatricyclo[5.2.1]de-
cane-3,5-dione (9). 4,10-Dioxatricyclo[5.2.1]decane-3,5-dione
(5) (1.581 g, 10 mmol) was dissolved in THF (15 cm3). To
this, N,N-dimethlyethane-1,2-diamine (0.971 g, 11 mmol) was
added and the mixture reflux overnight (16 h). The product
was extracted with ethyl acetate (40 cm3) and washed with
saturated NaHCO3 (3 ꢃ 40 cm3). The organic layer was dried
over MgSO4 and filtered, and the ethyl acetate was removed
by rotary evaporation to give a yellow oil (1.573 g, 70%).
1H NMR (CDCl3): d (ppm): 4.85 (2H, dd, J = 2.2 Hz, 1.0
Notwithstanding this adverse interaction with dynamin,
alkyl ammonium norcantharimides represents a novel class
of RTILs that are amenable to further manipulations to fine
tune their properties.
Experimental
Hz, CH2–CH(–O)–CH), 3.59 (2H, t,
J = 6.7 Hz,
Materials
(OQC–)N–CH2–CH2), 2.94 (2H, s, CH(–O)–CH(–CH)–
CQO), 2.49 (2H, t, J = 6.8 Hz, (OQC–)N–CH2–CH2), 2.28
(6H, s, CH2–CH2–N(–CH3)2), 1.84 (2H, m, CH(–O)–CH2–
CH2), 1.62 ( 2H, m, CH(–O)–CH2–CH2).
13C NMR (CDCl3): d (ppm): 177.1 (2 ꢃ CH–C(QO)–N),
78.7 (CH2–CH(–O)–CH), 55.7 ((OQC–)N–CH2–CH2), 49.7
(CH(–O)–CH(–CH)–CQO), 45.0 (CH2–CH2–N(–CH3)2), 36.4
((OQC–)N–CH2–CH2), 28.2 (CH(–O)–CH2–CH2).
All reagents were of commercial quality and were used as
received from Aldrich. Solvents were dried and purified using
standard techniques. Both 1H and 13C NMR spectra were
recorded using a Bruker Avance DPX-300 spectrometer,
calibrated using the residual 1H peak associated with the
deuterated solvent. MALDI-TOF mass spectra were recorded
on an Ettan MALDI-TOF Pro Mass Spectrometer (Amersham
Biosciences). Samples were dissolved in CH3CN (B5 mg per
mL), and then diluted 1 : 1 with the matrix solution: 1.5 mg mlꢀ1
4-HCCA (a-cyano-4-hydroxycinnamic acid) in 50%
ACN–0.1% TFA (trifluoroacetic acid). In each MS run 2 mL
of sample was injected (MALDI-TOF traces are available in
the ESIw). Microanalysis were conducted at the Microanalyis
Unit at the Australian National University, Canberra,
Australia.
4-(N,N-Dimethyl-N-propyl)-4-aza-10-oxatricyclo[5.2.1]de-
cane-3,5-dione (10). The synthesis of 10 was carried out as
described for 9 from 5 and N,N-dimethylpropane-1,3-diamine
in a 65% yield.
1H NMR (CDCl3): d (ppm): 4.88 (2H, dd, J = 2.3 Hz, 0.8
Hz, CH2–CH(–O)–CH), 3.53 (2H, t,
J = 7.2 Hz,
(OQC–)N–CH2–CH2), 2.87 (2H, s, CH(–O)–CH(–CH)–
CQO), 2.26 (2H, t, J = 7.3 Hz, CH2–CH2–N(–CH3)2), 2.19
(6H, s, CH2–CH2–N(–CH3)2), 1.87 (2H, m, CH(–O)–CH2–
CH2), 1.72 (2H, m, N–CH2–CH2–CH2–N), 1.60 (2H, m,
CH(–O)–CH2–CH2).
13C NMR (CDCl3): d (ppm): 176.6 (2 ꢃ CH–C(QO)–N),
78.5 (CH2–CH(–O)–CH), 56.2 ((OQC–)N–CH2–CH2), 49.3
(CH(–O)–CH(–CH)–CQO), 44.8 (CH2–CH2–N(–CH3)2), 36.8
4,10-Dioxa-7,8-dehydrotricyclo[5.2.1]decane-3,5-dione (8).
Furan (6) (17.234 g, 0.25 mol) was added to solution of maleic
anhydride (7) (4.893 g, 0.05 mol) dissolved in diethyl ether (50
cm3) and the mixture stirred at room temperature overnight.
The white precipitate produced was then filtered off and dried
under suction (6.657 g, 80%).
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New J. Chem., 2008, 32, 28–36 | 31

(CH2–CH2–N(–CH3)2), 28.0 (CH(–O)–CH2–CH2), 25.1
(N–CH2–CH2–CH2–N).
1H NMR (CDCl3):
d (ppm): 4.80 (2H, s, CH2–
CH(–O)–CH), 3.92 (4H, overlapping, (OQC–)N–CH2–CH2),
3.51 (2H, t, J = 8.3 Hz, N+–CH2–CH2–(CH2)15–CH3),
3.37 (6H, s, CH2–CH2–N(–C(–CH3)2), 3.08 (2H, s,
CH(–O)–CH(–CH)–CQO), 1.78 (2H, m, CH(–O)–CH2–CH2),
1.70 (2H, m, N+–CH2–CH2–(CH2)15–CH3), 1.62 (2H, m,
CH(–O)–CH2–CH2), 1.31–1.21 (30H, overlapping, N+–CH2–
4-(N,N-Dimethyl-N-butyl-N-ethyl)-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione bromide (11). 4-(N,N-dimethyl-N-
ethyl)-4-aza-10-oxatricyclo[5.2.1]decane-3,5-dione (9) (1.187
g, 5 mmol) was dissolved in ethanol (10 cm3). To this, 1-
bromobutane (0.695 g, 5 mmol) was added and the mixture
refluxed overnight (16 h). The ethanol was removed by rotary
evaporation, and the residue was stirred with petroleum spirit
(20 cm3). The solvent was removed to afford a white solid
(1.363 g, 73%). Mp 216–220 1C; MS (MALDI-TOF): m/z
294.5 (M+ ꢀ Br). Calc. for C16H27BrN2O3 ꢄ 0.5H2O: C 49.99,
H 7.36, N 7.29. Found: C 50.00, H 7.16, N 7.11%.
1H NMR (CDCl3): d (ppm): 4.86 (2H, dd, J = 2.7 Hz,
2.1 Hz, CH2–CH(–O)–CH), 3.97 (4H, overlapping,
(OQC–)N–CH2–CH2), 3.58 (2H, t, J = 8.6 Hz, N+–CH2–
CH2–CH2–CH3), 3.41 (6H, s, CH2–CH2–N(–C(–CH3)2), 3.12
(2H, s, CH(–O)–CH(–CH)–CQO), 1.83 (2H, m,
CH(–O)–CH2–CH2), 1.74 (2H, m, N+–CH2–CH2–CH2–CH3),
1.67 (2H, m, CH(–O)–CH2–CH2), 1.43 (2H, m,
CH2–(CH2)15–CH3), 0.83 (3H, t,
N+–CH2–CH2–(CH2)15–CH3).
J
=
7.2 Hz,
13C NMR (CDCl3): d (ppm): 177.0 (2 ꢃ CH–C(QO)–N),
79.1 (CH2–CH(–O)–CH), 65.0 ((OQC–)N–CH2–CH2), 60.6
(CH2–CH2–N(–CH3)2), 51.2 (CH2–CH2–N(–CH3)2), 50.4
(CH(–O)–CH(–CH)–CQO), 33.0 (N+–CH2–(CH2)16–CH3),
31.9 (CH(–O)–CH2–CH2), 29.6–22.6 (N+–CH2–(CH2)14–
CH3), 14.1 (N+–(CH2)16–CH3).
4-(N,N-Dimethyl-N-butyl-N-propyl)-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione bromide (14). The synthesis of 14 was
carried out as described for 11 from 10 and 1-bromobutane in
a 72% yield. Mp 199–202 1C; MS (MALDI-TOF): m/z 309.5
(M+ ꢀ Br). Calc. for C17H29BrN2O3: C 52.43, H 7.52, N 7.20.
Found: C 52.04, H 7.17, N 6.94%.
1H NMR (CDCl3): d (ppm): 4.81 (2H, d, J = 2.0 Hz,
CH2–CH(–O)–CH), 3.64 (4H, overlapping, (OQC–)N–
CH2–CH2–CH2), 3.46 (2H, t, J = 8.3 Hz, N+–CH2–
CH2–CH2–CH3), 3.35 (6H, s, CH2–CH2–N(–CH3)2), 3.22
(2H, s, CH(–O)–CH(–CH)–CQO), 2.08 (2H, m, (OQC–)-
N–CH2–CH2–CH2), 1.81 (2H, m, CH(–O)–CH2–CH2), 1.68
(4H, overlapping, N+–CH2–CH2–CH2–CH3 and CH(–O)–
CH2–CH2), 1.41 (2H, m, N+–CH2–CH2–CH2–CH3), 1.00
(3H, t, J = 7.3 Hz, N+–CH2–CH2–CH2–CH3).
N+–CH2–CH2–CH2–CH3), 1.01 (3H, t,
N+–CH2–CH2–CH2–CH3).
J = 7.3 Hz,
13C NMR (CDCl3): d (ppm): 177.1 (2 ꢃ CH–C(QO)–N),
79.1 (CH2–CH(–O)–CH), 64.7 ((OQC–)N–CH2–CH2), 60.8
(CH2–CH2–N(–CH3)2), 51.2 (CH2–CH2–N(–CH3)2), 50.4
(CH(–O)–CH(–CH)–CQO), 33.1 (N+–CH2–CH2–CH2–CH3),
28.5 (CH(–O)–CH2–CH2), 24.7 (N+–CH2–CH2–CH2–CH3),
19.6 (N+–CH2–CH2–CH2–CH3), 13.7 (N+–CH2–CH2–
CH2–CH3).
4-(N,N-Dimethyl-N-dodecyl-N-ethyl)-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione bromide (12). The synthesis of 12 was
carried out as described for 11 from 9 and 1-bromododecane
in a 71% yield. Mp 172–175 1C; MS (MALDI-TOF): m/z
407.0 (M+ ꢀ Br). Calc. for C24H43BrN2O3 ꢄ 0.5H2O: C 58.04,
H 8.95, N 5.64. Found: C 57.81, H 8.02, N 5.76%.
13C NMR (CDCl3): d (ppm): 178.0 (2 ꢃ CH–C(QO)–N), 79.2
(CH2–CH(–O)–CH), 64.3 ((OQC–)N–CH2–CH2–CH2), 61.3
((OQC–)N–CH2–CH2–CH2), 51.1 (CH2–CH2–N(–CH3)2),
51.0 (CH(–O)–CH(–CH)–CQO), 35.4 (N+–CH2–CH2–
CH2–CH3), 28.5 (CH(–O)–CH2–CH2), 24.6 (N+–CH2–CH2–
CH2–CH3), 21.3 ((OQC–)N–CH2–CH2–CH2), 19.7 (N+–CH2
–CH2–CH2–CH3), 13.7 (N+–CH2–CH2–CH2–CH3).
1H NMR (CDCl3): d (ppm): 4.80 (2H, d, J = 2.0 Hz,
CH2–CH(–O)–CH),
3.92
(4H,
overlapping,
(OQC–)N–CH2–CH2), 3.50 (2H, t, J = 8.3 Hz, N+–CH2–
CH2–(CH2)9–CH3), 3.37 (6H, s, CH2–CH2–N(–C(–CH3)2),
3.08 (2H, s, CH(–O)–CH(–CH)–CQO), 1.79 (2H, m,
CH(–O)–CH2–CH2), 1.70 (2H, m, N+–CH2–CH2–(CH2)9–
CH3), 1.63 (2H, m, CH(–O)–CH2–CH2), 1.32–1.22 (18H,
overlapping, N+–CH2–CH2–(CH2)9–CH3), 0.84 (3H, t, J =
7.1 Hz, N+–CH2–CH2–(CH2)9–CH3).
13C NMR (CDCl3): d (ppm): 177.0 (2 ꢃ CH–C(QO)–N),
79.1 (CH2–CH(–O)–CH), 64.8 ((OQC–)N–CH2–CH2), 60.7
(CH2–CH2–N(–CH3)2), 51.2 (CH2–CH2–N(–CH3)2), 50.4
(CH(–O)–CH(–CH)–CQO), 33.0 (N+–CH2–(CH2)10–CH3),
31.9 (CH(–O)–CH2–CH2), 29.5–22.6 (N+–CH2–(CH2)10–CH3),
14.1 (N+–CH2–(CH2)10–CH3).
4-(N,N-Dimethyl-N-dodecyl-N-propyl)-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione bromide (15). The synthesis of 15 was
carried out as described for 11 from 10 and 1-bromododecane
in a 70%. Mp 148–151 1C; MS (MALDI-TOF): m/z 421.1
(M+ ꢀ Br). Calc. for C25H45BrN2O3 ꢄ 0.5H2O: C 58.80, H
9.10, N 5.49. Found: C 58.59, H 8.42, N 5.19%.
1H NMR (CDCl3): d (ppm): 4.73 (2H, s, CH2–CH-
(–O)–CH), 3.54 (4H, overlapping, (OQC–)N–CH2–
CH2–CH2), 3.35 (2H, t, J = 8.5 Hz, N+–CH2–CH2–
(CH2)9–CH3), 3.26 (6H, s, CH2–CH2–N(–CH3)2), 3.14 (2H,
s, CH(–O)–CH(–CH)–CQO), 2.04 (2H, m, (OQC–)N–CH2–
CH2–CH2), 1.73 (2H, m, CH(–O)–CH2–CH2), 1.60 (4H, over-
lapping, N+–CH2–CH2–(CH2)9–CH3 & CH(–O)–CH2–CH2),
1.25–1.18 (18H, overlapping, N+–CH2–CH2–(CH2)9–CH3),
0.80 (3H, t, J = 6.4 Hz, N+–CH2–CH2–(CH2)9–CH3).
13C NMR (CDCl3): d (ppm): 177.8 (2 ꢃ CH–C(QO)–N), 79.0
(CH2–CH(–O)–CH), 64.3 ((OQC–)N–CH2–CH2–CH2), 61.1
((OQC–)N–CH2–CH2–CH2), 51.0 (CH2–CH2–N(–CH3)2), 50.5
(CH(–O)–CH(–CH)–CQO), 35.3 (N+–CH2–(CH2)10–CH3),
4-(N,N-Dimethyl-N-octadecyl-N-ethyl)-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione bromide (13). The synthesis of 13 was
carried out as described for 11 from 9 and 1-bromooctadecane
in a 75% yield. Mp 168–172 1C; MS (MALDI-TOF): m/z
491.1 (M+ ꢀ Br). Calc. for C30H55BrN2O3: C 63.01, H 9.72, N
4.90. Found: C 62.67, H 8.59, N 4.30%.
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32 | New J. Chem., 2008, 32, 28–36

31.7 (CH(–O)–CH2–CH2), 29.4–21.4 (N+–CH2–(CH2)10–CH3
and (OQC–)N–CH2–CH2–CH2), 14.0 (N+–CH2–(CH2)10–CH3).
4-(N,N-Dimethyl-N-dodecyl-N-ethyl)-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione methanesulfonate (18). The synthesis of
18 was carried out described as 17 from 12 in a quantitative
4-(N,N-Dimethyl-N-butyl-N-ethyl-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione bromide tetrafluoroborate (16). A solu-
tion of 4-(N,N-dimethyl-N-butyl-N-ethyl)-4-aza-10-oxatricy-
clo[5.2.1]decane-3,5-dione bromide (11) (0.260 g, 0.7 mmol)
in water (15 cm3) was cooled to B0 1C, and HBF4 (0.147 g, 48
wt% solution, 0.8 mmol) was added and solution was stirred
for 1 h. The solution was rotary evaporated for several hours
to remove HBr and water. The residue was recrystallised from
ethyl acetate to afford a white solid (0.188 g, 71%). Mp
192–195 1C; MS (MALDI-TOF): m/z 294.9. Calc. for
C16H27BF4N2O3: C 50.27, H 7.13, N 7.33. Found: C 49.79,
H 7.26, N 7.27%.
1H NMR (DMSO-d6): d (ppm): 4.69 (2H, s, CH2–CH-
(–O)–CH), 3.75 (2H, t, J = 7.3 Hz, (OQC–)N–CH2–CH2),
3.35 (4H, overlapping, (OQC–)N–CH2–CH2 and N+–CH2–
CH2–CH2–CH3), 3.09 (2H, s, CH(–O)–CH(–CH)–CQO), 3.06
(6H, s, CH2–CH2–N(–CH3)2), 1.65 (6H, overlapping,
CH(–O)–CH2–CH2 and N+–CH2–CH2–CH2–CH3), 1.28
(2H, m, N+–CH2–CH2–CH2–CH3), 0.93 (3H, t, J = 7.5 Hz,
N+–CH2–CH2–CH2–CH3).
yield. Mp 46–50 1C; MS (MALDI-TOF): m/z 407.0 (M+
ꢀ
CH3SO3H). Calc. for C25H46N2O6S ꢄ 2H2O: C 55.74, H 9.35,
N 5.20; Found: C 55.21, H 9.98, N 4.73%.
1H NMR (CDCl3): d (ppm): 4.82 (2H, s, CH2–CH(–O)–CH),
3.90 (2H, t, J = 5.3 Hz, (OQC–)N–CH2–CH2), 3.78 (2H, t, J =
5.5 Hz, (OQC–)N–CH2–CH2), 3.42 (2H, t, J = 8.6 Hz,
N+–CH2–CH2–(CH2)9–CH3), 3.29 (6H, s, CH2–CH2–
N(–CH3)2), 3.07 (2H, s, CH(–O)–CH(–CH)–CQO), 2.86 (3H,
s, CH3SO3), 1.80 (2H, m, CH(–O)–CH2–CH2), 1.71 (2H, m,
N+–CH2–CH2–(CH2)9–CH3), 1.64 (2H, m, CH(–O)–CH2–
CH2), 1.33–1.23 (18H, overlapping, N+–CH2–CH2–(CH2)9–
CH3), 0.85 (3H, t, J = 7.0 Hz, N+–CH2–CH2–(CH2)9–CH3).
13C NMR (CDCl3): d (ppm): 177.2 (2 ꢃ CH–C(QO)–N),
79.2 (CH2–CH(–O)–CH), 65.0 ((OQC–)N–CH2–CH2), 60.1
(CH2–CH2–N(–CH3)2), 51.5 (CH2–CH2–N(–CH3)2), 50.4
(CH(–O)–CH(–CH)–CQO), 39.5 (CH3SO3), 33.0 (N+–CH2–
(CH2)10–CH3),
31.9
(CH(–O)–CH2–CH2),
29.6–22.7
(N+–CH2–(CH2)10–CH3), 14.1 (N+–CH2–(CH2)10–CH3).
Synthesis of 4-(N,N-dimethyl-N-butyl-N-propyl)-4-aza-10-
oxatricyclo[5.2.1]decane-3,5-dione methanesulfonate (19). The
synthesis of 19 was carried out described as 17 from 14 in a
quantitative yield. Mp 80–83 1C; MS (MALDI-TOF): m/z
308.7 (M+ ꢀ CH3SO3H). Calc. for C18H32N2O6S ꢄ H2O: C
51.17, H 8.11, N 6.63. Found: 50.74, H 7.48, N 6.21%.
1H NMR (CDCl3): d (ppm): 4.82 (2H, t, J = 2.2 Hz,
CH2–CH(–O)–CH), 3.63 (2H, t, J = 5.8 Hz, (OQC–)N–
13C NMR (DMSO-d6):
d
(ppm): 177.3 (2
ꢃ
CH–
C(QO)–N), 78.5 (CH2–CH(–O)–CH), 62.8 ((OQC–)N–
CH2–CH2), 58.5 (CH2–CH2–N(–CH3)2), 50.3 (CH2–CH2–
N(–CH3)2), 49.7 (CH(–O)–CH(–CH)–CQO), 31.8 (N+–CH2–
CH2–CH2–CH3), 27.9 (CH(–O)–CH2–CH2), 23.7 (N+–CH2–
CH2–CH2–CH3), 19.1 (N+–CH2–CH2–CH2–CH3), 13.5
(N+–CH2–CH2–CH2–CH3).
CH2–CH2–CH2),
3.37
(4H,
overlapping,
(OQC–)-
4-(N,N-Dimethyl-N-butyl-N-ethyl)-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione methanesulfonate (17). A sample of
4-(N,N-dimethyl-N-butyl-N-ethyl)-4-aza-10-oxatricyclo[5.2.1]-
decane-3,5-dione bromide (11) (0.291 g, 0.8 mmol) was dis-
solved in water (15 cm3). To this, ulfonic acid (0.109 g, 70% w/
w solution, 0.8 mmol) was added and the resulting solution
was stirred for 1 h. The solution was rotary evaporated several
hours to remove HBr and water giving a yellow waxy solid
(0.302 g, 99%). Mp 93–95 1C; MS (MALDI-TOF): m/z 294.9
(M+ ꢀ CH3SO3H). Calc. for C17H30N2O6S ꢄ 4H2O: C 44.14,
H 8.26, N 6.06. Found: C 43.95, H 7.95, N 5.65%.
1H NMR (CDCl3): d (ppm): 4.80 (2H, t, J = 2.5 Hz,
CH2–CH(–O)–CH), 3.88 (2H, t, J = 5.2 Hz, (OQC–)N–
CH2–CH2), 3.80 (2H, t, J = 5.4 Hz, (OQC–)N–CH2–CH2),
3.47 (2H, t, J = 8.5 Hz, N+–CH2–CH2–CH2–CH3), 3.30
(6H, s, CH2–CH2–N(–CH3)2)), 3.06 (2H, s, CH(–O)–CH-
(–CH)–CQO), 2.82 (3H, s, CH3SO3), 1.79 (2H, m,
CH(–O)–CH2–CH2), 1.70 (2H, m, N+–CH2–CH2–CH2–CH3),
1.63 (2H, m, CH(–O)–CH2–CH2), 1.38 (2H, m, N+–CH2–
CH2–CH2–CH3), 0.97 (3H, t, J = 7.4 Hz, N+–CH2–
CH2–CH2–CH3).
N–CH2–CH2–CH2 and N+–CH2–CH2–CH2–CH3), 3.22
(6H, s, CH2–CH2–N(–CH3)2)), 3.14 (2H, s, CH(–O)–
CH(–CH)–CQO), 3.00 (3H, s, CH3SO3), 1.82 (2H, m,
(OQC–)N–CH2–CH2–CH2),
1.69
(4H,
overlapping,
N+–CH2–CH2–CH2–CH3 and CH(–O)–CH2–CH2), 1.41
(2H, m, N+–CH2–CH2–CH2–CH3), 1.00 (3H, t, J = 7.3 Hz,
N+–CH2–CH2–CH2–CH3).
13C NMR (CDCl3): d (ppm): 177.8 (2 ꢃ CH–C(QO)–N),
79.2 (CH2–CH(–O)–CH), 64.5 ((OQC–)N–CH2–CH2–CH2),
61.5
((OQC–)N–CH2–CH2–CH2),
51.2
(CH2–CH2–
N(–CH3)2), 50.3 (CH(–O)–CH(–CH)–CQO), 39.6 (CH3SO3),
35.5 (N+–CH2–CH2–CH2–CH3), 28.5 (CH(–O)–CH2–CH2),
24.4 (N+–CH2–CH2–CH2–CH3), 21.2 ((OQC–)N–CH2–
CH2–CH2),
19.6
(N+–CH2–CH2–CH2–CH3),
13.6
(N+–CH2–CH2–CH2–CH3).
4-(N,N-Dimethyl-N-dodecyl-N-propyl)-4-aza-10-oxatricyclo-
[5.2.1]decane-3,5-dione methanesulfonate (20). The synthesis of
20 was carried out described as 17 from 15 in a quantitative
yield. Mp o ꢀ18 1C; MS (MALDI-TOF): m/z 421.1 (M+
ꢀ
CH3SO3H). Calc. for C20H48N2O6S: C 60.43, H 9.36, N 5.42.
Found: C 60.51, H 8.96, N 5.51%.
13C NMR (CDCl3): d (ppm): 177.1 (2 ꢃ CH–C(QO)–N), 79.1
(CH2–CH(–O)–CH), 64.7 ((OQC–)N–CH2–CH2), 60.6
(CH2–CH2–N(–CH3)2), 51.3 (CH2–CH2–N(–CH3)2), 50.3
1H NMR (CDCl3):
d (ppm): 4.78 (2H, s, CH2–CH-
(–O)–CH), 3.59 (2H, t, J = 5.6 Hz, (OQC–)N–CH2–CH2–CH2),
3.49 (2H, t, J = 7.9 Hz, (OQC–)N–CH2–CH2–CH2), 3.33 (2H, t,
(CH(–O)–CH(–CH)–CQO),
39.4
(CH3SO3),
33.0
(N+–CH2–CH2–CH2–CH3), 28.4 (CH(–O)–CH2–CH2), 24.6
(N+–CH2–CH2–CH2–CH3), 19.5 (N+–CH2–CH2–CH2–CH3),
13.6 (N+–CH2–CH2–CH2–CH3).
J =
8.5 Hz, N+–CH2–CH2–(CH2)9–CH3), 3.24 (6H, s,
CH2–CH2–N(–CH3)2), 3.13 (2H, s, CH(–O)–CH(–CH)–CQO),
2.89 (3H, s, CH3SO3), 2.07 (2H, m, (OQC–)N–CH2–CH2–CH2),
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New J. Chem., 2008, 32, 28–36 | 33

1.78 (2H, m, CH(–O)–CH2–CH2), 1.62 (4H, overlapping,
N+–CH2–CH2–(CH2)9–CH3 and CH(–O)–CH2–CH2), 1.30–1.22
(18H, overlapping, N+–CH2–CH2–(CH2)9–CH3), 0.85 (3H, t,
J = 6.4 Hz, N+–CH2–CH2–(CH2)9–CH3).
13C NMR (CDCl3): d (ppm): 177.9 (2 ꢃ CH–C(QO)–N),
79.2 (CH2–CH(–O)–CH), 64.3 ((OQC–)N–CH2–CH2–CH2),
61.1 ((OQC–)N–CH2–CH2–CH2), 51.2 (CH2–CH2–N-
(–CH3)2), 50.5 (CH(–O)–CH(–CH)–CQO), 39.6 (CH3SO3),
35.3 (N+–CH2–(CH2)10–CH3), 31.9 (CH(–O)–CH2–CH2),
29.5–22.7 (N+–CH2–(CH2)10–CH3 and (OQC–)N–CH2–
CH2–CH2), 14.1 (N+–CH2–(CH2)10–CH3).
methanesulfonic acid (0.146 g, 70% w/w solution, 1.1 mmol)
and the resultant solution stirred for 1 h. The solution was
rotary evaporated to remove residual HI, water and any excess
methanesulfonic acid present to afford a pale yellow waxy
solid (0.375 g, 96%). Mp 89–91 1C; MS (MALDI-TOF): m/z
293.0 (M+ ꢀ CH3SO3H). Calc. for C17H28N2O6: C 52.56, H
7.26, N 7.21. Found: C 52.62, H 7.70, N 7.57%.
1H NMR (CDCl3): d (ppm): 1.63–1.91 (10H, overlapping,
(CH2–)N+–CH2–CH2–CH2–CH2, and CH(–O)–CH2–CH2),
2.89 (3H, s, CH3SO3), 3.10 (2H, s, CH(–O)–CH(–CH)–CQO),
3.29 (3H, s, CH3–(CH2–)N+(–CH2)–CH2), 3.59 (4H, m,
CH3–(CH2–)N+(–CH2)–CH2), 3.88–3.92 (4H, overlapping,
(OQC–)N–CH2–CH2–N+ and (OQC–)N–CH2–CH2–N+),
4.81 (2H, d, J = 2.3 Hz, 1.0 Hz, CH2–CH(–O)–CH).
4-(N-Methyl-N-ethylpiperidine)-4-aza-10-oxatricyclo[5.2.1]-
decane-3,5-dione methanesulfonate (21). The synthesis of 21
was conducted as outlined in Scheme 1.
13C NMR (CDCl3):
d
(ppm): 20.1 (2 ꢃ(CH2–)N+
Firstly 5 (1.000 g, 6.0 mmol) was treated as per the synthesis
of 9 with 1-(2-aminoethyl)piperidine (0.928 g, 98%, 7.1 mmol)
to afford 4-(N-ethylpiperidine)-4-aza-10-oxatricyclo[5.2.1]-
decane-3,5-dione as a white solid (1.405 g, 85%).
–CH2–CH2–CH2), 20.6 ((CH2–)N+–CH2–CH2–CH2), 28.5
(CH(–O)–CH2–CH2), 32.6 (OQC–)N–CH2–CH2–N+), 39.5
(CH3SO3),
48.5
(CH3–(CH2–)N+(–CH2)–CH2),
50.5
(CH(–O)–CH(–CH)–CQO), 59.7 ((OQC–)N–CH2–CH2–N+),
61.9 (CH2–)N+–CH2–CH2–CH2), 79.2 (CH2–CH(–O)–CH),
177.2 (2 ꢃ CH–C(QO)–N).
1H NMR (CDCl3): d (ppm): 1.35 (2H, m, (CH2–)-
N–CH2–CH2–CH2), 1.48 (4H, m,
CH2–CH2), 1.55 (2H, m, CH(–O)–CH2–CH2), 1.81 (2H, m,
CH(–O)–CH2–CH2), 2.35–2.43 (6H, overlapping,
(OQC–)N–CH2–CH2–N(–CH2)–CH2), 2.82 (2H, s, CH(–O)–
CH(–CH)–CQO), 3.55 (2H, t, 7.1 Hz,
2
ꢃ
(CH2–)N–CH2–
4-(N,N-Dimethyl-N-dodecyl-N-propyl)-4-aza-10-oxa-6-
methyltricyclo[5.2.1]decane-3,5-dione methanesulfonate (22).
The synthesis of 22 was carried out described in Scheme 1
commencing with 2-methylfuran and maleic anhydride.
A solution of maleic anhydride (15.075 g, 0.15 mol) in
anhydrous diethyl ether (50 cm3) was heated under reflux
and treated dropwise with freshly distilled 2-methylfuran
(15.484 g, 0.189 mol). The mixture was refluxed for 2 h, and
then stirred at room temperature overnight. The white pre-
cipitate produced was then filtered off and dried under suction
(18.473 g, 67%).
J
=
(OQC–)N–CH2–CH2–N), 4.81 (2H, dd, J = 2.2 Hz, 1.0 Hz,
CH2–CH(–O)–CH).
13C NMR (CDCl3):
d (ppm): 24.2 ((CH2–)N–CH2–
CH2–CH2), 25.9 (2 ꢃ(CH2–)N–CH2–CH2–CH2), 28.6
(CH(–O)–CH2–CH2), 36.4 (OQC–)N–CH2–CH2–N), 50.0
(CH(–O)–CH(–CH)–CQO), 54.4 (CH2–)N–CH2–CH2–CH2),
55.4 (OQC–)N–CH2–CH2–N), 79.0 (CH2–CH(–O)–CH),
177.1 (2 ꢃ CH–C(QO)–N).
4-(N-ethylpiperidine)-4-aza-10-oxatricyclo[5.2.1]decane-3,5-
dione (1.405 g, 5.0 mmol) was dissolved in ethanol (10 cm3).
To this was added 1-methyl iodide (0.745 g, 99%, 5.2 mmol)
and the mixture refluxed for 16 hours. The ethanol was
removed in vacuo. Recrystallization from ethanol and chloro-
form afforded an off-white solid 4-(N-methyl-N-ethylpiperi-
The resultant Diels–Alder adduct, 4,10-dioxa-7,8-dehydro-
6-methyltricyclo[5.2.1]decane-3,5-dione (10.013 g, 0.06 mol)
was dissolved in acetone (150 cm3) and degassed by using
ultrasonic cleaner for 20 min, then was cooled to B0 1C. To
this, palladium catalyst (1.008 g, 10%-Pd/C) was added and
hydrogenated at 50 psi overnight at room temperature. After
this time, the catalyst was filtered off through a Celite pad, the
pad washed with ice-cold acetone (3 ꢃ 30 cm3), and the solvent
was removed by rotary evaporation. Recrystallisation from
ethyl acetate afforded an off-white solid (7.975 g, 81%).
1H NMR (CDCl3): d (ppm): 4.91 (1H, d, J = 5.3 Hz,
CH2–CH(–O)–CH–(CQO)), 3.25 (1H, d, J = 7.4 Hz, (O–)-
dine)-4-aza-10-oxatricyclo[5.2.1]decane-3,5-dione
iodide
(0.98 g, 47%).
1H NMR (D2O): d (ppm): 1.63–1.88 (10H, overlapping,
(CH2–)N+–CH2–CH2–CH2–CH2 and CH(–O)–CH2–CH2), 3.13
(3H, s, CH3–(CH2–)N+(–CH2)–CH2), 3.25 (2H, s,
CH(–O)–CH(–CH)–CQO), 3.39 (4H, m, CH3–(CH2–)N+-
(–CH2)–CH2), 3.54 (2H, t,
J
=
6.9 Hz, (OQC–)-
CH–CH–(CQO)), 3.02 (1H, d, J = 7.4 Hz, (O–)C-
N–CH2–CH2–N+), 3.97 (2H, t, J = 7.1 Hz, (OQC–)N–CH2–
CH2–N+), 4.94 (2H, d, J = 2.3 Hz, 1.0 Hz, CH2–
CH(–O)–CH).
(–CH3)–CH–(CQO)), 2.00 (2H, m, (O–)CH–CH2–CH2–
(CH3–)C(–O)), 1.67 (2H, m, (O–)CH–CH2–CH2–(CH3–)-
C(–O)), 1.63 (3H, s, (O–)C(–CH2)–CH3).
13C NMR (CDCl3): d (ppm): 171.4 ((CH–)CH–C(QO)–O),
170.0 ((C–)CH–C(QO)–O), 86.8 ((CH2–)C(–O)–CH3), 79.7
((CH2–)CH(–O)–CH(CQO)), 52.7 ((O–)CH–CH–C(QO)),
52.3 ((O–)C(CH3)–CH–C(QO)), 35.7 ((O–)CH–CH2–CH2–
(CH3–)C(–O)), 30.0 ((O–)CH–CH2–CH2–(CH3–)C(–O)), 17.5
((O–)C(CH2)–CH3).
13C NMR (D2O):
d
(ppm): 19.0 (2 ꢃ(CH2–)N+
–CH2–CH2–CH2), 19.9 ((CH2–)N+–CH2–CH2–CH2), 27.4
(CH(–O)–CH2–CH2), 31.6 (OQC–)N–CH2–CH2–N+), 47.6
(CH3–(CH2–)N+(–CH2)–CH2), 50.0 (CH(–O)–CH(–CH)–
CQO), 57.9 ((OQC–)N–CH2–CH2–N+), 61.4 (CH2–)N+
–CH2–CH2–CH2), 79.2 (CH2–CH(–O)–CH), 179.0 (2
ꢃ
CH–C(QO)–N).
4.10-Dioxa-6-methyltricyclo[5.2.1]decane-3,5-dione (0.891
g, 4.9 mmol) was dissolved in THF (15 cm3). To this, N,N-
dimethylethylenediamine (0.623 g, 6.1 mmol) was added and
the mixture refluxed overnight, cooled and poured onto water
4-(N-methyl-N-ethylpiperidine)-4-aza-10-oxatricyclo[5.2.1]-
decane-3,5-dione iodide (0.420 g, 1.0 mmol) was dissolved in
water (15 cm3) and cooled to 0 1C. To this was added
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34 | New J. Chem., 2008, 32, 28–36

(100 cm3) and extracted with dichloromethane (3 ꢃ 40 cm3).
The organic layer was washed with saturated NaHCO3 (2 ꢃ 40
cm3), dried over MgSO4 and filtered, and the solvent removed
in vacuo to afford a yellow oil (1.185 g, 91%).
1H NMR (CDCl3): d (ppm): 4.76 (1H, d, J = 5.3 Hz, CH2–
CH(–O)–CH–(CQO)), 3.50 (2H, t, J = 7.1 Hz, (OQC–)-
N–CH2–CH2–CH2), 2.91 (1H, d, J = 7.4 Hz, (O–)CH–CH–
(CQO)), 2.71 (1H, d, J = 7.4 Hz, (O–)C(–CH3)–CH–(CQO)),
2.25 (2H, t, J = 7.4 Hz, (OQC–)N–CH2–CH2–CH2), 2.18
(6H, s, CH2–CH2–N(–CH3)2), 1.98 (2H, m, (O–)CH–CH2–
CH2–(CH3–)C(–O)), 1.70 (2H, m, (OQC–)N–CH2–
CH2–CH2), 1.64 (2H, m, (O–)CH–CH2–CH2–(CH3–)C(–O)),
1.57 (3H, s, (O–)C(–CH2)–CH3).
2H2O: C 57.21, H 9.60, N 4.94. Found: C 57.67, H 9.14,
N 4.59%.
1H NMR (CDCl3): d (ppm): 4.70 (1H, d, J = 5.0 Hz,
CH2–CH(–O)–CH–(CQO)), 3.60 (2H, m, overlapping,
(OQC–)N–CH2–CH2–CH2), 3.30 (2H, t, J = 8.3 Hz,
N+–CH2–CH2–(CH2)9–CH3), 3.20 (6H, s, CH2–CH2–
N(–CH3)2), 3.16 (1H, d, J = 6.9 Hz, (O–)CH–CH–(CQO)),
2.93 (1H, d, J = 6.9 Hz, (O–)C(–CH3)–CH–(CQO)), 2.89
(3H, s, CH3SO3), 2.07 (2H, m, (OQC–)N–CH2–CH2–CH2),
1.82 (2H, m, CH(–O)–CH2–CH2), 1.61 (4H, overlapping,
N+–CH2–CH2–(CH2)9–CH3 and CH(–O)–CH2–CH2), 1.42
(3H, s, (O–)C(–CH2)–CH3), 1.31–1.23 (18H, overlapping,
N+–CH2–CH2–(CH2)9–CH3), 0.85 (3H, t, J = 6.6 Hz,
N+–CH2–CH2–(CH2)9–CH3).
13C NMR (CDCl3): d (ppm): 177.3 ((CH–)CH–C(QO)–O),
176.1 ((C–)CH–C(QO)–O), 85.7 ((CH2–)C(–O)–CH3), 78.8
((CH2–)CH(–O)–CH(CQO)), 56.8 ((OQC–)N–CH2–CH2–CH2),
51.9 ((O–)CH–CH–C(QO)), 51.6 ((O–)C(CH3)–CH–C(QO)),
13C NMR (CDCl3): d (ppm): 178.0 ((CH–)CH–C(QO)–O),
176.6 ((C–)CH–C(QO)–O), 85.7 ((CH2–)C(–O)–CH3), 78.9
((CH2–)CH(–O)–CH(CQO)), 65.0 ((OQC–)N–CH2–CH2–
CH2), 61.7 ((OQC–)N–CH2–CH2–CH2), 52.4 ((O–)CH–
CH–C(QO)), 52.1 ((O–)C(CH3)–CH–C(QO)), 51.6 (CH2–
45.3
(CH2–CH2–N(–CH3)2),
37.2
(CH2–CH2–CH2–
N(–CH3)2), 36.4 ((O–)CH–CH2–CH2–(CH3–)C(–O)), 30.3
((O–)CH–CH2–CH2–(CH3–)C(–O)), 25.6 (N–CH2–CH2–
CH2–N), 17.7 ((O–)C(CH2)–CH3).
CH2–N(–CH3)2),
39.5
(CH3SO3),
36.2
(N+–CH2–
(CH2)10–CH3),
31.9
(CH(–O)–CH2–CH2),
29.6–22.6
4-(N,N-dimethylamino-N-propyl)-4-aza-6-methyl-10-oxatri-
cyclo[5.2.1]decane-3,5-dione (1.161 g, 4.36 mmol) was dis-
solved in ethanol (10 cm3). To this was added 1-bromodode-
cane (1.123 g, 4.37 mmol) and the mixture refluxed for 16 h.
The ethanol was removed in vacuo, and purified via column
chromatography (DCM–MeOH–AcOH 90 : 5 : 5 solvent),
afforded a clear waxy solid 4-(N,N-dimethylamino-N-butyl-N-
propyl)-4-aza-6-methyl-10-oxatricyclo[5.2.1]decane-3,5-dione
(1.506 g, 67%).
(N+–CH2–(CH2)10–CH3 and (OQC–)N–CH2–CH2–CH2),
17.8 ((O–)C(CH2)–CH3), 14.0 (N+–CH2–(CH2)10–CH3).
4-(N,N-Dimethyl-N-dodecyl-N-propyl)-4-aza-10-oxa-6-ethyltri-
cyclo[5.2.1]decane-3,5-dione methanesulfonate (23). The synth-
esis of 23 was carried out described as 22 by using 2-ethylfuran
instead of 2-methylfuran. MS (MALDI-TOF): m/z 449.1
(M+ ꢀ CH3SO3H). Calc. for C28H52N2O6S ꢄ 2H2O: C 57.90,
H 9.72, N 4.62. Found: C 57.46, H 9.46, N 3.96%.
1H NMR (CDCl3): d (ppm): 4.71 (1H, d, J = 5.0 Hz,
CH2–CH(–O)–CH–(CQO)), 3.60 (2H, m, overlapping,
(OQC–)N–CH2–CH2–CH2), 3.30 (2H, t, J = 8.3 Hz, N+–
CH2–CH2–(CH2)9–CH3), 3.20 (6H, s, CH2–CH2–N(–CH3)2),
3.16 (1H, d, J = 6.9 Hz, (O–)CH–CH–(CQO)), 2.93 (1H, d, J
= 6.9 Hz, (O–)C(–C2H5)–CH–(CQO)), 2.90 (3H, s, CH3SO3),
2.07 (2H, m, (OQC–)N–CH2–CH2–CH2), 1.82 (2H, m,
CH(–O)–CH2–CH2), 1.92–1.52 (6H, overlapping, N+–
CH2–CH2–(CH2)9–CH3, CH(–O)–CH2–CH2 and (O–)C-
(–CH2)–CH2–CH3), 1.31–1.23 (18H, overlapping, N+–CH2–
CH2–(CH2)9–CH3), 1.09 (3H, t, J = 7.5 Hz, (O–)C(–CH2)–
CH2–CH3), 0.84 (3H, t, J = 5.0 Hz, N+–CH2–CH2–
(CH2)9–CH3).
13C NMR (CDCl3): d (ppm): 178.0 ((CH–)CH–C(QO)–O),
176.4 ((C–)CH–C(QO)–O), 89.7 ((CH2–)C(–O)–CH2–CH3),
78.7 ((CH2–)CH(–O)–CH(CQO)), 65.0 ((OQC–)N–CH2–
CH2–CH2), 61.7 ((OQC–)N–CH2–CH2–CH2), 51.8 ((O–)CH–
CH–C(QO)), 51.6 ((O–)C(CH3)–CH–C(QO)), 51.2 (CH2–
CH2–N(–CH3)2), 39.5 (CH3SO3), 35.4 (N+–CH2–(CH2)10–
CH3), 31.9 (CH(–O)–CH2–CH2), 29.7–22.6 (N+–CH2–
(CH2)10–CH3, (OQC–)N–CH2–CH2–CH2 and (O–)C(–CH2)–
CH2–CH3), 14.1 (N+–CH2–(CH2)10–CH3), 9.43 ((O–)C-
(–CH2)–CH2–CH3).
1H NMR (CDCl3): d (ppm): 4.59 (1H, d, J = 5.2 Hz,
CH2–CH(–O)–CH–(CQO)), 3.49 (4H, m, overlapping,
(OQC–)N–CH2–CH2–CH2), 3.28 (2H, t, J = 8.3 Hz,
N+–CH2–CH2–(CH2)9–CH3), 3.20 (6H, s, CH2–CH2–N-
(–CH3)2), 3.16 (1H, d, J = 6.9 Hz, (O–)CH–CH–(CQO)),
2.93 (1H, d, J = 6.9 Hz, (O–)C(–CH3)–CH–(CQO)), 2.07
(2H, m, (OQC–)N–CH2–CH2–CH2), 1.82 (2H, m,
CH(–O)–CH2–CH2), 1.61 (4H, overlapping, N+–CH2–
CH2–(CH2)9–CH3 and CH(–O)–CH2–CH2), 1.42 (3H, s,
(O–)C(–CH2)–CH3), 1.20–1.13 (18H, overlapping, N+–CH2–
CH2–(CH2)9–CH3), 0.75 (3H, t, J = 6.6 Hz, N+–CH2–
CH2–(CH2)9–CH3).
13C NMR (CDCl3): d (ppm): 177.8 ((CH–)CH–C(QO)–O),
176.4 ((C–)CH–C(QO)–O), 85.4 ((CH2–)C(–O)–CH3), 78.6
((CH2–)CH(–O)–CH(CQO)),
CH2–CH2), 61.2 ((OQC–)N–CH2–CH2–CH2),
64.4
((OQC–)N–CH2–
52.2
((O–)CH–CH–C(QO)), 51.9 ((O–)C(CH3)–CH–C(QO)),
51.0 (CH2–CH2–N(–CH3)2), 35.9 (N+–CH2–(CH2)10–CH3),
31.6 (CH(–O)–CH2–CH2), 29.3–22.4 (N+–CH2–(CH2)10–CH3
and (OQC–)N–CH2–CH2–CH2), 17.5 ((O–)C(CH2)–CH3),
13.8 (N+–CH2–(CH2)10–CH3).
N-Butyl-N-ethylpiperidine-10-oxa-4-azatricyclo[5.2.1]decane-
3,5-dione (0.286 g, 0.55 mmol) was dissolved in water (15 cm3)
and cooled to 0 1C. To this was added methanesulfonic acid
(0.104 g, 70% w/w water solution) and the resultant solution
stirred for 1 h. The solution was rotary evaporated to remove
residual HBr and any excess ulfonic acid present
to afford a pale yellow oil (0.290 g, 99%). MS (MALDI-
TOF): m/z 435.1 (M+ ꢀ CH3SO3H). Calc. for C27H50N2O6S ꢄ
Thermogravimetric analysis (TGA)
Thermogravimetric analysis was undertaken using a Perkin
Elmers Pyris Diamond TG/DTA to determine the impurity
content and onset temperature of decomposition. The tem-
perature was increased from room temperature to a maximum
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New J. Chem., 2008, 32, 28–36 | 35

of 800 1C linearly at a rate of 10 1C minꢀ1 with nitrogen used
as the purge gas.
7 J. A. Whitehead, G. A. Lawrance and A. McCluskey, Green
Chem., 2004, 6, 313–315.
8 K. Booker, M. C. Bowyer, C. J. Lennard, C. I. Holdsworth and A.
McCluskey, Aust. J. Chem., 2007, 60, 51–56.
9 K. Booker, M. C. Bowyer, C. I. Holdsworth and A. McCluskey,
Chem. Commun., 2006, 1970–1972.
Malachite Green GTPase assay
The assay was modified from that reported earlier,30 with the
main change being a reduction of dynamin I from 200 nM to
20 nM in the present study. Purified dynamin I (20 nM)
(diluted in dynamin diluting buffer: 6 mM Tris-HCl, 20 mM
NaCl, 0.01% Tween 80, pH 7.4) was incubated in GTPase
buffer (5 mM Tris-HCl, 10 mM NaCl, 2 mM Mg2+, 0.05%
Tween 80, pH 7.5, 1 mg mLꢀ1 leupeptin and 0.1 mM PMSF)
and GTP at 0.3 mM in the presence of RTIL for 30 min at
37 1C in a final assay volume of 150 mL. Plates were incubated
in a dry heating block with shaking at 300 rpm (Eppendorf
Thermomixer). Dynamin GTPase activity was stimulated by
phosphatidylserine liposomes (2 mg/mL). The reaction was
terminated with 10 mL of 0.5 M EDTA pH 8.0 followed by
40 mL of Malachite Green solution (2% w/v ammonium
molybdate tetrahydrate, 0.15% w/v malachite green and
4 M HCl). Colour was developed for 5 min (stable up to
2 h), and sample absorbance was determined on a microplate
spectrophotometer at 650 nm. Phosphate release was quanti-
fied by comparison with a standard curve of dry baked sodium
dihydrogen orthophosphate monohydrate. GraphPad Prism 4
(GraphPad Software Inc., San Diego, CA) was used for
plotting data points and calculation of IC50.
10 A. McCluskey, A. T. R. Sim and J. A. Sakoff, J. Med. Chem., 2002,
45, 1151–1175.
11 A. McCluskey and J. A. Sakoff, Mini Rev. Med. Chem., 2001, 1,
43–45.
12 A. McCluskey and J. A. Sakoff, Curr. Pharm. Des., 2004, 10,
1139–1159.
13 J. A. Sakoff, S. P. Ackland, M. L. Baldwin, M. A. Keane and A.
McCluskey, Invest. New Drugs, 2002, 21, 1–11.
14 A. McCluskey, M. C. Bowyer, C. Walkom, S. P. Ackland, E.
Gardiner and J. A. Sakoff, Bioorg. Med. Chem. Lett., 2001, 11,
2941–2946.
15 M. E. Hart, A. R. Chamberlin, C. Walkom, J. A. Sakoff and
A. McCluskey, Bioorg. Med. Chem. Lett., 2004, 14, 1969–1973.
16 T. A. Hill, L. R. Odell, A. Quan, R. Abagyan, G. Ferguson, P. J.
Robinson and A. McCluskey, Bioorg. Med. Chem. Lett., 2004, 14,
3275–3278.
17 A. McCluskey, L. R. Odell, J. K. Edwards, J. Rusak, R. Abagyan,
J. L. Scott, P. J. Robinson and T. Hill, J. Med. Chem., 2005, 48,
7781–7788.
18 C. M. Gordon and A. McCluskey, Chem. Commun., 1999,
1431–1432.
19 A. McCluskey, J. Garner, S. Caballero and D. J. Young, Tetra-
hedron Lett., 2000, 41, 8147–8151.
20 Z. M. A. Judeh, C. C. Bun, J. Bu and A. McCluskey, Tetrahedron
Lett., 2002, 29, 5089–5091.
21 A. McCluskey, M. C. Bowyer, C. M. Gordon, S. L. Leitch and C.
Ritchie, Aust. J. Chem., 2004, 57, 135–137.
22 S. Otto, Curr. Opin. Drug Discovery Dev., 2003, 6, 509.
23 S. Otto, S. Furlan and J. K. M. Sanders, Drug Discovery Today,
2002, 7, 117–125.
Acknowledgements
24 M. Hochguertel, R. Biesinger, H. Kroth, D. Piecha, M. W.
Hofmann, S. Krause, O. Schaaf, C. Nicolau and A. V. Eliseev,
J. Med. Chem., 2003, 46, 356–358.
25 M. S. Congreve, D. J. Davis, L. Devine, C. Granata, M. O’Reilly,
P. G. Wyatt and H. Jhoti, Angew. Chem., Int. Ed., 2003, 42,
4479–4482.
This work was supported by the Australian Research Council
and the National Health & Medical Research Council
(Australia). J. Z. acknowledges the receipt of a University of
Newcastle PhD scholarship.
26 S. Zuchner, S. Noureddine, M. Kennerson, M. Verhoeven, K.
Claeys, K. de Jonghe, P. Merory, J. Oliveira, S. A. Speer, M. C.
Stenger, J. E. Walizada, G. Zhu, M. A. Pericak-Vance, G. Nichol-
son, V. Timmerman and J. M. Vance, Nat. Genet., 2005, 37,
289–294.
27 J. A. Sakoff, I. J. Howitt, S. P. Ackland and A. McCluskey, Can.
Chemother. Pharm., 2004, 53, 225–232.
28 T. Efferth, R. Rauh, S. Kahl, M. Tomicic, H. Bochzelt, M. E.
¨
References
1 S. A. Forsyth, J. M. Pringle and D. R. MacFarlane, Aust. J.
Chem., 2004, 57, 113–119.
2 R. D. Rodgers and K. R. Seddon, Science, 2003, 302,
792–793.
3 K. R. Seddon, A. Stark and M.-J. Torres, Pure Appl. Chem., 2000,
72, 2275–2287.
Tome, M. M. Briehl, R. Bauer and B. Kaina, Biochem. Pharmacol.,
2005, 69, 81–181.
4 T. Welton, Chem. Rev., 1999, 99, 2071–2083.
5 J. A. Whitehead, J. Zhang, N. Pereira, A. McCluskey and G. A.
Lawrance, Hydrometallurgy, 2007, 88, 109–120.
6 J. A. Whitehead, G. A. Lawrance and A. McCluskey, Aust. J.
Chem., 2004, 57, 151–155.
29 F. Massicot, H. Dutertre-Catella, C. Pham-Huy, X.-H. Liu,
H. T. Duc and J. M. Warnet, Pharm. Toxicol., 2005, 96,
26–32.
30 A. Quan and P. J. Robinson, Methods Enzymol., 2005, 404,
556–569.
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36 | New J. Chem., 2008, 32, 28–36