Synthesis of 2,3-dihydroxy-1-epilupinine

Article abstract of DOI:10.1080/07328300701351540

The 1,3-dipolar cycloaddition of unsaturated D-threo-hexaldonolactone 3 and a six-membered cyclic nitrone 11 led to a single adduct 15, which could be transformed into (1S, 2S, 3S, 9aS)-2,3-dihydroxy-1-hydroxymethyl-quinolizidine 28 related to epilupinine

Full text of DOI:10.1080/07328300701351540

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Synthesis of 2,3‐Dihydroxy‐1‐Epilupinine
Konrad Paśniczek a , Margarita Jurczak a , Jolanta Solecka b , Zofia
Urbańczyk‐Lipkowska a & Marek Chmielewski a
a Institute of Organic Chemistry of the Polish Academy of Sciences , Warsaw,
Poland
b National Institute of Hygiene , Warsaw, Poland
Published online: 01 Jun 2007.
To cite this article: Konrad Paśniczek , Margarita Jurczak , Jolanta Solecka , Zofia Urbańczyk‐Lipkowska &
Marek Chmielewski (2007) Synthesis of 2,3‐Dihydroxy‐1‐Epilupinine, Journal of Carbohydrate Chemistry, 26:3,
195-211, DOI: 10.1080/07328300701351540
To link to this article: http://dx.doi.org/10.1080/07328300701351540
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Journal of Carbohydrate Chemistry, 26:195–211, 2007
Copyright # Taylor & Francis Group, LLC
ISSN: 0732-8303 print 1532-2327 online
DOI: 10.1080/07328300701351540
Synthesis of 2,3-Dihydroxy-
1-Epilupinine
´
Konrad Pasniczek and Margarita Jurczak
Institute of Organic Chemistry of the Polish Academy of Sciences, Warsaw, Poland
Jolanta Solecka
National Institute of Hygiene, Warsaw, Poland
´
Zofia Urbanczyk-Lipkowska and Marek Chmielewski
Institute of Organic Chemistry of the Polish Academy of Sciences, Warsaw, Poland
The 1,3-dipolar cycloaddition of unsaturated D-threo-hexaldonolactone 3 and a
six-membered cyclic nitrone 11 led to a single adduct 15, which could be transformed
into (1S, 2S, 3S, 9aS)-2,3-dihydroxy-1-hydroxymethyl-quinolizidine 28 related to epilu-
pinine via a reaction sequence involving rearrangement of the six-membered lactone
ring into a five-membered one, removal of the terminal carbon atom from the sugar
chain, cleavage of the N-O bond, and the intramolecular alkylation of the nitrogen atom.
Keywords Iminosugars, Nitrones, Aldono-1,5-lactone, 1,3-Dipolar cycloaddition
INTRODUCTION
Recently, we have reported that the cycloaddition of 2,3-unsaturated aldono-
1,5-lactones 1–3 and the five-membered cyclic nitrones 4–6 proceeded
Received January 19, 2007; accepted March 20, 2007.
Address correspondence to Marek Chmielewski, Institute of Organic Chemistry of the
Polish Academy of Sciences, 01-224 Warsaw, Poland. E-mail: chmiel@icho.edu.pl
195

´
K. Pasniczek et al.
196
exclusively in the exo mode to provide in many cases a sole product.[1–3] In
particular, reaction between 3 and 5 afforded only one cycloadduct 7 as a result
of the anti addition to both the acetoxymethyl- and the 4-acetoxy-group of the
lactone (Chart 1).[3] The application of Brandi’s methodology[4] to cycloadduct 7
offers a convenient approach to the indolizidine alkaloids. This has been demon-
strated by the synthesis of 8-homocastanospermine (8)[5] and 1-homoaustraline
(9) (Chart 1).[6] Both reported syntheses demonstrated an exceptional effective-
ness of the 1,3-dipolar cycloaddition of nitrones and sugar unsaturated
d-lactones, which led to formation of only one diastereomer with fully defined con-
figuration at all stereogenic centers, which corresponded well with those existing
in both natural compounds, castanospermine[7] and australine.[8] Surprisingly,
iminosugars 8 and 9 showed only a trace inhibition of a-glucosidase activity
and no inhibition of b-glucosidase.[5,6] Both synthesized compounds have a hydro-
xymethyl group at the position adjacent to the bridgehead carbon atom in the
place of the hydroxyl group. Such substituted pyrrolizidines,[9] indolizidines,[10]
and quinolizidines[11] exist in nature, or have been obtained by the total
synthesis.[12]
It was of interest to apply the same methodology to the synthesis of
polyhydroxylated quinolizidines. It should, however, be pointed out that such
compounds, except lupinine (10),[11] have not been found in nature. Polyhy-
droxylated quinolizidines,[13] particularly related to castanospermine, have
been synthesized in order to find active glycosidase inhibitors.[14]
RESULTS AND DISCUSSION
Six-membered ring nitrone 11 (Chart 1) was obtained following the known
procedure[15]; the dipole is not stable and has to be obtained directly before
the use for the cycloaddition. The nitrone 11 was subjected to 1,3-dipolar
Chart 1:

Synthesis of 2,3-Dihydroxy-1-Epilupinine
197
cycloaddition with lactones 1–3. Reaction between 1 and 11 provided a single
adduct 12 as the result of anti-exo approach of reactants. The 1H NMR
spectrum of 12 at rt displayed lines characteristic of definite single nitrogen
invertomers 12a and 12b in a ratio of about 2:1, respectively. Assignments
were made on the basis of chemical shifts of H-5b protons, 2.24 ppm (syn to the
free electron pair) for 12a and 3.62 ppm (anti) for 12b. In toluene-d8 at 1008C,
owing to the fast inversion process the 1H NMR spectrum of adduct 12 displayed
a presence of average signals only, but with substantial line broadening (Chart 2).
Reaction between 2 and 11 provided two adducts 13 and 14 in the ratio of
about 3:2, respectively; the anti-exo approach to the terminal acetoxymethyl
group dominated. Both adducts 13 and 14 at rt existed as two nitrogen inver-
tomers in a ratio of 1.8:1 for 13a/13b and 3:1 for 14a/14b. As it was made
before, the configuration at the nitrogen atom in both pairs of invertomers
was assigned on the basis of the chemical shift of H-5b carbon atoms; upfield
shifts testified the syn location of the proton and the free electron pair.
Configuration of adducts 13 and 14 were assigned on the basis of coupling
constants (toluene-d8, 1108C) J1a,2 ¼ 3.7 Hz for 13 (axial-psedoeqatorial) and
7.5 Hz (axial-pseudoaxial) for 14 (Chart 2).
Lactone 3 and nitrone 11 gave only one adduct 15 as the result of the
exo-anti approach to both substituents in the dipolarophile. As with the
others adducts, compound 15 at rt displayed the presence of two invertomers
15a/15b in a ratio of about 1.25:1 (Chart 2). The major conformer has syn
location of the H-5b proton and the free electron pair.
Adduct 15 was deacetylated with sodium methoxide in methanol and
gave compound 16. The reaction proceeded with the rearrangement of the
Chart 2:

´
K. Pasniczek et al.
198
six-membered lactone ring into a five-membered one. The glycolic cleavage of the
terminal diol group in 16 with NaIO4 followed by the reduction of the aldehyde
group with sodium triacetoxyborohydride gave compound 19 in 83% yield
(Sch. 1). The structure of 19 was proved by X-ray crystallography (Fig. 1).
Subsequently, the hydroxymethyl group was protected as a t-butyldiphe-
nylsilyl derivative 21 and the lactone was reduced with sodium borohydride
to give diol 22. Both hydroxyl groups in 22 were masked by the formation of
isopropylidene moiety (24). The desilylation of 24 with tetrabutylammonium
fluoride led to the alcohol 25. Introduction of the seven-membered ring to the
piperidino[1,2-b]izoxazolidine fragment caused substantial broadening of
1
signals in H NMR spectra of compounds 24 and 25 due to the slow inversion
process at the nitrogen atom. Therefore, the structure determinations of both
compounds were made on the basis of assignments made for the final
products of the synthesis, 27 and 28.
Due to the low stability of isopropylidene fragment and the tendency of the
terminal mesyloxymethyl group to undergo intramolecular alkylation of the
nitrogen atom, the next three steps were performed with only partial purification
of intermediary products. The alcohol 25 was mesylated to afford 26, the
Scheme 1: (a) Na2CO3, MeOH; (b) NaIO4, MeOH, H2O; (c) NaBH(OAc)3, CH2Cl2; (d) TBDPSCl,
imidazole, CH2Cl2; (e) LiBH4, THF; (f) 2,2-dimethoxypropane, TsOH; (g) n-Bu4NF, THF; (h) MsCl,
TEA, CH2Cl2; (i) 80% AcOH; H2, Pd/C, K2CO3, AcOEt, MeOH; Ac2O, TEA, DMAP, CH2Cl2;
(j) 1.3% NH3 in MeOH.

Synthesis of 2,3-Dihydroxy-1-Epilupinine
199
Figure 1: X-ray structure of compound 19 with crystallographical numbering scheme.
isopropylidene protection was removed using 80% acetic acid, and the sequence
was completed by the hydrogenolysis of the N-O bond over Pd/C and intramole-
cular alkylation of the nitrogen atom. The final product of this reaction sequence
(quinolizidine 28) was acetylated and characterized as the triacetate 27. The
complete deacetylation of 27 with ammonia in methanol furnished the (1S, 2S,
3S, 9aS)-2,3-dihydroxy-1-hydroxymethyl-quinolizidine 28.
Compound 28 was tested on bovine kidney a-L-fucosidase, bovine liver b-D-
galactosidase, bovine liver b-D-glucuronidase, rice a-D-glucosidase, almond
b-D-glucosidase, and jack bean a-D-mannosidase inhibition. Under procedures
described previously,[16–20] quinolizidine 28 did not show activity against any
of the tested enzymes.
In summary, we have reported the simple synthesis of 2,3-dihydroxy-
epilupinine 28 in which a proper selection of readily available components of
the 1,3-dipolar cycloaddition controlled the absolute stereochemistry at all
four stereogenic centers present in the target molecule. The inferences
drawn from previous work allowed us to predict the stereochemical pathway
of the 1,3-dipolar cycloaddition of six-membered-ring nitrone 11 and sugar
unsaturated d-lactone 3. Consequently, only one diastereomer 15 with a fully
defined configuration at all stereogenic centers was obtained and was used
for the synthesis of title quinolizidine.
EXPERIMENTAL
1H NMR spectra were recorded on a Bruker DRX 500 Avance Spectrometer. IR
spectra were obtained on an FT-IR-1600 Perkin-Elmer spectrophotometer. The
optical rotations were measured with a JASCO Dip-360 digital polarimeter.
Mass spectra were recorded using an AMD-604 instrument from GmbH and
HPLC-MS were recorded with Mariner and API 356 detectors. Column chrom-
atography was performed with E. Merck Kiesel Gel (230–400 mesh).

´
K. Pasniczek et al.
200
Adduct 7 was obtained according to the known procedure.[3] Crystallo-
graphic data for the structure reported in this paper have been deposited
with the Cambridge Crystallographic Data Center, Cambridge, UK, as a
supplementary publication: 19 (CCDC 634033).
(1aR, 3S, 5aR, 5bR)-3-Acetoxymethyl-piperidino[1,2-b]-
tetrahydropyrano[3,4-d]isoxazol-5(3H)-one (12)
Lactone 1 (34 mg, 0.2 mmol) and nitrone 11 (30 mg, 0.3 mmol) were dis-
solved in dry toluene (2 mL), and kept at rt for 3 days. The progress of
reaction was monitored using TLC. Subsequently, the solvent was evaporated
and the product was purified by chromatography using hexane/AcOEt 1:2 v/v
as an eluent to afford 12 (37 mg, 68%). [a]D mixture of invertomers þ15.9 (c 0.7,
1
CH2Cl2); IR (film, CHCl3): v 1740 cm21; H NMR (500 MHz, CDCl3) taken for
the mixture d: major component: 4.77 (dddd, 1H, J ¼ 1.7, 3.5, 5.5, 11.6 Hz,
H-3), 4.46 (ddd, 1H, J ¼ 1.4, 3.7, 8.3 Hz, H-1a), 4.25 (dd, 1H, J ¼ 3.5,
12.1 Hz, CHHOAc), 4.20 (dd, 1H, J ¼ 5.5, 12.1 Hz, CHHOAc), 3.46 (m, 1H,
H-9), 3.15 (dd, 1H, J ¼ 8.3, 10.3 Hz, H-5a), 2.48 (m, 1H, H-90), 2.24 (ddd, 1H,
J ¼ 2.3, 10.3, 11.0 Hz, H-5b), 2.16 (m, 1H, H-6), 2.09 (s, 3H, OAc), 2.00 (ddd,
1H, J ¼ 1.4, 1.7, 15.4 Hz, H-2), 1.87 (ddd, 1H, J ¼ 3.7, 11.6, 15.4 Hz, H-20),
1.85–1.72 (m, 2H, H-7,8), 1.66 (m, 1H, H-80), 1.52 (m, 1H, H-60), 1.22 (m, 1H,
H-70); minor component: 4.85 (m, 1H, H-1a), 4.77 (m, 1H, H-3), 4.26–4.18
(m, 2H, CH2OAc), 3.62 (m, 1H, H-5b), 3.40 (m, 1H, H-5a), 3.16 (m, 1H, H-9),
2.57 (m, 1H, H-90), 2.09 (m, 1H, H-6), 2.08 (s, 3H, OAc), 2.00–1.92 (m, 3H,
H-2,20,60), 1.78 (m, 1H, H-8), 1.59 (m, 1H, H-7), 1.56 (m, 1H, H-80), 1.38
(m, 1H, H-70); 1H NMR (500 MHz, toluene-d8, 1008C) d: 4.49 (m, 1H, H-3),
4.07 (m, 1H, H-1a), 3.95 (dd, 1H, J ¼ 5.6, 11.9 Hz, CHHOAc), 3.89 (dd, 1H,
J ¼ 4.1, 11.9 Hz, CHHOAc), 3.05 (m, 1H, H-5a), 2.84 (t, 1H, J ¼ 8.9 Hz, H-9),
2.40 (m, 1H, H-90), 1.90 (m, 1H, H-2), 1.68 (s, 3H, OAc), 1.56 (m, 1H, H-5b),
1.46–1.20 (m, 6H, H-20,6, 60, 7, 8, 80), 0.95 (m, 1H, H-70); 13C NMR (125 MHz,
CDCl3) d: major component 170.5, 169.3, 72.8, 71.3, 70.7, 65.0, 55.0, 51.6,
28.9, 28.8, 24.4, 23.3, 20.7; minor component 170.5, 169.7, 72.7, 72.2, 65.6,
65.0, 50.0, 47.5, 29.6, 24.2, 23.7, 20.7, 18.1; MSHR (ESI) m/z [M þ H]þ, calcd.
for C13H20NO5: 270.1336. Found: 270.1334.
(1aS, 2S, 3R, 5aR, 5bR)-2-Acetoxy-3-acetoxymethyl-
piperidino[1,2-b]-tetrahydropyrano[3,4-d]isoxazol-5
(3H)-one (13) and (1aR, 2S, 3R, 5aS, 5bS)-2-Acetoxy-3-
acetoxymethyl-piperidino[1,2-b]-tetrahydropyrano
[3,4-d] isoxazol-5(3H)-one (14)
Lactone 2 (46 mg, 0.2 mmol) and nitrone 11 (30 mg, 0.3 mmol) were
dissolved in dry toluene (3 mL) and left at rt for 3 days. The progress of

Synthesis of 2,3-Dihydroxy-1-Epilupinine
201
reaction was monitored by TLC. Subsequently, the solvent was evaporated and
the products were separated by chromatography using hexane/AcOEt 1:1 v/v
as an eluent to afford 13 (31 mg, 47%) and 14 (21 mg, 32%).
13: m.p. 109.5–110.58C; [a]D mixture of invertomers þ120.2 (c 1.2, CH2Cl2); IR
(film CHCl3): v 1745 cm21; 1H NMR (500 MHz, CDCl3) taken for the mixture of
invertomers d: major component 13a, 5.23 (dd, 1H, J ¼ 3.7, 9.5 Hz, H-2), 4.94
(ddd, 1H, J ¼ 2.2, 3.9, 9.5 Hz, H-3), 4.54 (dd, 1H, J ¼ 3.7, 8.5 Hz, H-1a), 4.37
(dd, 1H, J ¼ 3.9, 12.6 Hz, CHHOAc), 4.27 (dd, 1H, J ¼ 2.2, 12.6 Hz,
CHHOAc), 3.52 (m, 1H, H-9), 3.26 (dd, 1H, J ¼ 8.5, 10.0 Hz, H-5a), 2.54
(m, 1H, H-90), 2.32 (ddd, 1H, J ¼ 2.3, 10.0, 11.2 Hz, H-5b), 2.22 (m, 1H, H-6),
2.14, 2.08 (2s, 6H, 2 ꢀ OAc), 1.85 (m, 1H, H-8), 1.66 (m, 1H, H-80), 1.56–1.45
(m, 2H, H-60,7), 1.23 (m, 1H, H-70); minor component 13b, 5.16 (dd,
1H, J ¼ 3.2, 9.8 Hz, H-2), 5.01 (ddd, 1H, J ¼ 2.1, 3.0, 9.8 Hz, H-3), 4.84 (dd,
1H, J ¼ 3.2, 8.4 Hz, H-1a), 4.38 (dd, 1H, J ¼ 3.0, 12.6 Hz, CHHOAc), 4.28
(dd, 1H, J ¼ 2.1, 12.6 Hz, CHHOAc), 3.66 (m, 1H, H-5b), 3.42 (dd, 1H,
J ¼ 6.8, 8.4 Hz, H-5a), 3.10 (m, 1H, H-9), 2.84 (m, 1H, H-90), 2.14, 2.08 (2s,
6H, 2 ꢀ OAc), 1.94–1.73 (m, 4H, H-6,7,70,8), 1.58–1.42 (m, 2H, H-60,80);
1H NMR (500 MHz, toluene-d8 1008C) d: 5.02 (dd, 1H, J ¼ 3.7, 9.3 Hz, H-2),
4.70 (ddd, 1H, J ¼ 2.7, 4.3, 9.3 Hz, H-3), 4.36 (dd, 1H, J ¼ 3.7, 8.3 Hz, H-1a),
4.21 (dd, 1H, J ¼ 4.3, 12.4 Hz, CHHOAc), 4.04 (dd, 1H, J ¼ 2.7, 12.4 Hz,
CHHOAc), 3.04 (m, 1H, H-9), 2.80 (t, 1H, 8.3 Hz, H-5a), 2.46 (m, 1H, H-90),
1.78 (m, 1H, H-5b), 1.72 (2s, 6H, 2 ꢀ OAc), 1.48–1.24 (m, 5H, H-6, 60, 7, 8,
80), 0.97 (m, 1H, H-70); 13C NMR (125 MHz, CDCl3) taken for the mixture of
invertomers d: major component, 170.4, 169.4, 167.6, 73.0, 71.2, 71.1, 66.2,
61.4, 55.1, 52.3, 28.9, 24.4, 23.2, 20.7, 20.6; minor component, 170.4, 169.7,
168.5, 72.8, 71.4, 66.8, 66.1, 61.4, 50.3, 50.2, 24.5, 22.0, 20.8, 20.6, 19.6;
MSHR (ESI) m/z [M þ H]þ, calcd. for C15H22NO7: 328.13908. Found:
328.13965.
14: [a]D mixture of invertomers þ33.5 (c 0.5, CH2Cl2); IR (film, CHCl3): v
1
1746 cm21; H NMR (500 MHz, CDCl3) taken for the mixture of invertomers
d: major component, 5.19 (dd, 1H, J ¼ 7.7, 9.0 Hz, H-2), 4.48 (ddd, 1H, J ¼ 2.0,
5.0, 9.0 Hz, H-3), 4.42 (dd, 1H, J ¼ 5.0, 12.4 Hz, CHHOAc), 4.35 (dd, 1H,
J ¼ 7.7, 9.7 Hz, H-1a), 4.22 (dd, 1H, J ¼ 2.0, 12.4 Hz, CHHOAc), 3.46
(m, 1H, H-9), 3.25 (dd, 1H, J ¼ 9.7, 9.8 Hz, H-5a), 2.56 (m, 1H, H-90), 2.46
(ddd, 1H, J ¼ 2.0, 9.8, 10.9 Hz, H-5b), 2.38 (m, 1H, H-6), 2.12, 2.08 (2s, 6H,
2 ꢀ OAc), 1.86–1.74 (m, 2H, H-7,8), 1.64 (m, 1H, H-80), 1.51 (m, 1H, H-60),
1.30 (m, 1H, H-70); minor component, 5.21 (m, 1H, H-2), 4.59 (m, 1H, H-3),
4.48 (m, 1H, H-1a), 4.42 (m, 1H, CHHOAc), 4.25 (m, 1H, CHHOAc), 3.75
(m, 1H, H-5b), 3.35 (m, 1H, H-5a), 3.10 (m, 1H, H-9), 2.95 (m, 1H, H-90),
2.12, 2.08 (2s, 6H, 2 ꢀ OAc), 2.00–1.20 (m, 6H, H-6,60,7,70,8,80); 1H NMR
(500 MHz, toluene-d8 1008C) d: 5.16 (dd, 1H, J ¼ 7.5, 9.1 Hz, H-2), 4.30

´
K. Pasniczek et al.
202
(dd, 1H, J ¼ 5.1, 12.4 Hz, CHHOAc), 4.07 (dd, 1H, J ¼ 7.5, 9.5 Hz, H-1a), 4.01
(dd, 1H, J ¼ 2.8, 12.4 Hz, CHHOAc), 3.92 (ddd, 1H, J ¼ 2.8, 5.1, 9.1 Hz, H-3),
3.14 (m, 1H, H-9), 2.67 (dd, 1H, J ¼ 8.1, 9.5 Hz, H-5a), 2.42 (m, 1H, H-90), 1.75,
1.68 (2s, 6H, 2 ꢀ OAc), 1.70 (m, 1H, H-5b), 1.50–1.25 (m, 5H, H-6, 60, 7, 8, 80),
1.03 (m, 1H, H-70); 13C NMR (125 MHz, CDCl3) d: major component, 170.5,
169.1, 169.1, 75.5, 74.9, 70.0, 67.6, 61.0, 55.1, 50.3, 29.6, 24.6, 23.3, 20.8,
20.7; MSHR (EI) m/z Mþ†, calcd. for C15H21NO7: 327.13180. Found:
327.13167.
(1aS, 2R, 3R, 5aR, 5bR)-2-Acetoxy-3-acetoxymethyl-
piperidino[1,2-b]-tetrahydropyrano[3,4-d]isoxazol-
5(3H)-one (15)
Lactone 3 (91 mg, 0.4 mmol) and nitrone 11 (59 mg, 0.6 mmol) were dis-
solved in dry toluene (4 mL) and left and rt for 72 h and then it was refluxed
for 2 h. The progress of reaction was monitored using TLC. Subsequently, the
solvent was evaporated and the product was purified by chromatography
using hexane/AcOEt 1:1 v/v as an eluent to afford 15 (112 mg, 86%). m.p.
115–1178C; [a]D mixture of invertomers þ17.6 (c 1.1, CH2Cl2); IR (film,
1
CH2Cl2): v 1746 cm21; H NMR (500 MHz, CDCl3) taken for the mixture of
invertomers d: major component, 5.13 (m, 1H, H-2), 4.91 (m, 1H, H-3), 4.24
(m, 1H, H-1a), 4.23 (d, 2H, CH2OAc), 3.50 (m, 1H, H-9), 3.22 (dd, 1H,
J ¼ 8.7, 10.0 Hz, H-5a), 2.50 (m, 1H, H-90), 2.26 (ddd, 1H, J ¼ 2.2, 10.0,
11.2 Hz, H-5b), 2.17–1.30 (m, 6H, H-6,60,7,70,8,80), 2.12, 2.10 (2s, 6H,
2 ꢀ OAc); minor component, 5.13 (m, 1H, H-2), 4.91 (m, 1H, H-3), 4.60 (dd,
1H, J ¼ 2.2, 8.6 Hz, H-1a), 4.23 (d, 2H, CH2OAc), 3.60 (ddd, 1H, J ¼ 4.1, 4.1,
8.5 Hz, H-5b), 3.42 (dd, 1H, J ¼ 8.5, 8.6 Hz, H-5a), 3.15 (m, 1H, H-9), 2.63
(m, 1H, H-90), 2.17–1.30 (m, 6H, H-6, 60, 7, 70, 8, 80), 2.12, 2.08 (2s, 6H,
2 ꢀ OAc); 13C NMR (125 MHz, CDCl3) taken for the mixture d: major com-
ponent, 170.2, 169.1, 168.5, 73.8, 73.5, 70.5, 65.8, 61.9, 55.1, 50.6, 28.7, 24.3,
23.2, 20.6, 20.6; minor component, 170.2, 169.3, 167.9, 74.3, 73.4, 65.7, 64.8,
61.9, 50.2, 47.2, 24.4, 22.9, 20.6, 20.6, 18.7; MSHR (ESI) m/z [M þ Na]þ,
calcd. for C15H21NO7Na: 350.1207. Found: 350.1210.
(1aS, 2R, 4aR, 4bR, 10R)-2-(10,20-Dihydroxyethyl)-
piperidino[1,2-b]-tetrahydrofuro[3,4-d]isoxazol-
4(3H)-one (16)
Cycloadduct 15 (327 mg, 1.0 mmol) dissolved in MeOH (60 mL) was treated
with sodium carbonate (106 mg, 1.0 mmol) and stirred at rt for 40 min; the
progress of reaction was monitored by TLC. Subsequently, the reaction

Synthesis of 2,3-Dihydroxy-1-Epilupinine
203
mixture was neutralized with amberlit IR-1200 [Hþ] resin, diluted with
methylene chloride (70 mL), filtered, and evaporated. The residue was
purified by chromatography using hexane/AcOEt 1:4 v/v as an eluent to
afford compound 16 (221 mg; 91%). m.p. 136–1388C; [a]D–28.2 (c 0.15,
1
CH2Cl2); IR (film, CH2Cl2): v 3388, 1751 cm21; H NMR (500 MHz, CDCl3) d:
4.97 (dd, 1H, J ¼ 6.6, 8.1 Hz, H-1a), 4.70 (dd, 1H, J ¼ 2.8, 6.6 Hz, H-2), 4.17
(ddd, 1H, J ¼ 2.8, 5.4, 6.1 Hz, CHOH), 3.80 (dd, 1H, J ¼ 6.1, 11.0 Hz,
CHHOH), 3.73 (dd, 1H, J ¼ 5.4, 11.0 Hz, CHHOH), 3.67 (dd, 1H, J ¼ 4.9,
11.2 Hz, H-4b), 3.46 (m, 1H, H-8), 3.23 (d, 1H, J ¼ 8.1 Hz, H-4a), 3.00 (ddd,
1H, J ¼ 3.4, 12.6, 15.6 Hz, H-80), 1.78 (dddd, 1H, J ¼ 2.0, 3.5, 3.8, 12.6 Hz,
H-6), 1.73 (tt, 1H, J ¼ 3.8, 12.6 Hz, H-7), 1.63 (m, 1H, H-5), 1.55 (dddd, 1H,
J ¼ 3.5, 11.2, 12.6, 13.1 Hz, H-50), 1.44 (tt, 1H, J ¼ 3.3, 12.6 Hz, H-60), 1.35
(m, 1H, H-70); 13C NMR (125 MHz, CDCl3) d: 175.7, 82.9, 76.3, 69.4, 63.9,
63.6, 54.9, 49.9, 25.7, 22.3, 18.7; MSHR (ESI) m/z [M þ Na]þ, calcd. for
C11H17NO5Na: 266.0999. Found: 266.0989.
(1aS, 2R, 4aR, 4bR, 10R)-2-(10,20-Diacetoxyethyl)-
piperidino[1,2-b]-tetrahydrofuro[3,4-d]isoxazol-
4(3H)-one (17)
Diol 16 (12 mg, 0.05 mmol) dissolved in triethylamine (2 mL) was treated
with acetic anhydride (2 mL) and DMAP (0.01 mmol), and left for 30 min.
After a standard workup the crude product was purified by chromatography
using hexane/AcOEt 2:1 v/v as an eluent to afford 17 (14 mg, 87%). [a]D
221.6 (c 0.48, CH2Cl2); IR (film CH2Cl2): v 1771, 1745 cm21 1H NMR
;
(500 MHz, CDCl3) d: 5.45 (dd, 1H, J ¼ 2.6, 8.3 Hz, H-9), 4.86 (dd, 1H, J ¼ 5.4,
6.4 Hz, H-1a), 4.65 (dd, 1H, J ¼ 5.4, 8.3 Hz, H-2), 4.50 (d, 1H, J ¼ 12.3 Hz,
H-10), 4.40 (dd, 1H, J ¼ 2.6, 12.3 Hz, H-100), 3.60 (dd, 1H, J ¼ 3.7, 9.8 Hz,
H-4b), 3.38 (dd, 1H, J ¼ 14.9 Hz, H-8), 3.26 (d, 1H, J ¼ 6.4, Hz, H-4a), 2.10,
2.09 (2s, 6H, 2 ꢀ OAc), 1.80–1.20 (m, 6H, H-5, 50, 6, 60, 7, 70); 13C NMR
(125 MHz, CDCl3) d: 175.7, 170.5, 169.8, 80.9, 74.7, 70.1, 63.5, 62.8, 55.3,
50.0, 25.0, 22.2, 20.9, 20.7, 18.9; MSHR (ESI) m/z [M þ Na]þ, calcd. for
C15H21NO7Na: 350.1210. Found: 350.1204.
(1aS, 2R, 4aR, 4bR)-2-Formyl-piperidino[1,2-b]-
tetrahydrofuro[3,4-d]isoxazol-4(3H)-one (18)
Compound 16 (243 mg, 1.0 mmol) was dissolved in methanol/water 6:1
(20 mL). Upon stirring at rt, sodium metaperiodide (428 mg, 2.0 mmol) was
added. The stirring was continued for 3 h. Subsequently, the mixture was
filtered, evaporated, and passed through a silica gel using CH2Cl2:methanol

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95:5 v/v to afford partially purified product (80%). A small sample of 18 was
purified by chromatography using CH2Cl2/methanol 4:1 v/v as an eluent.
1
[a]D þ18.6 (c 0.8, CH2Cl2); IR (film): v 3374, 1770 cm21; H NMR (500 MHz,
CDCl3) d: 9.55 (d, 1H, J ¼ 1.7 Hz, CHO), 5.14 (dd, 1H, J ¼ 7.1, 7.6 Hz, H-1a),
4.78 (dd, 1H, J ¼ 1.7, 7.1 Hz, H-2), 3.65 (dd, 1H, J ¼ 6.7, 9.4 Hz, H-4b), 3.35
(m, 1H, H-8), 3.15 (d, 1H, J ¼ 7.6 Hz, H-4a), 2.93 (m, 1H, H-80), 1.78 (m, 1H,
H-6), 1.71 (m, 1H, H-7), 1.58 (m, 2H, H-5,50), 1.43 (m, 1H, H-60), 1.30 (m, 1H,
H-70); 13C NMR (125 MHz, CDCl3) d: 195.8, 176.1, 84.5, 76.6, 64.8, 53.8, 49.5,
25.4, 22.5, 18.9; MSHR (ESI) m/z [M þ MeOH þ Na]þ, calcd. for
C11H17NO5Na: 266.0999. Found: 266.0998; MSHR (ESI) m/z [M þ EtOH þ
Na]þ, calcd. for C12H19NO5Na: 280.1155. Found: 280.1155.
(1aS, 2S, 4aR, 4bR)-2-Hydroxymethyl-piperidino[1,2-b]-
tetrahydrofuro[3,4-d]isoxazol-4(3H)-one (19)
Aldehyde 18 (169 mg, 0.8 mmol) was dissolved in dry CH2Cl2 (45 mL) and
treated with 2 equiv. NaBH(OAc)3. The mixture was stirred for 5 h at rt. After
disappearance of the substrate (TLC), it was filtered through Celite and evap-
orated. The crude product was purified by chromatography using hexane/
AcOEt 1:2 v/v as an eluent to afford 19 (130 mg, 76%). m.p. 101–1038C; [a]D
1
22.8 (c 0.2, CH2Cl2); IR (film CHCl3): v 3417, 1767 cm21; H NMR (500 MHz,
CDCl3) d: 4.94 (dd, 1H, J ¼ 6.3, 8.0 Hz, H-1a), 4.68 (ddd, 1H, J ¼ 4.1, 5.2,
6.3 Hz, H-2), 4.04 (dd, 1H, J ¼ 4.1, 12.2 Hz, CHHOH), 3.97 (dd, 1H, J ¼ 5.2,
12.2 Hz, CHHOH), 3.65 (dd, 1H, J ¼ 4.8, 10.6 Hz, H-4b), 3.43 (m, 1H, H-8),
3.23 (d, 1H, J ¼ 8.0 Hz, H-4a), 3.00 (ddd, 1H, J ¼ 3.5, 11.7, 15.3 Hz, H-80),
1.80–1.70 (m, 2H, H-6,7), 1.63–1.50 (m, 2H, H-5,50), 1.45 (m, 1H, H-60), 1.34
(m, 1H, H-70); 13C NMR (125 MHz, CDCl3) d: 175.7, 82.9, 76.1, 63.7, 60.3,
54.9, 49.9, 25.4, 22.3, 18.9; MSHR (ESI) m/z [M þ Na]þ, calcd. for
C10H15NO4Na: 236.0893. Found: 236.0888.
(1aS, 2S, 4aR, 4bR)-2-Acetoxymethyl-piperidino[1,2-b]-
tetrahydrofuro[3,4-d]isoxazol-4(3H)-one (20)
Compound 20 was obtained according to the procedure described for 17
(97%). m.p. 108–1118C; [a]D 231.1 (c 0.7, CH2Cl2); IR (film CH2Cl2): v 1766,
1739 cm21
;
1H NMR (500 MHz, C6D6) d: 4.59 (dd, 1H, J ¼ 3.6, 12.2 Hz,
CHHOAc), 4.42 (dd, 1H, J ¼ 8.4, 12.2 Hz, CHHOAc), 4.25 (ddd, 1H, J ¼ 3.6,
5.7, 8.4 Hz, H-2), 3.99 (dd, 1H, J ¼ 5.7, 7.3 Hz, H-1a), 3.31 (dd, 1H, J ¼ 4.4,
11.0 Hz, H-4b), 3.10 (br d, 1H, J ¼ 15.0 Hz, H-8), 2.47 (ddd, 1H, J ¼ 3.3, 12.5,
15.0 Hz, H-80), 2.38 (d, 1H, J ¼ 7.3 Hz, H-4a), 1.68 (s, 3H, OAc), 1.45 (m, 1H,
H-7), 1.28 (m, 1H, H-6), 1.07–0.73 (m, 4H, H-5,50,60,70); 13C NMR (125 MHz,
CDCl3) d: 176.0, 170.7, 80.9, 75.0, 63.7, 62.5, 55.0, 49.9, 25.0, 22.3, 20.8,

Synthesis of 2,3-Dihydroxy-1-Epilupinine
205
18.9; MSHR (ESI) m/z [M þ Na]þ, calcd. for C12H17NO5Na: 278.0999.
Found: 278.1008.
(1aS, 2S, 4aR, 4bR)-2-(tert-Butyldiphenylsiloxymethyl)-
piperidino[1,2-b]-tetrahydrofuro[3,4-d]isoxazol-5(3H)-
one (21)
Alcohol 19 (149 mg, 0.7 mmol) was dissolved in dry CH2Cl2 (60 mL) and
treated with tert-butylodiphenylsililyl chloride (241 mg, 0.88 mmol) and imida-
zole (95 mg, 1.4 mmol). The mixture was left at rt for 24 h. Subsequently, the
mixture was washed with water (30 mL), brine (30 mL), and water (30 mL).
The organic layer was dried and evaporated. The crude product was purified
by chromatography using hexane/AcOEt 5:1 v/v as an eluent to afford 21
(316 mg, 81%). [a]D þ5.1 (c 0.5, CH2Cl2); IR (film CH2Cl2): v 1773 cm21
;
1H NMR (500 MHz, CDCl3) d: 4.84 (dd, 1H, J ¼ 5.4, 7.3 Hz, H-1a), 4.65 (ddd,
1H, J ¼ 5.4, 5.6, 6.8 Hz, H-2), 4.05 (dd, 1H, J ¼ 5.6, 11.0 Hz, CHHOSi), 4.01
(dd, 1H, J ¼ 6.8, 11.0 Hz, CHHOSi), 3.53 (ddd, 1H, J ¼ 1.4, 5.0, 9.9 Hz,
H-4b), 3.25 (dd, 1H, J ¼ 1.4, 7.3 Hz, H-4a), 3.20 (m, 1H, H-8), 2.88 (m, 1H,
H-80), 1.74–1.23 (4 m, 6H, H-5,50,6,60,7,70), 1.06 (s, 9H, Ot-Bu); 13C NMR
(125 MHz, CDCl3) d: 176.5, 83.9, 75.2, 63.5, 61.6, 54.9, 49.9, 26.8, 25.0, 22.2,
19.2, 19.1; MSHR (ESI) m/z [M þ H]þ, calcd. for C26H34NO4Si: 452.22516.
Found: 452.2264.
(2S, 10S, 3S, 3aS)-2-(20-tert-Butyldiphenylsiloxyethyl-10-
hydroxy)-3-(hydroxymethyl)-piperidino[1,2-b]dihydro-
(3H)-isoxazole (22)
Lactone 21 (316 mg, 0.7 mmol) was dissolved in THF (70 mL), treated with
LiBH4 (31 mg, 1.4 mmol), and left for 12 h. Subsequently, unreacted borohy-
dride was decomposed with water (0.5 mL). The mixture was filtered through
Celite, evaporated, and purified by chromatography using CH2Cl2/methanol
95:5 v/v as an eluent to afford 22 (229 mg, 72 %). [a]D þ0.5 (c 0.2, MeOH);
1
IR (film): v 3227 cm21; H NMR (500 MHz, CDCl3) d: 4.65 (d, 1H, J ¼ 9.8 Hz,
H-2), 3.92 (dd, 1H, J ¼ 3.2, 12.0, Hz, CHHOH), 3.89 (dd, 1H, J ¼ 5.9, 8.0 Hz,
H-10), 3.86 (dd, 1H, J ¼ 5.9, 12.0 Hz, CHHOH), 3.76 (dd, 1H, J ¼ 4.9,
12.5 Hz, H-3a), 3.73 (dd, 1H, J ¼ 5.9, 10.1 Hz, CHHOTBDPS), 3.66 (dd, 1H,
J ¼ 8.0, 10.1 Hz, CHHOTBDPS), 3.48 (m, 1H, H-7), 3.01 (dddd, 1H, J ¼ 3.2,
5.9, 9.8, 12.5 Hz, H-3), 2.92 (ddd, 1H, J ¼ 3.1, 11.6, 13.7 Hz, H-70), 2.29 (ddd,
1H, J ¼ 4.9, 4.9, 13.7, 15.4 Hz, H-4), 2.12 (qt, 1H, J ¼ 3.8, 13.7 Hz, H-6), 1.92
(m, 1H, H-40), 1.71 (m, 1H, H-5), 1.65 (m, 1H, H-60), 1.44 (qt, 1H, J ¼ 4.0,
13.7 Hz, H-50), 1.06 (s, 9H, t-Bu); 13C NMR (125 MHz, CDCl3) d: 77.5, 69.8,
67.8, 64.3, 58.6, 58.5, 45.7, 26.9, 24.1, 23.4, 19.2, 17.2; MSHR (ESI) m/z
[M þ H]þ, calcd. for C26H38NO4Si: 456.2565. Found: 456.2574.

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(1aS, 10S, 2S, 2aS)-1a-(10-Acetoxy-20-tert-
butylodiphenylsiloxyethyl)-3-acetoxymethyl-
piperidino[1,2-b]dihydro-(3H)-isoxazole (23)
Compound 23 was obtained according procedure described for 17 (89%).
1
[a]D þ2.1 (c 0.1, CH2Cl2); IR (film): v 1768, 1743 cm21; H NMR (500 MHz,
CDCl3) d: 5.24 (bt, 1H, H-10), 4.47 (m, 1H, H-2), 4.11 (m, 2H, CH2OAc), 3.75
(m, 2H, CH2OTBDPS), 3.45 (m, 1H, H-7), 2.65 (m, 1H, H-3), 2.50 (m, 1H,
H-70), 2.05, 2.03 (2s, 6H, 2 ꢀ OAc), 2.04 (m, 1H, H-3a), 1.94 (m, 1H, H-4),
1.85–1.60 (m, 3H, H-5,6,60), 1.45 (m, 1H, H-40), 1.26 (m, 1H, H-50), 1.04
(s, 9H, t-Bu); 13C NMR (125 MHz, CDCl3) d: 170.7, 169.9, 74.4, 71.4, 70.5,
62.5, 62.4, 55.1, 48.0, 29.0, 26.7, 24.7, 23.6, 21.2, 20.8, 19.2; MSHR (ESI) m/z
[M þ Na]þ, calcd. for C30H41NO8SiNa: 540.2776. Found: 540.2768.
(1aS, 2S, 6aS, 6bR)-2-(tert-Butyldiphenylsiloxymethyl)-
4,4-dimethyl-3,5-dioxa-piperidino[1,2-b]izoxazolidino
[4,5-c]cycloheptane (24)
Compound 22 (228 mg, 0.5 mmol) was dissolved in 2,2-dimethoxypropane
(50 mL) and treated with p-TsOH (5 mg). The mixture was refluxed for 1 h.
Subsequently, it was cooled and treated with Et3N (1 mL). After evaporation
of solvents the mixture was purified by chromatography using hexane/
AcOEt 3:1 v/v as an eluent to afford 24 (233 mg, 94%). [a]D þ13.2 (c 0.6,
CH2Cl2); 1H NMR (500 MHz, toluene-d8, 1008C) d: 4.19 (m,1H, H-1a), 4.17
(ddd, 1H, J ¼ 1.9, 5.6, 7.3 Hz, H-2), 4.04 (dd, 1H, J ¼ 5.6, 10.3 Hz,
CHHOTBDPS), 4.01 (dd, 1H, J ¼ 7.3, 10.3 Hz, CHHOTBDPS) 3.85 (dd, 1H,
J ¼ 9.0, 12.6 Hz, H-6), 3.52 (dd, 1H, J ¼ 5.0, 12.6 Hz, H-60), 3.26 (td, 1H,
J ¼ 3.6, 10.5 Hz, H-10), 2.56 (m, 1H, H-100), 2.50 (ddd, 1H, J ¼ 3.1, 10.5,
11.0 Hz, H-100), 2.26 (m, 1H, H-6b), 2.16 (m, 1H, H-6a), 1.54 (m, 1H, H-9),
1.44 (m, 1H, H-8), 1.38 (2s, 6H, 2 ꢀ CH3), 1.37–1.26 (m, 3H, H-7,7090), 1.16
(s, 9H, t-Bu); 1.05 (m, 1H, H-80); 13C NMR (125 MHz, CDCl3) d: 101.8, 77.2,
72.3, 64.3, 61.5, 50.3, 31.9, 29.7, 29.4, 26.8, 26.8, 22.7, 19.2, 19.2, 14.1; MSHR
(ESI) m/z [M þ H]þ, calcd. for C29H42NO4Si: 496.2878. Found: 496.2858.
(1aS, 2S, 6aS, 6bR)-4,4-Dimethyl-3,5-dioxa-2-
hydroxymethyl-piperidino[1,2-b]izoxazolidino[4,5-c]
cycloheptane (25)
Compound 24 (198 mg, 0.4 mmol) was dissolved in THF (30 mL) and
treated with 5 equiv. tetrabutylammonium fluoride. After 24 h at rt, the
mixture was filtered through celite and evaporated to afford partially
purified 25 (83 mg, 91%), which was used for the next step. Small sample
was purified by chromatography using methanol/AcOEt 5:95 v/v as an

Synthesis of 2,3-Dihydroxy-1-Epilupinine
207
eluent to prove identity of compound 25. [a]D þ2.1 (c 0.2, CH2Cl2); IR (film
CH2Cl2): v 3419 cm21; MSHR (ESI) m/z [M þ Na]þ, calcd. for C13H23NO4Na:
280.1519. Found: 280.1531.
(1aS, 2S, 6aS, 6bR)-4,4-Dimethyl-3,5-dioxa-2-
mesyloxymethyl-piperidine[1,2-b]izoxazolidino[4,5-c]
cycloheptane (26)
Alcohol 25 (68 mg, 0.3 mmol) dissolved in dry CH2Cl2 (20 mL) was treated
with TEA (61 mg, 0.6 mmol) and cooled to –58C. Subsequently, mesyl chloride
(41 mg, 0.36 mmol) was added and the temperature was allowed to raise to rt.
After 30 min the mixture was washed with brine (20 mL) and water (20 mL),
dried, and evaporated to afford crude 26 (88 mg, 96%). Small sample was
purified using hexane/AcOEt, 1:2 v/v as an eluent to prove identity of
compound 26. [a]D 211.7 (c 0.2, CH2Cl2); MSHR (ESI) m/z [M þ H]þ, calcd.
for C14H26NO6S: 336.1475. Found: 336.1491.
(1S, 2S, 3S, 9aS)-1-Acetoxymethyl-2,3-diacetoxy-
quinolizidine (27)
Compound 26 (91 mg, 0.3 mmol) was dissolved in 80% acetic acid (30 mL)
and the solution was refluxed for 10 min. Subsequently, solvents were evapor-
ated and the residue, in order to remove traces of water, was twice treated with
toluene (2 ꢀ 20 mL) and twice carefully evaporated. The oily residue was dis-
solved in AcOEt/methanol (4:1 v/v, 35 mL) and treated with anhydrous
K2CO3 (41 mg) and 10% Pd/C (11 mg). The mixture was hydrogenated at rt
for 24 h. Subsequently, the catalyst was filtered off and the solvents were evap-
orated. The residue was dissolved in TEA (10 mL) and treated with acetic anhy-
dride (10 mL) and DMAP (0.03 mmol). After 4 h at rt, solvents were evaporated
and the crude product was purified by chromatography using hexane/AcOEt
3:2 v/v as an eluent to afford 27 (72 mg, 73 %). [a]D þ0.8 (c 0.45, CH2Cl2); IR
(film CH2Cl2): v 1745 cm21 1H NMR (500 MHz, C6D6) d: 5.26 (dd, 1H,
;
J ¼ 9.6, 10.3 Hz, H-2), 5.22 (ddd, 1H, J ¼ 4.8, 9.6, 10.0 Hz, H-3), 4.20 (dd,
1H, J ¼ 2.8, 12.1 Hz, CHHOAc), 3.91 (dd, 1H, J ¼ 2.4, 12.1 Hz, CHHOAc),
2.90 (dd, 1H, J ¼ 4.8, 11.0 Hz, H-4), 2.48 (m, 1H, H-6), 1.94 (dd, 1H, J ¼ 10.0,
11.0 Hz, H-40), 1.80 (m, 1H, H-9a), 1.77, 1.75, 1.71 (3s, 9H, 3 ꢀ OAc), 1.70
(m, 1H, H-60), 1.65 (m, 1H, H-9), 1.51 (dddd, 1H, J ¼ 2.4, 2.8, 10.3, 10.5 Hz,
H-1), 1.48 (m, 1H, H-8), 1.38 (m, 1H, H-7), 1.30 (m, 1H, H-70), 0.95 (m, 1H,
H-80), 0.87 (m, 1H, H-90); 13C NMR (125 MHz, C6D6) d: 170.4, 170.1, 169.8,
71.8, 71.7, 60.8, 59.1, 57.7, 55.8, 45.8, 29.5, 25.5, 24.0, 20.5, 20.4, 20.3; MSHR
(ESI) m/z [M þ H]þ, calcd. For C16H26NO6: 328.1754. Found: 328.1749.

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(1S, 2S, 3S, 9aS)-2,3-Dihydroxy-1-hydroxymethyl-
quinolizidine (28)
Compound 27 (33 mg, 0.1 mmol) was dissolved in 1.3% solution of ammonia
in methanol (10 mL) and left at rt for 24 h. Subsequently, solvents were evap-
orated and the product was purified by chromatography using methanol/
CH2Cl2 4:1 v/v as an eluent to afford 28 (17 mg, 87%). [a]D þ3.5 (c 0.7,
1
MeOH); IR (film): v 3307 cm21; H NMR (500 MHz, CD3OD) d: 3.98 (dd, 1H,
J ¼ 2.5, 11.4 Hz, CHHOH), 3.77 (dd, 1H, J ¼ 3.3, 11.4 Hz, CHHOH), 3.60
(ddd, 1H, J ¼ 4.8, 8.9, 10.8 Hz, H-3), 3.42 (dd, 1H, J ¼ 8.9, 10.7 Hz, H-2),
2.92 (dd, 1H, J ¼ 4.8, 11.2 Hz, H-4), 2.93 (m, 1H, H-6), 2.16 (m, 1H, H-60),
2.10 (m, 1H, H-9), 2.06 (dd, 1H, J ¼ 10.8, 11.2 Hz, H-40), 2.02 (dt, 1H, J ¼ 2.6,
10.6 Hz, H-9a), 1.85 (m, 1H, H-8), 1.71 (m, 1H, H-7), 1.65 (m, 1H, H-70), 1.37
(m, 1H, H-80), 1.28 (dddd, 1H, J ¼ 2.5, 3.3, 10.6, 10.7 Hz, H-1), 1.20 (m, 1H,
H-90); 13C NMR (125 MHz, CD3OD) d: 74.5, 72.6, 62.7, 62.0, 58.5, 57.4, 30.2,
26.1, 24.9; MSHR (ESI) m/z [M þ H]þ, calcd. for C10H20NO3: 202.1447.
Found: 202.1447.
MEASUREMENTS OF ENZYME INHIBITION
The following hydrolases were used: a-L-glucosidase from rice (type V, 63.43
U/mg, 1.34 mg/mL, Sigma); b-D-glucosidase from almonds (25.8 U/mg,
95.4% protein, Sigma); a-D-mannosidase from jack bean (6.2 mg prot./mL,
22 U/mg, Sigma); a-L-fucosidase from bovine kidney (28.0 U/mg, 0.55 mg
prot./mL, Sigma); b-D-galactosidase from bovine liver (0.148 U/mg, Sigma)
solution (0.562 U/mL); and b-D-glucuronidase from bovine liver (2630 U/mg,
Sigma) solution (4909 U/mL). These enzymes were assayed with appropriate
p-nitrophenyl glycoside substrates (phenolphthalein b-glucuronide for
b-glucuronidase), which were also purchased from Sigma. Hydrolase activities
were measured by modification of the procedures described previously.[15–19]
ACKNOWLEDGEMENTS
This work was supported by the Ministry of Science and Information Grant # 3
T09A 025 28.
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nitrone to a,b-unsaturated d-lactones. Tetrahedron Asymm. 2000, 11, 2015–2022.
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[2] Socha, D.; Jurczak, M.; Frelek, J.; Klimek, A.; Rabiczko, J.; Urbanczyk-
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Lipkowska, Z.; Suwinska, K.; Chmielewski, M.; Cardona, F.; Goti, A.; Brandi, A.

Synthesis of 2,3-Dihydroxy-1-Epilupinine
209
1,3-Dipolar cycloaddition of a nitrone derived from (S)-malic acid to a,b-unsatu-
rated d-lactones. Tetrahedron Asymm. 2001, 12, 3163–3172.
´
´
´
[3] Pasniczek, K.; Socha, D.; Jurczak, M.; Frelek, J.; Suszczynska, A.; Urbanczyk-
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