Methyl D-arabino-hex-2-ulopyranosonate as a building block for spiro[1,4-benzoxazine-2,2'-pyrans]

Article abstract of DOI:10.1016/S0008-6215(99)00039-7

A novel glycosyl donor, methyl (3,4,5-tri-O-acetyl-β-D-arabino-hex-2-ulopyranosyl)onate bromide, obtained in two steps from methyl β-D-arabino-hex-2-ulopyranosonate, was converted into its α-nitrophenyl glycoside, which in turn was reductively cyclized to form acetylated benzoxazinoid spirans. Deprotection led to (2S)-3',4,4',5'-tetrahydroxy-D-arabino-2H-1,4-benzoxazin-2-spiro-2'-pyran-3(4H)-one and (2S)-3',4',5'-trihydroxy-D-arabino-2H-1,4-benzoxazin-2-spiro-2'-pyran-3(4H)-one. Analogous compounds are prepared from 5-methoxy-2-nitrophenol. The new class of spiro functionalized carbohydrates is structurally related to natural benzoxazinone acetal glucosides. The assignment of configuration and conformation of all products was based on ¹H NMR H,H coupling constants and optical rotation values. Copyright (C) 1999 Elsevier Science Ltd.

Full text of DOI:10.1016/S0008-6215(99)00039-7

Carbohydrate Research 316 (1999) 85–94
Methyl
D
-arabino-hex-2-ulopyranosonate as a building
block for spiro[1,4-benzoxazine-2,2%-pyrans]ꢀ
Jens Andersch, Dieter Sicker *, Horst Wilde
Institut fu¨r Organische Chemie der Uni6ersita¨t Leipzig, Talstraße 35, D-04103 Leipzig, Germany
Received 11 September 1998; accepted 28 January 1999
Abstract
A novel glycosyl donor, methyl (3,4,5-tri-O-acetyl-b-
steps from methyl b- -arabino-hex-2-ulopyranosonate, was converted into its a-nitrophenyl glycoside, which in turn
was reductively cyclized to form acetylated benzoxazinoid spirans. Deprotection led to (2S)-3%,4,4%,5%-tetrahydroxy-
arabino-2H-1,4-benzoxazin-2-spiro-2%-pyran-3(4H)-one and (2S)-3%,4%,5%-trihydroxy- -arabino-2H-1,4-benzoxazin-2-
D-arabino-hex-2-ulopyranosyl)onate bromide, obtained in two
D
D
-
D
spiro-2%-pyran-3(4H)-one. Analogous compounds are prepared from 5-methoxy-2-nitrophenol. The new class of spiro
functionalized carbohydrates is structurally related to natural benzoxazinone acetal glucosides. The assignment of
1
configuration and conformation of all products was based on H NMR H,H coupling constants and optical rotation
values. © 1999 Elsevier Science Ltd. All rights reserved.
Keywords:
D
-arabino-Hex-2-ulopyranosonates; Glycosidation; Spiro[1,4-benzoxazine-2,2%-pyran]ones; Cyclic hydroxamic acid
starting material for chemical synthesis is the
1. Introduction
crystalline methyl b-
nosonate (1) [8]. The b-
tion of crystalline 1 undergoes a slow iso-
merization in solution to form an a- -pyran-
oid as well as cis- and trans-furanoid isomers
in addition to the b- -pyranoid form [9].
D
-arabino-hex-2-ulopyra-
D-pyranose conforma-
Carbohydrates have often been used as in-
expensive chiral building blocks for syntheses
of various natural compounds, their analogues
or precursors [1,2]. However,
ulosonic acid (‘2-oxo- -gluconic acid’), used
on an industrial scale for the production of
isoascorbic acid [3], has received little atten-
tion with regard to the synthesis of O- or
C-glycosides [4] or as an a-keto carboxylate
building block [5]. This acid has been synthe-
D
D
-arabino-hex-2-
D
D
Recently, we reviewed the synthesis of ben-
zoxazinoids [10], naturally occurring in differ-
ent species of Gramineae [11], Acanthaceae
[12], Ranunculaceae [13], and Scrophulariaceae
[14]. We reported on the diastereoselective
synthesis of benzoxazinone acetal glucosides
[15] and on the first synthesis of an enan-
tiomer of a natural acetal glucoside [16]. The
spiroacetalic saccharide–heterocycle combina-
tion reported resembles the acetal glucosides,
structurally.
sized by biochemical oxidation of
[6–8] or chemically from
tives using different oxidants [8]. A suitable
D
-glucose
D
-fructose deriva-
ꢀ Dedicated to Professor Klaus Schulze on the occasion of
his 65th birthday.
* Corresponding author. Tel.: +49-341-973-6574; fax: +
49-341-973-6599.
We describe here the preparation of a novel
glycosyl donor, methyl (3,4,5-tri-O-acetyl-b-
D
-arabino-hex-2-ulopyranosyl)onate bromide,
E-mail address: sicker@orgchem.uni-leipzig.de (D. Sicker)
from methyl b- -arabino-hex-2-ulopyran-
D
0008-6215/99/$ - see front matter © 1999 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(99)00039-7

86
J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
osonate and its glycosidation with 2-nitro-
phenol and 5-methoxy-2-nitrophenol, res-
pectively, followed by reductive cyclization of
the glycosides to novel benzoxazinoid spiro
acetals (Scheme 1).
nosonate (5) as the product of partial hydro-
lysis. Glycosyl bromide 3 was nearly quantita-
tively obtained when the reaction was per-
formed with a solution of 33% hydrogen
bromide in glacial acetic acid. Hydrolysis of 3
with silver carbonate and water yielded the
stereoisomeric methyl 3,4,5-tri-O-acetyl-a- -
D
arabino-hex-2-ulopyranosonate (4), exclu-
sively. On standing in chloroform solution for
some days, the a isomer 4 underwent a com-
plete isomerization into the thermodynami-
cally stable b isomer 5.
2. Results and discussion
On reinvestigating the acetylation of methyl
b- -arabino-hex-2-ulopyranosonate (1) with
D
acetic anhydride [17,18] we have found that
this reaction, in the presence of an acidic
(H2SO4, HClO4, ZnCl2) or basic (4-DMAP in
pyridine) catalyst, led to methyl 2,3,4,5-tetra-
Bromide 3 was used as a glycosyl donor in
the reaction with potassium 2-nitro-phenolate
or its 5-methoxy derivative in acetone. Due to
the neighbouring group assistance of the 3-
acetyl group, this reaction proceeds with in-
version of the configuration at the anomeric
centre via an intermediate acetyl oxonium ion,
in which the axial position is shielded. There-
fore, a nucleophile can only attack from the
equatorial direction, which leads to an inver-
sion at the anomeric centre. Diastereoselec-
tively, methyl (2-nitrophenyl 3,4,5-tri-O-
O-acetyl-b- -arabino-hex-2-ulopyranosonate
D
(2) as the main product (78%). On the con-
trary, performing the reaction in pyridine at
0 °C led to an inseparable mixture of tetraac-
etate 2 with trans- and cis-furanoid tetraac-
etates (88%, 1:12:2).
Bromination of 2 by hydrogen bromide
generated in situ from phosphorus tribromide
and water afforded a mixture of the methyl
(3,4,5-tri-O-acetyl-b-
osyl)onate bromide (3) accompanied by methyl
3,4,5-tri-O-acetyl-b- -arabino-hex-2-ulopyra-
D
-arabino-hex-2-ulopyran-
acetyl-a-
(6) and methyl (5-methoxy-2-nitrophenyl 3,4,5
-tri-O-acetyl-a- -arabino-hex-2-ulopyranosid)-
D
-arabino-hex-2-ulopyranosid)onate
D
D
onate (7) have been obtained as 2,3-trans ni-
trophenyl glycosides in yields of 96 and 47%,
respectively. 5 - Methoxy - 2 - nitrophenolate
proved to be a weak nucleophile preventing a
complete reaction of 3 to 7. Prolongation of
the reaction time led to decomposition of 7
and 3, only. However, parts of 3 could be
recovered.
The nitrophenyl glycosides 6 and 7 are suit-
able precursors for reductive cyclizations to
form a new class of carbohydrates with the
spiro[1,4-benzoxazine-2,2%-pyrane]-skeleton. In
principle both products with a cyclic hydrox-
amic acid and a lactam unit are to be ex-
pected, depending on whether the hydrox-
ylamine or amine intermediate generated by
reduction of the nitro group reacts with the
ester group to form the benzoxazinone ring.
Which cyclization is favoured can be con-
trolled by the use of an appropriate reducing
system. We have investigated the catalytic hy-
drogenation with different catalysts and sol-
vents and the zinc dust reduction. Catalytic
hydrogenation of the nitrophenyl glycosides 6
Scheme 1. (a) Ac2O, H2SO4, 60 °C, 20 min; (b) HBr, HOAc;
(c) Ag2CO3, H2O; (d) CHCl3, rt, 20 days; (e) 2-nitrophenol
for 6, 5-methoxy-2-nitrophenol for 7, K2CO3, acetone, reflux;
(f) NH4Cl, Zn, MeOH, 2 h; (g) H2, 5% Pt–C, MeOH; (h) 1.
NaOMe, MeOH, 2. Amberlite IR 120.

J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
87
17 has been accessible in very good yield from
glycosyl bromide 3 adapting a zinc dust/
pyridine protocol in hot toluene used for the
synthesis of 2,6-anhydro-3-deoxy-hex-2-enone
nitriles [20].
and 7 in methanol over platinum on carbon at
normal pressure gave rise to the lactams (2S)-
3%,4%,5%-tri-O-acetyl-
azin-2-spiro-2%-pyran-3(4H)-one (10) (72%)
and (2S)-3%,4%,5%-tri-O-acetyl-7-methoxy-
D-arabino-2H-1,4-benzox-
D-
Some alternative reactions of glycosyl bro-
mide 3 have been studied. In principle, lactam
10 (21%) can be alternatively synthesized by
condensation of bromide 3 with 2-aminophe-
nol in the presence of potassium carbonate. In
this case, deprotonation of the ambident 2-
aminophenol results in the necessary 2-
aminophenyl O-glycosidic intermediate. How-
ever, this reaction is accompanied by a lot of
decomposition products. Therefore, the reduc-
tive cyclization of the isolated 2-nitrophenyl
glycosides is the preferred pathway to the
hydroxamic acids 8 and 9 as well as to lactams
10 and 11. Furthermore, any N-nucleophiles
like 1,2-phenylenediamine, 2-nitroaniline, ac-
etamidine, semicarbohydrazide or carbohy-
drazide did not react at all with bromide 3 to
form N-glycosides or cyclization products.
Only the elimination of hydrogen bromide
and dark-coloured decomposition products
were observed.
arabino-2H-1,4-benzoxazin-2-spiro-2%-pyran-
3(4H)-one (11) (95%), respectively. The cyclic
hydroxamic acids (2S)-3%,4%,5%-tri-O-acetyl- -
D
arabino-4-hydroxy-2H-1,4-benzoxazin-2-spiro-
2%-pyran-3(4H)-one (8) (23%) and (2S)-
3%,4%,5%-tri-O-acetyl- -arabino-4-hydroxy-7-
D
methoxy-2H-1,4-benzoxazin-2-spiro-2%-pyran-
3(4H)-one (9) (traces) were obtained as
by-products. However, due to their ability to
complex metal ions, cyclic hydroxamic acids
are of special interest. Therefore attempts to
increase the yields of 8 and 9 have been made.
Variations of the hydrogenation system that
have been successful in related cases, like us-
ing a deactivated catalyst (sulfided platinum
on carbon) and an acidic solvent (glacial
acetic acid) [19], have been of no avail in these
cases. Hydrogenations in basic solvents are
unusual but not impossible. Thus, interesting
results were obtained on hydrogenation with
the Pt–C catalyst in pyridine, which slows
down the reduction of the hydroxylamine in-
termediate and enhances its nucleophilicity.
Hydrogenation of 6 afforded 79% hydroxamic
acid 8 as the major product and 15% lactam
10. Glycoside 7 yielded hydroxamic acid 9
(39%) beside lactam 11 (49%). Finally, a stan-
dard reduction with zinc and ammonium chlo-
ride in methanol was performed directed on
hydroxamic acids. Thus, reductive cyclization
of 6 led to 8 (85%) accompanied by 10 (8%).
Similarly, cyclization of 7 yielded 9 (54%)
together with 11 (14%). Standard deprotection
of the acetates 8–11 with methanolate fol-
lowed by neutralization with an ion-exchange
The structures of compounds 2–17 were
assigned by spectroscopic methods. The
configurations at tertiary anomeric centres of
tetraacetate 2 and lactam 10 were unequivo-
cally elucidated by X-ray analyses [21]. The
tetraacetate 2 has the b-
D
- and the lactam 10
the (2S)-configuration. In conclusion, the
(2S)-configuration of 10 proves also the a- -
D
configuration of the starting nitrophenyl gly-
cosides 6 and 7 discussed above, because no
configurational change is to be expected dur-
ing their reductive cyclization.
The conformation of the pyranoid ring in
compounds 2–15 has been studied (Table 1).
2
5
resin gave rise to the (2S)-3%,4%,5%-trihydroxy-
D-
If a C5 or a C2 conformation is favoured,
this results in interactions of the substituents
at positions C-3% and C-4% of the saccharidic
moiety with the nitrophenoxy substituent at
C-2% or the benzoxazinone ring, respectively.
arabino-2H-1,4-benzoxazin-2-spiro-2%-pyran-
3(4H)-ones 12–15 in very good yield.
During the zinc dust reductions of the gly-
cosides 6 and 7, the formation of the glycals
was observed as result of elimination side
5
The glycosides 6 and 7 adopt a C2 pyran-
reactions. Thus, methyl 3,4,5-tri-O-acetyl-
D
-
oid ring geometry indicated by the small
H,H coupling constants (J3,4 4.4–4.6, J4,5 3.7–
3.8 Hz). According to an empirical increment
system for the determination of the optical
rotation of pyranoses [22], positive rotation
erythro-hex-2-enopyranosonate (16) (2%) was
obtained from 6 and methyl 4,5-di-O-acetyl-
2,6-anhydro-3-deoxy-
D
-erythro-hex-2-eno-
sonate (17) (9%) was derived from 7. Glycal

88
J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
D-arabino-hex-2-ulopyranosonates 2–15
Table 1
Conformational assignment of the
Structure
Compound
[h]D (°)
J3,4 (Hz)a
J4,5 (Hz)a
Conformation
2: X=OAc, R=CO2Me
3: X=Br, R=CO2Me
4: X=CO2Me, R=OH
5: X=OH, R=CO2Me
−132
−80
−85
10.3
9.3
10.1
10.1
3.5
3.4
3.3
3.2
2C5
−175
6: R=H
7: R=OCH3
+55
+45
4.6
4.4
3.8
3.7
5C2
8: R=H, R%=OH
9: R=OCH3, R%=OH
10: R=H, R%=H
−60
−66
−37
−44
10.6
10.4
10.4
10.4
3.6
3.2
3.6
3.8
2C5
11: R=OCH3, R%=H
12: R=H, R%=OH
13: R=OCH3, R%=OH
14: R=H, R%=H
−24
−76
−16
−43
9.6
9.5
9.3
9.1
3.7
3.7
3.7
3.6
2C5
15: R=OCH3, R%=H
a J3%,4% and J4%,5% for 8–15.
3. Experimental
values of 6 and 7 in chloroform are a feature
5
of the C2 conformation because of the domi-
Starting material.—Crystalline methyl b- -
D
nating +synclinal arrangement of the pyr-
anoid substituents. Analogously, the 2C5
conformation of 2–5 and 8–15 was inferred
also from their coupling patterns (J3%,4% 9.2–
10.4, J4%,5% 3.6–3.8 Hz) as well as from their
negative values for the optical rotation. A
arabino-hex-2-ulopyranosonate (1) was pre-
pared from a fermentation solution containing
-arabino-hex-2-ulopyranosonic acid and
D
sodium -arabino-hex-2-ulopyranosonate [8].
D
Analytical methods.—Melting points were
measured on a Boetius melting point appara-
tus and are corrected. NMR spectra were
recorded with a Varian Gemini 200 (1H,
199.975 MHz; 13C, 50.289 MHz) or Varian
Unity 400 (1H, 399.97552 MHz; 13C, 100.577
MHz) using hexamethyldisiloxane as internal
reference. Optical rotations were measured
with a semiautomatic polarimeter Polartronic-
D (Schmidt and Haensch) using the Na–D
line. MS measurements were made on a VG
12-250 spectrometer (VG Masslab, Man-
chester) with 70 eV EI ionization. TLC was
performed on precoated Silica Gel 60 F254
5
comparison of the C2-arranged glycosides 6
and 7 with the cyclization products 8–15
shows that the 1,4-benzoxazinone system
2
forces a conformational change back to C5
with 3%- and 4%-substituents disposed equatori-
ally as in 2–5.
5
The glycals 16 and 17 adopt a H6 confor-
mation according to their H,H coupling con-
stants. Furthermore, the optical rotation value
of glycal 17 is in good agreement with that of
5-di-O-acetyl-2,6-anhydro-3-deoxy- -erythro-
D
hex-2-enose, a close analogue with 5H6 confor-
mation [20,23].

J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
89
3.2 Hz, H-4), 4.33 (d, 1 H, J6a,b 13.4 Hz,
H-6a), 4.25 (d, 1 H, J6a,b 13.4 Hz, H-6b), 3.85
(s, 3 H, OCH3), 2.15, (s, 3 H, OAc), 2.10 (s, 3
H, OAc), 2.00 (s, 3 H, OAc); 13C NMR
(CDCl3): l 170.5 (CO), 170.3 (CO), 169.5
(CO), 165.5 (C-1), 95.9 (C-2), 69.9 (C-3), 67.7
(C-4), 67.4 (C-5), 66.9 (C-6), 54.4 (OCH3),
21.0 (CH3), 21.3 (CH3), 21.3 (CH3); EIMS:
m/z (%) 356 (8, [M+ +2-OAc], 354 (9,
[M+ −OAc], 317 (20, [M+ −HBr]), 259 (12),
197 (17), 173 (23), 155 (39), 128 (37), 43 (100).
Anal. Calcd for C13H17BrO9: C, 39.31; H,
4.31. Found: C, 38.66; H, 4.16.
aluminium sheets (E. Merck); spots were visu-
alized by gentle heating. Elemental analyses
were determined on a Heraeus CHN–O
Rapid analyser.
Methyl 2,3,4,5-tetra-O-acetyl-i- -arabino-
D
hex-2-ulopyranosonate (2).—To a stirred sus-
pension of 1 (4.16 g, 20 mmol) in Ac2O (25
mL) concentrated H2SO4 (0.5 mL) was added
at 20 °C. The temperature was raised to 60 °C
and kept there for 20 min. The solution was
cooled and then poured into ice. The precipi-
tate was filtered off, washed with water and
recrystallized from MeOH to yield 5.86 g
(78%) of 2 as colourless crystals; mp 171 °C,
lit 168–169 °C [18]; [h]2D2−130° (c 1.0,
CHCl3); Rf 0.43 (1:1 toluene–EtOAc); 1H
NMR (400 MHz, CDCl3): l 5.45 (d, 1 H, J3,4
10.4 Hz, H-3), 5.39 (m, 1 H, H-5), 5.38 (m, 1
H, H-4), 4.02 (d, 1 H, J6a,b 13.4 Hz, H-6b),
3.90 (d, 1 H, J6a,b 13.4 Hz, H-6a), 3.78 (s, 3 H,
OCH3), 2.21 (s, 3 H, OAc), 2.18 (s, 3 H, OAc),
2.04 (s, 3 H, OAc), 2.01 (s, 3 H, OAc); 13C
NMR (50 MHz, CDCl3): l 170.7 (CO), 170.3
(CO), 170.2 (CO), 168.6 (CO), 165.3 (C-1),
96.5 (C-2), 67.9 (C-3), 68.9 (C-4), 67.1 (C-5),
63.9 (C-6), 53.9 (OCH3), 21.3 (CH3), 21.2
(CH3), 21.0 (CH3), 20.9 (CH3); EIMS: m/z
(%): 317 (37, [M]+), 275 (11), 257 (5), 233 (7),
216 (10), 197 (16), 170 (40), 155 (19), 128 (40),
115 (18), 43 (100). Anal. Calcd for C15H20O11:
C, 47.88; H, 5.36. Found: C, 47.80; H, 5.21.
Methyl 2-hydroxy-3,4,5-tri-O-acetyl-h-
arabino-hex-2-ulopyranosonate (4).—To
D
-
a
stirred solution of 3 (1.59 g, 4.0 mmol) in dry
acetone (5 mL) water (42 mL, 2.3 mmol) was
added at 0 °C with a syringe, and within 10
min Ag2CO3 (0.93 g, 3.4 mmol) in portions.
After 30 min the mixture was allowed to warm
to room temperature (rt) and stirred for an
additional 10 min. The resultant silver salts
were filtered off, washed with acetone and the
filtrate was evaporated. The crude syrup crys-
tallized on treating with diisopropylether (1
mL). Recrystallization from diisopropylether
yielded 1.27 g (95%) of 4 as colourless crystals,
mp 105–108 °C; [h]2D2−85° (c 1.0, CHCl3); Rf
0.35 (1:1 toluene–EtOAc); 1H NMR (200
MHz, CDCl3): l 5.58 (dd, 1 H, J3,4 10.1, J4,5
3.2 Hz, H-4), 5.48 (d, 1 H, J3,4 10.1 Hz, H-3),
5.37 (m, 1 H, H-5), 4.59 (s, 1 H, 2-OH), 4.05
(m, 2 H, H-6a, H-6b), 3.95 (s, 3 H, OCH3),
2.17 (s, 3 H, OAc, 2.05 (s, 3 H, OAc), 2.02 (s,
3 H, OAc); 13C NMR (50 MHz, CDCl3): l
170.8 (CO), 170.5 (CO), 169.8 (CO), 168.6
(C-1), 96.5 (C-2), 70.2 (C-3), 69.7 (C-4), 68.0
(C-5), 64.8 (C-6), 53.9 (OCH3), 21.4 (2×
CH3), 21.1 (CH3); EIMS: m/z (%): 334 (7,
M+), 253 (6), 231 (10), 215 (6), 170 (28), 155
(12), 145 (19), 128 (17), 115 (20), 43 (100).
Anal. Calcd for C13H18O10: C, 46.71; H, 5.43.
Found: C, 46.52; H, 5.89.
Methyl (3,4,5-tri-O-acetyl-i- -arabino-hex-
D
2-ulopyranosyl)onate bromide (3).—A mixture
of powdered 2 (3.76 g, 10 mmol) in a 33%
solution of HBr in HOAc (40 mL) was stirred
for 2 h at 20 °C. The solution was diluted with
ice-cold CHCl3 (60 mL) and poured into ice
water (100 mL). The CHCl3 layer was sepa-
rated and the aq phase extracted again with
CHCl3 (15 mL). The CHCl3 extracts were
washed successively with ice water (60 mL),
twice with a cold solution of NaHCO3 (2%, 60
mL) and again with ice water (60 mL). After
drying the colourless solution over MgSO4 the
solvent was evaporated to yield 3.89 g (98%)
of 3 as colourless powder; mp 78–80 °C;
[h]2D2−175° (c 1.0, CHCl3); Rf 0.61 (1:1
toluene–EtOAc); 1H NMR (200 MHz,
CDCl3): l 5.48 (d, 1 H, J3,4 10.0 Hz, 3-H),
5.39 (m, 1 H, H-5), 5.13 (dd, 1 H, J3,4 10.0, J4,5
Methyl 2-hydroxy-3,4,5-tri-O-acetyl-i- -
D
arabino-hex-2-ulopyranosonate (5).—A solu-
tion of 4 (67 mg, 0.2 mmol) in CDCl3 (0.8
mL) was kept several days at rt until 1H NMR
monitoring showed the reaction to be com-
plete. The solvent was evaporated to yield 67
mg (100%) of 5 as colourless syrup; [h]2D2−80°

90
J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
EIMS: m/z (%): 455 (1, [M+]), 396 (5, [M+
−COOCH3]), 317 (30), 257 (3), 215 (8), 197
(30), 155 (52), 42 (100). Anal. Calcd for
C19H21NO12: C, 50.11; H, 4.65; N, 3.07.
Found: C, 50.09; H, 4.69; N, 2.75.
(c 1.0, CHCl3); Rf 0.35 (1:1 toluene–EtOAc);
1H NMR (200 MHz, CDCl3): l 5.60 (d, 1 H,
J3,4 9.3 Hz, H-3), 5.38 (m, 1 H, H-5), 5.35 (dd,
1 H, J3,4 9.3, J4,5 3.2 Hz, 4-H), 4.39 (d, 1 H,
J3,2-OH 1.0 Hz, 2-OH), 4.23 (d, 1 H, J6a,b 13.1
Hz, H-6b), 3.85 (s, 3 H, OCH3), 3.81 (m, 1 H,
H-6a), 2.18 (s, 3 H, OAc), 2.02 (s, 3 H, OAc),
1.98 (s, 3 H, OAc); 13C NMR (50 MHz,
CDCl3): l 170.9 (CO), 170.4 (CO), 170.1
(CO), 169.2 (C-1), 95.3 (C-2), 69.3 (C-4), 68.7
(C-5), 68.5 (C-3), 63.1 (C-6), 54.4 (OCH3),
21.5 (CH3), 21.1 (2×CH3); EIMS: m/z (%):
318 (14), 276 (32, [M+ −COOCH3]), 234 (22),
215 (20), 187 (8), 170 (10), 128 (17), 115 (9), 44
(100). Anal. Calcd for C13H18O10: C, 46.71; H,
5.43. Found: C, 46.63; H, 5.78.
General procedure for the glycosidation to
form the phenyl glycosides 6 and 7.—To a
stirred solution of 3 (1.98 g, 5.0 mmol) in dry
acetone (50 mL) were added the correspond-
ing pure phenol (0.77 g, 5.5 mmol of 2-nitro-
phenol for 6; 1.14 g, 5.5 mmol of
5-methoxy-2-nitrophenol for 7) and K2CO3
(1.38 g, 5.0 mmol). After refluxing (3 h for 6;
8 h for 7) CHCl3 (30 mL) was added and the
mixture was cooled to 0 °C. The solid was
filtered off and washed with CHCl3. The
filtrate was evaporated and the resulting syrup
was purified by column chromatography with
3:1 toluene–EtOAc.
Methyl (5-methoxy-2-nitrophenyl 3,4,5-tri-
O-acetyl-h- -arabino-hex-2-ulopyranosid)-
D
onate (7).—Column chromatography gave
successively 0.65 g (33%) of recovered 3 and a
product fraction which was crystallized from
MeOH to give 1.14 g (47%) of 7 as pale yellow
crystals; mp 54–57 °C; [h]2D2+45° (c 1.0,
CHCl3); Rf 0.36 (2:1 toluene–EtOAc); 1H
NMR (400 MHz, CDCl3): l 7.89 (d, 1 H, J3,4
9.2 Hz, H-3Ar), 6.96 (d, 1 H, J4,6 2.4 Hz,
H-6Ar), 6.59 (dd, 1 H, J3,4 9.2, J4,6 2.4 Hz,
H-4Ar), 5.53 (d, 1 H, J3,4 4.4 Hz, H-3), 5.40
(m, 1 H, H-4), 5.37 (m, 1 H, H-5), 4.12 (m, 2
H, H-6a, H-6b), 3.80 (s, 3 H, OCH3), 3.63 (s,
3 H, COOCH3), 2.15 (s, 3 H, OAc), 2.08 (s, 3
H, OAc), 2.02 (s, 3 H, OAc); 13C NMR (50
MHz, CDCl3): l 170.6 (CO), 170.2 (CO),
168.6 (CO), 166.0 (C-5Ar), 164.3 (C-1), 149.9
(C-1Ar), 135.0 (C-2Ar), 128.2 (C-3Ar), 108.5
(C-4Ar), 104.7 (C-6Ar), 100.4 (C-2), 69.9 (C-
3), 67.1 (C-4), 64.6 (C-5), 60.5 (C-6), 56.4
(OCH3), 53.7 (CO2CH3), 21.0 (CH3), 20.9
(2×CH3), EIMS: m/z (%): 485 (7, [M+]), 426
(21), 317 (100), 257 (11), 215 (16), 197 (53),
156 (46). Anal. Calcd for C20H23NO13: C,
49.49; H, 4.77; N, 2.88. Found: C, 49.36; H,
4.83; N, 2.53.
Methyl (2-nitrophenyl 3,4,5-tri-O-acetyl-h-
D
-arabino-hex-2-ulopyranosid)onate
(6).—
Crystallization of the syrupy product fraction
from MeOH gave 2.18 g (96%) of 6 as pale
yellow crystals; mp 46–47 °C; [h]2D2+55° (c
1.0, CHCl3,); CD Dm235 −17.2, Dm280+4.0,
Dm343+3.1 (c 0.54, CHCl3); Rf 0.64 (toluene–
EtOAc, 1:1 v/v); 1H NMR (400 MHz, CDCl3):
l 7.70 (dd, 1 H, J3,4 8.0, J3,5 1.5 Hz, H-3Ar),
7.43 (m, 2 H, 4-, H-6Ar), 7.16 (m, 1 H, H-5Ar),
5.49 (d, 1 H, J3,4 4.6 Hz, 3-H), 5.37 (dd, 1 H,
J3,4 4.6, J4,5 3.2 Hz, H-4), 5.34 (m, 1 H, H-5),
4.07 (m, 2 H, H-6a, H6-b), 3.62 (s, 3 H,
OCH3), 2.12 (s, 3 H, OAc), 2.04 (s, 3 H, OAc),
1.97 (s, 3 H, OAc); 13C NMR (50 MHz,
CDCl3): l 170.5 (CO), 170.2 (CO), 168.6
(CO), 165.9 (C-1), 147.2 (C-1Ar), 142.1 (C-
2Ar), 133.9 (C-5Ar), 125.7 (C-3Ar), 123.6 (C-
4Ar), 119.1 (C-6Ar), 100.3 (C-2), 70.1 (C-3),
67.1 (C-4), 64.6 (C-5), 60.5 (C-6), 53.8
(OCH3), 21.9 (CH3), 21.1 (CH3), 21.0 (CH3);
General procedure for the reduction of the
glycosides 6 and 7 with Zn and NH4Cl.—To a
solution of 2.0 mmol of the corresponding
glycoside (0.91 g of 6; 0.97 g of 7) in MeOH
(25 mL) were added NH4Cl (0.53 g, 10 mmol)
and zinc dust (0.65 g, 10 mmol). After the
mixture was stirred for 2 h at rt the solids
were filtered off and washed carefully with 7:3
CHCl3–MeOH. The filtrate was evaporated
and the resulting products were purified by
column chromatography. First, the glycal and
the lactam fraction were eluted with 1:1
toluene–EtOAc. Then, the hydroxamic acid
fraction was eluted with CHCl3–MeOH (12:1
for 8, 7:3 for 9). The violet hydroxamic acid
fraction was treated with an ion-exchange
resin (Amberlite IR 120 (H+)) to remove any
metal ions. The fractions were evaporated to
dryness and crystallized as described.

J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
91
Reduction of 6 gave successively:
Methyl 3,4,5-tri-O-acetyl- -erythro-hex-2-
(m, 1 H, H-5%), 3.91 (m, 2 H, H-6%a, H-6%b),
2.16 (s, 3 H, OAc), 2.00 (s, 6 H, 2 OAc); 13C
NMR (50 MHz, CDCl3): l 171.0 (CO), 170.6
(CO), 170.1 (CO), 156.1 (C-3), 140.2 (C-8a),
125.9 (C-4a), 125.8 (C-6), 124.3 (C-7), 117.9
(C-8), 113.8 (C-5), 99.7 (C-2), 70.1 (C-3%), 69.9
(C-4%), 68.2 (C-5%), 66.1 (C-6%), 21.3 (CH3), 21.1
(CH3), 20.0 (CH3); EIMS: m/z (%): 409 (28,
[M+]), 393 (12), 381 (3), 367 (22), 349 (10),
233 (31), 215 (20), 202 (11), 44 (100), 275 (47).
Anal. Calcd for C18H19NO10: C, 52.82; H,
4.68; N, 3.42. Found: C, 52.29; H, 5.28; N,
3.40.
D
enopyranosonate (16).—A total of 12 mg (2%)
of 16 were obtained as colourless syrup; Rf
0.35 (3:1 toluene–EtOAc); 1H NMR (200
MHz, CDCl3): l 5.77 (dd, 1 H, J4,5 4.4, J4,6b
1.3 Hz, H-4), 5.29 (ddd, 1 H, J5,6a 9.3, J4,5 4.4,
J5,6b 3.6 Hz, H-5), 4.21 (ddd, 1 H, J6a,b 11.0,
J5,6b 3.6, J4,6b 1.3 Hz, H-6b), 4.07 (dd, 1 H,
J6a,b 11.0, J5,6a 9.3 Hz, H-6a), 3.80 (s, 3 H,
OCH3), 2.18 (s, 3 H, OAc), 2.10 (s, 3 H, OAc),
2.00 (s, 3 H, OAc); 13C NMR (50 MHz,
CDCl3): l 170.6 (CO), 170.0 (2×CO), 161.1
(C-1), 139.6 (C-2), 133.0 (C-3), 65.1 (C-4, and
C-5), 64.3 (C-6), 53.1 (OCH3), 21.0 (2×CH3),
20.9 (CH3); EIMS: m/z (%): 274 (17, [M+ −
CH3OH]), 257 (42, [M+ −COOCH3]), 215
(40), 197 (66), 172 (42), 155 (100).
Reaction of 7 gave successively:
Methyl 4,5-di-O-acetyl-2,6-anhydro-3-de-
oxy- -erythro-hex-2-enosonate (17).—A total
D
of 46 mg (9%) of 17 was obtained as colour-
less syrup; [h]D22+178° (c 1.0, CHCl3); Rf 0.55
1
(2S)-3%,4%,5%-Tri-O-acetyl-
D
-arabino-2H-
(1:1 toluene–EtOAc); H NMR (200 MHz,
1,4-benzoxazin-2-spiro-2%-pyran-3(4H)-one
(10).—A total of 63 mg (8%) of 10 crystal-
lized from MeOH as colourless prisms; mp
207–208 °C; [h]2D2−37° (c 1.0, CHCl3,); CD
Dm236+43.9, Dm259–7.6 (c 0.49, CHCl3,); Rf
0.54 (1:1 toluene–EtOAc); 1H NMR (200
MHz, CDCl3): l 9.60 (s, 1 H, NH), 6.92–7.20
(m, 4Harom), 6.12 (dd, 1 H, J3%,4% 10.4, J4%,5% 3.6
Hz, H-4%), 5.72 (d, 1 H, J3%,4% 10.4 Hz, H-3%),
5.43 (m, 1 H, H-5%), 4.03 (m, 2 H, H-6%a,
H-6%b), 2.19 (s, 3 H, OAc), 2.01 (s, 6 H, 2
OAc); 13C NMR (50 MHz, CDCl3): l 21.1
(CH3), 21.2 (CH3), 21.4 (CH3), 65.9 (C-6%),
68.4 (C-5%), 70.0 (C-4%), 70.1 (C-3%), 98.1 (C-2),
116.0 (C-8), 118.3 (C-6), 124.2 (C-5), 124.9
(C-7), 125.0 (C-4a), 140.8 (C-8a), 161.4 (C-3),
170.2 (CO), 170.6 (CO), 171.1 (CO); EIMS:
m/z (%): 393 (40, [M+]), 351 (5), 249 (4), 164
(37), 136 (40), 42 (100). Anal. Calcd for
C18H19NO9: C, 54.96; H, 4.87; N, 3.56. Found:
C, 54.60; H, 4.85; N, 3.47.
CDCl3): l 5.97 (d, 1 H, J3,4 4.4 Hz, H-3), 5.59
(dd, 1 H, J3,4 4.4, J4,5 3.8 Hz, H-4), 5.24 (m, 1
H, H-5), 4.20 (m, 2 H, H-6%a, H-6%b), 3.66 (s,
13
3 H, OCH3), 2.07 (s, 6 H, 2 OAc); C NMR
(50 MHz, CDCl3): l 170.5 (CO), 170.3 (CO),
162.5 (C-1), 146.6 (C-2), 106.5 (C-3), 65.3
(C-6), 64.8 (C-4), 63.4 (C-5), 53.1 (OCH3),
21.2 (2×CH3); EIMS: m/z (%): 199 (23,
[M+ −COOCH3]), 156 (17), 139 (100). Anal.
Calcd for C11H14O7: C, 55.82; H, 5.46. Found:
C, 55.62; H, 5.21.
(2S) - 3%,4%,5% - Tri - O - acetyl - 7 - methoxy - -
D
arabino-2H-1,4-benzoxazin-2-spiro-2%-pyran-
3(4H)-one (11).—A total of 118 mg (14%) of
11 crystallized from MeOH as colourless
needles; mp 235–236 °C; [h]2D2−44° (c 1.0,
1
CHCl3); Rf 0.48 (toluene–EtOAc, 1:1 v/v); H
NMR (200 MHz, CDCl3): l 11.13 (s, 1 H,
NH), 6.81 (d, 1 H, J5,6 8.8 Hz, H-5), 6.70 (d,
1 H, J6,8 2.6 Hz, H-8), 6.59 (dd, 1 H, J5,6 8.8,
J6,8 2.6 Hz, H-6), 6.13 (dd, 1 H, J3%,4% 10.4, J4%,5%
3.8 Hz, H-4%), 5.70 (d, 1 H, J3%,4% 10.4 Hz,
H-3%), 5.43 (m, 1 H, H-5%), 4.05 (m, 2 H,
H-6%a, H-6%b), 3.74 (s, 3 H, OCH3), 2.11 (s, 3
H, OAc), 1.99 (s, 3 H, OAc), 1.92 (s, 3 H,
OAc); 13C NMR (50 MHz, CDCl3): l 171.0
(CO), 170.5 (CO), 170.3 (CO), 159.7 (C-7),
156.8 (C-3), 141.5 (C-8a), 119.5 (C-4a), 116.9
(C-5), 110.6 (C-6), 103.7 (C-8), 98.0 (C-2),
70.0 (C-4%), 69.9 (C-3%), 68.4 (C-5%), 65.9 (C-6%),
56.1 (OCH3), 21.4 (CH3), 21.2 (CH3), 21.1
(CH3); EIMS: m/z (%): 423 (23, [M+]), 381
(2S)-3%,4%,5%-Tri-O-acetyl- -arabino-4-hy-
D
droxy-2H-1,4-benzoxazin-2-spiro-2%-pyran-
3(4H)-one (8).—A total of 690 mg (85%) of 8
crystallized from MeOH as colourless needles;
mp 100–101 °C; [h]2D2−60° (c 1.00, CHCl3);
CD Dm235+16.7, Dm258 –5.7 (c 0.41, CHCl3); Rf
0.56 (CHCl3–MeOH, 12:1 v/v); 1H NMR (200
MHz, CDCl3): l 9.45 (s, 1 H, OH), 7.40 (d, 1
H, J5,6 8.0 Hz, H-5), 7.10 (m, 3 H, H-6, H-7,
H-8), 6.00 (dd, 1 H, J3%,4% 10.4, J4%,5% 3.6 Hz,
H-4%), 5.68 (d, 1 H, J3%,4% 10.6 Hz, H-3%), 5.32

92
J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
subjected to column chromatography (3:1
toluene–EtOAc) to give by crystallization
from MeOH 490 mg (21%) of 10 as colourless
crystals.
(5), 364 (4), 261 (7), 194 (13), 165 (42), 42
(100). Anal. Calcd for C19H21NO10: C, 53.90;
H, 5.00; N, 3.31. Found: C, 53.59; H, 4.81; N,
3.11.
(2S) - 3%,4%,5% - Tri - O - acetyl -
D
- arabino-4-
General procedure for the deacetylation to
form 12, 13, 14 and 15.—A solution of 0.5
mmol of the corresponding acetate (204 mg 8
for 12; 218 mg 9 for 13; 196 mg 10 for 14; 211
mg 11 for 15) was stirred in a solution of
NaOMe in MeOH (8 mL, 0.1 M) for 15 min.
The solution was neutralized by addition of an
ion-exchange resin (Amberlite IR 120 (H+)).
The resin was filtered off and the filtrate evap-
orated. The residue was recrystallized from 7:3
CHCl3–MeOH.
hydroxy - 7 - methoxy - 2H - 1,4 - benzoxazin - 2-
spiro-2%-pyran-3(4H)-one (9).—A total of 470
mg (54%) of 9 crystallized from CHCl3–
MeOH as colourless crystals; mp 105–107 °C;
[h]2D2−66° (c 1.0, CHCl3); Rf 0.32 (CHCl3–
MeOH, 7:3 v/v); 1H NMR (200 MHz,
CDCl3): l 11.27 (s, 1 H, OH), 7.23 (d, 1 H,
J5,6 8.8 Hz, H-5), 6.77 (d, 1 H, J6,8 2.0 Hz,
H-8), 6.67 (dd, 1 H, J5,6 8.8, J6,8 2.0 Hz, H-6),
6.04 (dd, 1 H, J3,4 10.2, J4,5 3.2 Hz, H-4%), 5.45
(d, 1 H, J3%,4% 10.4 Hz, H-3%), 5.32 (m, 1 H,
H-5%), 3.94 (m, 2H, H-6%a, H-6%b), 3.70 (s, 3 H,
OCH3), 2.12 (s, 3 H, OAc), 1.98 (s, 3 H, OAc),
1.92 (s, 3 H, OAc); 13C NMR (50 MHz,
CDCl3): (170.8 (CO), 170.6 (CO), 170.3 (CO),
157.3 (C-7), 154.8 (C-3), 141.5 (C-8a), 122.3
(C-4a), 115.0 (C-5), 110.1 (C-6), 103.5 (C-8),
100.1 (C-2), 70.0 (C-4%), 70.2 (C-3%), 68.4 (C-
5%), 66.1 (C-6%), 56.5 (OCH3), 21.5 (CH3), 21.3
(2×CH3); EIMS: m/z (%): 439 (34, [M+]),
422 (61), 395 (3), 380 (14), 233 (22), 215 (59),
206 (38), 43 (100). Anal. Calcd for
C19H21NO11: C, 51.94; H, 4.82; N, 3.91.
Found: C, 51.78; H, 4.50; N, 3.42.
General procedure for the catalytic hydro-
genation of the glycosides 6 and 7.—A solu-
tion of the corresponding glycoside (0.91 g, 2
mmol of 6; 0.97 g, 2 mmol of 7) in MeOH (20
mL) was hydrogenated over 5% Pt–C (0.11 g)
at normal pressure and rt until the consump-
tion of hydrogen was complete. The catalyst
was filtered off and the filtrate evaporated.
The products resulting from 6 were purified
as described above to give 190 mg (23%) of 8
and 570 mg (72%) of 10.
(2S)-3%,4,4%,5%-Tetrahydroxy- -arabino-2H-
D
1,4-benzoxazin-2-spiro-2%-pyran-3(4H)-one
(12).—A total of 134 mg (95%) of 12 was
obtained as colourless crystals; mp 211–
212 °C; [h]2D2−24° (c 1.0, MeOH–WATER
1:1, v/v,); CD Dm234+25.3, Dm258−10.8 (c
1
0.41, MeOH,); H NMR (200 MHz, CD3OD):
l 7.08–7.40 (m, 4Harom), 4.65 (dd, 1 H, J3%,4%
9.5, J4%,5% 3.7 Hz, H-4%), 4.07 (d, 1 H, J3%,4% 9.6
Hz, H-3%), 3.96 (m, 1 H, H-5%), 3.63 (m, 2H,
H-6%a, H-6%b); 13C NMR (50 MHz, CD3OD):
l 158.9 (C-3), 142.7 (C-8a), 129.3 (C-4a),
125.7 (C-6), 124.3 (C-7), 118.1 (C-8), 114.6
(C-5), 102.3 (C-2), 74.6 (C-3%), 72.4 (C-4%), 69.9
(C-5%), 68.7 (C-6%); EIMS: m/z (%): 283 (37,
[M+]), 266 (6), 255 (22), 164 (100), 136 (100).
Anal. Calcd for C12H13NO7: C, 50.89; H, 4.62;
N, 4.94. Found: C, 50.88; H, 4.97; N, 4.84.
(2S)-3%,4,4%,5%-Tetrahydroxy- -arabino-7-
D
methoxy-2H-1,4-benzoxazin-2-spiro-2%-pyran-
3(4H)-one (13).—A total of 152 mg (97%) of
13 was obtained as colourless needles; mp
1
205–207 °C; [h]2D2−76° (c 1.0, MeOH); H
NMR (200 MHz, CD3OD): l 7.89 (s, 1 H,
OH), 7.23 (d, 1 H, J5,6 9.5 Hz, 5-H), 6.68 (m,
2H, 6-, 8-H), 4.56 (dd, 1 H, J3%,4% 9.5, J4%,5% 3.7
Hz, H-4%), 4.02 (d, 1 H, J3%,4% 9.5 Hz, H-3%),
3.93 (m, 1 H, H-5%), 3.86 (m, 2H, H-6%a,
H-6%b), 3.77 (s, 3 H, OCH3); 13C NMR (50
MHz, CD3OD): l 158.7 (C-7), 158.4 (C-3),
143.3 (C-8a), 123.0 (C-4a), 114.7 (C-5), 109.4
(C-6), 104.7 (C-8), 102.5 (C-2), 74.5 (C-3%),
72.3 (C-4%), 69.8 (C-5%), 68.6 (C-6%), 56.4
(OCH3); EIMS: m/z (%): 313 (3, [M+]), 296
(5), 215 (38), 200 (19), 165 (7), 45 (100). Anal.
The product resulting from 7 was recrystal-
lized (MeOH) to give 800 mg (95%) of 11.
Alternati6e synthesis of 10 by cyclization of 3
with 2-aminophenol.—To a stirred solution of
3 (2.38 g, 6.0 mmol) and 2-aminophenol (0.71
g, 6.5 mmol) in dry acetone (850 mL) was
added powdered K2CO3. The suspension was
refluxed for 6 h, then cooled to 0 °C, filtered
and the solid remaining washed with acetone
(10 mL). The filtrate was evaporated to dry-
ness in vacuo. The brown syrup obtained was

J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
93
filtrate was evaporated. The resulting residue
was immediately purified by column chro-
matography with toluene–EtOAc (1:1, v/v) to
give 237 mg (92%) of 17 as colourless syrup.
Calcd for C13H15NO8: C, 49.84; H, 4.83; N,
4.47. Found: C, 49.80; H, 4.54; N, 4.83.
(2S)-3%,4%,5%-Trihydroxy- -arabino-2H-1,4-
D
benzoxazin-2-spiro-2%-pyran-3(4H)-one (14).
—A total of 155 mg (94%) of 14 was obtained
as colourless crystals; mp 126–127 °C; [h]2D2−
16° (c 1.0, MeOH); CD Dm236+48.2, Dm261
−
Acknowledgements
1
10.0 (c 0.40, MeOH); H NMR (200 MHz,
CD3OD): l 9.45 (s, 1 H, NH), 7.04–6.91 (m,
4Harom), 4.53 (dd, 1 H, J3%,4% 9.3, J4%,5% 3.7 Hz,
4%-H), 4.03 (d, 1 H, J3%,4% 9.3 Hz, H-3%), 3.92 (m,
1 H, H-5%), 3.84 (m, 2H, H-6%a, H-6%b); 13C
NMR (50 MHz, CD3OD): l 163.5 (C-3),
142.7 (C-8a), 127.3 (C-4a), 125.7 (C-7), 124.3
(C-5), 118.1 (C-6), 114.6 (C-8), 99.0 (C-2),
72.9 (C-3%), 71.1 (C-4%), 68.5 (C-5%), 67.0 (C-6%);
EIMS: m/z (%): 267 (52, [M+]), 249 (3), 223
(4), 164 (100), 136 (30). Anal. Calcd for
C12H13NO6·H2O: C, 50.53; H, 5.30; N, 4.91.
Found: C, 50.94; H, 5.43; N, 4.95.
The authors thank M. Su¨ße (Institut fu¨r
Pflanzenbiochemie Halle) for generous sup-
port in measuring CD spectra. The financial
support for this work by the Umwelt-
forschungszentrum Leipzig–Halle and the
Fonds der Chemischen Industrie is gratefully
acknowledged.
References
[1] F.W. Lichtenthaler, Carbohydrates as Organic Raw Ma-
terials, VCH, Weinheim, 1990.
(2S)-3%,4%,5%-Trihydroxy-7-methoxy- -ara-
D
bino - 2H - 1,4 - benzoxazin - 2 - spiro - 2% - pyran-
3(4H)-one (15).—A total of 146 mg (98%) of
15 was obtained as colourless crystals; mp
251–252 °C; [h]2D2−43° (c 0.859, MeOH–
WATER, 6:1 v/v); 1H NMR (400 MHz,
CD3OD): l 6.81 (d, 1 H, J5,6 8.7 Hz, H-5),
6.67 (d, 1 H, J6,8 1.1 Hz, H-8), 6.57 (dd, 1 H,
J5,6 8.7, J6,8 1.1 Hz, H-6), 4.50 (dd, 1 H, J3%,4%
9.1, J4%,5% 3.6 Hz, H-4%), 4.00 (d, 1 H, J3%,4% 9.2
Hz, H-3%), 3.91 (m, 1 H, H-5%), 3.87 (d, 1 H,
J6a,6b 12.3 Hz, H-6%b), 3.81 (d, 1 H, J6%a,6%b 12.3
Hz, H-6%a), 3.74 (s, 3 H, OCH3); 13C NMR
(100 MHz, CD3OD): l 162.8 (C-7), 157.9
(C-3), 143.3 (C-8a), 120.6 (C-4a), 116.6 (C-5),
109.4 (C-6), 104.5 (C-8), 99.9 (C-2), 73.9 (C-
3%), 72.1 (C-4%), 69.3 (C-5%), 67.8 (C-6%), 56.1
(OCH3); EIMS: m/z (%): 297 (7, [M+]), 221
(2), 209 (4), 196 (100), 167 (25), 151 (11).
Anal. Calcd for C13H15NO7: C, 52.53; H, 5.09;
N, 4.71. Found: C, 52.22; H, 5.47; N, 4.58.
Alternati6e synthesis of methyl 4,5-di-O-
[2] M. Bols, Carbohydrate Building Blocks, Wiley, New
York, 1996.
[3] P. Fahrni, T. Siegfried, Eur. Patent EP 133 493 (1985);
Chem. Abstr., 103 (1985), 178578c.
[4] (a) W.N. Haworth, E.L. Hirst, J. Chem. Soc., (1926)
1858–1868. (b) W.N. Haworth, E.L. Hirst, A. Learner,
J. Chem. Soc., (1927) 1040–1049. (c) C.G. Anderson, W.
Charlton, W.N. Haworth, V.S. Nicholson, J. Chem.
Soc., (1929) 1337–1346. (d) M.L. Wolfrom, W.W. Bink-
ley, W.L. Shilling, H.W. Hilton, J. Am. Chem. Soc., 73
(1951) 3553–3557.
[5] (a) M. Bobek, J. Farkas, F. Sorm, Collect. Czech. Chem.
Commun., 32 (1967) 3572–3580. (b) H. Ohle, Ber. Dtsch.
Chem. Ges., 67 (1934) 155–162.
[6] J. Geigert, S.L. Neidleman, D.S. Hirano, B. Wolf, B.M.
Panschar, Carbohydr. Res., 113 (1983) 163–165.
[7] O.M.M. Bouvet, P. Lenormand, P.A.D. Grimont, Int. J.
Syst. Bacteriol., 39 (1989) 61–67.
[8] S. Kirrbach, R.-R. Schnelle, S. Hauptmann, G. Mann,
H. Wilde, D. Sicker, U. Stottmeister, J. Prakt. Chem.,
334 (1992) 537–539.
[9] T.C. Crawford, G.C. Andrews, H. Faubl, G.N.
Chmurny, J. Am. Chem. Soc., 102 (1980) 2220–2225.
[10] D. Sicker, H. Hartenstein, M. Kluge, Natural benzoxazi-
noids—Synthesis of acetal glucosides, aglucones, ana-
logues, in S.G. Pandalai (Ed.), Recent Research
De6elopments in Phytochemistry, Vol. 1, Research Sign-
post, Trivandrum, India, 1997, pp. 203–223.
[11] M. Kluge, H.J. Grambow, D. Sicker, Phytochemistry, 44
(1997) 639–641.
acetyl-2,6-anhydro-3-deoxy- -erythro-hex-2-
D
enosonate (17).—To a stirred solution of 3
(397 mg, 1.0 mmol) in dry toluene (12 mL)
was added dry pyridine (97 mL, 1.2 mmol) and
zinc dust (0.33 g, 5.0 mmol). The mixture was
heated at 80–90 °C for 2 h and than refluxed
for another 15 min. The zinc residue was
filtered off, washed with toluene and the
[12] R.B. Wolf, G.F. Spencer, R.D. Plattner, J. Nat. Prod.,
48 (1985) 59–63.
8
8
[13] S. Ozden, T. Ozden, J. Attila, M. Ku¨cu¨kislamoglu, A.
Okatan, J. Chromatogr., 609 (1992) 402–406.
[14] K. Pratt, P. Kumar, W.S. Chilton, Biochem. Syst. Ecol.,
23 (1995) 781–785.
[15] M. Kluge, D. Sicker, Tetrahedron, 52 (1996) 10389–
10398.

94
J. Andersch et al. / Carbohydrate Research 316 (1999) 85–94
[20] L. Somsa´k, I. Bajaza, L. Kossuth, Liebigs Ann. Chem.,
(1990) 1265–1268.
[21] J. Andersch, PhD thesis, Fakulta¨t fu¨r Chemie und Min-
eralogie der Universita¨t Leipzig, 1998.
[22] J. Lehmann, Kohlenhydrate, Georg Thieme Verlag, Stutt-
gart, 1996, pp. 49–54.
[23] P. Ko¨ll, E. Steinweg, J. Metzger, B. Meyer, Liebigs Ann.
Chem. (1982) 1052–1062.
[16] M. Kluge, B. Schneider, D. Sicker, Carbohydr. Res., 298
(1997) 147–152.
[17] H. Ohle, R. Wolter, Ber. Dtsch. Chem. Ges., 63 (1930)
843–852.
[18] M. Major, W.J. Cook, J. Am. Chem. Soc., 58 (1936)
2477–2478.
[19] H. Hartenstein, D. Sicker, J. Prakt. Chem., 335 (1993)
359–362.
.
.