Novel reversion reaction of D-arabino-hexose phenylosotriazole. A useful model in natural glycoside and polysaccharide analysis

Article abstract of DOI:10.1081/NCN-100105904

Treatment of D-arabino-hexose phenylosotriazole with conc. hydrochloric acid afforded a new type of α- and β-glycosides of D-erythrose formed by reaction of the 3,6-anhydro derivative with the in situ formed 2-phenyl-4-(formylmethyl)-1,2,3-triazole.

Full text of DOI:10.1081/NCN-100105904

This article was downloaded by: [Queensland University of Technology]
On: 06 November 2014, At: 22:10
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,
37-41 Mortimer Street, London W1T 3JH, UK
Nucleosides, Nucleotides and Nucleic Acids
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/lncn20
NOVEL REVERSION REACTION OF D-ARABINO-HEXOSE
PHENYLOSOTRIAZOLE. A USEFUL MODEL IN NATURAL
GLYCOSIDE AND POLYSACCHARIDE ANALYSIS
a
a
Hammed H. A. M. Hassan & Amel H. F. El-Husseiny
a
Chemistry Department, Faculty of Science , Alexandria University , P.O. Box 426 Ibrahimia,
Alexandria, 21321, Egypt
Published online: 21 Aug 2006.
To cite this article: Hammed H. A. M. Hassan & Amel H. F. El-Husseiny (2001) NOVEL REVERSION REACTION OF D-ARABINO-
HEXOSE PHENYLOSOTRIAZOLE. A USEFUL MODEL IN NATURAL GLYCOSIDE AND POLYSACCHARIDE ANALYSIS, Nucleosides,
Nucleotides and Nucleic Acids, 20:9, 1683-1690, DOI: 10.1081/NCN-100105904
To link to this article: http://dx.doi.org/10.1081/NCN-100105904
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the
Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and
should be independently verified with primary sources of information. Taylor and Francis shall not be liable for
any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever
or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of
the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS, 20(9), 1683–1690 (2001)
NOVEL REVERSION REACTION OF
D-ARABINO-HEXOSE PHENYLOSOTRIAZOLE.
A USEFUL MODEL IN NATURAL GLYCOSIDE
AND POLYSACCHARIDE ANALYSIS
Hammed H. A. M. Hassan* and Amel H. F. El-Husseiny
Chemistry Department, Faculty of Science,
Alexandria University, P.O. Box 426 Ibrahimia,
21321-Alexandria, Egypt
ABSTRACT
Treatment of D-arabino-hexose phenylosotriazole with conc. hydro-
chloric acid afforded a new type of a- and b-glycosides of D-erythrose
formed by reaction of the 3,6-anhydro derivative with the in situ formed
2-phenyl-4-(formylmethyl)-1,2,3-triazole.
INTRODUCTION
The last decade has witnessed a remarkable growth in the field of
1
glycoconjugates syntheses, purification and structural analyses . The analysis
progresses through the identification of any monosaccharides present,
characterization of oligosaccharide size and monosaccharide sequence and
2
determination of the linkages between the monosaccharides and the protein .
To carry out this analysis, the glycoprotein under investigation is digested by
chemical degradation (usually highly acidic conditions) to release the
oligosaccharides followed by structural and conformational analysis by
*
Corresponding author. E-mail: hassan@safwa.com.eg
683
1
Copyright # 2001 by Marcel Dekker, Inc.
www.dekker.com

1684
HASSAN AND EL-HUSSEINY
spectroscopic methods. Nevertheless, the problem arises from the unusual
3
changes that glycosides may undergo in such drastic acidic conditions and
the typical question arises, is such unusual modification present in the pro-
tein or it is an artificial product of analysis. In continuation of our work in
4
the chemistry of natural C-glycosides and their analogues , we recently
5–7
8
reported our effort towards the synthesis of C-mannosylated tryptophan , an
9
unusual C-glycoside linkage to protein . This research led us to re-address
the problem of the unusual modifications that may occur for simple C-gly-
3
cosides when treated with concentrated mineral acids . In particular, rever-
sion products can be troublesome in natural glycoside and polysaccharide
analysis. In this paper we wish to report the isolation of a new sterically less
favored reversion product upon heating the well known D-arabino-hexose
10
phenylosotriazole with conc. HCl. We selected the C-glycoside 1,2,3-tria-
zole as a model compound because it resembles, to some extent, the
9
C(1)sugar-C(2)-amino acid bond and also due to the fact that so many
kinds of Cephalosporins bearing 1,2,3-triazole or its heterocyclic analogue as
a partial structure are still under active investigations in the search of more
1
1
active and safer compounds .
RESULTS AND DISCUSSIONS
1
Since the first preparation of sugar osazones and their osotriazole
2
10
13
derivatives a long time ago, their chemistry still has renewed interest .
Osazones are usually prepared by the action of three molecular propor-
tions of the unsubstituted hydrazine (or its hydrochloride salt) on one
molecular proportion of the saccharide in aqueous acetic acid (or sodium
acetate). They can be easily converted into their osotriazole derivatives 1
(
II)
(0)
by oxidation-reduction process mediated by (Cu ! Cu ) through a
14
dimeric complex . Boiling a solution of sugar phenylosotriazole in
CH OH=H SO (10%) or MeOH=HCl (15%) causes the elimination of
water and formation of a 3,6-anhydro ring with partial epimerization at
3
2
4
15
C-3 of the hexose, leading to a mixture of D-arabino and D-ribo cyclized
products 2 and 3, which can be considered as a- and b-C-glycosides of D-
erythrose, Scheme 1. To the best of our knowledge, the ratio of a- and b-
C-glycosides 2 and 3 has not been reported previously. To obtain some
information, the mixture was masked as acetonide derivatives 4 and 5 by
treatment with 2,2-dimethoxypropane=p-TsOH mixture. Spectral data (H-
H COSY experiment) proved that the product contains a 90:10 mixture of
b- and a-isomers, respectively. The protection of the anhydro derivatives
as acetonides 4 and 5 not only improve the limited solubility of the
mixture in organic solvents, but also made their separation on a cation-
exchange resin column possible using a 10% mixture of MeOH in H O
2
as eluent.

D-ARABINO-HEXOSE PHENYLOSOTRIAZOLE
1685
Scheme 1.
Upon treatment of 1 with methanol=mineral acid mixture, we observed
the formation of a dark brown oil layer after 10–15 min reaction. Increasing
the concentration of acid (conc. HCl) was found to strongly affect the yield of
2
and 3 and increase to some extent the amount of the oil layer. Longer
reaction time did not show any influence on the ratio of the two phases, even
after heating for 24h. Heating of 1 with conc. HCl in the absence of
methanol for several hours followed by separation of the oil layer and
standard work-up purification by successive cation-exchange resin column
chromatography yielded a colorless crystalline product (15% yield, m.p.
ꢀ
91 C). Spectral data proved that this product consists of a mixture of two
stereoisomers 6 and 7 (90:10 ratio). Separation of these two stereoisomers
using cation-exchange resin column chromatography was quite difficult
owing to their relatively long separation time using a 10%, 20% and 30%
ethanol-water gradient as eluent.
The structure of the major and minor isomers 6 and 7 were deter-
mined by NMR techniques (H-H-COSY and H-C HETCOR experiments),
1
accurate mass spectrometry and elemental analysis. The H-NMR of 6
0
shows H-1, H-2, H-3 and H-1 of the stereogenic centers at d 5.351 ppm, d
5
.225 ppm (J2,1 ¼ 0.9 Hz, J ¼ 6.3 Hz), d 4.890 ppm (J ¼ 3.9 Hz), d
0 0
,2
2,3
3,4
1
3
5.325 ppm (J1
¼ 4.6 Hz), respectively, whereas the C NMR spectrum

1686
HASSAN AND EL-HUSSEINY
shows these carbons at d 78.61, 85.23, 82.03 and 105.27 ppm, respectively.
On the other hand, the H NMR shows these chiral centers for the minor
1
isomers 7 at d 5.351 (hidden 1H (COSY)), d 5.252 ppm (J ¼ 1.2 Hz,
2
,1
1
3
J2,3 ¼ 5.6 Hz), d 4.945 ppm, d 5.620 ppm (J
0
0
¼ 4.4 Hz) and the C NMR
1 ,2
shows signals of these carbons at d 79.12 (C-1), 84.31 (C-2), 81.11 (C-3),
and 105.07 ppm (C-1 ), respectively. The J
0
values (0.9 and 1.2 Hz)
1
,2
accord with the eq,eq relationship and thus confirm the given stereo-
chemistry at the anomeric carbons atoms. Furthermore, the structure 6
was confirmed by accurate mass spectrometry (calculated for C H O N
2
2
20
3
6
4
16.190; Found 416.1550). The FAB-MS technique shows the base peak at
þ
m=z 417 (M þ1, 100%) whereas the EI-MS technique clearly showed two
characteristic fragments at m=z 212 (100%) and m=z 188 (29%) which are
probably due to the cleavage of the C-O bonds at C-2 and C-3 to give the
corresponding 2-phenyl-4-(furan-2-yl)-1,2,3-triazole 8 and 2-phenyl-4-(for-
mylmethyl)-1,2,3-triazole 9, Scheme 2. The molecular ion in the EI-MS
spectrum is found at m=z 416 (5%).
As demonstrated in Scheme 2, a plausible pathway of this reaction is
related to the typical reactions of free sugars and acyclic C-glycosides with
1
concentrated mineral acids . Formation of the 3,6-anhydro phenyloso-
6
triazole 2 from 1 involves initial protonation of the OH group on the
a-carbon of 1, intermediate (A), followed by either an SN
1
or SN intramo-
2
lecular ring closure to yield 2. Furthermore, dehydration=cyclization of (A)
gives the dehydro non-carbohydrate analogue 8. A further competing reac-
tion with ring closure occurs under heating conditions causing fragmentation
of (A) to produce aldehyde 9. The formation of 9 could proceed by a con-
certed hydration-fragmentation of (A) to give the enol form of aldehyde (C)
which could then react with 2 to give 6 (path a). Alternatively, 9 could form
by a step-wise loss of H O from (A) followed by fragmentation of the
2
intermediate carbocation (B) (path b).
It is worth mentioning that further addition of 2 to the separated
aqueous layer, without heating, increased the yield of 6 up to 70% yield.
Additionally, placing a mixture of anhydro derivatives 2 and 3 under the
conditions where 1 produces 6 and 7 yielded only an inseparable mixture of
dehydrated products. This observation serves not only as further evidence for
the fragmentation of 1 to produce 9 and thus confirms the present reaction
mechanism, but also affords a simple method to obtain new types of
C-glycosides which may have a synthetic value.
In conclusion, a new type of reversion products are isolated from the
reaction of D-arabino-hexose phenylosotriazole 1 with conc. HCl. To our
knowledge, such types of C-glycosides have not been reported previously.
In addition, according to the present reaction mechanism, the formation of
aldehyde 9 gives an additional angle to the well established reactions of
1
4
furan derivatives with conc. HCl . These findings could find immediate use
in natural glycoside and polysaccharide analyses, since some disaccharides

D-ARABINO-HEXOSE PHENYLOSOTRIAZOLE
1687
Scheme 2.
isolated from the hydrolysates in low yield may be reversion products of
this type.
EXPERIMENTAL
General: Melting points were determined on a Reichert-Jung thermo-
meter apparatus and were uncorrected. Spectra were recorded as follows:
1
H-NMR, Va r i a n G e m i n i 300 spectrometer at 300 MHz and Va r i a n V XR
13
spectrometer at 200 MHz; C-NMR, Va r i a n G e m i n i at 75 MHz and Va r i a n
VXR spectrometer at 50 MHz in deuterated chloroform solutions; mass
spectra (electron impact), VG Micromass 16F spectrometer, operating at
7
0 eV with an accelerating voltage of 4kV and a variable source temperature.
High resolution mass spectra (FAB) were determined on a KRATOS limited
MS 9=50 spectrometer. Microanalyses were performed at the Physical and
Chemical Research (Riken), Wako-shi, Saitama, Japan.
Preparation of 4-(2,3-O-isopropylidene-b-D-erythrofuranosyl)-2-phenyl-
1,2,3-triazole (4) and 4-(2,3-O-isopropylidene-a-D-erythrofuranosyl)-2-phenyl-

1688
HASSAN AND EL-HUSSEINY
1
(
2
,2,3-triazole (5). To a mixture of anhydroosotriazole derivatives 2 and 3
1 g, 4.0 mmol) dissolved in 10 ml of MeOH, 20 mg of p-TsOH and 10 ml of
,2-dimethoxypropane were added. The reaction mixture was stirred at r.t.
for 12 h and then the solvent was evaporated to dryness to give 1 g (86%
yield) of compounds 4 and 5 (9:1 mixture, respectively). The following
1
spectral data were recorded: H-NMR (4) (200 MHz): d 8.02–7.98 (m, 2H,
0
arom), 7.85 (s, 1H, H-5 ), 7.50–7.30 (m, 3H, arom), 5.24(d, J ¼ 7.6 Hz, 1H,
1
,2
H-1), 4.34 (dd, J2,3 ¼ 7.8, J ¼ 7.6 Hz, 1H, H-2), 4.14–4.04 (m, 1H, H-3),
2,1
13
3
.79 (m, 2H, H-4), 1.50 (s, 3H, CH ), 1.48 (s, 3H, CH ). C-NMR (4)
3
3
(
9
(
50 MHz): d 134.05 (1C), 129.49 (2C), 127.95 (1C), 118.94 (2C), 110.34 (1C),
0.68 (-O C(CH ) ), 81.94(C-1), 72.30 (C-2), 71.51 (C-3), 63.28 (C- 4) , 26.57
2
3 2
1
0
CH ), 26.95 (CH ). H-NMR (5) (200 MHz): d 7.82 (s, 1H, H-5 ), 5.18 (d,
3
3
J1,2 ¼ 7.0 Hz, 1H, H-1), 4.36–4.04 (2H, hidden (COSY), H-2, H-3), 3.85–3.74
13
(
m, 1H, H-4), 1.31 (s, 3H, CH ), 1.27 (s, 3H, CH ). C-NMR (5) (50 MHz):
3
3
d 134.35 (1C), 129.40 (2C), 128.04 (1C), 121.36 (2C), 112.70 (1C), 92.03
(
-O C(CH ) ), 81.32 (C-1), 73.00 (C-2), 71.40 (C-3), 63.45 (C-4), 25.53 (CH ),
2 3 2 3
25.26 (CH3).
Preparation of 2-Phenyl-4-[2,3-O-(2-(2-phenyl-1,2,3-triazol-4-yl)ethylid-
ene)-a-D-erythrofuranosyl]-1,2,3-triazole (6) and 2-phenyl-4-[2,3-O-(2-(2-
phenyl-1,2,3-triazol-4-yl)ethylidene)-b-D-erythrofuranosyl]-1,2,3-triazole (7).
A solution of D-arabino-hexose phenylosotriazole (1) (5 g) in 25 ml of
conc. HCl was heated at reflux for 3 h. The resulting oil layer was
separated, dissolved in 20 ml of CHCl , neutralized with solid Na CO
3
2
3
(
3 g), filtered and the filtrate was evaporated to dryness. The remaining
dark brown residue was dissolved in EtOH (10 ml) and passed through an
Amberlite 1 IR-120 (plus) column (500 g) using pre-boiled distilled water
as eluent. The solvent was evaporated under diminished pressure (bath
ꢀ
temperature 30 C). The residue was once again passed through an
Amberlite 1 IRA 410 column (500 g) using pre-boiled water as eluent
followed by removal of the solvent. The remaining brown residue was
purified over an Amberlyst 1 A-21 column (500 g) using a 10%, 20% and
3
0% EtOH-H O gradient as eluent. The collected colorless fractions were
2
left to stand several days (2–3 days) after which compounds 6 and 7 had
crystallized out as a colorless needles. Yield 1.2 g (15%), m.p. 91 C.
ꢀ
Accurate mass for C H O N is 416.1550 (require 416.190). FAB - M S:
2
2
20
3
6
þ
4
2
7
17 (M þ1) (100%), 357 (14), 341 (3), 315 (3), 272 (6), 258 (34), 230 (19),
12 (58), 200 (9), 188 (27), 172 (14), 158 (54), 136 (25), 107 (10), 91 (18),
7 (44). EI-MS-: 416 (M )(5%), 258 (95), 240 (4), 229 (56), 212 (100), 200
þ
1
(
5), 188 (9), 184(29), 172 ( 41 ), 158 (53), 103 (31), 91 (51), 77 (51).
H-
NMR (6) (300 MHz): d 8.075–8.00 (m, 4H, o-H, arom), d 7.80 (s, 1H,
0
H-a), d 7.757 (s, 1H, H-a ), d 7.494–7.429 (m, 4H, m-H, arom),
d 7.373–7.289 (m, 2H, p-H, arom), d 5.351 (br s, 1H, H-1), d 5.325 (t,
0
1H, J1
0
0
¼ 4.6 Hz, H-1 ), d 5.225 (dd, 1H, J ¼ 6.3, J2,1 ¼ 0.9 Hz, H-2),
2,3
,2

D-ARABINO-HEXOSE PHENYLOSOTRIAZOLE
1689
d 4.890 (dd, 1H, J3,2 ¼ 6.3, J
¼ 3.9 Hz, H-3), d 4.156 (d, 1H,
4b,4a
3,4b
J4a,4b ¼ 10.8 Hz, H-4 ), d 3.822 (ddd, 1H, J
¼ 10.8, J
¼ 3.9 Hz,
4b,3
13
a
0
J4b,1 ¼ 0.6 Hz H-4 ), d 3.310 (d, 2H, J
0 0
2 ,1
¼ 4.6 Hz, H-2 ). C-NMR
b
0
(
(
75 MHz): d 146.75 (s, C-b), d 144.16 (s, C-b ), d 139.92 (N-C), d 135.70
d, C-a), d 134.29 (d, C-a ), d 129.32 (d, m-C), d 129.23 (d, m-C), d 127.72
0
(
(
4
d, p-C), d 127.22 (d, p-C), d 118.86 (d, o-C), d 118.78 (d, o-C), d 105.27
0
d, C-1 ), d 85.23 (d, C-2), d 82.03 (d, C-3), d 78.61 (d, C-1), d 72.26 (t, C-
0
1
), d 30.70 (t, C-2 ). H-NMR (7) (300 MHz): d 5.620 (t, 1H, J
0
0
¼ 4.4 Hz,
1
,2
0
H-1 ), d 5.351 (hidden 1H (COSY), H-1), d 5.252 (dd, 1H, J ¼ 5.6,
2,3
J2,1 ¼ 1.2 Hz, H-2), d 4.945 (m, 1H, H-3), d 4.128 (d, 1H, J
¼ 11.1 Hz,
b
4a,4b
H-4 ), d 3.874(ddd, 1H,
J
¼ 11.1, J
¼ 4.4, J
¼ 0.7 Hz, H-4 ), d
a
4b,4a
4b,3
4b,1
0
13
3
.216 (d, 2H, J2
0
0
¼ 4.4 Hz, H-2 ). C-NMR (7) (75 MHz): d 146.85 (s, C-
,1
0
0
b), d 144.04 (s, C-b ), d 139.66 (N-C), d 135.59 (d, C-a), d 134.08 (d, C-a ),
d 104.07 (d, C-1 ), d 84.31 (d, C-2), d 81.11 (d, C-3), d 79.12 (d, C-1), d
7
0
0
2.94(t, C- 4) , d 30.78 (t, C-2 ). Anal. Calc. For C H O N : C, 63.4; H,
2
2
20
3
6
4.8; N, 20.1. Found: C, 63.1; H, 4.8; N, 19.7.
REFERENCES
1
.
.
.
.
Gabius, H.J.; Gabius, S. (Eds). Glycosciences, Status and Perspectives;
Chapmann & Hall: Weinheim, New York, 1997.
a) Hounsell, E.F. Adv. Carbohydr. Chem. Biochem. 1994, 50, 311. b) Hounsell,
E.F. Mol. Biotech. 1994 2, 4 5.
2
3
4
Goffey, S. (Ed). Rodd’s Chemistryof Carbon Compounds; Elsevier: Amsterdam,
1967; Vol. 1F, Chaps. 22, 23.
Hassan, H.H.A.M.; Bredenkamp, M.W. Abstracts Book, 19th International
Carbohydrate Symposium, San Diego, California, 1998, BP 295.
Hassan, H.H.A.M.; Abdel-Rahman, M.M. Synth. Comm. 2000, 30, 201.
Hassan, H.H.A.M. Heterocycles, 2000, 53, 397.
5
6
7
.
.
.
Hassan, H.H.A.M.; El-Husseiny, A.F.H. Polish J. Chem. accepted for publica-
tion.
8
9
.
.
Hassan, H.H.A.M.; Spies, H.S.; Bredenkamp, M.W. Polish J. Chem. 2000, 74,
in press.
Hofsteenge, J.; Muller, D.R.; De Beer, T.; Loffler, A.; Richter, W.J.;
Vliegenthart, J.F.G. Biochemistry 1994, 33, 13524.
0. Hann, R.M.; Hudson, C.S. J. Am. Chem. Soc. 1944, 66, 735.
1
11. a) Micetich, R.G.; Maiti, S.N.; Spevak, P.; Hall, T.W.; Yambe, S.; Ishida,
M.; Tanaka, T.; Yamazaki, T.; Nakai, A.; Ogawa, K. J. Med. Chem. 1987,
3
0, 1469. b) Harada, K.; Odo, M.; Matsushite, A.; Shirai, M. Syn. Lett.
1
998, 431.
1
1
2. Richtmyer, N.K. Methods Carbohydr. Chem. 1963, 2, 127.
3. Oikawa, N.; Muller, C.; Kunz, M.; Lichtenthaler, F.W. Carbohydr. Res. 1998,
3
09, 269.
14. El Khadem, H.S. Carbohydr. Res. 1998, 313, 255.

1690
HASSAN AND EL-HUSSEINY
1
5. a) Hardegger, E.; Schrier, E. Helv. Chim. Acta 1952, 35, 232, 623. b) Bayer, S.
J. Chem. Soc. 1952, 4993. c) Schrier, E.; Stohr, E.; Hardegger, E. Helv. Chim.
Acta 1954, 37, 34, 574.
1
6. Speck, J.C. Jr, Adv. Carbohydr. Chem. 1958, 13, 63.
Received June 29, 2000
Accepted February 20, 2001