New evidence for isomerism of the formazyl group. Synthesis of selectively protected 2-deoxy-galactose formazans

Article abstract of DOI:10.1081/CAR-100108287

A new application of the formazyl activation provided selectively protected new derivatives of both 2-deoxy-D-galactose and 2-acetamido-2-deoxy-D-galactose formazans from 6-amino-6-deoxy-D-galactose 6,4-cyclic carbamate (1) under very simple conditions. T

Full text of DOI:10.1081/CAR-100108287

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NEW EVIDENCE FOR ISOMERISM OF THE FORMAZYL
GROUP. SYNTHESIS OF SELECTIVELY PROTECTED 2-
DEOXY-GALACTOSE FORMAZANS
Virág Zsoldos-Mády a , István Pintér b , Péter Sándor c , Mária Peredy-Kajtár c & András
Messmer c
a Research Group for Structural Chemistry and Spectroscopy , Hungarian Academy of
Sciences-Eötvös Loránd University , H-1518, Budapest, 112 P.O.B. 32, Hungary
b PROCHEM Research and Development Ltd. , H-1118, Budapest, Fehérvári u. 79.,
Hungary
c Chemical Research Center of the Hungarian Academy of Sciences , H-1525, Budapest,
P.O.B. 17, Hungary
Published online: 16 Aug 2006.
To cite this article: Virág Zsoldos-Mády , István Pintér , Péter Sándor , Mária Peredy-Kajtár & András Messmer (2001)
NEW EVIDENCE FOR ISOMERISM OF THE FORMAZYL GROUP. SYNTHESIS OF SELECTIVELY PROTECTED 2-DEOXY-GALACTOSE
FORMAZANS, Journal of Carbohydrate Chemistry, 20:7-8, 747-754
To link to this article: http://dx.doi.org/10.1081/CAR-100108287
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J. CARBOHYDRATE CHEMISTRY, 20(7&8), 747–754 (2001)
NEW EVIDENCE FOR ISOMERISM OF
THE FORMAZYL GROUP. SYNTHESIS OF
SELECTIVELY PROTECTED
2-DEOXY-GALACTOSE FORMAZANS
Virág Zsoldos-Mády,1,* István Pintér,2 Péter Sándor,3
Mária Peredy-Kajtár,3 András Messmer3
1Research Group for Structural Chemistry and Spectroscopy,
Hungarian Academy of Sciences-Eötvös Loránd University,
H-1518 Budapest 112 P.O.B. 32, Hungary
E-mail: zsoldosb@elender.hu
2PROCHEM Research and Development Ltd., H-1118
Budapest, Fehérvári u. 79., Hungary
E-mail: pinter@szerves.chem.elte.hu
3Chemical Research Center of the Hungarian Academy of
Sciences, H-1525 Budapest P.O.B. 17, Hungary
ABSTRACT
A new application of the formazyl activation provided selectively protected
new derivatives of both 2-deoxy-D-galactose and 2-acetamido-2-deoxy-D-
galactose formazans from 6-amino-6-deoxy-D-galactose 6,4-cyclic carbamate
(1) under very simple conditions. The 1H NMR spectrum of the acetylated 2-
deoxy derivative 7 revealed an equilibrium between chelated and unusual non-
chelated forms of the formazan moiety in solution.
INTRODUCTION
Beginning in the 1960s, several attempts have been made to elucidate the fine
structure of the formazyl ring of sugar formazans.2 Based on NMR spectra and cir-
cular dichroism studies, the formazan ring had been thought to exhibit either tau-
tomeric or mesomeric equilibria between pseudoaromatic cyclic forms. An open
phenylazo-phenylhydrazone structure of the formazan, however, was not consid-
747
Copyright © 2001 by Marcel Dekker, Inc.
www.dekker.com

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ZSOLDOS-MÁDY ET AL.
ered. Recently, the aim of the synthesis of selectively protected 6-amino-6-deoxy-
galactosamine and 6-amino-2,6-dideoxygalactose derivatives, potential building
blocks of aminoglycoside antibiotics,3 led us to recognition of the unexpected tau-
tomeric equilibria between pseudoaromatic chelate and open phenylazo-phenylhy-
drazone forms in solution.
The synthesis was based on the successful exploitation of the activating ef-
fect of the formazyl group. As we reported earlier,4 regiospecific and stereoselec-
tive replacement of the AcO-2 substituent of various acyclic aldose formazans was
achieved with nucleophiles under mild conditions. Thus, we succeeded in intro-
ducing an acetamido group5,6 or a hydrogen atom7 onto C-2 of various aldose for-
mazans. Subsequent decomposition of the formazyl group provides a new method
for the synthesis of aldonic acid derivatives substituted at C-2.6
RESULTS AND DISCUSSION
Our attempts to synthesise the target compounds were initiated from 4-O,
6-N-carbonyl-6-amino-6-deoxy-ꢀ-D-galactopyranose 1,8 easily prepared from
6-azido-6-deoxy-D-galactose with triphenylphosphine–carbon dioxide. The corre-
sponding red-coloured acyclic formazan 3 was obtained by a conventional proce-
dure9 via phenylhydrazone 2, which was acetylated with Ac2O-pyridine to its tri-
O-acetate 4. Compounds 2, 3 and 4 are new crystalline derivatives.
The formazan character of 3 and 4 was supported by maxima at 424 and 460
nm, respectively, in their visible spectra as well as by a characteristic singlet of the
formazyl NH at ꢁ 12.68 ppm in the 1H NMR spectrum of 4 (Table 1). During the
reactions the 4,6-cyclic-carbamate moiety remained intact, as was revealed by the
unchanged ꢂC ꢃ O band of the carbamoyl group at ꢀ1670 cmꢄ1 in compounds 1–4.
Treatment of compound 4 with ammonia in aqueous ethanol afforded the new
crystalline 2-acetamido derivative 5, which was acetylated to give the di-O-acetate
6. The one-pot formation of 5 can be explained by nucleophilic 1,4 elimination-ad-
dition process and subsequent O→N acetyl migration, as it was suggested in anal-
ogous cases.5 Evidence for the structures was provided by their visible, IR and
NMR spectra. It is noteworthy, that in the 13C NMR spectra of acetyl derivatives
4 and 6, C-4, one of the bridge-heads of the carbamate ring, resonated at lower field
(74.61 and 75.18 ppm, respectively) than the other secondary carbon atoms (C-
1
2,3,5) of the molecules (60–70 ppm). On the other hand, in the H NMR spectra
(Table 1) of the same compounds, the signal of H-4 appeared at higher field (ꢀ4,7
ppm) than those (5.25–6.37 ppm) of the other protons (H-2,3,5).
Reaction of 4 with sodium borohydride in dry 2-methoxyethanol was ex-
pected to give 3,5-di-O-acetyl-4-O,6-N-carbonyl-6-amino-2,6-dideoxy-D-lyxo-
hexose formazan 7, as a single new compound. The visible and IR spectra of the
1
product were consistent with the structure 7, however, in its H NMR spectrum
(Table 1) two sets of signals separated in a ratio of 2:1.
The most characteristic feature of the spectrum was the duplication of the for-
mazyl NMH singlet in the low-field region. The signal of double intensity at 11.11

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ISOMERISM OF THE FORMAZYL GROUP
749
Table 1. 1H NMR Chemical Shifts (ꢁ ppm) and Coupling Constants (J, Hz) for Compounds 4, 5, 6,
7a and 7b
4
5
6
7a
7b
H-2a
H-2b
H-3
H-4
H-5
H-6a
H-6b
NH (formazyl)
NH (carbamate)
NH (acetamido)
Ar-H-2ꢅ
Ar-H-3ꢅ
Ar-H-4ꢅ
CH3 (OAc)
CH3 (NAc)
J2a,2b
6.37
—
5.82
—
5.98
—
3.55
2.99
5.47
4.54
5.29
3.58
3.44
11.11
6.13
—
7.54
7.41
7.22
1.88; 2.10
—
3.86
3.05
5.21
4.30
5.54
3.52
3.41
9.27
6.08
5.64
4.76
5.27
3.62
3.44
12.68
6.39
—
7.54
7.38
7.21
1.90; 2.04
2.21
—
4.42
4.31
4.39
3.52
3.39
12.04
7.42
6.28
7.76
7.48
7.28
5.44
4.67
5.25
3.59
3.38
12.34
6.68
6.50
7.55
7.41
7.23
1.93; 2.00
2.15
—
—
7.83, 7.47
7.47, 7.35
7.42, 7.01
1.89; 2.12
—
2.11
—
—
15.0
3.8
15.0
6.2
J2a,3
—
—
J2b,3
J3,4
J4,5
J5,6a
J5,6b
J6a,6b
J6b,NH
2.5
9.6
1.1
3.8
1.4
13.4
4.3
2.9
8.1
5.7
3.2
1.9
12.6
—
2.8
9.2
1.8
3.5
1.7
13.4
—
7.5
8.8
1.3
3.4
1.5
13.1
4.2
4.4
7.2
1.2
3.3
1.5
13.0
4.3
J2,NH
—
4.0
9.7
—
—
ppm corresponds to the proton of the pseudoaromatic NMHꢆꢆꢆN chelate ring, rep-
resented by 7a. At the same time, the singlet of lower intensity at 9.27 ppm was as-
signed to the NMH proton of the open phenylazo-phenylhydrazone structure 7b.
Recently, we found a similar non-chelated formazan structure in the solid
state as proved by the X-ray crystal structure of a 2-azido-2-deoxy-sugar for-
mazan.10 The stability of the open structure in the crystal lattice could be attributed
to intermolecular NMHꢆꢆꢆO bonds between the phenylhydrazone moiety and the
carbonyl oxygen of AcO-6 of other molecules.
Compound 7 has provided the first example for the equilibrium between the
pseudoaromatic formazan ring and the open phenylazo-phenylhydrazone struc-
ture of an aldose formazan in solution. In this case, the formation of the open
structure is, probably, allowed by the small size of the two H-atoms at C-2 and
stabilized by inter- or intramolecular NMHꢆꢆꢆO bonding similar to the above
mentioned case.
The new synthetic approach, with a successful combination of the phosphin-
imine reaction and formazyl activation, has resulted in conservation and simulta-
neous and selective protection of the O-4 and N-6 substituents of 6-amino-6-de-

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750
ZSOLDOS-MÁDY ET AL.
oxy-D-galactose by a cyclic carbamate. The unchanged configuration and confor-
mation of the 6-membered carbamate cycle during all the transformations has been
indicated by the 1H NMR spectra (Table 1) of compounds 4–7. The theoretically
interesting cyclic-acyclic isomerism of the formazan moiety found in the case of 7
will be further investigated.
EXPERIMENTAL
General Methods. TLC was performed on Silica Gel 60 F254 (E. Merck)
plates developed with eluents A (EtOAcM1,4-dioxaneMAcOH 5:5:0.3); B,
(CHCl3MMeOH 9:1); C, (EtOAcMCH2Cl2 2:1). Spots were detected visually
and by exposure to UV light. Column chromatography was carried out on silica

ORDER
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ISOMERISM OF THE FORMAZYL GROUP
751
gel (E. Merck, 0.020–0.043 mesh). IR spectra (KBr) were recorded with a Nicolet
205 FT spectrometer, UV spectra with an HP 8452 A spectrometer in
EtOHMH2O (19:1) solution. NMR spectra were determined on Varian XL-100
and Varian XLAA-400 spectrometers using Me4Si as an internal standard.
Assignments were confirmed by proton-proton homocorrelated and carbon-
proton heterocorrelated spectra.
4-O,6-N-Carbonyl-6-amino-6-deoxy-D-galactose Phenylhydrazone (2).
To a filtered solution of 6-amino-6-deoxy-D-galactose 6,4-cyclic carbamate 1,
(1.78 g, 8.67 mmol)8 in distilled water (26 mL) was added a filtered solution of
phenylhydrazine hydrochloride (1.78 g, 8.7 mmol) and sodium acetate trihydrate
(1.45 g) in distilled water (14 mL). Within a few minutes white crystals started to
separate. The reaction mixture was left to stand at room temperature for 2 hours
and at 0°C overnight, then filtered and washed with chilled EtOAc. The yellowish-
white crude phenylhydrazone (2, 2.32 g, 91%), mp 209–211°C, was pure enough
for further reaction. A sample (1.0 g) was crystallized twice from hot ethanol giv-
ing white needles (0.72 g), mp 212–214°C; Rf 0.29 (solvent A).
Anal. Calcd for C13H17N3O5 (295.30): C, 52.88; H, 5.80; N, 14.23. Found:
C, 52.97; H, 5.84; N, 14.11.
4-O,6-N-Carbonyl-6-amino-6-deoxy-D-galactose Nꢅ,Nꢇ-Diphenylformazan
(3). A solution of benzenediazonium chloride9 was prepared from aniline (1.94 g,
20.9 mmol), 1:1 concd hydrochloric acid–water (10.6 mL) and sodium nitrite (1.44 g)
in water (3.4 mL), and added dropwise to a solution of 2 (4.8 g, 16.2 mmol) in a mix-
ture of pyridine (77 mL), ethanol (58 mL) and water (19 mL) at ꢄ5°C. The red mix-
ture was stirred for 30 min at 0°C and for 30 min at room temperature, then was poured
into ice–water (1L) to give a red syrup. On trituration with ice–water and on standing
at 0°C a red solid was formed (5.45 g, 84%), mp 184–186°C, which was pure enough
for the preparation of compound 4. Crystallization of a sample of crude 3 (0.31 g) from
2-propanol resulted in red needles (0.21 g), mp 186–187°C; Rf 0.55 (solvent A); ꢈmax
424 nm; ꢂmax 3600–3200 (OH, NH), 1670 (CO) cmꢄ1.
Anal. Calcd for C19H21N5O5 (399.42): C, 57.14; H, 5.30; N, 17.54. Found:
C, 57.29; H, 5.42; N, 17.77.
2,3,5-Tri-O-acetyl-4-O,6-N-carbonyl-6-amino-6-deoxy-D-galactose
Nꢅ,Nꢇ-Diphenylformazan (4). Compound 3 (1.2 g, 3.0 mmol) was acetylated
with a mixture of pyridine (6 mL) and acetic anhydride (4 mL) at 0°C for 2 days,
then was poured into ice–water (200 mL), to give a red solid; (1.42 g, 90%), mp
167–170°C. Recrystallization from 2-propanol by precipitation with water gave
red needles of 4, (0.99 g, 63%), mp 172–173°C; Rf 0.67 (solvent B); ꢈmax 460 nm,
ꢂmax 3500–3300 (NH), 1760 (AcO), 1670 (carbamate CO), 1220 (ester COC)
cmꢄ1 13C NMR (100 MHz, CDCl3): ꢁ170.35, 169.65, 169.32 (CH3CO); 152.68
.
(NHCO); 147.62 (ArMC-1ꢅ); 139.91 (C-1); 129.35 (ArMC-3ꢅ); 127.35 (ArMC-
4ꢅ); 118.69 (ArMC-2ꢅ); 74.61 (C-4); 69.42 (C-2); 68.56 (C-3); 44.54 (C-6); 20.83,
20.52, 20.08 (CH3CO).
Anal. Calcd for C25H27N5O8 (525,53): C, 57.14; H, 5.18; N, 13.33. Found:
C, 57.39; H, 5.17; N, 13.48.

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ZSOLDOS-MÁDY ET AL.
2-N-Acetyl-4-O,6-N-carbonyl-2,6-diamino-2,6-dideoxy-D-galactose
Nꢅ,Nꢅ-Diphenylformazan (5). Compound 4 (3.0 g, 5.7 mmol) was allowed to
stand with a mixture of EtOH (30 mL) and 25% aqueous ammonia solution (30
mL) for 6 h at room temperature and for 24 h at 0°C, while TLC (solvent A) indi-
cated complete reaction. The separated solid was filtered, washed with chilled
EtOH–H2O (1:1) to give red needles (1.57 g), mp 187–190°C. Concentration of the
mother liquor (bath temperature below 30°C) resulted in a second crop of crystals
(0.44 g, total yield 80%). Recrystallization was made by dissolving the solid in hot
EtOHMH2O (9:1, 15 mL) and adding water (1.5 mL) till turbidity. On cooling, red
crystals (1.56 g, 62%) separated, mp 193–194°C; Rf 0.23 (solvent A); ꢈmax 464 nm;
ꢂmax 3600–3200 (OH, NH), 1685–1615 (carbamate CO, amide CO) cmꢄ1
.
Anal. Calcd for C21H24N6O5 (440.47): C, 57.26; H, 5.49; N, 19.08. Found:
C, 57.18; H, 5.56; N, 19.01.
2-N-Acetyl-3,5-di-O-acetyl-4-O,6-N-carbonyl-2,6-diamino-2,6-dideoxy-
D-galactose Nꢅ,Nꢇ-Diphenylformazan (6). Compound 5 (0.25 g, 0.57 mmol)
was acetylated with a mixture of pyridine (2 mL) and Ac2O (1.5 mL) for 2 days at
0°C. Conventional work-up afforded a red solid (263 mg, 86%), mp 206–208°C,
which was purified by column chromatography with a solvent mixture
CH2Cl2MMeOH (98:2, later 9:1). After concentration, the syrup was dissolved in
CH2Cl2 and precipitated with CCl4, to give red crystals (206 mg, 67%), mp
218–219°C; Rf 0.35 (solvent B); ꢈmax 462 nm; ꢂmax 3550–3200 (NH), 1747 (AcO),
1717, 1659 (carbamate CO, amide CO) cmꢄ1 13C NMR (100 MHz, CDCl3):
.
ꢁ170.36, 170.15, 169.15 (CH3CO); 152.60 (NHCO); 147.44 (ArMC-1ꢅ); 142.07
(C-1); 129.39 (ArMC-3ꢅ); 127.37 (ArMC-4ꢅ); 118.63 (ArMC-2ꢅ); 75.18 (C-4);
70.16 (C-3); 60.66 (C-5); 48.33 (C-2); 44.40 (C-6); 23.53, 20.77, 20.50 (CH3CO).
Anal. Calcd for C25H28N6O7 (524,55): C, 57.24; H, 5.38; N, 16.02. Found:
C, 57.11; H, 5.46; N, 16.15.
3,5-Di-O-acetyl-4-O,6-N-carbonyl-6-amino-2,6-dideoxy-D-lyxo-hexose
Nꢅ,Nꢇ-Diphenylformazan (7). A solution of 4 (0.52 g, 1.0 mmol) in dry 2-
methoxyethanol (14 mL) was cooled to 0°C, then sodium borohydride (1.2 g, 32
mmol) dissolved in 2-methoxyethanol (14 mL) was added dropwise. The mixture
was allowed to stand for 5 h at the same temperature when TLC (solvent C) re-
vealed the complete transformation of the starting formazan. After adding AcOH
(2 mL) the mixture was poured into ice-water (150 mL), and the red precipitate was
filtered to give the crude product (0.40 g). Separation by short-column chromatog-
raphy with 2:1 EtOAcMCH2Cl2 mixture furnished pure, red solid, (0.21 g, 45%),
Rf 0.51 (solvent C). On the basis of its NMR spectra the product is a 2:1 mixture of
7a and 7b in CDCl3 solution at room temperature (see Table 1). 13C NMR (100
MHz, CDCl3): for 7a: ꢁ170.33, 169.54, (CH3CO); 152.77 (NHCO); 147.92
(ArMC-1ꢅ); 144.23 (C-1); 129.37 (ArMC-3ꢅ); 126.78 (ArMC-4ꢅ); 118.50
(ArMC-2ꢅ); 77.42 (C-4); 68.08 (C-3); 60.77 (C-5); 30.65 (C-2); 44.77 (C-6);
20.82, 20.83, (CH3CO); for 7b: ꢁ170.21, 170.04, (CH3CO); 152.21 (NHCO);
151.69 and 151.99 (ArMC-1ꢅ); 143.01 (C-1); 129.17 and 129.42 (ArMC-3ꢅ);
130.71 and 122.52 (ArMC-4ꢅ); 122.81 and 114.60 (ArMC-2ꢅ); 76.87 (C-4); 68.53
(C-3); 60.33 (C-5); 21.32 (C-2); 44.95 (C-6); 20.89, 20.88, (CH3CO).

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ISOMERISM OF THE FORMAZYL GROUP
753
Anal. Calcd for C23H25N5O6 (467.49): C, 59.35; H, 5.41; N, 18.06. Found:
C, 59.62; H, 5.49; N, 17.98.
ACKNOWLEDGMENTS
This work was supported by the Hungarian Scientific Research Fund (OTKA
1758, T 14458 and T 23371). Authors acknowledge the valuable technical assis-
tance of Ms. J. Beregszászy.
REFERENCES
1. Dedicated to Professor J. Thiem on the occasion of his 60th anniversary.
2. a) Mester, L.; Stephen, A.; Parello, J. NMR studies on nitrogen-containing sugar
derivatives substituted by nitrogen-15. Tetrahedron Lett. 1968, 38, 4119–4122; b)
Fischer, P.B.; Kaul, B.L.; Zollinger, H. Untersuchungen über die Struktur von For-
mazanen I. 15N-H-Kopplung des Chelatwasserstoffatoms. Helv. Chim. Acta 1968,
51, 1449–1451; c) Mester, L.; Vass, G.; Mester, M. Circular dichroism of sugar for-
mazans. Z Chem. 1970, 10, 395–396.
3. a) Yoshikawa, M.; Ikeda, Y.; Takenaka, K.; Torihara, M.; Kitagawa, I. Synthesis of
ribostamycin. An application of a chemical conversion method from carbohydrate to
aminocyclitol. Chem. Lett. 1984, 2097–2100; b) Canas-Rodriguez, A.; Ruiz-Poveda,
S.G.; Coronel-Borges, L.A. Synthesis of apromycin analogs. Carbohydr. Res. 1987,
159, 217–227; c) Canas-Rodriguez, A.; Coronel-Borges, L.A. Apromycin analogs.
Carbohydr. Res. 1987, 165, 129–133; d) Ludin, C.; Weller, T.; Seitz, B.; Meier, W.;
Erbeck, S.; Hoenke, C.; Krieger, R.; Keller, M.; Knothe, L.; Pelz, K.; Wittmer, A.;
Prinzbach, H. Sannamycin-type aminoglycoside antibiotics of natural and non-natu-
ral (mirror-image) configuration–Total syntheses and biological activity. Liebigs
Ann. 1995, 291–316; e) Erbeck, S.; Prinzbach, H. Enantiopure Purpurosamine C type
glycosyl donors. An improved access from rac-acrolein dimer–Biocatalytic resolu-
tion. Tetrahedron Lett. 1997, 38, 2653–2656; f) Erbeck, S.; Liang, X.; Hunkler, D.;
Krieger, R.; Prinzbach, H. Sannamycin-type aminoglycoside antibiotics–Efficient
syntheses–Biological activity. Eur. J. Org. Chem. 1998, 1935–1948.
4. a) Zsoldos, V.; Messmer, A.; Pintér, I.; Neszmélyi, A. Formation of 2,5-anhydro
derivates in the Zemplén deacetylation of acetylated sugar formazans. Carbohydr.
Res. 1978, 62, 105–116; b) Messmer, A.; Pintér, I.; Zsoldosné Mády, V.; Neszmélyi,
A. 2,5-Anhidrogyurus származékok képzodése acetilezett cukorformazánok Zem-
plén-féle dezacetilezésénél. Magy. Kém. Foly. 1979, 85, 344–352.
5. Messmer, A.; Pintér, I.; Zsoldos-Mády, V.; Neszmélyi, A.; Hegedus-Vajda, J. Unex-
pected formation of 2-acetamido-2-deoxy derivatives of sugar formazans. Acta
Chim. Acad. Sci. Hung. 1983, 113, 393–402.
6. Zsoldos-Mády, V.; Pintér, I.; Neszmélyi, A.; Messmer, A.; Perczel, A. 2-Acetamido-
2-deoxyaldonolactones from sugar formazans. Carbohydr. Res. 1984, 252, 85–95.
7. Pintér, I.; Zsoldos-Mády, V.; Messmer, A.; Sándor, P.; Gero, S.D. A novel approach
towards acyclic 2-deoxyaldose derivatives. Carbohydr. Res. 1988, 175, 302–305.
8. Kovács, J.; Pintér, I.; Messmer, A.; Tóth, G. Unprotected sugar phosphinimines:
facile route to cyclic carbamates of aminosugars. Carbohydr. Res. 1985, 141, 57–65.

ORDER
REPRINTS
754
ZSOLDOS-MÁDY ET AL.
9. a) Mester, L. The formazan reaction in carbohydrate research. Adv. Carbohydr.
Chem. 1958, 13, 105–169; b) Mester, L.; Messmer, A. Formazans, In Methods in
Carbohydrate Chemistry, Whistler, R.L.; Wolfrom, M.L., Eds.; Academic Press:
New York, 1963; Vol. II, 117–122.
10. Argay, Gy.; Kálmán, A.; Pintér, I.; Zsoldos-Mády, V. Crystal structure of 3,4,5,6-
tetra-O-acetyl-2-azido-2-deoxy-D-glucose N,Nꢅ-diphenylformazan. Z. Kristallogr.
1997, 212, 189–190.

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