Synthesis of 2-amino derivatives of levoglucosenone

Article abstract of DOI:10.1007/s10600-005-0052-8

2-Amino derivatives of levoglucosenone were prepared by reaction of the 2-methanesulfonyl (or p-toluenesulfonyl) derivatives with ammonia, methylamine, or octylamine under various conditions. The analogous reaction did not occur for saturated derivative 15. The 2-amino-3,4-dihydro derivative was prepared by catalytic hydrogenation of unsaturated amine 9. 2004 Springer Science + Business Media, Inc.

Full text of DOI:10.1007/s10600-005-0052-8

Chemistry of Natural Compounds, Vol. 40, No. 6, 2004
SYNTHESIS OF 2-AMINO DERIVATIVES OF LEVOGLUCOSENONE
F. A. Valeev,1 L. Kh. Kalimullina,2 Sh. M. Salikhov,1
O. V. Shitikova,1 I. P. Tsypysheva,1 and M. G. Safarov2
UDC 547.917
2-Amino derivatives of levoglucosenone were prepared by reaction of the 2-methanesulfonyl (or
p-toluenesulfonyl) derivatives with ammonia, methylamine, or octylamine under various conditions. The
15
analogous reaction did not occur for saturated derivative . The 2-amino-3,4-dihydro derivative was
9
prepared by catalytic hydrogenation of unsaturated amine .
Key words: levoglucosenone, amino sugar, mucopolysaccharides, ketose oximes and hydrazone, nucleophilic
substitution, aminolysis, 1,6-anhydro sugar sulfonates.
Amino sugars act as structural components of many natural compounds including such large groups as
mucopolysaccharides and mixed biopolymers. However, theyare rarelyfound in the free state. As a rule, aminosugars required
for organic synthesis are obtained byaminolysis ofhalides, sulfonates, and anhydroderivatives ofmonosaccharides or reduction
of ketose oximes and hydrazones [1, 2]. The carbohydrate levoglucosenone (1), which is prepared by cellulose pyrolysis [3],
ispromisingfor preparing unsaturated aminosugars and their derivatives. N-Containing derivatives ofthis sugar enone include
heterocyclic products of tandem conversions [4-7], oxime 2 [8], and regioisomeric amines formed by hydroxyamination of
1,6-anhydro-3,4-dideoxy-β-D-threo-hex-3-enopyranose [9].
Oxime2wassynthesizedbythe literature method [8]. Furthermore, reaction oflevoglucosenonewith hydrazinesulfate
in pyridine produced a different azomethine, hydrazone 3. Unfortunately, attempts to reduce azomethines 2 and 3 with LiAlH
4
gave products that were difficult to isolate from aqueous solutions.
Alernativeapproachescouldbebasedon substitution reactions, which areknown toproceed difficultlyin six-membered
pyranose rings [1]. Nevertheless, keeping in mind the allylic position ofthe reaction center and the pseudoequatorial orientation
of the substituted group, we studied the possibility of this approach.
O
O
O
LiAlH
LiAlH
4
O
4
O
O
a
b
N
O
O
OH
O
N NH
2
2
3
1
c
O
O
O
O
O
O
d
e
+
Br
OH
OR
Br
6: R = Ms
7: R = Ts
5b
5a
4
a. NH OH HCl, Py; b. NH NH H SO , Py; c. NaBH , H O;
2
2
2
2
4
4
2
d.
e
PPh -CBr ; . TsCl, Py or MsCl, CH Cl , -10° C
3
4
2
2
1) Institute of Organic Chemistry, Ufa Scientific Center, Russian Academy of Sciences, 450054, Ufa, pr. Oktyabrya,
71, fax (3472) 35 60 66, e-mail: chemorg@anrb.ru; 2) Bashkir State University, Ufa. Translated from Khimiya Prirodnykh
Soedinenii, No. 6, pp. 429-432, November-December, 2004. Original article submitted July 2, 2004.
0009-3130/04/4006-0521 ©2004 Springer Science + Business Media, Inc.
521

Reaction of levoglucosenone with NaBH led stereospecifically to threo-alcohol 4 [10], bromination of which with
4
PPh —CBr gave a mixture of the epimeric bromides 5a and -b (11%) in a 2:1 ratio. Considering that the substitution reaction
3
4
in saturated sugars occurs via an S 2 mechanism [1], the retention of the initial configuration in the minor product 5b indicates
N
that an allylic carbocationic intermediate formed.
13
The structures of the prepared compounds were established using PMRand C NMR spectroscopy. Thus, the missing
1
2
or very small J for H-1 at 5.70 ppm in the PMR spectrum of erythro-bromide 5a indicates that the H–C –C –H torsion angle
1,2
is close to 90° and that the Br in 5a has the α-orientation, in contrast with the doublet at 5.60 ppm with SSCC 2.9 Hz for H-1
13
in threo-bromide 5b. The signals for C-1 and C-6 in the C NMR spectrum of 5b are shifted to strong field by6.2 and 5.8 ppm,
respectively, whereas that for C-5 undergoes a weak-field shift of 4.2 ppm compared with those in 5a. This difference is
probably a result of the syn-coupling of the substituents in 5b.
The low yields of the epimeric bromides 5a and 5b prompted us to study the possible aminolysis of the corresponding
sulfonates. Mesylate 6 and tosylate 7 that were required for this were prepared as before [10]. The presence of J coupling
1,2
in the PMR spectra of 6 and 7 indicate that C-2 has the threo configuration. For example, the signal for H-1 at 5.45 ppm in
the spectrum of 7 is the same as in the starting threo-alcohol 4 and has J = 2.3 Hz.
1,2
An attempt to substitute the sulfonate in the mesylate by boiling in acetone with NaBr with the hope that the
stereochemical features and the allylic levoglucosenone would appear in this instance also did not give the desired result.
Treatment of 7 with aqueous ammonia at 100°C for 10 h in a sealed ampul caused stereospecific substitution of the
tosyl group via an S 2-mechanism. This is consistent with the two products, the desired amine 9 in 30% yield and erythro-
N
alcohol 8 in 51% yield. Reaction in aqueous methylamine under analogous conditions gave the alcohol and the corresponding
amine in yields of 56 and 40%.
8 + 9
a
O
O
O
O
b
c
O
O
O
O
+
+
7
d, e
OH
OH
NH
OCH
3
2
4
8
9
10
O
O
NHR
R = H
9:
R = CH
11:
3
R = C H
17
12:
8
a. 40% NH OH, ampul, 100°C;b. 40% NH OH, hv;
4
4
c. NH , MeOH, ampul;d. CH NH , ampul or NH , ampul;
3
3
2
3
e. C H NH , C H , boiling
17
8
2
6 6
In addition, irradiation with UV light of 7 in aqueous ammonia removed the tosyl group to form quantitatively 4 in
a shorter time than by the known method [11].
Heating 7 in methanol saturated with ammonia in a sealed ampul [12] formed a mixture of the desired amine 9
(28.9%), the chromatographically less polar 8 (5%), and its methoxy ether 10 (51.2%).
PMR spectra of 10 give a signal for H-1, in contrast with the known threo-epimer [10], with J missing or verysmall.
1,2
1
2
This indicates that the H–C –C –H torsion angle is close to 90° and, therefore, the new asymmetric center has the
-configuration.
R
Heating 6 and 7 in liquid NH under analogous conditions formed 9 in yields of 70 and 63%, respectively. Reaction
3
of 6 with liquid methylamine under these same conditions gave secondary amine 11 in 83.7% yield; conversion of 96.9%. In
the case of tosylate 7 conversion - 80%. The high lability of 9 should be noted.
Prolonged contact of 6 and 7 with liquid ammonia or methylamine in sealed ampuls at room temperature gave amines
9 or 11, respectively, in quantitative yields.
522

Boiling 7 with octylamine in benzene gave another secondary amine 12 in 85% yield.
Saturated tosylate 15, which was prepared by hydrogenation of 1 and subsequent tosylation of dihydro derivative 14,
was subjected to aminolysis in order to estimate the magnitude of electronic and steric factors. However, heating a solution of
15 in liquid ammonia at 120°C for 15 h was unsuccessful. The equatorial orientation of the sulfonate probably prevents the
substitution in this instance, assuming that the nucleophile attacks from inside the pyran ring. Saturated 2-amino derivative
16 was prepared in quantitative yield by hydrogenation of 9.
O
O
O
O
O
d
a
b, c
O
O
O
O
O
e
OR
NH
2
O
O
NH
2
13
14, 15
16
9
1
14: R = H
15: R = OTs
a. 5% Pd/C, H ; b.NaBH , H O; c. TsCl, Py;d. NH , ampul; e. 5% Pd/C, H , MeOH
2
4
2
3
2
Tosylate 7 was not aminolyzed by secondary amines diisopropylamine, benzylamine, urea, or thiourea.
Thus, levoglucosenone is a convenient substrate for preparing the corresponding unsaturated 2-amino derivatives and
then the difficultly accessible saturated derivatives. This pathway is also promising for preparing 2-amino sugars modified at
the 3- and 4-positions.
EXPERIMENTAL
13
IR spectra were recorded on UR-20 and Specord M-80 instruments (as films or in mineral oil). PMR and C NMR
spectra were recorded on a Bruker AM-300 spectrometer at working frequencies 300 and 75.47 mHz, respectively, with TMS
internal standard and CDCl solvent. TLC analysis used Silufol UV-254:366 (Czech Rep.) chromatographic plates. Optical
3
rotation angles were measured on a Perkin—Elmer 141 instrument. Mass spectra were recorded in an MX-1306 instrument
(70 eV ionizing potential, 30-50°C ionization-chamber temperature). Analytical data agreed with those calculated.
Syn-andanti-oximesof1,6-anhydro-3,4-dideoxy-β-D-glycerohex-3-enopyranos-2-ylose(2)waspreparedasbefore
[7].
1,6-Anhydro-3,4-dideoxy-β-D-glycerohex-3-enopyranos-2-ylose hydrazone (3). A solution of 1 (1 g, 8 mmol) in
Py(10 mL) was treated in portions with stirring at room temperature with NH NH ·H SO (1.42 g, 9 mmol). After the reaction
2
2
2
4
was complete (TLC monitoring), the reaction mixture was evaporated. The solid was chromatographed over SiO to afford 3
2
20
(1.025 g, 90%), R 0.26 (petroleum ether:ethylacetate, 2:1), mp 175-179°C, [α]
-453 (c 1.0, CHCl ).
3
f
D
PMR spectrum (CDCl , δ, ppm, J/Hz): 3.82 (1H, d, J = 6.6, H
-6), 3.88 (1H, dd, J = 6.6, J = 4.4, H -6), 4.90 (1H,
exo
3
endo
dd, J = 4.4, J = 4.3, H-5), 5.77 (1H, s, H-1), 6.70 (2H, m, H-3, H-4).
13
C NMR spectrum (δ, ppm): 68.63 (C-6), 72.07 (C-5), 101.59 (C-1), 118.16 (C-3), 139.49 (C-4), 155.25 (C-2).
1,6-Anhydro-3,4-dideoxy-β-D-threo-hex-3-enopyranose (9) was prepared as before [10].
1,6-Anhydro-2-C-bromo-2,3,4-trideoxy-β-D-erythro-hex-3-enopyranose(5a)and1,6-Anhydro-2-C-bromo-2,3,4-
trideoxy-β-D-threo-hex-3-enopyranose (5b). A solution of 4 (0.5 g, 3.9 mmol) in CH Cl (5 mL) and triphenylphosphine
2
2
(1.13 g, 4.3 mmol) at room temperature was treated in portions with stirring with CBr (1.33 g, 4.0 mmol). After the reaction
4
was complete (TLC monitoring), the reaction mixture was evaporated. The solid was chromatographed over SiO to afford a
2
20
mixture of 5a and 5b (0.087 g, 11%) in a 2:1 ratio, R 0.27 (petroleum ether), [α]
-151.9° (c 1.0, CHCl ).
3
f
D
Threo-bromide (5b). PMR spectrum (CDCl , δ, ppm, J/Hz): 3.58 (1H, dd, J = 8.3, J = 1.6, H -6), 4.0 (1H, dd,
3
exo
J = 8.3, H
-6), 4.36 (1H, d, J = 3.4, H-2), 4.82 (1H, d, J = 6.5, J = 1.6, H-5), 5.2 (1H, d, J = 2.9, H-1), 5.90 (1H, m, H-4), 5.95
endo
(1H, dd, J = 9.4, J = 3.0, H-3).
523

13
C NMR spectrum (δ, ppm): 44.15 (C-2), 65.48 (C-6), 76.77 (C-5), 95.60 (C-1), 126.04 (C-3), 128.61 (C-4).
Erythro-bromide (5a). PMR spectrum (CDCl , δ, ppm, J/Hz): 3.75 (1H, dd, J = 6.6, J = 4.7, H -6), 3.83 (1H, d,
3
exo
J = 6.6, H
-6), 4.42 (1H, d, J = 3.8, H-2), 4.78 (1H, d, J = 4.7, H-5), 5.7 (1H, s, H-1), 5.90 (1H, dd, J = 9.7, J = 3.8, H-3), 6.1
endo
(1H, dd, J = 7.9, J = 4.7, H-4).
13
C NMR spectrum (δ, ppm): 45.36 (C-2), 70.53 (C-5), 71.31 (C-6), 101.84 (C-1), 125.97 (C-4), 129.31 (C-3).
1,6-Anhydro-3,4-dideoxy-2-O-(methanesulfonyl)-β-D-threo-hex-3-enopyranose (6)and1,6-anhydro-3,4-dideoxy-
2-O-(p-toluenesulfonyl)-β-D-threo-hex-3-enopyranose (7) were prepared as before [10].
6: R 0.4 (petroleum ether:ethylacetate, 1:1).
f
PMR spectrum (CDCl , δ, ppm, J/Hz): 3.12 (3H, s, CH ), 3.82 (1H, d, J = 6.8, J = 4.1, H -6), 3.98 (1H, d, J = 6.8,
3
3
exo
H
-6), 4.72 (1H, dd, J = 4.2, J = 4.1, H-5), 5.41 (1H, d, J = 2.2, H-1), 5.68 (1H, ddd, J = 10.3, J = 2.4, J = 2.2, H-3), 5.7 (1H,
endo
t, J = 2.2, H-2), 6.28 (1H, dd, J = 10.3, J = 4.2, H-4).
13
C NMR spectrum (δ, ppm): 36.89 (CH ), 71.21 (C-5), 71.37 (C-6), 76.26 (C-2), 99.02 (C-1), 123.63 (C-3), 134.20
3
(C-4).
7: R 0.7 (petroleum ether:ethylacetate, 1:1).
f
PMR spectrum (CDCl , δ, ppm, J/Hz): 2.46 (3H, s, CH ), 3.78 (1H, dd, J = 6.7, J = 4.1, H -6), 3.94 (1H, d, J = 6.7,
3
3
exo
H
-6), 4.65 (1H, dd, J = 4.1, J = 3.2, H-5), 5.20 (1H, d, J = 2.2, H-1), 5.45 (1H, t, J = 2.3, H-2), 5.52 (1H, dt, J = 10.0,
endo
J = 2.2, H-3), 6.20 (1H, dd, J = 10.0, J = 3.2, H-4), 7.32, 7.38 (2H, d, H3′, H-5′, Ph), 7.82, 7.86 (2H, d, H-2′, H-6′, Ph).
13
C NMR spectrum (δ, ppm): 21.51 (CH ), 71.04 (C-5), 71.11 (C-6), 76.91 (C-2), 96.75 (C-1), 123.35 (C-4), 133.38
3
(C-3), 127.69, 133.38, 133.81, 145.05 (Ph).
Aminolysis of Sulfonates in Aqueous Ammonia and Methylamine. A sealed ampul containing a solution of 7
(0.1 g) in aqueous ammonia (10 mL, 40%) was heated for 7 h at 120°C. The ampul was cooled and opened. The reaction
mixture was treated with saturated NaCl solution and extracted with ethylacetate (3 × 10 mL). The combined extracts were
dried over MgSO and evaporated. The solid was chromatographed over SiO to afford 8 (0.034 g, 51%) and 9 (0.018 g, 30%).
4
2
1,6-Anhydro-3,4-dideoxy-β-D-erythro-hex-3-enopyranose (8): R 0.25 (petroleum ether:ethylacetate, 1:1),
f
20
[α]
-206.5° (c 1.0, CH OH).
D
3
PMR spectrum (CDCl , δ, ppm, J/Hz): 3.64 (1H, d, J = 6.8, H
-6), 3.68 (1H, dd, J = 6.8, J = 3.2, H -6), 3.70 (1H,
exo
3
endo
d, J = 3.7, H-2), 4.7 (1H, dd, J = 4.7, J = 3.2, H-5), 5.53 (1H, s, H-1), 5.82 (1H, dd, J = 9.8, J = 3.7, H-3), 6.18 (1H, dd, J = 9.8,
J = 4.7, H-4).
13
C NMR spectrum (δ, ppm): 65.88 (C-2), 68.91 (C-6), 70.62 (C-5), 102.62 (C-1), 126.42 (C-3), 130.84 (C-4).
20
1,6-Anhydro-2-amino-2,3,4-trideoxy-β-D-erythro-hex-3-enopyranose(9):R 0.3(ethylacetate), [α]
-240°(c 1.0,
f
D
CHCl ).
3
PMR spectrum (CDCl , δ, ppm, J/Hz): 1.5 (2H, br.s, NH ), 2.8 (1H, d, J = 3.7, H-2), 3.64 (1H, dd, J = 6.4, J = 4.7,
3
2
H
-6), 3.72 (1H, d, J = 6.4, H
-6), 4.58 (1H, dd, J = 4.6, J = 4.4, H-5), 5.35 (1H, s, H-1), 5.68 (1H, dd, J = 9.8, J = 3.9, H-3),
exo
endo
6.0 (1H, dd, J = 9.8, J = 4.7, H-4).
13
C NMR spectrum (δ, ppm): 51.22 (C-2), 70.22 (C-6), 70.85 (C-5), 104.83 (C-1), 128.55 (C-3, C-4).
Aminolysis of 7 (0.1 g) in aqueous methylamine (40%) was performed under analogous conditions to afford 8
(0.034 g, 56.4%) and 11 (0.018 g, 40%).
1,6-Anhydro-2-aminomethyl-2,3,4-trideoxy-β-D-erythro-hex-3-enopyranose (11):
R
0.2 (petroleum
f
20
ether:ethylacetate, 1:1), [α]
-89° (c 1.0, CHCl ).
3
D
PMR spectrum (CDCl , δ, ppm, J/Hz): 2.53 (3H, s, CH ), 2.89 (1H, d, J = 3.7, H-2), 3.6 (1H, br.s, NHCH ), 3.7 (1H,
3
3
3
dd, J = 6.2, J = 4.3, H -6), 3.8 (1H, d, J = 6.2, H
-6), 4.68 (1H, t, J = 4.3, H-5), 5.6 (1H, s, H-1), 5.78 (1H, dd, J = 9.9,
exo
endo
J = 3.7, H-3), 6.1 (1H, dd, J = 4.3, J = 3.9, H-4).
13
C NMR spectrum (δ, ppm): 33.78(NCH ), 51.78(C-2), 70.15 (C-6), 70.65 (C-5), 101.08 (C-1), 126.28 (C-4), 129.05
3
(C-3).
Aminolysis of Sulfonates in Methanol. A solution of 7 (0.15 g) in methanol (5 mL) was saturated at 0°C with
ammonia and heated for 7 h at 120°C in an autoclave. The reaction mixture was evaporated. The solid was chromatographed
over SiO to afford 10 (0.039 g, 51%), the amino derivative (0.020 g, 28.9%), and 8 (0.005 g, 5%).
2
1,6-Anhydro-2-O-methyl-3,4-trideoxy-β-D-erythro-hex-3-enopyranose (10): R 0.4 (petroleum ether:ethylacetate,
f
20
3:1), [α]
-208° (c 1.0, CHCl ).
D
3
524

PMR spectrum (CDCl , δ, ppm, J/Hz): 3.30 (1H, d, J = 3.8, H-2), 3.48 (3H, s, OMe), 3.68 (1H, dd, J = 6.7, J = 4.7,
3
H
-6), 3.78 (1H, d, J = 6.7, H
-6), 4.72 (1H, dd, J = 4.7, H-5), 5.65 (1H, s, H-1), 5.68 (1H, dd, J = 9.8, J = 3.7, H-3), 6.25
exo
endo
(1H, dd, H-4, J = 9.8, J = 4.7, H-4).
Aminolysis in Liquid Ammonia and Methylamine. Compound 7 (0.28 g, 1 mmol) and liquid ammonia (5 mL) were
placed into two thick-walled ampuls; 7 (0.28 g) and liquid methylamine (5 mL), into two others. The ampuls were sealed. One
of each pair was held for 60 d at room temperature; the other, heated at 100°C for 10 h. After each period had expired, the
ampuls were opened and volatile compounds were removed. The solid was chromatographed over silica gel. The reaction
mixture from the heated ampuls gave 9 (0.082 g, 64.9%) and 11 (0.098 g, 70%). The reaction mixture from the long-term
stored ampuls gave 9 (0.105 g, 83.7%) and 11 (0.130 g, 93%).
1,6-Anhydro-2-aminooctyl-2,3,4-trideoxy-β-D-erythro-hex-3-enopyranose (12). A solution of 7 (0.1 g) and
octylamine (0.1 g) in benzene was boiled for 25 d. The reaction mixture was evaporated in a rotary evaporator. The solid was
20
chromatographed over SiO to afford 12 (0.065 g, 85%), R 0.4 (petroleum ether:ethylacetate, 1:1), [α]
-72° (c 1.0, CHCl ).
3
f
2
D
PMR spectrum (CDCl , δ, ppm, J/Hz): 0.88 (3H, t, CH , J = 7.0), 1.20 (10H, m, CH ), 1.5 (2H, m, H-2′), 2.83 (1H,
3
3
2
d, J = 3.8, H-2), 2.72 (1H, t, J = 6.6, H = 1′), 3.25 (1H, q, J = 6.6, H = 1′), 3.65 (1H, dd, J = 6.35, J = 4.4, H -6), 3.8 (1H,
b
a
exo
d, J = 6.35, H
-6), 5.5 (1H, s, H-1), 5.75 (1H, dd, J = 9.8, J = 3.8, H-3), 6.07 (1H, dd, J = 9.8, J = 4.4, H-4), 8.15 (1H, br.s,
endo
NH).
13
C NMR spectrum (δ, ppm): 14.0, 22.63, 27.24, 29.19, 30.25, 31.82, 38.25, 47.16 (8CH ), 56.43 (C-2), 70.44 (C-6),
2
70.89 (C-5), 101.61 (C-1), 126.39 (C-4), 129.47 (C-3).
1,6-Anhydro-β-D-glycerohexopyranos-2-ylose (13) was prepared as before [7].
1,6-Anhydro-β-D-glycerohexopyranos-2-ylose (14) and 1,6-anhydro-2-O-(p-toluenesulfonyl)-β-D-hexopyranose
(15) were prepared as before [10].
1,6-Anhydro-2-C-aminomethyl-2,3,4-trideoxy-β-D-erythro-hexopyranose (16). Asolution of9(0.100g, 0.78mmol)
in methanol (10 mL) was treated with Pd/C (0.005 g, 5%). The reaction mixture was stirred under a H atmosphere with TLC
2
monitoring. After 36 h the reaction mixture was filtered and concentrated. The solid was chromatographed over SiO to afford
2
20
16 (0.075 g, 78%): R 0.20 (ethylacetate), [α]
-39° (c 1.0, CHCl ).
f
D
3
eq
eq
ax
ax
PMR spectrum (CDCl , δ, ppm, J/Hz): 1.36 (1H, m, CH ), 1.6 (1H, m, CH ), 1.7-2.0 (3H, m, H-2, CH , CH ),
3
2
2
2
2
2.47 (2H, br.s, NH ), 3.72 (1H, t, J = 6.2, H -6), 3.88 (1H, d, J = 6.2, H -6), 4.47 (1H, m, H-5), 5.35 (1H, s, H-1).
endo
2
exo
13
C NMR spectrum (δ, ppm): 19.09 (C-4), 25.10 (C-3), 57.10 (C-2), 66.90 (C-6), 73.26 (C-5), 102.25 (C-1).
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