A route to functionalized pyrimidines from carbohydrates via amine-driven dehydrative ring transformations

Article abstract of DOI:10.1016/j.tetlet.2008.02.067

A novel and expeditious synthetic protocol for functionalized pyrimidines using unprotected aldoses as biorenewable resources is reported. The synthesis involves aza-Michael addition of aromatic amines to aldose-derived 1,3-oxazin-2-ones(thiones) followed

Full text of DOI:10.1016/j.tetlet.2008.02.067

Available online at www.sciencedirect.com
Tetrahedron Letters 49 (2008) 2377–2380
A route to functionalized pyrimidines from carbohydrates
via amine-driven dehydrative ring transformations
Lal Dhar S. Yadav *, Chhama Awasthi, Vijai K. Rai, Ankita Rai
Green Synthesis Lab, Department of Chemistry, University of Allahabad, Allahabad 211 002, India
Received 20 January 2008; revised 10 February 2008; accepted 13 February 2008
Available online 16 February 2008
Abstract
A novel and expeditious synthetic protocol for functionalized pyrimidines using unprotected aldoses as biorenewable resources is
reported. The synthesis involves aza-Michael addition of aromatic amines to aldose-derived 1,3-oxazin-2-ones(thiones) followed by
dehydrative ring transformation to afford 4-polyhydroxyalkylpyrimidin-2-ones(thiones) in excellent yields. This is a one-pot Montmo-
rillonite K-10 clay-catalyzed amine-driven process proceeding under solvent-free microwave irradiation conditions.
Ó 2008 Elsevier Ltd. All rights reserved.
Keywords: Carbohydrates; Pyrimidines; Mineral-catalyzed; Microwaves; Solvent-free; 1,3-Oxazin-2-ones(thiones)
Pyrimidines are an important class of compounds and
have widespread applications from pharmaceuticals to
materials.1 A number of synthetic pharmacophores with
antibacterial, antimicrobial, antifungal and antimycotic
activities2–4 are based on the pyrimidyl motif. Also, pyr-
imidines are present in numerous natural products and,
significantly, in the pyrimidine and purine bases ribo- and
deoxyribonucleosides.5 The electron-deficient nature of
pyrimidines can impart highly electron-accepting ability
to conjugated polymers.6 In addition, conjugate molecules
which have a pyrimidine core as the key unit have received
much attention recently, and they are prospective candi-
dates for light-emitting devices.7 Owing to their strong
deactivation towards electrophilic substitution and greater
reactivity in nucleophilic additions and substitutions,5a,f,8
pyrimidines may become increasingly important as inter-
esting structural coordinating substituted ligands for
pyridyl units in supramolecular metallo-grid-like architec-
tures9 and in novel inorganic/organic hybrid type mole-
cular wires.10
These unique properties have triggered renewed interest
to develop new synthetic methods which enable rapid
access to pyrimidines. In most of the cases, construction
of the pyrimidine ring is based on the bis-nucleophile plus
bis-electrophile methods11 or cross coupling reactions12
and is restricted to methods involving Pinner synthesis
via 3,4- and 1,6- (I);11 1,2- and 2,3- (II);13 1,2- and 3,4-
(III);14 4,5- and 1,6- (IV);15 2,3- and 4,5- (V) bond forming
reactions.16 Recently, a four component coupling strategy
was reported for pyrimidine synthesis by 3,4- and 4,5-
(VI) bond forming reactions17 (Scheme 1). However, in
N
C
C
C
N
N
N
C
I
N
C
II
N
III
4
C
N
N
C
5
6
C
N
N
3
N
IV
VII
C
2
C
N
1
Present work
C
C
N
C
C
N
VI
V
C
N
N
*
Corresponding author. Tel.: +91 5322500652; fax: +91 5322460533.
Scheme 1.
E-mail address: ldsyadav@hotmail.com (L. D. S. Yadav).
0040-4039/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2008.02.067

2378
L. D. S. Yadav et al. / Tetrahedron Letters 49 (2008) 2377–2380
Table 1
most of the established methods, condensation occurs
between two-nitrogen-containing building blocks, viz.
amidines, guanidines, ureas, isoureas, thioureas and iso-
thioureas, and 1,3-dielectrophilic three-carbon units under
alkaline conditions. The literature records only a few exam-
ples of pyrimidine synthesis using one-nitrogen-containing
building blocks.14,18
In this Letter, we disclose a novel approach, viz. 1,2- and
1,6-bond forming reactions (VII, Scheme 1) for pyrimidine
synthesis using D-glucose-/D-xylose-derived 1,3-oxazin-2-
ones(thiones) 4 and aromatic amines 5 as structural vari-
ants of the building blocks. The present synthesis of func-
tionalized pyrimidines results from our quest for novel
solvent-free heterocyclization strategies,19 especially using
carbohydrates as raw materials.20 Furthermore, the present
synthetic protocol is in accord with ‘renewable resources’, a
new and rapidly developing concept in environmental and
chemical sciences that concerns the wide use of biorenew-
able materials for industry.21
1,3-Oxazin-2-ones(thiones) 4, the starting materials for
the envisaged synthetic protocol, were synthesized in 79–
85% yields by a solvent-free microwave (MW) irradiation
of D-glucose/D-xylose 1, semi(thiosemi)carbazide 2 and M
ontmorillonite K-10 clay via acid-catalyzed domino cyclo-
isomerization, dehydrazination and dehydration of
semi(thiosemi)carbazones 3 (Scheme 2).22 The mechanism
shown in Scheme 2 is supported by the formation of hydr-
azine during the reaction detected using the p-dimethyl-
aminobenzaldehyde method.23 It was noted that other
mineral catalysts, viz. silica gel and neutral or basic
Solvent-free synthesis of compounds 4 and 6 catalyzed by Montmoril-
lonite K-10 clay
Product
Timea (min)
Yieldb,c (%)
4a
4b
4c
4d
6a
6b
6c
6d
6e
6f
6g
6h
6i
10
10
10
10
12
9
82
81
79
85
88
91
85
83
92
89
87
94
93
83
92
91
9
10
11
11
8
12
9
12
10
10
6j
6k
6l
a
Microwave irradiation time at 90 °C.
Yield of isolated and purified products.
All compounds gave C, H and N analyses within 0.35% and satis-
b
c
factory spectral (IR, 1H NMR, 13C NMR and EIMS) data.
alumina, were far less effective resulting in either no reac-
tion (in the case of basic alumina) or very low yields (15–
28%) of 4 (in the cases of silica gel and neutral alumina).
The target polyhydroxyalkyl pyrimidines
6 were
obtained in 83–94% yields24 (Table 1) by solvent-free
microwave (MW) irradiation of an intimate mixture of
1,3-oxazin-2-ones(thiones) 4 and aromatic amines 5 in the
presence of K-10 clay via amine-driven dehydrative ring
transformations (Scheme 3). The use of other mineral cat-
alysts, viz. silica gel, neutral or basic alumina, resulted in
relatively low yields of 6 (21–32%). Formation of com-
pounds 6 may be rationalized by the nucleophilic attack
of the nitrogen of aromatic amines 5 on C-2 of the oxazine
ring driving the dehydrative ring transformation to afford 6
(Scheme 3).
X
N
CHO
(CHOH)n
CH2OH
HO
H2NNHCNH2
(X = O, S)
NH
NH2
2
OH
X
K-10 clay, MW
(CHOH)n
-2
n
n
= 3,
D
-xylose
= 4,
D
-glucose
CH2OH
1
3
N.NH2
NH2
HO
N
K-10
clay
HO
N
NH
NH2
X
N
MW
NH2Ar
X
O
HO
O
-2
HO
MW
10 min
X
n-2
OH
ArHN
n
-2
X
O
K-10
clay
(CHOH)n
CH2OH
OH
OH
(CHOH)n
-2
H
5
4
CH2OH
NH.NH2
N H
CH2OH
(CHOH)n-2
HO
N
HO
N
Ar
X
O
-NH2NH2
N
HO
n
O
X
n
-2
X
O
(CHOH)n
-2
-H2O
OH
ArHN
(CHOH)n
-2
N
X
CH2OH
6
CH2OH
N
6
n
X
Ar
Ar
Ph
6
X
O
O
O
S
X
O
a
b
c
d
e
f
g
h
i
j
k
l
4
4
4
4
4
4
Ph
O
O
O
S
S
S
3
3
3
3
3
3
-H2O
(CHOH)n
-2
4-ClC6H4
4-MeOC6H4
Ph
4-ClC6H4
4-MeOC6H4
4-ClC6H4
4-MeOC6H4
Ph
4-ClC6H4
4-MeOC6H4
4a, X = O, n =
3
3
4
4
CH2OH
4b, X = S, n =
4c, X = O, n =
4d, X = S, n =
4
S
S
Scheme 2. Formation of 1,3-oxazin-2-ones(thiones) 4 from D-glucose/D-
xylose 1.
Scheme 3. A plausible mechanism for the formation of pyrimidines 6.

L. D. S. Yadav et al. / Tetrahedron Letters 49 (2008) 2377–2380
2379
12. (a) Schmaker, J. M.; Delia, T. J. J. Org. Chem. 2001, 66, 7125; (b)
In summary, we have documented an original and prac-
tical route for the synthesis of novel polyhydroxyalkylpyr-
imidines of remarkable pharmacological potential from
unprotected aldoses as biorenewable resources. The synthe-
sis is effected under Montmorillonite K-10 clay catalysis
and solvent-free microwave irradiation conditions.
´
Turck, A.; Pre, N.; Lepretre-Gaquere, A.; Queguiner, G. Heterocycles
1998, 49, 205.
13. Eilingfeld, H.; Patsch, M.; Scheuermann, H. Chem. Ber. 1968, 101,
2426.
14. (a) Sing, Y. L.; Lee, L. F. J. Heterocycl. Chem. 1989, 26, 7; (b)
Alberola, A.; Andreˆs, C.; Ortega, A. G.; Pedrosa, R.; Vicente, M.
Synth. Commun. 1987, 17, 1309.
15. (a) Guzmaˆn, A.; Romero, M.; Talamaˆs, F. X.; Villena, R.; Green-
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Guzmaˆn, A.; Romero, M.; Talamaˆs, F. X.; Muchowski, J. M.
Tetrahedron Lett. 1992, 24, 3449.
Acknowledgement
We sincerely thank SAIF, CDRI, Lucknow, for provid-
ing microanalyses and spectra.
´
16. (a) Pourzal, A.-A. Synthesis 1983, 717; (b) Martınez, A. G.;
Fernandez, A. H.; Alvarez, R. M.; Losada, M. C. S.; Vilchez, D.
M.; Subramanian, L. R.; Hanack, M. Synthesis 1990, 881; (c)
Martˆınez, A. G.; Fernaˆndez, A. H.; Fraile, A. G.; Subramanian, L.
References and notes
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R.; Hanack, M. J. Org. Chem. 1992, 57, 1627; (d) Martınez, A. G.;
ˆ
1. Brown, D. In Comprehensive Heterocyclic Chemistry II; Katritzky, A.
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Chem. 1993, 32B, 449.
Fernaˆndez, A. H.; Alvarez, R. M.; Vilchez, M. D. M.; Gutieˆrrez, M.
L. L.; Subramanian, L. R. Tetrahedron 1999, 55, 4825; (e) Ghosez, L.;
Jnoff, E.; Bayard, P.; Sainte, F.; Beaudegnies, R. Tetrahedron 1999,
55, 3387.
17. Sakai, N.; Aoki, Y.; Sasada, T.; Konakahara, T. Org. Lett. 2005, 7,
4705.
4. Keutzberger, A.; Gillessen, J. Arch. Pharm. 1985, 318, 370.
5. (a) Brown, D. J. In The Pyrimidines; Weissberger, A., Ed.; The
Chemistry of Heterocyclic Compounds; Wiley Interscience: New
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The Purines; Weissberger, A., Taylor, E. C., Eds.; The Chemistry of
Heterocyclic Compounds; Wiley Interscience: New York, 1971; Vol.
24; (c) Hoffmann, M. G. In Houben-Weyl, Methoden der Organischen
Chemie; Schaumann, E., Ed.; G. Thieme: Stuttgart, 1996; Vol. E9; (d)
Hurst, D. T. In An Introduction to the Chemistry and Biochemistry of
Pyrimidines, Purines and Pteridines; Wiley: Chichester, 1980; (e)
18. (a) Kakiya, H.; Yagi, K.; Shinokubo, H.; Oshima, K. J. Am. Chem.
Soc. 2002, 124, 9032; (b) Karpov, A. S.; Muller, T. J. J. Synthesis
¨
2003, 2815; (c) Zhao, F.-L.; Liu, J.-T. J. Fluorine Chem. 2004, 125,
1491.
19. (a) Yadav, L. D. S.; Rai, A.; Rai, V. K.; Awasthi, C. Tetrahedron
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A. Tetrahedron Lett. 2007, 48, 8033; (c) Yadav, L. D. S.; Rai, V. K.
Tetrahedron 2007, 63, 6924; (d) Yadav, L. D. S.; Rai, V. K.
Tetrahedron Lett. 2006, 47, 395; (e) Yadav, L. D. S.; Yadav, S.;
Rai, V. K. Green Chem. 2006, 8, 455; (f) Yadav, L. D. S.; Yadav, S.;
Rai, V. K. Tetrahedron 2005, 61, 10013.
´
Bojarski, J. T.; Mokrosz, J. L.; Barton, H. J.; Paluchowska, M. H.
Adv. Heterocycl. Chem. 1985, 38, 229; (f) Brown, D. J. In Compre-
hensive Heterocyclic Chemistry; Katritzky, A. R., Rees, C. W., Eds.;
Pergamon Press: Oxford, 1984; Vol. 3; Chapter 2.13.
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Tetrahedron Lett. 2007, 48, 4899.
6. (a) Gompper, R.; Mair, H.-J.; Polborn, K. Synthesis 1997, 696; (b)
Kanbara, T.; Kushida, T.; Saito, N.; Kuwajima, I.; Kubota, K.;
Yamamoto, T. Chem. Lett. 1992, 583.
21. Renewable Bioresources: Scope and Modification for Non-Food Appli-
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Chichester, England, 2004.
7. Wong, K.-T.; Hung, T.-S.; Lin, Y.; Wu, C.-C.; Lee, G.-H.; Peng, S.-
M.; Chou, C. H.; Su, Y. O. Org. Lett. 2002, 4, 513.
8. (a) Eicher, T.; Hauptmann, S. Chemie der Heterocyclen; Georg
Thieme: Stuttgart, New York, 1994; p 398; (b) Gilchrist, T. L. In
Heterocyclenchemie; Neunhoeffer, H., Ed.; Wiley-VCH: New York,
1995; p 270.
9. (a) Lehn, J.-M. Supramolecular Chemistry-Concepts and Perspectives;
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Int. Ed. 1997, 36, 1842; (c) Semenov, A.; Spatz, J. P.; Mo¨ller, M.;
Lehn, J.-M.; Sell, B.; Schubert, D.; Weidl, C. H.; Schubert, U. S.
Angew. Chem., Int. Ed. 1999, 38, 2547.
22. General procedure for the synthesis of 1,3-oxazin-2-ones(thiones) 4:
Thoroughly mixed D-xylose/D-glucose (1 mmol) 1, semicarbazide
hydrochloride/thiosemicarbazide (1 mmol) 2, sodium acetate
(1 mmol) and Montmorillonite K-10 clay (0.10 g) were taken in a
20 mL vial and subjected to microwave irradiation in a CEM
Discover Focused Microwave Synthesis System for 10 min at 90 °C.
After the completion of the reaction as indicated by TLC, water
(10 mL) was added to precipitate the crude product, which was
recrystallized from ethanol to afford analytically pure sample of 4.
Physical data of representative compounds: Compound 4a: White
solid, yield 82%, mp 145–148 °C. IR (KBr) mmax 3392, 3386, 3011,
.
1692 cmꢀ1 1H NMR (400 MHz; DMSO-d6) d: 4.11 (dd, 1H,
J2 H ;2 H ¼ 10:1 Hz, J1 H;2 H ¼ 5:4 Hz, 20Ha), 4.30 (dd, 1H,
0
0
0
0
10. (a) Harriman, A.; Ziessel, R. Coord. Chem. Rev. 1998, 171, 331; (b)
Harriman, A.; Ziessel, R. Chem. Commun. 1996, 1707.
a
b
a
J1 H;2 H ¼ 5:4 Hz, J1 H;2 H ¼ 2:9 Hz, 10H), 4.63 (dd, 1H, J2 H ;2 H
¼
0
0
0
0
0
0
a
b
a
b
10:1 Hz, J1 H;2 H ¼ 2:9 Hz, 20Hb), 4.93–5.21 (br s, 2H, 2 ꢁ OH,
0
0
11. (a) Taylor, E. C.; Knoff, R. J.; Meyer, R. F.; Holmes, A.; Hoefle, M.
L. J. Am. Chem. Soc. 1960, 82, 5711; (b) Inoue, S.; Saggiomo, A. J.;
Nodiff, E. A. J. Org. Chem. 1961, 26, 4504; (c) Bredereck, H.;
Effenberger, F.; Botsch, H.; Rehn, H. Chem. Ber. 1965, 98, 1081; (d)
Chauhan, S. M. S.; Junjappa, H. Synthesis 1974, 880; (e) Kreutz-
berger, A.; Tesch, U.-H. Chem. Ber. 1976, 109, 3255; (f) Potts, K. T.;
Cipullo, M. J.; Ralli, P.; Theodoridis, G. J. Org. Chem. 1983, 48,
4841; (g) Kvita, V. Synthesis 1986, 786; (h) Schenone, P.; Sanse-
bastiano, L.; Mosti, L. J. Heterocycl. Chem. 1990, 27, 295; (i) Papet,
A.-L.; Marsura, A. Synthesis 1993, 478; (j) Yamanaka, H.; Takekawa,
T.; Morita, K.; Ishihara, T.; Gupton, J. T. Tetrahedron Lett. 1996, 37,
1829; (k) Wang, T.; Cloudsdale, I. S. Synth. Commun. 1997, 27, 2521;
(l) Ghosh, U.; Katzenellenbogen, J. A. J. Heterocycl. Chem. 2002, 39,
1101.
b
exchangeable with D2O), 7.48 (d, 1H, J5H,6H = 8.1 Hz, 5-H), 7.89 (d,
1H, J5H,6H = 8.1 Hz, 4-H). 13C NMR (100 MHz, DMSO-d6): d 64.5,
65.3, 73.7, 86.2, 105.9, 174.5. MS (FAB) m/z 158 (MH+). Anal. Calcd
for C6H7NO4: C, 45.86; H, 4.49; N, 8.91. Found: C, 46.17; H, 4.58; N,
8.79. Compound 4c: White solid, yield 79%, mp153–155 °C. IR
(KBr): 3399–3382, 3008, 1689 cmꢀ1. 1H NMR (400 MHz, DMSO-d6)
0
0
0
0
0
d: 3.88 (ddd, 1H, J2 H;3 H ¼ 5:4 Hz, J1 H;2H ¼ 4:6 Hz, J2 H;3 H
¼
a
b
2:7 Hz, 20H), 4.03 (dd, 1H, J3 H ;3 H ¼ 10:5 Hz, J2 H;3 H ¼ 5:4 Hz,
0
0
0
0
a
b
a
30Ha), 4.37 (d, 1H, J1 H;2 H ¼ 4:6 Hz, 10H), 4.59 (dd, 1H, J3 H ;3 H
¼
0
0
0
0
a
b
10:5 Hz, J2 H;3 H ¼ 2:7 Hz, 30Hb), 5.01–5.37 (br s, 3H, 3 ꢁ OH,
0
0
b
exchangeable with D2O), 7.51 (d, 1H, J4H,5H = 8.1 Hz, 5-H), 7.85 (d,
1H, J4H,5H = 8.1 Hz, 4-H). 13C NMR (100 MHz, DMSO-d6) d: 64.3,
65.9, 71.7, 73.5, 86.5, 106.3, 174.8. MS (FAB) m/z = 188 [MH+].

2380
L. D. S. Yadav et al. / Tetrahedron Letters 49 (2008) 2377–2380
0
0
0
0
Anal. Calcd for C7H9NO5: C, 44.92; H, 4.85; N, 7.48. Found: C,
44.69; H, 4.73; N, 7.73.
23. Audrieth, L. F.; Ogg, B. A. The Chemistry of Hydrazines; John Wiley
and Sons: New York, 1951.
J1 H;2 H ¼ 5:5 Hz, J1 H;2 H ¼ 2:9 Hz, 10H), 5.01–5.16 (br s, 2H,
a
b
2 ꢁ OH, exchangeable with D2O), 7.13–7.55 (m, 5Harom), 7.91 (d,
1H, J5H,6H = 7.5 Hz, 5-H), 8.04 (d, 1H, J5H,6H = 7.5 Hz, 6-H). 13C
NMR (100 MHz, DMSO-d6) d: 63.9, 71.6, 125.9, 127.4, 128.1, 129.3,
131.9, 134.7, 136.4, 173.1. MS (FAB) m/z = 233 [MH+]. Anal. Calcd
for C12H12N2O3: C, 62.06; H, 5.21; N, 12.06. Found: C, 61.83; H,
5.43; N, 11.98. Compound 6g: White solid, yield 87%, mp 131–133 °C.
24. General procedure for the synthesis of 4-polyhydroxyalkylpyrimidin-2-
ones(thiones) 6: An intimate solvent-free mixture of 1,3-oxazin-2-
one(thione) 4 (2.4 mmol) and aromatic amine 5 (2.4 mmol) in the
presence of Montmorillonite K-10 clay (0.25 g) was taken in a 20 mL
vial and subjected to MW irradiation in a CEM Discover Focused
Microwave Synthesis System at 90 °C for 8–12 min. After the
completion of the reaction as indicated by TLC, water (10 mL) was
added to precipitate the crude product, which was recrystallized from
ethanol to give an analytically pure sample of 6 as a white solid.
Physical data of representative compounds: Compound 6a: White
solid, yield 88%, mp 168–170 °C. IR (KBr): 3398, 3013, 1696, 1607,
IR (KBr): 3395, 3017, 1693, 1598, 1585, 1455 cmꢀ1 1H NMR
.
0
0
0
0
(400 MHz, DMSO-d6) d: 3.51 (ddd, 1H, J
¼ 5:6 Hz, J1 H;2 H ¼
0 0
a
b
2 H;3 Ha
4:2 Hz, J2 H;3 H ¼ 2:8 Hz, 20H), 3.71 (dd, 1H, J3 H ;3 H ¼ 10:3 Hz,
0
0
b
J2 H;3 H ¼ 5:6 Hz, 30Ha), 4.01 (dd, 1H, J3 H ;3 H ¼ 10:3 Hz,
0
0
0
0
a
a
b
J2 H;3 H ¼ 2:8 Hz, 30Hb), 4.22 (d, 1H, J1 H;2 H ¼ 4:2 Hz, 10H), 5.03–
0
0
0
0
b
5.21 (br s, 3H, 3 ꢁ OH, exchangeable with D2O), 7.09–7.59 (m,
5Harom), 7.95 (d, 1H, J5H,6H = 7.6 Hz, 5-H), 8.06 (d, 1H, J5H,6H
=
7.6 Hz, 6-H). 13C NMR (100 MHz, DMSO-d6) d: 63.3, 71.8, 81.7,
126.4, 128.2, 129.5, 130.3, 132.5, 134.9, 136.8, 173.3. MS (FAB)
m/z = 263 [MH+]. Anal. Calcd for C13H14N2O4: C, 59.54; H, 5.38; N,
10.68. Found: C, 59.89; H, 5.21; N, 10.47.
1579, 1454 cmꢀ1 1H NMR (400 MHz, DMSO-d6) d: 3.73 (dd, 1H,
.
J2 H ;2 H ¼ 10:4 Hz, J1 H;2 H ¼ 5:5 Hz, 20Ha), 4.09 (dd, 1H,
0
0
0
0
a
b
a
J2 H ;2 H ¼ 10:4 Hz, J1 H;2 H ¼ 2:9 Hz, 20Hb), 4.30 (dd, 1H,
0
0
0
0
a
b
b