A. I. Hashem, W. S. I. Abou-Elmagd, A. K. El-Ziaty, and S. K. Ramadan
Vol 000
General procedure for preparation of 4-(furan-2-
ylmethylene)-6-phenyl-3,4-dihydro-2H-1,3-oxazin-2-one (4).
223 (55), 208 (42), 166 (29), 91 (80), 77 (32). Anal.
Calcd. for C22H18N2O2 (342.14): C, 77.17; H, 5.30; N,
8.18. Found: C, 77.08; H, 5.21; N, 8.02.
A
solution of the azide 3 (5 mmol) in dry benzene (20 mL)
was heated under reflux for 1 h. The separated solid after
cooling was collected by filtration and recrystallized from
petroleum ether, 80–100/benzene, (2:1) to afford oxazinone 4
as red crystals; mp. 170–172°C, yield 49%. IR (KBr) (ν,
cmÀ1): 3175 (NH), 3057, 3040 (Aryl-H), 1732
Reaction of the azide 3 with hydrazine hydrate: synthesis of
E,Z-N-(1-(furan-2-yl)-4-oxo-4-phenylbut-1-en-2-yl)hydrazinecar
boxamide (7). Hydrazine (2 mmol) was added dropwise to
a solution of azide 3 (2 mmol) in dry benzene (20 mL) and
the mixture was stirred at room temperature. The obtained
solid was collected by filtration and recrystallized from
benzene to give the semicarbazide derivative 7 as brown
crystals, mp. 205–207°C, yield 39%. IR (KBr) (ν, cmÀ1):
3331, 3208 (NH, NH2), 3064, 3032 (Aryl–H), 2923, 2859
(Alkyl–H), 1700 (C═OKetone), 1659 (C═OAmide), 743, 699
(δ5H). 1H-NMR (DMSO-d6): δH (ppm) 9.01 (br.s, 1H, NH,
exchangeable), 7.34 (s, 1H, NHNH2, D2O-Exchangeable),
7.75–6.72 (m, 8H, Ar–H), 6.56, 6.45 (Two singlets, 1H, E
and Z isomers, CH═), 4.50 (br.s, 2H, NH2, exchangeable),
3.19–3.00 (dd, 2H, CH2, J = 16.4 Hz). MS (m/z, %): 285
(M+, 14), 255 (39), 227 (21), 150 (12), 180 (10), 119 (20),
77 (100). Anal. Calcd. for C15H15N3O3 (285.11): C, 63.15;
H, 5.30; N, 14.73. Found: C, 63.04; H, 5.19; N, 14.61.
1
(C═OOxazinone), 730, 684 (δ5H). H-NMR (DMSO-d6): δH
(ppm) 13.28 (br.s, 1H, OH, Lactim form, exchangeable),
13.25 (br.s, 1H, NH, Lactam form, exchangeable), 8.10–6.91
(m, 8H, Ar–H), 6.78 (s, 1H, C–HOxazinone), 6.48 (s, 1H,
CH═). MS (m/z, %): 253 (M+, 46), 252 (100), 222 (62), 194
(67), 115 (34), 104 (23), 81 (36), 77 (64). Anal. Calcd. for
C15H11NO3 (253.07): C, 71.14; H, 4.38; N, 5.53. Found: C,
71.08; H, 4.27; N, 5.42.
Pyrolysis of azide 3. In a 10-mL round-bottomed flask
fitted with an air condenser, 0.5 g of the azide 3 was
placed. The flask was heated on a sand bath whereby the
azide was fused. Heating was continued for another 1 h.
The product obtained after recrystallization from
petroleum ether, 80–100/benzene, (2:1) was proved by
direct comparison (mp., mixed mp. and TLC) to be the
oxazinone 4.
Synthesis of 1-amino-4-(furan-2-ylmethylene)-6-phenyl-3,4-
dihydropyrimidin-2(1H)-one (8). A solution of the azide 3
(2 mmol) and hydrazine (2 mmol) in dry benzene (20 mL)
was heated at 90°C for 1 h. The reaction mixture was
concentrated and then cooled. The obtained solid was
collected by filtration and recrystallized from petroleum
ether, 60–80/benzene (2:1) to give 1-aminopyrimidinone
derivative 8 as faint brown crystals, mp. 160–162°C, yield
35%. IR (KBr) (ν, cmÀ1): 3330, 3204 (NH, NH2), 3063,
Reaction of the azide 3 with benzylamine. Benzylamine
(2 mmol) was added dropwise to a solution of azide 3
(2 mmol) in dry benzene (20 mL) and the mixture was
stirred at room temperature for 2 h or heated under reflux
for 1 h. The precipitated solid was collected by filtration
and recrystallized from petroleum ether, 80–100/benzene
(3:1) to give benzylurea 5 and N-benzylpyrimidine 6,
respectively.
1
3032 (Aryl–H), 1659 (C═O), 743, 699 (δ5H). H-NMR
(DMSO-d6): δH (ppm) 13.10 (br.s, 1H, NH, exchangeable),
7.94–6.81 (m, 8H, Ar–H), 6.69 (s, 1H, CHPyrimidine), 6.39
(s, 1H, CH═), 4.99 (br.s, 2H, NH2, exchangeable). MS
(m/z, %): 267 (M+, 100), 239 (21), 162 (28), 102 (19), 81
(15), 77 (30). Anal. Calcd. for C15H13N3O2 (267.10): C,
67.40; H, 4.90; N, 15.72. Found: C, 67.28; H, 4.75; N, 15.58.
E,Z-1-Benzyl-3-(1-(furan-2-yl)-4-oxo-4-phenylbut-1-en-2-
yl)urea (5). Brown crystals, mp. 195–197°C, yield 52%.
IR (KBr) (ν, cmÀ1): 3247 (NH), 3059, 3028 (Aryl–H),
2937, 2922 (Alkyl–H), 1671 (C═OKetone), 1643
1
(C═OAmide), 759, 692 (δ5H). H-NMR (DMSO-d6): δH
(ppm) 9.51 (br.s, 1H, NHCO, exchangeable), 9.20 (br.s,
1H, NHCH2, exchangeable), 7.75–7.05 (m, 13H, Ar–H),
6.73, 6.56 (Two singlets, 1H, E and Z isomers, CH═),
4.33 (s, 2H, NHCH2), 3.19–3.01 (dd, 2H, CH2CO,
J = 16.4 Hz). MS (m/z, %): MS (m/z, %): 360 (M+, 10),
253 (42), 210 (50), 192 (60), 106 (3), 91 (100), 77 (51).
Anal. Calcd. for C22H20N2O3 (360.15): C, 73.32; H,
5.59; N, 7.77. Found: C, 73.21; H, 5.43; N, 7.68.
Reaction of the azide 3 with p-toluidine; synthesis of 1-(1-
(furan-2-yl)-4-oxo-4-phenylbut-1-en-2-yl)-3-p-tolylurea (9).
p-Toluidine (2 mmol) was added to a solution of the azide 3
(2 mmol) in dry benzene (20 mL), and the mixture was
heated on water bath for 2 h. The obtained solid was
collected by filtration and recrystallized from petroleum
ether, 80–100/benzene (2:1) to give p-tolylurea derivative 9
as brown crystals, mp. 220–222°C, yield 49%. IR (KBr) (ν,
cmÀ1): 3316, 3209 (2 NH), 3088, 3025 (Aryl–H), 2915,
2858 (Alkyl–H), 1699 (C═OKetone), 1650 (C═OAmide), 733,
1-Benzyl-4-(furan-2-ylmethylene)-6-phenyl-3,4-dihydropy-
rimidin-2(1H)-one (6). Yellow crystals, mp. 148–150°C,
yield 47%. IR (KBr) (ν, cmÀ1): 3259 (NH), 3065, 3021
(Aryl–H), 2955, 2935 (Alkyl–H), 1652 (C═O), 738, 692
687 (δ5H). H-NMR (DMSO-d6): δH (ppm) 9.80 (s, 1H,
1
NHTolyl, D2O-Exchangeable), 9.05 (s, 1H, NH, D2O-
Exchangeable), 7.75–6.83 (m, 8H, Ar–H), 7.19–7.17
1
(δ5H). H-NMR (DMSO-d6): δH (ppm) 10.04 (s, 1H, OH,
Lactim form, D2O-Exchangeable), 10.03 (s, 1H, NH,
Lactam form, D2O-Exchangeable), 7.75–7.05 (m, 13H,
Ar–H), 6.83 (s, 1H, C–HPyrimidine), 6.66 (s, 1H, CH═),
4.81 (s, 2H, CH2). MS (m/z, %): 342 (M+, 100), 251 (40),
(d, 2H, HTolyl, J = 8 Hz), 7.05–7.03 (d, 2H, HTolyl,
J = 8 Hz), 6.73, 6.56 (Two singlets, 1H, E and Z isomers,
CH═), 3.20–3.05 (dd, 2H, CH2, J = 16 Hz), 2.27 (s, 3H,
CH3). MS (m/z, %): 360 (M+, 51), 345 (41), 270 (25),
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet