İ. Koser, N. Ocal, and I. Erden
Vol 000
were obtained with a “Perkin Elmer FTIR” system (Perkin-
Elmer Corporation, Norwalk, CT) and are reported in
terms of frequency of absorption (cmÀ1). Melting points
129.6 (Cq), 135.8 (CAr), 136.3 (Cq), 136.4 (Cq), 138.2
(CAr), 139.8 (CH), 163.8 (C=O), 198.0 (C=O) ppm; LCMS
(ESI-QTOF) m/z: Anal. Calcd for C15H12ClNO2S 305.0279.
Found 328.0172 [M+Na]+.
were determined with
a
“Gallenkamp” digital
thermometer equipment (Northhampton, UK). All melting
points are uncorrected. NMR spectra were determined
N-Benzyl-3-oxo-2-(thiophen-2-ylmethylene)butanamide (12).
This compound was obtained as yellow oil; yield: 66%;
Rf = 0.24 (1:2, ethyl acetate/n-hexane); IR (ATR): 3292
with
a “Bruker Ac-400 MHz NMR” (Rheinstetten,
1
Germany) and “Varian-INOVA-500 MHz NMR” (Palo
Alto, CA). Tetramethylsilane was used as an internal
standard, and CDCl3 was used as the solvent. Signal
multiplicities in the NMR spectra are reported as follows:
s, singlet; brs, broad singlet; d, doublet; dd, doublet of
doublets; and m, multiplet. Mass spectra were measured
with Agilent 6890 N GC-System-5973 IMSD or Agilent
LC-MSD Trap SL (Santa Clara, CA).
General procedure for synthesis of (5–9). The imines
were prepared by the reaction of thiophene-2-
carbaldehyde (1 mmol) with substituted aromatic amines
(1 mmol) by stirring at 110°C without solvent (5 and 6)
or at room temperature by sonication in an ultrasonic
bath for 15min (7–9). The progress of the reactions was
monitored by TLC.
General procedure for synthesis of (10–16). A solution
of 2,2,6-trimethyl-1,3-dioxin-4-one (1) (1mmol) and aryl
aldimines (5–9) (1 mmol) was refluxed in 10 mL toluene
(for 12, m-xylene) for 7–8h in the presence of
trimethylamine (0.2 mmol). After the reaction mixture
was cooled to room temperature, subsequent column
chromatography on silica gel gave (10–16) as pure
compounds.
(NH), 1634 (C=O) cmÀ1; H-NMR (CDCl3): δ 2.31 (s,
3H, CH3), 4.46 (d, J = 5.99Hz, 2H, CH2), 7.01–7.03 (m,
1H, ArH), 7.07 (brs, 1H, NH), 7.12 (d, J = 3.78Hz, 1H,
ArH), 7.22–7.29 (m, 5H, ArH), 7.45 (d, J =5.99 Hz, 1H,
ArH), 7.90 (s, 1H, CH) ppm; 13C-NMR (CDCl3): δ 29.7
(CH3), 44.1 (CH2), 127.4 (CAr), 127.9 (CAr), 128.6
(CAr), 128.9 (CAr), 131.1 (CAr), 132.6 (CAr), 133.6
(Cq), 134.0 (CAr) 134.2 (CH), 136.4 (Cq), 136.5 (Cq),
137.8 (Cq), 163.1 (C=O), 198.0 (C=O) ppm; LCMS
(ESI-QTOF) m/z: Anal. Calcd for C16H15NO2S 285.0818.
Found 286.0896 [M +H]+.
3-(4-Fluorophenyl)-6-methyl-2-(thiophene-2-yl)-2H-1,3-
oxazin-4(3H)-one (13). This compound was obtained as
yellow oil; yield: 52%; Rf = 0.67 (1:1, ethyl acetate/n-
hexane); IR (ATR): 3073, 2962, 2923, 2855, 1666 (C=O)
1
cmÀ1; H-NMR (CDCl3): δ 1.90 (s, 3H, CH3), 5.33 (s,
1H, CH), 6.65 (s, 1H, =CH), 6.90 (dd, J = 3.46; 5.04 Hz,
1H, ArH), 6.96 (d, J =8.82 Hz, 2H, ArH), 7.05 (d,
J = 3.46Hz, 1H, ArH), 7.18 (d, J= 8.82Hz, 2H, ArH),
7.27 (dd, J = 1.26; 5.04Hz, 1H, ArH) ppm; 13C-NMR
(CDCl3): δ 18.9 (CH3), 86.1 (CH), 98.6 (CH), 114.8
(CAr), 115.0 (CAr), 125.6 (CAr), 126.2 (CAr), 126.3
(CAr), 126.4 (CAr), 127.0 (CAr), 134.0 (Cq), 139.1 (Cq),
158.8 (Cq), 160.8 (Cq), 163.6 (C=O) ppm; LCMS (ESI-
QTOF) m/z: Anal. Calcd for C15H12FNO2S 289.0567.
Found 290.0645 [M +H]+.
3-(4-Chlorophenyl)-6-methyl-2-(thiophene-2-yl)-2H-1,3-
oxazin-4(3H)-one (10).
This compound was obtained
yield: 64%; Rf =0.14 (40:1,
as
brown oil;
dichloromethane/n-hexane); IR (ATR): 3095, 2957, 2921,
1666 (C=O) cmÀ1; 1H-NMR (CDCl3): δ 1.97 (s, 3H, CH3),
5.40 (s, 1H, CH), 6.74 (brs, 1H, ArH), 6.97 (dd, J=3.46;
5.04Hz, 1H, ArH), 7.11–7.12 (m, 1H, ArH), 7.23 (d,
J=8.82Hz, 2H, ArH), 7.31 (d, J= 8.82 Hz, 2H, ArH), 7.35
(dd, J=0.94; 4.73Hz, 1H, ArH) ppm; 13C-NMR (CDCl3):
δ 19.8 (CH3), 86.9 (CH), 101.3 (CH), 126.4 (2xCAr), 126.7
(CAr), 127.3 (CAr), 128.1 (CAr), 129.2 (2xCAr), 131.9
(Cq), 137.6 (Cq), 140.2 (Cq), 161.6 (Cq), 164.7 (C=O)
ppm; LCMS (ESI-QTOF) m/z: Anal. Calcd for
C15H12ClNO2S 305.0279. Found 306.0351 [M+ H]+.
N-(4-Chlorophenyl)-3-oxo-2-(thiophen-2-ylmethylene)
butanamide (11). This compound was obtained as yellow
solid; yield: 23%; mp 140–141°C; Rf =0.07 (40:1,
dichloromethane/n-hexane); IR (ATR): 3283 (NH), 3110,
1651 (C=O) cmÀ1; 1H-NMR (CDCl3): δ 2.44 (s, 3H, CH3),
7.04–7.06 (m, 1H, ArH), 7.24 (d, J=8.51Hz, 2H, ArH),
7.43 (d, J= 3.46Hz, 1H, ArH), 7.53 (d, J=8.51Hz, 2H,
ArH), 7.58 (d, J=5.04Hz, 1H, ArH), 7.84 (s, 1H, CH),
9.19 (brs, 1H, NH) ppm; 13C-NMR (CDCl3): δ 27.3 (CH3),
121.6 (2xCAr), 127.6 (CAr), 129.0 (CAr), 129.2 (2xCq),
N-(4-Fluorophenyl)-3-oxo-2-(thiophen-2-ylmethylene)
butanamide (14). This compound was obtained as yellow
solid; yield: 37%; mp 177–179°C; Rf = 0.45 (1:1, ethyl
acetate/n-hexane); IR (ATR): 3293 (NH), 3135, 3075,
2921, 2850, 1662 (C=O) cmÀ1 1H-NMR (CDCl3): δ
;
2.44 (s, 3H, CH3), 6.98 (d, J = 8.51Hz, 2H, ArH), 7.05
(dd, J= 3.78; 5.04Hz, 1H, ArH), 7.43 (d, J = 3.78Hz, 1H,
ArH), 7.55 (d, J = 8.51Hz, 2H, ArH), 7.57 (d,
J = 5.04Hz, 1H, ArH), 7.83 (s, 1H, =CH), 9.05 (brs, 1H,
NH) ppm; 13C-NMR (CDCl3): δ 27.2 (CH3), 115.3
(CAr), 122.2 (CAr), 127.3 (CAr), 129.6 (Cq), 133.7 (Cq),
135.4 (CAr), 136.2 (Cq), 137.9 (CAr), 138.7 (CAr),
139.0 (CAr), 139.2 (CH), 158.6 (Cq), 163.8 (C=O),
197.8 (C=O) ppm; LCMS (ESI-QTOF) m/z: Anal. Calcd
for C15H12FNO2S 289.0567. Found 290.0647 [M + H]+.
N-(4-Bromophenyl)-3-oxo-2-(thiophen-2-ylmethylene)
butanamide (15).
This compound was obtained as
colorless solid; yield: 65%; mp 95–96°C; Rf =0.40 (1:2,
ethyl acetate/n-hexane); IR (ATR): 3258 (NH), 3104,
1
3046, 2922, 2841, 1644 (C=O) cmÀ1; H-NMR (CDCl3):
δ 2.43 (s, 3H, CH3), 7.04 (dd, J =3.46; 5.04Hz, 1H,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet