7622
B. Das et al. / Tetrahedron Letters 47 (2006) 7619–7623
1 and 2
MeC(OEt)3
HClO4-SiO2
/ NaHSO4-SiO2
OEt
OEt
Me
O
C
EWG
R
A
HClO4-SiO2
Path A
NaHSO4-SiO2
Path B
OEt
R
+
HO
OEt
Me
C
EWG
5
3
O
EWG
and
and
R
6
4
C
EtO
..
EtOH
Scheme 2.
After completion the mixture was filtered and the filtrate
was concentrated. The residue was subjected to column
chromatography (silica gel, 2% (for 3 and 4) and 3% (for
5 and 6) EtOAc in hexane) to obtain pure trisubstituted
alkene.
7.48–7.13 (4H, m), 4.12, 4.08 (2H, 2q, J = 7.0 Hz),
3.84, 3.55 (3H, 2s), 2.74, 2.71 (2H, 2t, J = 7.0 Hz),
2.55, 2.46 (2H, 2t, J = 7.0 Hz), 1.25, 1.10 (3H, 2t,
J = 7.0 Hz); FABMS: m/z 321, 319 [M+Na]+. Anal.
Calcd for C15H17ClO4: C, 60.71; H, 5.73. Found: C,
60.78; H, 5.68.
The spectral (IR, 1H NMR and MS) and analytical data
of some representative allyl ethyl ethers and the
unknown alk-4-enoates6b are given below.
Compound 6b: IR (KBr): tmax 2361, 1734, 1622,
1
1438 cmÀ1; H NMR (CDCl3, 200 MHz): d 7.93 (1H,
d, J = 8.0 Hz), 7.45–7.23 (4H, m), 4.12 (2H, q,
J = 7.0 Hz), 2.76 (2H, t, J = 7.0 Hz), 2.66 (2H, t, J =
7.0 Hz), 1.28 (3H, t, J = 7.0 Hz); FABMS: m/z 288,
286 [M+Na]+. Anal. Calcd for C14H14ClNO2: C,
63.76; H, 5.31; N, 5.31. Found: C, 63.71; H, 5.28; N,
5.39.
Compound 3c: IR (KBr): tmax 1720, 1637, 1468,
1
1236 cmÀ1; H NMR (CDCl3, 200 MHz): d 7.92 (1H,
s), 7.69 (1H, d, J = 8.0 Hz), 7.48 (1H, d, J = 2.0 Hz),
7.32 (1H, dd, J = 8.0, 2.0 Hz), 4.16 (2H, s), 3.89 (3H,
s), 3.55 (2H, q, J = 7.0 Hz), 1.22 (3H, t, J = 7.0 Hz);
FABMS: m/z 315, 313, 311 [M+Na]+. Anal. Calcd for
C13H14Cl2O3: C, 53.98; H, 4.84. Found: C, 53.91; H,
4.89.
Acknowledgement
The authors thank UGC and CSIR, New Delhi for their
financial assistance.
Compound 3e: IR (KBr): tmax 1674, 1638, 1353,
1
1219 cmÀ1; H NMR (CDCl3, 200 MHz): d 6.20 (1H, t,
J = 7.0 Hz), 4.08 (2H, s), 3.75 (3H, s), 3.48 (2H, q,
J = 7.0 Hz), 2.42 (2H, t, J = 7.0 Hz), 1.75 (1H, m), 1.21
(3H, t, J = 7.0 Hz), 0.94 (6H, d, J = 7.0 Hz); FABMS:
m/z 223 [M+Na]+. Anal. Calcd for C11H20O3: C,
66.00; H, 10.00. Found: C, 66.13; H, 10.17.
References and notes
1. Baylis, A. B.; Hillman, M. E. D. German Patent 2155113,
1972; Chem. Abstr. 1972, 77, 34174q.
2. (a) Basavaiah, D.; Rao, A. J.; Satyanarayana, T. Chem.
Rev. 2003, 103, 811–891; (b) Hoffmann, H. M. R.; Rabe, J.
Angew. Chem., Int. Ed. Engl. 1985, 24, 94–110; (c)
Buchholz, R.; Hoffmann, H. M. R. Helv. Chim. Acta
1991, 74, 1213–1220.
3. (a) Das, B.; Banerjee, J.; Ravindranath, N.; Venkataiah,
B. Tetrahedron Lett. 2004, 45, 2425–2426; (b) Das, B.;
Banerjee, J.; Ravindranath, N. Tetrahedron 2004, 60,
8357–8361; (c) Das, B.; Banerjee, J.; Mahender, G.; Majhi,
A. Org. Lett. 2004, 6, 3349–3352; (d) Das, B.; Majhi, A.;
Banerjee, J.; Chowdhury, N.; Venkateswarlu, K. Tetra-
hedron Lett. 2005, 46, 7913–7915; (e) Das, B.; Chowdhury,
Compound 4b: IR (KBr): tmax 2214, 1625, 1592,
1
1481 cmÀ1; H NMR (CDCl3, 200 MHz): d 7.70 (2H,
d, J = 8.0 Hz), 7.39 (2H, d, J = 8.0 Hz), 7.08 (1H, s),
4.16 (2H, s), 3.59 (2H, q, J = 7.0 Hz), 1.25 (3H, t,
J = 7.0 Hz); FABMS: m/z 246, 244 [M+Na]+. Anal.
Calcd for C12H12ClNO: C, 65.01; H, 5.42; N, 6.32.
Found: C, 65.17; H, 5.36; N, 6.38.
Compound 5b: IR (KBr): tmax1729, 1637, 1437 cmÀ1
1H NMR (CDCl3, 200 MHz): d 7.73, 6.88 (1H, 2s),
;