Regiospecific and regioselective 1,3-dipolar cycloaddition of dipolar reagents to unsymmetrical bisolefinic ketones in the presence of chloramine-T (CAT)

Article abstract of DOI:10.1081/SCC-120003614

The reaction of 1,5-diaryl-3-methyl-1,4-pentadien-3-one with araldehyde phenylhydrazone/araldoxime in the presence of chloramine-T proceeds regiospecifically in MeOH and regioselectively in AcOH leading to mono- and bis-pyrazolines/isoxazolines.

Full text of DOI:10.1081/SCC-120003614

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REGIOSPECIFIC AND REGIOSELECTIVE 1,3-DIPOLAR
CYCLOADDITION OF DIPOLAR REAGENTS TO
UNSYMMETRICAL BISOLEFINIC KETONES IN THE
PRESENCE OF CHLORAMINE-T (CAT)
V. Padmavathi a , K. Venugopal Reddy a , A. Padmaja a & D. Bhaskar Reddy a
a Department of Chemistry , Sri Venkateswara University , Tirupati, 517 502, India
Published online: 16 Aug 2006.
To cite this article: V. Padmavathi , K. Venugopal Reddy , A. Padmaja & D. Bhaskar Reddy (2002) REGIOSPECIFIC AND
REGIOSELECTIVE 1,3-DIPOLAR CYCLOADDITION OF DIPOLAR REAGENTS TO UNSYMMETRICAL BISOLEFINIC KETONES IN THE
PRESENCE OF CHLORAMINE-T (CAT), Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 32:8, 1227-1235, DOI: 10.1081/SCC-120003614
To link to this article: http://dx.doi.org/10.1081/SCC-120003614
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SYNTHETIC COMMUNICATIONS, 32(8), 1227–1235 (2002)
REGIOSPECIFIC AND REGIOSELECTIVE
1,3-DIPOLAR CYCLOADDITION OF
DIPOLAR REAGENTS TO
UNSYMMETRICAL BISOLEFINIC
KETONES IN THE PRESENCE OF
CHLORAMINE-T (CAT)
*
V. Padmavathi, K. Venugopal Reddy, A. Padmaja,
and D. Bhaskar Reddy
Department of Chemistry, Sri Venkateswara University,
Tirupati-517 502, India
ABSTRACT
The reaction of 1,5-diaryl-3-methyl-1,4-pentadien-3-one with
araldehyde phenylhydrazone/araldoxime in the presence of
chloramine-T proceeds regiospecifically in MeOH and regio-
selectively in AcOH leading to mono- and bis-pyrazolines/
isoxazolines.
The olefinic groups has versatile functions in organic synthesis, offers
manifold possibilities of c-hetero bond formations and has received consid-
erable attention in recent times. As part of the development of new, simple
and efficient procedures for the synthesis of pyrazolines and isoxazolines, we
have examined the reaction of nitrile imines and nitrile oxides generated
*Corresponding author.
1227
Copyright & 2002 by Marcel Dekker, Inc.
www.dekker.com

1228
PADMAVATHI ET AL.
from araldehyde phenylhydrazones and araldoximes with bifunctional ole-
finic systems.1,2
In continuation of our study, the present paper deals with the reac-
tion of these dipolar reagents with unsymmetrical bisolefinic ketones. The
former can be generated by the dehydrogenation of araldehyde phenyl-
hydrazones and araldoximes with lead tetraacetate,3 mercuric acetate,4
1-chlorobenzotriazole,5 chloramine-T (CAT)6 etc. When the reaction of 1,5-
diaryl-3-methyl-1,4-pentadien-3-one7 (1) with two moles of araldehyde phe-
nylhydazone was carried out in the presence of CAT in refluxing MeOH, a
solid was separated after 2 h and identified as 1-phenyl-3,5-diaryl-4-(30-aryl-
20-methyl-20-propenone)-2-pyrazoline (2) by NMR spectra (Scheme). A
similar reaction of 1 with two moles of araldoxime in the presence of CAT
in refluxing MeOH gave 3,5-diaryl-4-(30-aryl-20-methyl-20-propenone)-2-iso-
xazoline (3) whose structure was confirmed by NMR spectra. The com-
pounds 2a and 3a showed dH 5.64, 5.61 (d, 4-H), 5.18, 5.23 (d, 5-H), dC
155.28, 155.13 (3-C), 87.64, 87.88 (4-C), 64.65, 64.62 (5-C), 197.19, 197.10
(C¼O), 161.04, 161.02 (20-C) and 141.38, 141.69 (30-C). The DEPT spectra
of these compounds exhibited signal at 141.60, 141.61 which indicates the
presence of olefinic proton at 30-C. Thus, the formation of 2 and 3 illustrates
that this reaction proceeds in a regiospecific manner. Attempts were made to
prepare 1-phenyl-3,5-diaryl-2-pyrazolinyl-10-phenyl-30,50-diaryl-40-methyl-
20-pyrazolinyl-[4,40]-ketones (4) and 3,5-diaryl-2-isoxazolinyl-30,50-diaryl-40-
methyl-20-isoxazolinyl-[4,40]-ketones (5) by refluxing 2 and 3 with one mole
of araldehyde phenylhydrazone and araldoxime in the presence of CAT in
MeOH, but could not meet with success, since this forms a heterogeneous
medium. However, this was accomplished by refluxing in AcOH. Contrary
to the above, when the reaction of 1 was carried out with two moles of
araldehyde phenylhydrazone and araldoxime in the presence of CAT in
AcOH, it gave 2 & 4 and 3 & 5 in 2.5 : 1 ratio respectively, indicating that
the reaction proceeded regioselectively. The two were separated by column
chromatography. The authenticity of these compounds was confirmed by
their relative NMR spectra. The formation of 4 and 5 in minor amounts
may be due to the presence of an alkyl group which deactivates the reactivity
of the olefinic bond. The formation of 2 and 3 led us to develop two different
heterocycles within the same molecule. Thus 2 on treatment with one mole
of araldoxime in the presence of CAT in AcOH gave a product which
was found to be 1-phenyl-3,5-diaryl-2-pyrazolinyl-30,50-diaryl-40-methyl-20-
isoxazolinyl-[4,40]- ketones (6). Similar reaction of 3 with araldehyde
phenylhydrazone and CAT in AcOH resulted in 3,5-diaryl-2-isoxazolinyl-
10-phenyl-30,50-diaryl-40-methyl-20-pyrazolinyl-[4,40]-ketones (7). The dehy-
drogenation of 4, 5, 6 and 7 with chloranil in AcOH8,9 resulted in
1-phenyl-3,5-diaryl-2-pyrazolyl-10-phenyl-30,50-diaryl-40-methyl-20-pyrazolin-

UNSYMMETRICAL BISOLEFINIC KETONES
1229
Scheme.
yl-[4,40]-ketones (8), 3,5-diaryl-2-isoxazolyl-30,50-diaryl-40-methyl-20-isoxazol-
inyl-[4,40]-ketones (9), 1-phenyl-3,5-diaryl-2-pyrazolyl-30,50-diaryl-40-methyl-
20-isoxazolinyl-[4,40]-ketones (10) and 3,5-diaryl-2-isoxazolyl-10-phenyl-30,50-
diaryl-40-methyl-20-pyrazolinyl-[4,40]-ketones (11). Theabsence ofadoublet at

1230
PADMAVATHI ET AL.
1
dH 5.61–5.64 and 5.18–5.23 in their H NMR spectra supports their forma-
tion. This reaction sequence shows that the 1,3-dipolar cycloaddition of
dipolar reagents to unsymmetrical bisolefinic ketones in the presence of
chloramine-T proceeds regiospecifically when the reaction is carried out in
methanol and regioselectively in acetic acid.
EXPERIMENTAL
All melting points were determined in open capillaries on Tempo Mel-
Temp apparatus and are uncorrected. The purity of the compounds was
checked by thin layer chromatography over silica gel (Silica gel-G (60–120
mesh, BDH), hexane : ethyl acetate (3 : 1) as eluents). The IR spectra were run
as KBr pellets using a Perkin-Elmer 993 infrared spectrometer and 1H NMR
spectra were recorded in CDCl3/DMSO-d6 at 200 MHz on a Brucker
Spectrospin with TMS as an internal standard (chemical shifts in d ppm).
Microanalytical data were obtained from Dr. Reddy’s Research Foundation,
Hyderabad, India. The araldoximes and araldehyde phenylhydrazones
were prepared from araldehydes following standard procedures.10
1-Phenyl-3,5-diaryl-4-(30-aryl-20-methyl-20-propenone)-2-pyrazoline 2
General
procedure:
1,5-Diaryl-3-methyl-1,4-pentadien-3-one
1
(10 mmol) in MeOH was added to a mixture of araldehyde phenylhydrazone
(20 mmol) and chloramine-T (20 mmol) in MeOH (20 ml) and refluxed for
5–6 h. Salts formed were filtered off. The solvent was removed under
vacuum and the solid obtained was recrystallized from AcOH to get pure 2.
2a: Yield 72%; m.p. 135–136ꢀC; IR nmax (cmꢁ1) 1444 (C¼N), 1638
(C¼C), 1669 (C¼O); H NMR d 2.12 (s, 3H, CH3, C-20), 3.79 (s, 3H, Ar-
1
OCH3), 5.23 (d, 1H, C4-H, J ¼ 6.0 Hz), 5.61 (d, 1H, C5-H, J ¼ 6.0 Hz), 7.18–
8.04 (m, 20H, C3 -H & Ar-H); 13C NMR d 13.56 (CH3, C-20), 64.62 (C-4),
0
87.88 (C-5), 141.69 (C-30), 155.13 (C-3), 161.02 (C-20), 197.10 (C¼O); DEPT
13.28 (CH3, C-20), 64.53 (C-4), 87.79 (C-5), 141.61 (C-30); Anal. calcd for
C32H28N2O2: C, 81.32; H,5.97; N,5.92. Found: C, 81.45; H, 5.90; N, 6.01.
2b: Yield 75%; m.p. 147–148ꢀC; IR nmax (cmꢁ1) 1448 (C¼N), 1644
(C¼C), 1668 (C¼O); 1H NMR d 2.12 (s, 3H, CH3, C-20), 5.25 (d, 1H, C4-H,
0
J ¼ 5.9 Hz), 5.58 (d, 1H, C5-H, J ¼ 5.9 Hz), 7.22–8.02 (m, 20H, C3 -H
& Ar-H); Anal. calcd for C31H25ClN2O: C, 78.05; H, 5.28; N, 5.87.
Found: C, 77.94; H, 5.25; N, 5.94.
2c: Yield 70%; m.p. 128–129ꢀC; IR nmax (cmꢁ1) 1445 (C¼N), 1638
(C¼C), 1670 (C¼O); 1H NMR d 2.10 (s, 3H, CH3, C-20), 3.81 (s, 3H,

UNSYMMETRICAL BISOLEFINIC KETONES
1231
Ar-OCH3) 5.22 (d, 1H, C4-H, J ¼ 6.0 Hz), 5.63 (d, 1H, C5-H, J ¼ 6.0 Hz),
0
7.19–8.06 (m, 19H, C3 -H & Ar-H); Anal. calcd for C32H27ClN2O2: C, 75.80;
H, 5.36; N, 5.52. Found: C, 75.71; H, 5.42; N, 5.59.
3,5-Diaryl-4-(30-aryl-20-methyl-20-propenone)-2-isoxazoline 3
General
procedure:
1,5-Diaryl-3-methyl-1,4-pentadien-3-one
1
(10 mmol) in MeOH was added to a mixture of araldoxime (20 mmol) and
chloramine-T (20 mmol) in MeOH (20 ml) and the mixture was refluxed for
5–6 h. Further workup of the reaction mixture was similar to that of 2.
3a: Yield 68%; m.p. 142–143ꢀC; IR nmax (cmꢁ1) 1446 (C¼N), 1627
(C¼C), 1672 (C¼O); 1H NMR d 2.14 (s, 3H, CH3, C-20), 3.79 (s, 3H,
Ar-OCH3), 5.20 (d, 1H, C4-H, J ¼ 5.9 Hz), 5.65 (d, 1H, C5-H, J ¼ 5.9 Hz),
7.12–7.94 (m, 15H, C3 -H & Ar-H); 13C NMR d 12.78 (CH3 at C-20), 64.57
0
(C-4), 85.62 (C-5), 142.63 (C-30), 153.84 (C-30), 160.98 (C-20), 198.02 (C¼O);
DEPT 12.24 (CH3 at C-20), 64.48 (C-4), 85.52 (C-5), 142.62 (C-30); Anal. calcd
for C26H23NO3: C, 78.50; H, 5.83; N, 3.52. Found: C, 78.64; H, 5.80; N, 3.58.
3b: Yield 71%; m.p. 137–138ꢀC; IR nmax (cmꢁ1) 1448 (C¼N), 1634
(C¼C), 1670 (C¼O); H NMR d 2.13 (s, 3H, CH3, C-20), 5.24 (d, 1H C4-H,
1
0
J ¼ 6.1 Hz), 5.63 (d, 1H, C5-H, J ¼ 6.1 Hz), 7.09-8.01 (m, 15H, C3 -H &
Ar-H); Anal. calcd for C25H20ClNO2: C, 74.75; H, 5.00; N, 3.48; Found:
C, 74.84; H, 5.04; N, 3.55.
3c: Yield 66%; m.p. 130–131ꢀC; IR nmax (cmꢁ1) 1444 (C¼N), 1637
(C¼C), 1669 (C¼O); 1H NMR d 2.10 (s, 3H, CH3, C-20), 3.80 (s, 3H,
Ar-OCH3), 5.22 (d, 1H, C4-H, J ¼ 6.0 Hz), 5.66 (d,1H, C5-H, J ¼ 6.0 Hz),
0
7.12–7.98 (m, 14H, C3 -H & Ar-H); Anal. calcd for C26H22ClNO3: C, 72.30;
H, 5.13; N, 3.24. Found: C, 72.41; H, 5.17; N, 3.29.
1-Phenyl-3,5-diaryl-2-pyrazolinyl-10-phenyl-30,50-diaryl-40-methyl-20-
pyrazolinyl-[4,40]-ketones 4/3,5-Diaryl-2-isoxazolinyl-10-phenyl-30,50-
diaryl-40-methyl-20-pyrazolinyl-[4,40]-ketones 7
General procedure: A mixture of 2/3 (6 mmol), araldehyde phenyl-
hydrazone (6 mmol) and two-fold excess of chloramine-T in AcOH (20 ml)
was added and refluxed for 4–5 h. The contents were cooled and poured
onto crushed ice. It was extracted with ether (30 ml), washed with sat.
NaHCO3 solution, water and dried over an. Na2SO4. Evaporation of the
solvent under reduced pressure gave a crude product which was purified by
column chromatography.

1232
PADMAVATHI ET AL.
4a: Yield 66%; m.p. 162–163ꢀC; IR nmax (cmꢁ1) 1444 (C¼N), 1706
(C¼O); H NMR d 0.81 (s, 3H, CH3 at C-40), 3.81 (s, 6H, Ar-OCH3), 5.25
1
0
(d, 1H, C4-H, J ¼ 5.7 Hz), 5.39 (s, 1H, C5 -H), 5.58 (d, 1H, C5-H, J ¼ 5.7 Hz),
7.24–8.12 (m, 28H, Ar-H). 13C NMR d 12.21 (CH3 at C-40), 59.87 (C-40),
64.62 (C-4), 85.92 (C-50), 87.88 (C-5), 153.24 (C-30), 155.13 (C-3), 199.24
(C¼O); Anal. calcd for C46H40N4O3: C, 79.28; H, 5.78; N, 8.04. Found: C,
79.42; H, 5.70; N, 7.93.
4b: Yield 62%; m.p. 155–156ꢀC; IR nmax (cmꢁ1) 1447 (C¼N), 1710
(C¼O); H NMR d 0.84 (s, 3H, CH3, C-40), 5.27 (d, 1H, C4-H, J ¼ 5.6 Hz),
1
0
5.38 (s, 1H, C5 -H) 5.56 (d, 1H, C5-H, J ¼ 5.8 Hz), 7.26–8.03 (m, 28H, Ar-H).
Anal. calcd for C44H34Cl2N4O: C, 74.90; H, 4.85; N, 7.94. Found: C, 76.79;
H, 4.89; N, 7.85.
4c: Yield 68%; m.p. 171–172ꢀC; IR nmax (cmꢁ1) 1445 (C¼N), 1702
(C¼O); 1H NMR d 0.83 (s, 3H, CH3, C-40), 3.81 (s, 3H, Ar-OCH3), 5.22 (d,
0
1H, C4-H, J ¼ 5.6 Hz), 5.35 (s, 1H, C5 -H), 5.59 (d, 1H, C5-H, J ¼ 5.6 Hz),
7.24–8.12 (m, 27H, Ar-H). Anal. calcd for C45H36Cl2N4O2: C, 73.46; H,
4.93; N, 7.61. Found: C, 73.59; H, 5.01; N, 7.74.
7a: Yield 69%; m.p. 182–183ꢀC; IR nmax (cmꢁ1) 1442 (C¼N), 1712
(C¼O); 1H NMR d 0.84 (s, 3H, CH3, C-40), 3.79 (s, 3H, Ar-OCH3), 5.21 (d,
0
1H, C4-H, J ¼ 5.9 Hz), 5.44 (s, 1H, C5 -H), 5.63 (d, 1H, C5-H, J ¼ 5.9 Hz),
7.14–8.04 (m, 23H, Ar-H). Anal. calcd for C40H35N3O4: C, 77.20; H, 5.67;
N, 6.75. Found: C, 77.39; H, 5.75; N, 6.80.
7b: Yield 62%; m.p. 173–174ꢀC; IR nmax (cmꢁ1) 1438 (C¼N), 1710
(C¼O); 1H NMR d 0.82 (s, 3H, CH3, C-40), 3.78 (s, 3H, Ar-OCH3), 5.19 (d,
0
1H, C4-H, J ¼ 5.8 Hz), 5.39 (s, 1H, C5 -H), 5.64 (d, 1H, C5-H, J ¼ 5.8 Hz),
7.12–8.07 (m, 23H, Ar-H). Anal. calcd for C39H32ClN3O3: C, 74.57; H, 5.13;
N, 6.68. Found: C, 74.44; H, 5.09; N, 6.73.
7c: Yield 66%; m.p. 173–174ꢀC; IR nmax(cmꢁ1) 1444 (C¼N), 1713
(C¼O); H NMR d 0.83 (s, 3H, CH3, C-40), 3.778 (s, 3H, Ar-OCH3), 5.19
1
0
(d, 1H, C4-H, J ¼ 5.9 Hz), 5.43 (s, 1H, C5 -H), 5.62 (d, 1H, C5-H, J ¼ 5.9 Hz),
7.09–8.02 (m, 22H, Ar-H). Anal. calcd for C39H31Cl2N3O3: C, 70.91; H,
4.72; N, 6.36. Found: C, 70.83; H, 4.81; N, 6.45.
3,5-Diaryl-2-isoxazolinyl-30,50-diaryl-40-methyl-20-isoxazolinyl-[4,40]-
ketones 5/1-phenyl-3,5-diaryl-2-pyrazolinyl-30,50-diaryl-40-methyl-20-
isoxazolinyl-[4,40]-ketones 6
General procedure: A mixture of 2/3 (6 mmol), araldoxime (6 mmol)
and two-fold excess of chloramine-T in AcOH (20 ml) was refluxed for
2–3 h. Further workup of the reaction mixture was similar to 4/7.

UNSYMMETRICAL BISOLEFINIC KETONES
1233
5a: Yield 69%; m.p. 171–172ꢀC; IR nmax (cmꢁ1) 1452 (C¼N), 1712
(C¼O); 1H NMR d 0.84 (s, 3H, CH3, C-40), 3.74 (s, 6H, Ar-OCH3), 5.23 (d,
0
1H, C4-H, J ¼ 6.1 Hz), 5.40 (s, 1H, C5 -H) 5.62 (d, 1H, C5-H, J ¼ 6.1 Hz)
7.19–8.13 (m, 18H, Ar-H). 13C NMR d 12.46 (CH3 at C-40), 59.48 (C-40),
63.24 (C-4), 84.29 (C-50), 88.90 (C-5), 154.45 (C-30), 156.27 (C-3), 197.48
(C¼O); Anal. calcd for C34H30N2O5: C, 74.70; H, 5.53; N, 5.12. Found: C,
74.79; H, 5.45; N, 5.04.
5b: Yield 72%; m.p. 155–156ꢀC; IR nmax (cmꢁ1) 1450 (C¼N), 1707
(C¼O); H NMR d 0.84 (s, 3H, CH3, C-40), 5.20 (d, 1H, C4-H, J ¼ 6.0 Hz),
1
0
5.38 (s, 1H, C5 -H) 5.65 (d, 1H, C5-H, J ¼ 6.0 Hz) 7.16–8.15 (m, 18H, Ar-H).
Anal. calcd for C32H24Cl2N2O3: C, 69.19; H, 4.35; N, 5.04. Found: C, 69.20;
H, 4.31; N, 5.09.
5c: Yield 70%; m.p. 184–185ꢀC; IR nmax (cmꢁ1) 1442 (C¼N), 1712
(C¼O); 1H NMR d 0.85 (s, 3H, CH3, C-40), 3.82 (s, 3H, Ar-OCH3), 5.25 (d,
0
1H, C4-H, J ¼ 6.1 Hz), 5.37 (s, 1H, C5 -H) 5.58 (d, 1H, C5-H, J ¼ 6.1 Hz)
7.17–8.07 (m, 17H, Ar-H). Anal. calcd for C33H26Cl2N2O4: C, 67.69; H,
4.47; N, 4.78. Found: C, 67.65; H, 4.49; N, 4.88.
6a: Yield 65%; m.p.157-158ꢀC; IR nmax (cmꢁ1) 1438 (C¼N), 1724
(C¼O); H NMR d 0.80 (s, 3H, CH3, C-40), 3.84 (s, 3H, Ar-OCH3), 5.27
1
(d, 1H, C4-H, J ¼ 6.1 Hz), 5.31 (s, 1H, C5’-H), 5.52 (d, 1H, C5-H, J ¼ 6.1 Hz),
7.19–8.10, (m, 23H, Ar-H). Anal. calcd for C40H35N3O4: C,77.29; H,5.67;
N,6.75. Found: C, 77.29; H, 5.59; N, 6.84.
6b: Yield 69%; m.p. 142–143ꢀC; IR nmax (cmꢁ1) 1442 (C¼N), 1722
(C¼O); H NMR d 0.81 (s, 3H, CH3, C-40), 3.82 (s, 3H, Ar-OCH3), 5.25
1
0
(d, 1H, C4-H, J ¼ 6.0 Hz), 5.34 (s, 1H, C5 -H), 5.50 (d, 1H, C5-H, J ¼ 6.0 Hz),
7.19–8.14, (m, 23H, Ar-H). Anal. calcd for C39H32ClN3O3: C, 74.57; H,
5.13; N, 6.68. Found: C, 74.42; H, 5.20; N, 6.75.
6c: Yield 61%; m.p. 162–163ꢀC; IR nmax (cmꢁ1) 1432 (C¼N), 1721
(C¼O); H NMR d 0.83 (s, 3H, CH3, C-40), 3.82 (s, 3H, Ar-OCH3), 5.25
1
0
(d, 1H, C4-H, J ¼ 6.0 Hz), 5.33 (s, 1H, C5 -H), 5.51 (d, 1H, C5-H, J ¼ 6.0 Hz),
7.17–8.08 (m, 22H, Ar-H). Anal. calcd for C39H31Cl2N3O3: C, 70.91; H,
4.72; N, 6.36. Found: C, 71.05; H, 4.79; N, 6.41.
When the reaction was carried out with 1 and araldehyde phenyl-
hydrazone/araldoxime (1.2 mmol) in the presence of chloramine-T in AcOH,
the mixture of products 2 & 4/3 & 5 were obtained in 2.5 : 1 ratio. These com-
pounds have the same physical and spectral characteristics as above.
Dehydrogenation of 4/5/6/7
General procedure: A mixture of 4/5/6/7 (6 mmol) and chloranil
(6.5 mmol) in xylene (15 ml) was refluxed for 24–32 h. The organic layer

1234
PADMAVATHI ET AL.
was washed with 1N NaOH, water and dried. The solvent was removed
under reduced pressure. The solid remaining was purified by recrystalliza-
tion from AcOH to obtain 8/9/10/11.
8a: Yield 71%; m.p. 145–146ꢀC; IR nmax (cmꢁ1) 1448 (C¼N), 1629
(C¼C), 1674 (C¼O); H NMR d 0.90 (s, 3H, CH3 at C-40), 3.81 (s, 6H,
1
0
Ar-OCH3), 5.35 (s,1H C5 -H) 7.14–8.12, (m, 28H, Ar-H).
8b: Yield 66%; m.p. 137–138ꢀC; IR nmax (cmꢁ1) 1448 (C¼N), 1627
1
0
0
(C¼C), 1675 (C¼O); H NMR d 0.87 (s, 3H, CH3, C-4 ) 5.32 (s, 1H, C5 -H),
7.05–8.10 (m, 28H, Ar-H).
8c: Yield 70%; m.p. 153–154ꢀC; IR nmax (cmꢁ1) 1448 (C¼N), 1628
(C¼C), 1670 (C¼O); 1H NMR d 0.85 (s, 3H, CH3, C-40) 3.80 (s, 3H,
0
Ar-OCH3), 5.36 (s,1H C5 -H,) 7.07–8.12 (m, 27H, Ar-H).
9a: Yield 66%; m.p. 156–157ꢀC; IR nmax (cmꢁ1) 1434 (C¼N), 1642
(C¼C), 1680 (C¼O); H NMR d 0.87 (s, 3H, CH3 at C-40), 3.80 (s, 6H,
1
0
Ar-OCH3), 5.39 (s, 1H C5 -H,) 7.19–8.20, (m, 18H, Ar-H).
9b: Yield 65%; m.p. 134–135ꢀC; IR nmax (cmꢁ1) 1432 (C¼N), 1639
1
0
0
(C¼C), 1684 (C¼O); H NMR d 0.86 (s, 3H, CH3, C-4 ), 5.40 (s, 1H C5 -H),
7.16–8.22 (m, 18H, Ar-H).
9c: Yield 69%; m.p. 159–160ꢀC; IR nmax (cmꢁ1) 1437 (C¼N), 1642
(C¼C), 1681 (C¼O); H NMR d 0.89 (s, 3H, CH3 at C-40), 3.82 (s, 3H,
1
0
Ar-OCH3), 5.41 (s, 1H C5 -H,) 7.08–8.15, (m, 17H, Ar-H).
10a: Yield 69%; m.p. 135–136ꢀC; IR nmax (cmꢁ1) 1436 (C¼N), 1630
(C¼C), 1676 (C¼O); 1H NMR d 0.82 (s, 3H, CH3, C-40), 3.88 (s, 3H,
0
Ar-OCH3), 5.38 (s, 1H, C5 -H,) 7.24–8.19 (m, 23H, Ar-H).
10b: Yield 62%; m.p. 112–113ꢀC; IR nmax (cmꢁ1) 1435 (C¼N), 1632
(C¼C), 1673 (C¼O); 1H NMR d 0.85 (s, 3H, CH3, C-40), 3.82 (s, 3H,
0
Ar-OCH3), 5.35 (s, 1H, C5 -H,) 7.17–8.16 (m, 22H, Ar-H).
10c: Yield 65%; m.p. 151–152ꢀC; IR nmax (cmꢁ1) 1438 (C¼N), 1630
(C¼C), 1669 (C¼O); 1H NMR d 0.84 (s, 3H, CH3, C-40), 3.82 (s, 3H,
0
Ar-OCH3), 5.38 (s, 1H, C5 -H), 7.19–8.14 (m, 22H, Ar-H).
11a: Yield 73%; m.p. 165–166ꢀC; IR nmax (cmꢁ1) 1448 (C¼N), 1632
(C¼C), 1678 (C¼O); 1H NMR d 0.85 (s, 3H, CH3, C-40), 3.82 (s, 3H,
0
Ar-OCH3), 5.32 (s, 1H C5 -H), 7.18–8.10 (m, 22H, Ar-H).
11b: Yield 66%; m.p 143–144ꢀC; IR nmax (cmꢁ1) 1444 (C¼N), 1635
(C¼C), 1674 (C¼O); 1H NMR d 0.84 (s, 3H, CH3, C-40), 3.81 (s, 3H,
0
Ar-OCH3), 5.33 (s, 1H C5 -H), 7.05–8.02 (m, 22H, Ar-H).
11c: Yield 70%; m.p. 137–138ꢀC; IR nmax (cmꢁ1) 1443 (C¼N), 1632
(C¼C), 1675 (C¼O); H NMR d 0.85 (s, 3H, CH3 at C-40), 3.82 (s, 3H,
1
0
Ar-OCH3), 5.35 (s, 1H C5 -H), 7.07–8.05 (m, 21H, Ar-H).

UNSYMMETRICAL BISOLEFINIC KETONES
ACKNOWLEDGMENT
1235
The authors are grateful to Council of Scientific and Industrial
Research (CSIR), New Delhi, for financial assistance.
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Received in the UK January 2, 2001