Synthesis of 1,4-diphenylbutadiene derivatives: Novel inducer of tissue-type plasminogen activator (t-PA) in cultured bovine endothelial cells

Article abstract of DOI:10.1248/cpb.54.1686

(E,E)-1,4-Diphenylbutadiene derivatives were synthesized by utilizing the Stobbe reaction of dimethyl succinate as a key step. Their stereoisomers were also synthesized stereoselectively by means of the cross-coupling reaction of the vinylstannanes and the vinylbromides, which were obtained from the propiolic acid esters by stereoselective hydrostannation, as a key step. To discover novel stimulators of fibrinolysis in vascular endothelial cells, the synthesized compounds were added to cultured bovine endothelial cells to determine the activity of the plasminogen activator in the conditioned medium. Of the synthesized compounds, three compounds were found to stimulate the activity of the plasminogen activator in endothelial cells. In addtition, these compounds inhibited thrombus formation in a rat model of venous thrombosis.

Full text of DOI:10.1248/cpb.54.1686

1686
Chem. Pharm. Bull. 54(12) 1686—1693 (2006)
Vol. 54, No. 12
Synthesis of 1,4-Diphenylbutadiene Derivatives: Novel Inducer of Tissue-
Type Plasminogen Activator (t-PA) in Cultured Bovine Endothelial Cells
,a
c
Hiroshi SAI, Tsuyoshi OGIKU, ,b Hiroshi OHMIZU,b and Akio OHTANI
*
*
a Clinical Research Division, Tanabe Seiyaku Co., Ltd.; 3–2–10 Dosho-machi, Chuo-ku, Osaka 541–8505, Japan:
b Medicinal Chemistry Research Laboratories, Tanabe Seiyaku Co., Ltd.; 3–16–89 Kashima, Yodogawa-ku, Osaka
532–8505, Japan: and c Strategic Research Planning & Management Division, Tanabe Seiyaku Co., Ltd.; 2–2–50
Kawagishi, Toda, Saitama 335–8505, Japan.
Received August 9, 2006; accepted September 13, 2006; published online September 19, 2006
(E,E)-1,4-Diphenylbutadiene derivatives were synthesized by utilizing the Stobbe reaction of dimethyl succi-
nate as a key step. Their stereoisomers were also synthesized stereoselectively by means of the cross-coupling re-
action of the vinylstannanes and the vinylbromides, which were obtained from the propiolic acid esters by stere-
oselective hydrostannation, as a key step. To discover novel stimulators of fibrinolysis in vascular endothelial
cells, the synthesized compounds were added to cultured bovine endothelial cells to determine the activity of the
plasminogen activator in the conditioned medium. Of the synthesized compounds, three compounds were found
to stimulate the activity of the plasminogen activator in endothelial cells. In addtition, these compounds inhibited
thrombus formation in a rat model of venous thrombosis.
Key words plasminogen activator; dipheylbutadiene derivative; cross-coupling reaction; stereoselective olefin synthesis; Stobbe
condensation; plasminogen activator inhibitor-1
It is well known that plasminogen activator in blood plays monomethyl esters 14a—c were synthesized utilizing twice
an important role in endogenous fibrinolysis by converting the Stobbe condensation.10) The (E)-benzylidenesuccinic
plasminogen to plasmin. Thus, stimulation of endogenous acid methyl ester obtained stereoselectively in the first Sto-
fibrinolysis by a pharmaceutical agent may be useful for pre- bbe condensation of benzaldehyde 12a, b with dimethyl suc-
vention and treatment of patients with thrombosis. Since vas- cinate,11) was transformed into the (E)-dimethyl esters 13a, b
cular endothelial cells synthesize and secrete plasminogen by treatment with a catalytic amount of c.H2SO4 in MeOH.
activator, cultured endothelial cells are suitable for the study The second Stobbe condensation of 13a, b with benzalde-
of the modulation of endogenous fibrinolytic activity in an in hyde or 3,4,5-trimethoxybenzaldehyde, steroselectively af-
vitro system.1—4) It has been reported that physiological sub- forded the (E,E)-half-esters 14a—c. Treatment of 14a—c
stances such as thrombin,5,6) short-chain fatty acids7) and with SOCl2 followed by excess aqueous NH3 afforded the
retinoids8,9) induce an increase in the fibrinolytic activity in imide derivatives 1a, g. The intermediate succinamate 2 was
cultured endothelial cells via enhancement of plasminogen spontaneously cyclized to succinimide 1 in this reaction con-
activator synthesis. Of these, we have been interested in dition because of the basicity of ammonia. The Stobbe con-
retinoids because the inducing activity of plasminogen acti- densation of 13a, b with substituted benzaldehyde and suc-
vator synthesis could easily be improved by chemical modifi- cessive amidation with ammonia afforded the imide deriva-
cation of its conjugated polyene functionality.
tives 1b—f, 1h—m. Instead of ammonia, various amines
We performed random screening of polyene compounds in were used to afford N-substituted succinimide derivatives
Tanabe libraries and found that (3E,4E)-3,4-dibenzyli- 1n—r from 14b. The syntheses of the succinamate type de-
denepyrrolidine-2,5-dione (1a) showed high potency of plas- rivatives 2a—k were performed by treatment of equimolar
minogen activator induction (Fig. 1). We selected 1a as the ammonia or amine and at low reaction temperature.
lead compound, and carried out its chemical modification to
The syntheses of the (E,E)-dibenzylidenesuccinic anhy-
enhance the activity. In this paper, we describe stereoselec- dride 3, (E,E)-dibenzylidene-g-butyrolactone 4a, b and
tive syntheses, structure–activity relationships (SAR), and (E,E)-dibenzylidene-g-butyrolactam 5a, b are shown in
antithrombotic activities of 1,4-diphenylbutadiene deriva- Chart 2. The anhydride 3 was obtained by treatment of half-
tives.
ester 14b with SOCl2 and SnCl4 successively. The half-ester
14b, c was reduced with diisobutylaluminum hydride
(DIBAL-H) to give the corresponding alcohol, which was
Chemistry
The typical synthetic route of the succinimide type deriva- successively treated with aqueous HCl to afford the lactone
tives of 1,4-diphenylbutadiene 1a—r is shown in Chart 1. 4a, b. Treatment of amide 2b, c with PPh3 and CCl4 afforded
The key intermediate (E,E)-dibenzylidenesuccinic acid the nitrile 15a, b. Hydrogenation of the nitrile 15a, b in the
presence of Raney-Ni followed by cyclization by heating af-
forded the lactam 5a, b.
In order to explore the effect of stereochemistry on butadi-
ene moiety, we decided to synthesize all isomers of 1g and
2b, which possessed a high potency of t-PA induction. The
stereoisomers of dibenzylidenesuccinimide 1g and methyl
dibenzylidenesuccinamate 2b were synthesized by utilizing a
Fig. 1. Lead Compound
cross-coupling reaction12) as a key step, as shown in Chart 3.
∗ To whom correspondence should be addressed. e-mail: h-sai@tanabe.co.jp
© 2006 Pharmaceutical Society of Japan

December 2006
1687
Chart 1. Synthesis of Dibenzylidenesuccinimide Derivatives 1a—r and Dibenzylidenesuccinamate Derivatives 2a—k
Chart 2. Synthesis of Other Ring Derivatives 3, 4a, b and 5a, b
The bromide 21, 22 and the stannane 25, 26 were synthe- tion of phenylacetylene (23) followed by bubbling of carbon
sized as follows. Methyl 3,4,5-trimethoxypropiolate (18) was dioxide afforded the propiolic acid, which was converted to
prepared from 3,4,5-trimethoxybenzaldehyde (16) by Corey’s the amide 24. Hydrostannation of the propiolic amide 24 in
method.13) Treatment of the aldehyde 16 with CBr4 and PPh3 the presence of Pd(PPh3)4 or AIBN afforded (E)-vinylstan-
afforded the dibromoolefin 17. Lithiation of 17 with 2 eq of nane 25 or (Z)-vinylstannane 26 steroselectively. The cross-
n-butyllithium followed by addition of methyl chloroformate coupling reaction of the (Z)-vinylbromide 22 with the (E)-
afforded the propiolate 18. Hydrostannation of the propiolate vinylstannane 25 smoothly proceeded in the presence of
14,15)
18 in the presence of Pd(PPh3)4
stereoselectively gave Pd(PPh3)2Cl2 in DMF at 60 °C18) to provided the (E,Z)-amide
the (E)-vinylstannane 19. On the other hand, hydrostannation 9. The (E,Z)-imide 6 was obtained in high yield by treatment
of 18 in the presence of AIBN16) proceeded stereoselectively of 9 with aqueous NaOH. Similarly, the appropriate combi-
to afford (Z)-vinylstannane 20. Treatment of the vinylstan- nation of the (E)-vinylbromide 21 and the (Z)-vinylstannane
nanes 19, 20 with bromine gave the vinylbromides 21, 2217) 26 gave the corresponding (Z,E)-amide 10 and (Z,E)-imide
with retention of the configuration in high yields. The stan- 7. Next, the (Z,Z)-amide 11 and (Z,Z)-imide 8 was obtained
nannes 25, 26 were synthesized in a similar manner. Lithia- from the (E)-vinylbromide 21 and the (E)-vinylstannane 25.

1688
Vol. 54, No. 12
Chart 3. Synthesis of Stereoisomers 6—11
Biological Result and Discussion
1g was examined. As a result, all of the R3-substituted deriv-
To determine whether the synthesized compounds can atives 1n—r exhibited much lower activity than 1g.
stimulate the fibrinolytic activity in vascular endothelial Table 2 summarizes the relative PA activity of dibenzylide-
cells, the cells were treated with the compounds for 24 h, and nesuccinamate derivatives 2a—k compared to the control
the activity of the plasminogen activator (PA) in the condi- cells treated with vehicle alone. First, the 3,4,5-trimethoxy-
tioned medium was measured.
substituted derivatives 2b, c were examined due to effective
Table 1 summarizes the relative PA activity of vascular en- substituent in dibenzylidenesuccinimide derivatives. The R2-
dothelial cells treated with dibenzylidenesuccinimide deriva- substituted derivative 2b was revealed to possess equal po-
tives 1a—r, compared to the control cells treated with vehi- tency with the dibenzylidenesuccinimide derivative 1g. How-
cle alone. First, the effect of the electron-withdrawing (1b, c) ever, the R1-substituted derivative 2c was revealed to be less
and electron-donating (1d—g) substituents R1 of the diben- potent than 1g. Next, the effect of substituents R1 in 2b was
zylidenesuccinimide was examined. Among the compounds examined. All of the R1-substituted derivatives 2d—f exhib-
1b—g, the 3,4,5-trimethoxy-substituted derivative 1g was re- ited much lower activity than 2b. Finally, the effect of the N-
vealed to possess good potency of the PA activity. Next, the substituents R3 in 2b was examined. Among the compounds
effect of the electron-withdrawing (1h, i) and electron-donat- of 2g—k, the methyl-substituted derivative 2g and the
ing (1j—m) substituents R2 in 1g was examined. All of the amino-substituted derivative 2j were revealed to possess
R2-substituted derivatives 1h—m exhibited much lower ac- good potency of the PA activity. However, the potency did
tivity than 1g. Finally, the effect of the N-substituents R3 in not exceed 2b. These results suggest that a small substituent

December 2006
1689
Table 1. Plasminogen Activator Stimulating Activity of Dibenzylidene- Table 3. Plasminogen Activator Stimulating Activity of Other Ring Deriv-
succinimide Derivatives atives
Relative PA
activitya)
R1
R2
R3
Relative PA
activitya)
Compound
Compound
X
Y
Z
1a
1b
1c
1d
1e
1f
1g
1h
1i
1j
1k
1l
1m
1n
1o
1p
1q
1r
H
3-NO2
4-Cl
4-NMe2
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
1.96
0.49
1.32
0.35
0.75
1.08
2.33
1.23
1.40
1.53
1.02
0.95
1.53
1.64
1.26
1.54
1.23
0.71
3
O
H2
O
O
H2
O
O
H2
H2
O
O
O
O
NH
NH
1.05
2.69
2.25
0.93
1.18
4a
4b
5a
5b
4-OMe
3,4-(OMe)2
3,4,5-(OMe)3
3,4,5-(OMe)3
3,4,5-(OMe)3
3,4,5-(OMe)3
3,4,5-(OMe)3
H
H
a) See Experimental.
3-NO2
4-Cl
4-NMe2
4-OMe
Table 4. Plasminogen Activator Stimulating Activity for Stereoisomers of
1g and 2b
3,4,5-(OMe)3 3,4-(OMe)2
3,4,5-(OMe)3 3,4,5-(OMe)3
3,4,5-(OMe)3
3,4,5-(OMe)3
3,4,5-(OMe)3
3,4,5-(OMe)3
3,4,5-(OMe)3
H
H
H
H
H
Me
CH2Ph
CH2CH2OH
NH2
Configuration at C-2
and C-3 positions
Relative PA
activitya)
OMe
Compound
a) See Experimental. Retinyl palmitate, a reference compound, at 20 mM showed rel-
ative PA activity ranging from 2.00 to 3.00 in this assay.
1g
6
7
8
2b
9
2E,3E
2E,3Z
2Z,3E
2Z,3Z
2E,3E
2E,3Z
2Z,3E
2Z,3Z
2.33
1.60
0.68
0.60
2.54
1.40
1.15
1.05
Table 2. Plasminogen Activator Stimulating Activity of Dibenzylidene-
succinamate Derivatives
10
11
a) See Experimental.
Relative PA
Compound
R1
R2
R3
activitya)
Table 5. Antithrombotic Activities of 1g, 2b and 4a in the Rat Venous
Thrombosis Model
2a
2b
2c
2d
2e
2f
2g
2h
2i
H
H
H
H
H
H
H
H
H
Me
CH2Ph
1.74
2.54
1.33
0.94
1.50
0.95
2.27
1.06
1.55
2.16
1.83
3,4,5-(OMe)3
H
3,4,5-(OMe)3
3,4,5-(OMe)3
Decrease (%) in
thrombus weight
3,4,5-(OMe)3
4-NMe2
4-OMe
Compound
Dose (mg/kg)
1g
2b
4a
10
100
10
100
10
53
73
25
52
43
79
3,4-(OMe)2 3,4,5-(OMe)3
H
H
H
H
H
3,4,5-(OMe)3
3,4,5-(OMe)3
3,4,5-(OMe)3 CH2CH2OH
3,4,5-(OMe)3
3,4,5-(OMe)3
2j
2k
NH2
OMe
100
a) See Experimental. Retinyl palmitate, a reference compound, at 20 mM showed rel-
ative PA activity ranging from 2.00 to 3.00 in this assay.
of venous thrombosis (Table 5). In this model, the antithrom-
botic activity of 1g was more potent than that of 2b and 4a.
in R3 is particularly favorable for good potency.
As shown in Table 3, the effect of the other ring deriva- Conclusion
tives was examined. The anhydride 3 and the lactams 5a, b
On the basis of modification conjugated polyene function-
exhibited much lower activity than 1g, whereas the lactones ality in retinoid, we have prepared 1,4-diphenylbutadiene de-
4a, b possessed the good potency of the PA activity. In partic- rivatives to obtain a compound with plasminogen activator
ular, 4a exhibited much higher activity than 1g.
inducing activity. After identifying the optimum substituent
The activity of stereoisomers in 1g and 2b are summarized on the two phenyl rings of dibenzylidenesuccinimide 1a, var-
in Table 4. Both succinimide derivatives 6—8 and succina- ious modifications to the N-substituent, the ring system, and
mate derivatives 9—11 showed no strong activity. These re- the stereochemistry of double bonds have been investigated.
sults show that the E,E-isomer is most effective.
Among the series of compounds obtained, we selected 1g (T-
In the compounds that showed strong activity, 1g, 2b and 686) for further evaluation as an antithrombotic agent.
4a were evaluated the antithrombotic activity in a rat model

1690
Vol. 54, No. 12
Experimental
for 1a.
(3E,4E)-3-Benzylidene-4-(3-nitrobenzylidene)-pyrrolidine-2,5-dione
Melting points were measured using a Büchi 535 capillary melting point
1
apparatus and are uncorrected. IR spectra were recorded on a Perkin-Elmer (1b) Yield: 45%. mp 216—218 °C. H-NMR (CDCl3) d: 6.76—6.90 (4H,
1640 infrared spectrophotometer. 1H-NMR spectra were recorded on a m), 7.08 (1H, m), 7.19 (1H, m), 7.36—7.48 (2H, m), 7.77 (1H, s), 7.92 (1H,
Bruker AC-200 spectrometer with Me4Si as an internal standard. Mass spec-
s), 7.94 (1H, m), 8.67 (1H, bs). IR (KBr) cmꢀ1: 3160, 1765, 1705, 1625. MS
tra were recorded on a Hitachi M-2000A spectrometer at 70eV, and high-res- m/z: 320 (Mꢁ). Anal. Calcd for C18H12N2O4: C, 67.50; H, 3.78; N, 8.75.
olution mass spectra (HR-MS) were measured with a JEOL JMS HX-100 Found: C, 67.52; H, 3.65; N, 8.64.
spectrometer. Elemental analyses were carried out in this laboratory. Silica
(3E,4E)-3-Benzylidene-4-(4-chlorobenzylidene)-pyrrolidine-2,5-dione
gel (Kieselgel 60, Merck) was used for column chromatography, and silica (1c) Yield: 62%. mp 263—265 °C. 1H-NMR (DMSO-d6) d: 6.76—6.90
gel (Kieselgel 60 F254, layer thickness 0.25 mm, Merck) for analytical thin (4H, m), 7.08 (1H, m), 7.19 (1H, m), 7.36—7.48 (2H, m), 7.77 (1H, s), 7.92
layer chromatography (TLC).
Dimethyl (E)-2-Benzylidenesuccinate (13a) A solution of benzalde-
(1H, s), 7.94 (1H, m), 8.67 (1H, bs). IR (KBr) cmꢀ1: 3160, 1765, 1705,
1625. MS m/z: 311, 309 (Mꢁ). Anal. Calcd for C18H12NClO2: C, 69.80; H,
hyde (15.9 g, 0.15 mol) and dimethyl succinate (26.3 g, 0.18 mol) in tert- 3.90; Cl, 11.45; N, 4.52. Found: C, 69.56; H, 3.78; Cl, 11.72; N, 4.44.
BuOH (20 ml) was added to a solution of potassium tert-butoxide (16.8 g,
0.15 mol) in tert-BuOH (150 ml) below 50 °C and the mixture was stirred at
room temperature for 30 min. The reaction mixture was poured into ice- (6H, s), 6.10 (2H, d, Jꢂ9.0 Hz), 6.71 (2H, d, Jꢂ9.0 Hz), 6.87 (2H, m), 6.90
(3E,4E)-3-Benzylidene-4-(4dimethylaminobenzylidene)-pyrrolidine-
2,5-dione (1d) Yield: 62%. mp 220—222 °C. H-NMR (CDCl3) d: 2.90
1
water and the aqueous layer was washed with i-Pr2O and acidified with
(2H, s), 7.13 (1H, m), 7.71 (1H, s), 7.72 (1H, s), 8.12 (1H, bs). IR (KBr)
c.HCl. The organic layer was extracted with AcOEt and washed with brine, cmꢀ1: 3165, 1750, 1705, 1580. MS m/z: 318 (Mꢁ). Anal. Calcd for
dried (MgSO4), and concentrated in vacuo. The residue was dissolved in C20H18N2O2: C, 75.45; H, 5.70; N, 8.80. Found: C, 75.21; H, 5.94; N, 8.58.
MeOH (75 ml). To this solution was added c.H2SO4 (0.75 ml) and the mix-
ture was refluxed for 5 h. After the removal of solvent, saturated aqueous dione (1e) Yield: 66%. mp 181—183 °C. H-NMR (CDCl3) d: 3.69 (3H,
NaHCO3 was added and the mixture was extracted with AcOEt. The organic s), 6.36 (2H, d, Jꢂ8.8 Hz), 6.80 (2H, d, Jꢂ8.8 Hz), 6.88 (2H, m), 6.90 (2H,
(3E,4E)-3-Benzylidene-4-(4-methoxybenzylidene)-pyrrolidine-2,5-
1
layer was washed with brine, dried (MgSO4), and concentrated in vacuo.
s), 7.13 (1H, m), 7.76 (1H, s), 7.77 (1H, s), 8.40 (1H, bs). IR (KBr) cmꢀ1
:
The residue was chromatographed on silica gel. Elution with hexane/AcOEt 3170, 1760, 1705, 1620. MS m/z: 305 (Mꢁ). Anal. Calcd for C19H15NO3: C,
1
(4 : 1) gave 13a (23.2 g, 66%) as an oil. H-NMR (CDCl3) d: 3.55 (2H, s),
74.74; H, 4.95; N, 4.59. Found: C, 74.73; H, 5.02; N, 4.59.
3.74 (3H, s), 3.83 (3H, s), 7.30—7.45 (5H, m), 7.91 (1H, s). IR (film) cmꢀ1
:
(3E,4E)-3-Benzylidene-4-(3,4-dimethoxybenzylidene)-pyrrolidine-2,5-
3150, 1750, 1720. MS m/z: 234 (Mꢁ). HR-MS Calcd for C13H14O4 (Mꢁ): dione (1f) Yield: 86%. mp 162—163 °C. H-NMR (CDCl3) d: 3.56 (3H,
1
234.0892. Found: 234.0904.
s), 3.80 (3H, s), 6.41 (2H, m), 6.57 (1H, dd, Jꢂ8.4, 1.6 Hz), 6.94 (4H, m),
Dimethyl (E)-2-(3,4,5-Trimethoxybenzylidene)-succinate (13b) This 7.13 (1H, m), 7.75 (1H, s), 7.77 (1H, s), 8.68 (1H, bs). IR (KBr) cmꢀ1: 3160,
compound was prepared in 68% yield from 3,4,5-trimethoxybenzaldehyde 1760, 1705, 1620. MS m/z: 335 (Mꢁ). Anal. Calcd for C20H17NO4: C, 71.63;
1
by a method similar to that described for 13a. H-NMR (CDCl3) d: 3.58 H, 5.11; N, 4.18. Found: C, 71.52; H, 5.22; N, 4.11.
(2H, s), 3.74 (3H, s), 3.75 (6H, s), 3.82 (3H, s), 3.83 (3H, s), 6.87 (2H, s),
7.87 (1H, s). IR (film) cmꢀ1: 3050, 1750, 1720. MS m/z: 324 (Mꢁ). HR-MS
Calcd for C16H20O7 (Mꢁ): 324.1209. Found: 324.3197.
(3E,4E)-3-Benzylidene-4-(3,4,5-trimethoxybenzylidene)-pyrrolidine-
1
2,5-dione (1g) Yield: 70%. mp 158—159 °C. H-NMR (CDCl3) d: 3.57
(6H, s), 3.72 (3H, s), 6.18 (2H, s), 6.90 (1H, s), 6.95 (2H, s), 7.00—7.30
Methyl Hydrogen (2E,3E)-2,3-Dibenzylidenesuccinate (14a) A solu- (2H, m), 7.71 (1H, s), 7.77 (1H, s), 9.22 (1H, bs). IR (KBr) cmꢀ1: 3150,
tion of 13a (23.2 g, 99 mmol) and benzaldehyde (10.6 g, 99 mmol) in THF
(40 ml) was added to a solution of potassium tert-butoxide (11.1 g, 99 mmol) 69.03; H, 5.24; N, 3.83. Found: C, 68.98; H, 5.22; N, 3.88.
3050, 1760, 1710, 1620. MS m/z: 365 (Mꢁ). Anal. Calcd for C21H19NO5: C,
in tert-BuOH (100 ml) below 50 °C and the mixture was stirred at room tem-
(3E,4E)-3-(3-Nitrobenzylidene)-4-(3,4,5-trimethoxybenzylidene)-
perature for 30 min. The reaction mixture was poured into ice-water and the pyrrolidine-2,5-dione (1h) Yield: 46%. mp 239—242 °C. 1H-NMR
aqueous layer was washed with i-Pr2O and acidified with c.HCl. The organic (DMSO-d6) d: 3.49 (6H, s), 3.53 (3H, s), 6.26 (2H, s), 7.40 (2H, m), 7.63
layer was extracted with AcOEt and washed with brine, dried (MgSO4), and
(1H, s), 7.66 (1H, s), 7.76 (1H, d, Jꢂ7.8 Hz), 8.01 (1H, d, Jꢂ8.3 Hz), 11.81
concentrated in vacuo. The residue was chromatographed on silica gel. Elu- (1H, bs). IR (KBr) cmꢀ1: 3165, 1760, 1710, 1625. MS m/z: 410 (Mꢁ). Anal.
tion with hexane/AcOEt (4 : 1) gave 14a (19.9 g, 65%). mp 148—149 °C. Calcd for C21H18N2O7: C, 61.46; H, 4.42; N, 6.83. Found: C, 61.30; H, 4.42;
1H-NMR (CDCl3) d: 3.66 (3H, s), 7.25—7.35 (6H, m), 7.40—7.50 (4H, m), N, 6.55.
7.85 (1H, s), 7.90 (1H, s). IR (KBr) cmꢀ1: 1730, 1680, 1595, 1510. MS m/z:
(3E,4E)-3-(4-Chlorobenzylidene)-4-(3,4,5-trimethoxybenzylidene)-
308 (Mꢁ). Anal. Calcd for C19H16O4: C, 74.01; H, 5.23. Found: C, 73.87; H, pyrrolidine-2,5-dione (1i) Yield: 65%. mp 148—150 °C. 1H-NMR
5.05.
(CDCl3) d: 3.62 (6H, s), 3.80 (3H, s), 6.25 (2H, s), 6.91 (2H, d, Jꢂ8.8 Hz),
Methyl Hydrogen (2E,3E)-2-Benzylidene-3-(3,4,5-trimethoxybenzyli- 6.97 (2H, d, Jꢂ8.8 Hz), 7.69 (1H, s), 7.73 (1H, s), 8.77 (1H, bs). IR (KBr)
dene)-succinate (14b) This compound was prepared in 78% yield from cmꢀ1: 3165, 1760, 1710, 1620. MS m/z: 401, 399 (Mꢁ). Anal. Calcd for
13a and 3,4,5-trimethoxybenzaldehyde by a method similar to that described C21H18ClNO5: C, 63.08; H, 4.54; Cl, 8.87; N, 3.50. Found: C, 62.87; H,
1
for 14a. mp 157—158 °C. H-NMR (CDCl3) d: 3.64 (9H, s), 3.73 (3H, s),
4.47; Cl, 8.59; N, 3.43.
(3E,4E)-3-(4-Dimethylaminobenzylidene)-4-(3,4,5-trimethoxybenzyli-
6.58 (2H, s), 7.10—7.40 (5H, m), 7.68 (1H, s), 7.82 (1H, s). IR (KBr) cmꢀ1
:
1725, 1675, 1590, 1510. MS m/z: 398 (Mꢁ). Anal. Calcd for C22H22O7: C, dene)-pyrrolidine-2,5-dione (1j) Yield: 75%. mp 199—202 °C. H-NMR
1
66.32; H, 5.57. Found: C, 66.16; H, 5.46.
Methyl Hydrogen (2E,3E)-3-Benzylidene-2-(3,4,5-trimethoxybenzyli- s), 6.81 (2H, d, Jꢂ8.8 Hz), 7.46 (1H, s), 7.50 (1H, s), 11.42 (1H, bs). IR
dene)-succinate (14c) This compound was prepared in 76% yield from
13b by a method similar to that described for 14a. mp 131—133 °C. H-
(DMSO-d6) d: 2.86 (6H, s), 3.50 (9H, s), 6.24 (2H, d, Jꢂ8.8 Hz), 6.36 (2H,
(KBr) cmꢀ1: 3155, 1745, 1695, 1580. MS m/z: 408 (Mꢁ). Anal. Calcd for
C23H24N2O5: C, 67.63; H, 5.92; N, 6.86. Found: C, 67.55; H, 6.04; N, 6.76.
(3E,4E)-3-(4-Methoxybenzylidene)-4-(3,4,5-trimethoxybenzylidene)-
1
NMR (CDCl3) d: 3.64 (3H, s), 3.66 (6H, s), 3.75 (3H, s), 6.56 (2H, s),
7.10—7.40 (5H, m), 7.66 (1H, s), 7.84 (1H, s). IR (KBr) cmꢀ1: 1715, 1665, pyrrolidine-2,5-dione (1k) Yield: 87%. mp 185—186 °C. 1H-NMR
1590, 1510. MS m/z: 398 (Mꢁ). Anal. Calcd for C22H22O7: C, 66.32; H, (CDCl3) d: 3.59 (6H, s), 3.72 (3H, s), 3.74 (3H, s), 6.23 (2H, s), 6.48 (2H, d,
5.57. Found: C, 66.18; H, 5.47.
Jꢂ8.8 Hz), 6.90 (2H, d, Jꢂ8.8 Hz), 7.68 (1H, s), 7.73 (1H, s), 8.34 (1H, bs).
IR (KBr) cmꢀ1: 3160, 1755, 1705, 1600. MS m/z: 395 (Mꢁ). Anal. Calcd for
C22H21NO6: C, 66.83; H, 5.35; N, 3.54. Found: C, 66.88; H, 5.18; N, 3.46.
(3E,4E)-3,4-Dibenzylidenepyrrolidine-2,5-dione (1a) To a solution of
14a (8.1 g, 26 mmol) in CHCl3 (40 ml) were added SOCl2 (1.9 ml, 26 mmol)
and DMF (2 drops) below 10 °C and the mixture was refluxed for 30 min.
(3E,4E)-3-(3,4-Dimethoxybenzylidene)-4-(3,4,5-trimethoxybenzyli-
1
This solutuon was added to 28% aqueous NH3 (10 ml) and the mixture was dene)-pyrrolidine-2,5-dione (1l) Yield: 74%. mp 185—189 °C. H-NMR
stirred at room temperature for 1 h. To this solution, 2 N HCl was added to
pH 7 and the mixture was extracted with CHCl3 and dried (MgSO4), and
(CDCl3) d: 3.59 (3H, s), 3.61 (6H, s), 3.75 (3H, s), 3.81 (3H, s), 6.30 (2H,
s), 6.47 (1H, d, Jꢂ1.8 Hz), 6.57 (1H, d, Jꢂ8.4 Hz), 6.73 (1H, dd, Jꢂ1.8,
8.4 Hz), 7.68 (1H, s), 7.72 (1H, s), 8.71 (1H, bs). IR (KBr) cmꢀ1: 3200,
concentrated in vacuo. The residue was crystalized in AcOEt to give 1a
1
(4.4 g, 79%). mp 205—207 °C. H-NMR (CDCl3) d: 6.79—6.90 (8H, m), 1765, 1715, 1600. MS m/z: 425 (Mꢁ). Anal. Calcd for C23H23NO7: C, 64.93;
7.08—7.12 (2H, m), 7.81 (2H, s), 8.79 (1H, bs). IR (KBr) cmꢀ1: 3150, 3185, H, 5.45; N, 3.29. Found: C, 64.76; H, 5.51; N, 3.17.
1760, 1710, 1620. MS m/z: 275 (Mꢁ). Anal. Calcd for C18H13NO2: C, 78.53;
H, 4.76; N, 5.09. Found: C, 78.23; H, 4.82; N, 5.02.
(3E,4E)-2,3-Bis-(3,4,5-trimethoxybenzylidene)-pyrrolidine-2,5-dione
1
(1m) Yield: 77%. mp 186—187 °C. H-NMR (CDCl3) d: 3.64 (12H, s),
The following compounds (1b—r) were prepared from the corresponding
3.77 (6H, s), 6.29 (4H, s), 7.68 (2H, s), 8.49 (1H, bs). IR (KBr) cmꢀ1: 3180,
half-ester (14a—c) or diester (13a, b) by a method similar to that described 1755, 1710, 1580. MS m/z: 455 (Mꢁ). Anal. Calcd for C24H25NO8: C, 63.29;

December 2006
1691
1670, 1610, 1590. MS m/z: 427 (Mꢁ). Anal. Calcd for C23H25NO7: C, 64.63;
H, 5.89; N, 3.32. Found: C, 64.48; H, 5.75; N, 3.19.
H, 5.53; N, 3.08. Found: C, 62.57; H, 5.83; N, 2.86.
(3E,4E)-3-Benzylidene-1-methyl-4-(3,4,5-trimethoxybenzylidene)-
pyrrolidine-2,5-dione (1n) Yield: 79%. mp 131—133 °C. 1H-NMR
(CDCl3) d: 3.25 (3H, s), 3.58 (6H, s), 3.73 (3H, s), 6.19 (2H, s), 6.93 (2H,
Methyl (2E,3E)-3-Carbamoyl-4-(3,4-dimethoxyphenyl)-2-(3,4,5-tri-
methoxybenzylidene)-but-3-enoate (2f) Yield: 49%, mp 148—149 °C.
1H-NMR (CDCl3) d: 3.71 (3H, s), 3.79 (6H, s), 3.86 (3H, s), 3.87 (3H, s),
5.43 (1H, br), 5.81 (1H, br), 6.81 (1H, d, Jꢂ8.9 Hz), 6.92 (2H, s), 7.09—
7.13 (2H, m), 7.92 (2H, s). IR (KBr) cmꢀ1: 3450, 3300,1720, 1690, 1605,
1585. MS m/z: 457 (Mꢁ). Anal. Calcd for C24H27NO8: C, 63.01; H, 5.95; N,
3.06. Found: C, 62.78; H, 5.79; N, 2.87.
Methyl (2E,3E)-3-Methylcarbamoyl-4-phenyl-2-(3,4,5-trimethoxyben-
zylidene)-but-3-enoate (2g) Yield: 87%, mp 155—157 °C. 1H-NMR
(CDCl3) d: 2.89 (3H, d, Jꢂ4.8 Hz), 3.65 (3H, s), 3.77 (6H, s), 3.85 (3H, s),
5.97 (1H, m), 6.87 (2H, s), 7.20—7.50 (5H, m), 7.88 (1H, s), 7.94 (1H, s).
IR (KBr) cmꢀ1: 3400, 1715, 1665, 1600. MS m/z: 411 (Mꢁ). Anal. Calcd for
C23H25NO6: C, 67.14; H, 6.12; N, 3.40. Found: C, 67.19; H, 6.24; N, 3.31.
Methyl (2E,3E)-3-Benzylcarbamoyl-4-phenyl-2-(3,4,5-trimethoxyben-
zylidene)-but-3-enoate (2h) Yield: 88%, mp 130—132 °C. 1H-NMR
(CDCl3) d: 3.61 (3H, s), 3.74 (6H, s), 3.88 (3H, s), 4.24 (1H, dd, Jꢂ6.8,
5.7 Hz), 4.61 (1H, dd, Jꢂ6.8, 5.7 Hz), 6.21 (1H, d, Jꢂ5.7 Hz), 6.86 (1H, s),
6.85 (2H, m), 7.14—7.47 (2H, m), 7.89 (1H, s), 8.03 (1H, s). IR (KBr)
cmꢀ1: 3450, 3400, 1715, 1665, 1605, 1585. MS m/z: 487 (Mꢁ). Anal. Calcd
for C29H29NO6: C, 71.44; H, 6.00; N, 2.87. Found: C, 71.30; H, 5.94; N,
2.67.
s), 6.96 (2H, s), 7.16 (1H, m), 7.72 (1H, s), 7.77 (1H, s). IR (KBr) cmꢀ1
:
1750, 1700, 1615. MS m/z: 379 (Mꢁ). Anal. Calcd for C22H21NO5: C, 69.64;
H, 5.58; N, 3.69. Found: C, 69.36; H, 5.43; N, 3.57.
(3E,4E)-1-Benzyl-3-benzylidene-4-(3,4,5-trimethoxybenzylidene)-
pyrrolidine-2,5-dione (1o) Yield: 80%. mp 132—134 °C. 1H-NMR
(CDCl3) d: 3.57 (6H, s), 3.72 (3H, s), 4.92 (2H, s), 6.17 (2H, s), 6.91 (2H,
s), 6.94 (2H, s), 7.16 (1H, m), 7.30—7.40 (3H, m), 7.52 (2H, m), 7.71 (1H,
s), 7.76 (1H, s). IR (KBr) cmꢀ1: 1765, 1705, 1625. MS m/z: 455 (Mꢁ). Anal.
Calcd for C28H25NO5: C, 73.83; H, 5.53; N, 3.08. Found: C, 73.68; H, 5.35;
N, 2.85.
(3E,4E)-3-Benzylidene-1-(2-hydroxyethyl)-4-(3,4,5-trimethoxybenzyli-
dene)-pyrrolidine-2,5-dione (1p) Yield: 73%. mp 103—105 °C. 1H-NMR
(CDCl3) d: 2.73 (1H, m), 3.57 (6H, s), 3.73 (3H, s), 3.85—4.05 (4H, m),
6.18 (2H, s), 6.91 (1H, s), 6.95 (2H, s), 6.95—7.25 (2H, m), 7.72 (1H, s),
7.77 (1H, s). IR (KBr) cmꢀ1: 3500, 1755, 1700, 1620. MS m/z: 409 (Mꢁ).
Anal. Calcd for C23H23NO6: C, 67.47; H, 5.66; N, 3.42. Found: C, 67.72; H,
5.87; N, 3.30.
(3E,4E)-1-Amino-3-benzylidene-4-(3,4,5-trimethoxybenzylidene)-
pyrrolidine-2,5-dione Hydrochloride (1q) Yield: 85%. mp 108—114 °C.
1H-NMR (CDCl3) d: 3.58 (6H, s), 3.73 (3H, s), 6.19 (2H, s), 6.93 (2H, s),
6.95 (2H, s), 7.19 (1H, m), 7.29 (2H, s), 7.72 (1H, s), 7.77 (1H, s). IR (KBr)
cmꢀ1: 3300, 1765, 1700, 1620. MS m/z: 380 (Mꢁ). Anal. Calcd for
C21H20N2O5·HCl: C, 60.51; H, 5.08; Cl, 8.50; N, 6.72. Found: C, 60.71; H,
5.36; Cl, 8.25; N, 6.34.
(3E,4E)-3-Benzylidene-1-methoxy-4-(3,4,5-trimethoxybenzylidene)-
pyrrolidine-2,5-dione (1r) Yield: 70%. mp 131—133 °C. 1H-NMR
(CDCl3) d: 3.59 (6H, s), 3.73 (3H, s), 4.13 (3H, s), 6.19 (2H, s), 6.95 (4H, d,
Jꢂ4.4 Hz), 7.18 (1H, m), 7.73 (1H, s), 7.78 (1H, s). IR (KBr) cmꢀ1: 1765,
1715, 1620. MS m/z: 395 (Mꢁ). Anal. Calcd for C22H21NO6: C, 66.83; H,
5.35; N, 3.54. Found: C, 67.79; H, 5.32; N, 3.45.
Methyl (2E,3E)-2-Benzylidene-3-carbamoyl-4-phenylbut-3-enoate
(2a) To a solution of 14a (4.0 g, 13 mmol) in CHCl3 (50 ml) were added
SOCl2 (1.0 ml, 13 mmol) and DMF (2 drops) below 10 °C and the mixture
was refluxed for 30 min. This solutuon was added dropwise to 28% aqueous
NH3 (0.8 ml, 13 mmol) below 0 °C and the mixture was stirred at same tem-
perature for 30 min. The organic layer was extracted with CHCl3 and dried
(MgSO4), and concentrated in vacuo. The residue was crystalized in i-Pr2O
to give 2a (3.7 g, 90%). mp 148—149 °C. 1H-NMR (CDCl3) d: 3.66 (3H, s),
5.61 (1H, m), 5.86 (1H, m), 7.25—7.35 (6H, m), 7.40—7.45 (2H, m),
7.55—7.60 (2H, m), 7.95 (1H, s), 8.00 (1H, s). IR (KBr) cmꢀ1: 3430, 1710,
1680, 1595, 1500. MS m/z: 307 (Mꢁ). Anal. Calcd for C19H17NO3: C, 74.25;
H, 5.57; N, 4.56. Found: C, 74.34; H, 5.67; N, 4.51.
The following compounds (2b—k) were prepared from the corresponding
half-ester (14a—c) or diester (13a, b) by a method similar to that described
for 2a.
Methyl (2E,3E)-3-Carbamoyl-4-phenyl-2-(3,4,5-trimethoxybenzyli-
dene)-but-3-enoate (2b) Yield: 95%. mp 179—180 °C. 1H-NMR (CDCl3)
d: 3.66 (3H, s), 3.75 (6H, s), 3.83 (3H, s), 5.82 (2H, m), 6.87 (2H, s), 7.20—
7.50 (5H, m), 7.88 (1H, s), 7.92 (1H, s). IR (KBr) cmꢀ1: 3400, 3200, 1725,
1675, 1590. MS m/z: 365 (Mꢁ). Anal. Calcd for C22H23NO6: C, 66.49; H,
5.83; N, 3.52. Found: C, 66.42; H, 5.78; N, 3.34.
Methyl (2E,3E)-3-(2-Hydroxyethylcarbamoyl)-4-phenyl-2-(3,4,5-tri-
methoxybenzylidene)-but-3-enoate (2i) Yield: 81%, mp 110—111 °C.
1H-NMR (CDCl3) d: 2.19 (1H, bs), 3.23—3.76 (4H, m), 3.62 (3H, s), 3.77
(6H, s), 3.84 (3H, s), 6.40 (1H, m), 6.85 (2H, s), 7.23—7.48 (5H, m), 7.88
(1H, s), 7.93 (1H, s). IR (KBr) cmꢀ1: 3600, 3400, 1700, 1660. MS m/z: 441
(Mꢁ). Anal. Calcd for C24H27NO7: C, 65.29; H, 6.16; N, 3.17. Found: C,
65.24; H, 6.06; N, 3.01.
Methyl (2E,3E)-3-Hydrazinocarbonyl-4-phenyl-2-(3,4,5-trimethoxy-
benzylidene)-but-3-enoate (2j) Yield: 64%, mp 174—175 °C. 1H-NMR
(CDCl3) d: 3.65 (3H, s), 3.75 (6H, s), 3.83 (3H, s), 3.65—4.04 (2H, m), 6.83
(2H, s), 7.12—7.48 (6H, m), 7.87 (1H, s), 7.93 (1H, s). IR (KBr) cmꢀ1
:
3350, 3300, 1710, 1660. MS m/z: 412 (Mꢁ). Anal. Calcd for C22H24N2O6: C,
64.07; H, 5.86; N, 6.79. Found: C, 64.21; H, 6.05; N, 6.64.
Methyl (2E,3E)-3-Methoxycarbamoyl-4-phenyl-2-(3,4,5-trimethoxy-
1
benzylidene)-but-3-enoate (2k) Yield: 51%, mp 148—150 °C. H-NMR
(CDCl3) d: 3.60 (3H, s), 3.65 (3H, s), 3.77 (6H, s), 3.83 (3H, s), 6.84 (2H,
s), 7.21—7.50 (5H, m), 7.82 (1H, s), 7.88 (1H, s), 8.63 (1H, bs). IR (KBr)
cmꢀ1: 3200, 1710, 1660. MS m/z: 427 (Mꢁ). Anal. Calcd for C23H25NO7: C,
64.63; H, 5.89; N, 3.28. Found: C, 64.69; H, 5.87; N, 3.04.
(3E,4E)-3-Benzylidene-4-(3,4,5-trimethoxybenzylidene)-dihydro-
furan-2,5-dione (3) To a solution of 14b (7.3 g, 18 mmol) in toluene
(50 ml) were added SOCl2 (1.3 ml, 18 mmol) and DMF (1 drop) and the
mixture was stirred at 80 °C for 30 min. To this solutuon, SnCl4 (2.7 ml,
23 mmol) was added below 10 °C and the mixture was stirred at room tem-
perature for 16 h. The reaction mixture was poured into ice-water and the or-
ganic layer was extracted with AcOEt and washed with 1 N NaOH and brine,
dried (MgSO4), and concentrated in vacuo. The residue was crystalized in
1
Et2O to give 3 (4.8 g, 72%). mp 201—203 °C. H-NMR (CDCl3) d: 3.95
(3H, s), 4.00 (3H, s), 4.10 (3H, s), 6.52 (1H, s), 7.09 (1H, s), 7.35 (5H, s),
7.84 (1H, s), 9.70 (1H, s). IR (KBr) cmꢀ1: 1800, 1745. MS m/z: 366 (Mꢁ).
Anal. Calcd for C21H18O6: C, 68.85; H, 4.95. Found: C, 68.76; H, 4.86.
(3E,4E)-3-Benzylidene-4-(3,4,5-trimethoxybenzylidene)-dihydro-
furan-2-one (4a) To a solution of 14b (5.0 g, 13 mmol) in CH2Cl2 (50 ml)
was added 1.5 M diisobutylaluminum hydride in toluene (25 ml, 38 mmol)
under nitrogen below 10 °C and the mixture was stirred at room temperature
for 1 h. To this solution, 10% aqueous HCl was added carefully until pH 1
below 10 °C and the mixture was stirred at 50 °C for 1 h. The organic layer
was extracted with CHCl3 and dried (MgSO4), and concentrated in vacuo.
The residue was chromatographed on silica gel (hexane : AcOEtꢂ2 : 1) to
Methyl (2E,3E)-2-Benzylidene-3-carbamoyl-4-(3,4,5-trimethoxy-
phenyl)-but-3-enoate (2c) Yield: 73%. mp 121—122 °C. 1H-NMR
(CDCl3) d: 3.70 (3H, s), 3.73 (6H, s), 3.80 (3H, s), 5.94 (2H, bs), 6.70 (2H,
s), 7.25—7.40 (3H, m), 7.50—7.65 (2H, m), 7.81 (1H, s), 7.96 (1H, s). IR
(KBr) cmꢀ1: 3470, 3310,1700, 1655, 1630, 1580. MS m/z: 365 (Mꢁ). Anal.
Calcd for C22H23NO6: C, 66.49; H, 5.83; N, 3.52. Found: C, 66.57; H, 5.82;
N, 3.44.
1
Methyl (2E,3E)-3-Carbamoyl-4-(4-dimethylaminophenyl)-2-(3,4,5-
trimethoxybenzylidene)-but-3-enoate (2d) Yield: 90%, mp 171—
give 4a (2.3 g, 53%); mp 145—146 °C. H-NMR (CDCl3) d: 3.49 (6H, s),
3.60 (3H, s), 4.92 (1H, d, Jꢂ2.0 Hz), 5.94 (2H, s), 6.47 (1H, s), 6.70—7.10
(5H, m), 7.54 (1H, s). IR (KBr) cmꢀ1: 1770, 1755, 1620, 1585, 1505. MS
m/z: 352 (Mꢁ). Anal. Calcd for C21H20O5: C, 71.58; H, 5.72. Found: C,
71.73; H, 5.64.
1
172 °C. H-NMR (CDCl3) d: 2.96 (6H, s), 3.70 (3H, s), 3.75 (6H, s), 3.82
(3H, s), 5.66 (2H, br), 6.58 (2H, d, Jꢂ8.8 Hz), 6.93 (2H, s), 7.41 (1H, d,
Jꢂ8.8 Hz), 7.90 (2H, s). R (KBr) cmꢀ1: 3350, 3200, 1710, 1670, 1610. MS
m/z: 440 (Mꢁ). Anal. Calcd for C24H28N2O6: C, 65.44; H, 6.41; N, 6.36.
Found: C, 65.31; H, 6.39; N, 36.30.
(3E,4E)-4-Benzylidene-3-(3,4,5-trimethoxybenzylidene)-dihydro-
furan-2-one (4b) This compound was prepared in 78% yield from 14c by
a method similar to that described for 4a. mp 140—142 °C. 1H-NMR
(CDCl3) d: 3.58 (6H, s), 3.73 (3H, s), 5.03 (2H, d, Jꢂ2.0 Hz), 6.24 (2H, s),
6.64 (1H, s), 6.70—7.15 (5H, m), 7.62 (1H, s). IR (KBr) cmꢀ1: 1750, 1585.
MS m/z: 352 (Mꢁ). Anal. Calcd for C21H20NO5: C, 71.58; H, 5.72. Found: C,
71.74; H, 5.61.
Methyl (2E,3E)-3-Carbamoyl-4-(4-methoxyphenyl)-2-(3,4,5-trimetho-
xybenzylidene)-but-3-enoate (2e) Yield: 88%, mp 169—170 °C. 1H-
NMR (CDCl3) d: 3.70 (3H, s), 3.78 (6H, s), 3.79 (3H, s), 3.85 (3H, s), 5.39
(1H, br), 5.80 (1H, br), 6.83 (2H, d, Jꢂ8.8 Hz), 6.91 (2H, s), 7.45 (2H, d,
Jꢂ8.9 Hz), 7.91 (1H, s), 7.94 (1H, s). IR (KBr) cmꢀ1: 3440, 3200, 1705,

1692
Methyl (2E,3E)-3-Cyano-4-phenyl-2-(3,4,5-trimethoxybenzylidene)-
Vol. 54, No. 12
1
8 : 1) to give 20 (7.4 g, 86 %) as an oil. H-NMR (CDCl3) d: 0.76—0.89
(15H, m), 1.16—1.42 (12H, m), 3.78 (3H, s), 3.86 (3H, s), 3.87 (6H, s), 6.51
(2H, s), 8.30 (1H, s). IR (film) cmꢀ1: 2955, 1710, 1575, 1505, 1235. MS (SI-
MS) m/z: 542 (Mꢁꢁ1).
Methyl (E)-2-Bromo-3-(3,4,5-trimethoxyphenyl)-acrylate (21) To a
stirred solution of 19 (5.0 g, 9.8 mmol) in dry CH2Cl2 (70 ml) was added
dropwise bromine (0.51 ml, 9.8 mmol) in dry CH2Cl2 (100 ml) over 3.5 h
under nitrogen below 10 °C. Solvent was removed in vacuo. Ether and aque-
ous KF were added to the residue and the mixture was stirred for 1 h. The in-
soluble material was filtered off and the filtrate was extracted with ether. The
organic layer was washed with brine, dried (MgSO4), and concentrated in
vacuo. The residue was chromatographed on silica gel (hexane : AcOEtꢂ
but-3-enoate (15a) A solution of 2b (4.0 g, 10 mmol) in THF (15 ml) was
added to a solution of PPh3 (5.2 g, 20 mmol) in CCl4 (15 ml) and the mixture
was stirreded at 50 °C for 3 h. The resulting precipitate was filtered off, and
the filtrate was concentrated in vacuo. The residue was chromatographed on
silica gel (hexane : AcOEtꢂ2 : 1) to give 15a (3.1 g, 82%); mp 104—106 °C.
1H-NMR (CDCl3) d: 3.72 (3H, s), 3.81 (6H, s), 3.87 (3H, s), 6.83 (2H, s),
7.28—7.39 (5H, m), 7.45 (1H, s), 7.86 (1H, s). IR (KBr) cmꢀ1: 2230, 1720,
1630, 1605, 1590. MS m/z: 379 (Mꢁ). Anal. Calcd for C22H21NO5: C, 69.64;
H, 5.58; N, 3.69. Found: C, 69.82; H, 5.60; N, 3.70.
Methyl (2E,3E)-2-Benzylidene-3-cyano-4-(3,4,5-trimethoxyphenyl)-
but-3-enoate (15b) This compound was prepared in 85% yield from 2c by
a method similar to that described for 15a. mp 112—114 °C. 1H-NMR
(CDCl3) d: 3.73 (3H, s), 3.75 (6H, s), 3.85 (3H, s), 6.64 (2H, s), 7.33 (1H,
1
2 : 1) to give 21 (3.1 g, 94%) as an oil. H-NMR (CDCl3) d: 3.79 (3H, s),
3.84 (6H, s), 3.86 (3H, s), 6.57 (2H, s), 7.26 (1H, s). IR (film) cmꢀ1: 2945,
1730, 1580, 1505, 1220. MS m/z: 332, 330 (Mꢁ). HR-MS Calcd for
C13H15BrO2 (Mꢁ): 330.0102. Found: 330.0115.
s), 7.38—7.43 (3H, m), 7.55—7.60 (2H, m), 7.94 (1H, s). IR (KBr) cmꢀ1
:
2240, 1725, 1620, 1600. MS m/z: 379 (Mꢁ). Anal. Calcd for C22H21NO5: C,
69.64; H, 5.58; N, 3.69. Found: C, 69.44; H, 5.32; N, 3.85.
Methyl (Z)- 2-Bromo-3-(3,4,5-trimethoxyphenyl)-acrylate (22) This
compound was prepared in 85% yield from 20 by a method similar to that
described for 21. mp 65—66 °C. 1H-NMR (CDCl3) d: 3.90 (6H, s), 3.91
(6H, s), 7.19 (2H, s), 8.16 (1H, s). IR (KBr) cmꢀ1: 2945, 1720, 1580, 1505,
1235. MS m/z: 332, 330 (Mꢁ). Anal. Calcd for C13H15BrO2: C, 47.15; H,
4.57. Found: C, 47.05; H, 4.67.
(3E,4E)-4-Benzylidene-3-(3,4,5-trimethoxybenzylidene)-pyrrolidin-2-
one (5a) A mixture of 15a (5.7 g, 15 mmol) and Raney Ni (10 ml) in
MeOH (250 ml) was stirred under hydrogen atmosphere (1 atm) at room
temperature for 2 h. After removal of the catalyst by filtration, the filtrate
was refluxed for 1 h and concentrated in vacuo. The residue was chro-
matographed on silica gel (CHCl3 : acetoneꢂ5 : 1) to give 5a (3.6 g, 65%);
mp 125—127 °C. 1H-NMR (CDCl3) d: 3.61 (6H, s), 3.72 (3H, s), 4.30 (2H,
s), 6.27 (2H, s), 6.63 (1H, s), 6.63—7.05 (5H, m), 7.09 (1H, bs), 7.47 (1H,
s). IR (KBr) cmꢀ1: 3200, 1695, 1630, 1605, 1580. MS m/z: 351 (Mꢁ). Anal.
Calcd for C21H21NO5: C, 71.78; H, 6.02; N, 3.99. Found: C, 71.92; H, 6.05;
N, 4.02.
(3E,4E)-3-Benzylidene-4-(3,4,5-trimethoxybenzylidene)-pyrrolidin-2-
one (5b) This compound was prepared in 69% yield from 15b by a
method similar to that described for 5a. mp 125—127 °C. 1H-NMR (CDCl3)
d: 3.59 (6H, s), 3.67 (3H, s), 4.28 (2H, s), 6.12 (2H, s), 6.58 (1H, s), 6.87—
7.13 (6H, m), 7.54 (1H, s). IR (KBr) cmꢀ1: 3460, 1700, 1685, 1615, 1585.
MS m/z: 351 (Mꢁ). Anal. Calcd for C21H21NO5: C, 71.78; H, 6.02; N, 3.99.
Found: C, 71.87; H, 6.07; N, 3.94.
3-Phenylpropiolamide (24) To a solution of phenylacetylene (5.0 g,
49 mmol) in dry THF (100 ml) was added n-butyllithium (1.6 M in hexane)
(34 ml, 54 mmol) below ꢀ50 °C under nitrogen and the mixture was stirred
at ꢀ78 °C for 30 min. Then CO2 gas was bubbled below 0 °C for 30 min.
The reaction mixture was acidified to pH 1 with 10% aqueous HCl and ex-
tracted with CHCl3. The organic layer was washed with brine, dried
(MgSO4), and concentrated in vacuo. The residue was dissolved in CHCl3
(50 ml). To this solution was added SOCl2 (4.3 ml, 59 mmol) and DMF (2
drops) and the mixture was stirred at room temperature for 1 h. This solution
was added to 28% aqueous NH3 (20 ml) below 10 °C and the mixture was
stirred at room temperature for 30 min. The organic layer was extracted with
CHCl3 and dried (MgSO4), and concentrated in vacuo. The residue was
chromatographed on silica gel (CHCl3 : MeOHꢂ20 : 1) to give 24 (2.5 g,
35%); mp 102—104 °C. 1H-NMR (CDCl3) d: 5.89 (2H, br), 7.30—7.42
(3H, m), 7.52—7.58 (2H, m). IR (KBr) cmꢀ1: 3385, 3190, 2225, 1640,
1490. MS m/z: 145 (Mꢁ). Anal. Calcd for C9H7NO: C, 74.47; H, 4.86; N,
9.65. Found: C, 74.35; H, 4.81; N, 9.44.
1,1-Dibromo-2-(3,4,5-trimethoxyphenyl)-ethylene (17) A mixture of
CBr4 (67.6 g, 0.20 mol) and PPh3 (106.9 g, 0.40 mol) in CH2Cl2 (400 ml) was
stirred under nitrogen at room temperature for 1 h. To this mixture was
added 3,4,5-trimethoxybenzaldehyde (20 g, 0.10 mol) at 0 °C and the mix-
ture was stirred for 16 h at room temperature. The resulting precipitate was
filtered off and the filtrate was concentrated in vacuo. The residue was chro-
matographed on silica gel (hexane : AcOEtꢂ5 : 1) to give 17 (35.5 g, 99%)
(E)-3-Phenyl-2-(tributylstannyl)acrylamide (25) This compound was
prepared in 38% yield from 24 by a method similar to that described for 19
as an oil. H-NMR (CDCl3) d: 0.91 ( 9H, t, Jꢂ7.2 Hz), 1.09 (6H, m), 1.36
(6H, m), 1.60 (6H, m), 5.19 (2H, br), 6.66 (1H, s), 7.25—7.45 (m, 5H). IR
1
1
as an oil. H-NMR (CDCl3) d: 3.87 (9H, s), 6.80 (2H, s), 7.41 (1H, s). IR
(film) cmꢀ1: 3490, 3300, 1650, 1600. MS m/z: 436 (Mꢁ).
(film) cmꢀ1: 2940, 1580, 1505, 1240. MS m/z: 354, 352, 350 (Mꢁ). HR-MS
Calcd for C11H12Br2O3 (Mꢁ): 349.9152. Found: 349.9164.
(Z)-3-Phenyl-2-(tributylstannyl)acrylamide (26) This compound was
prepared in 52% yield from 24 by a method similar to that described for 20.
mp 59—60 °C. H-NMR (CDCl3) d: 0.83 (9H, t, Jꢂ7.2 Hz), 0.87 (6H, m),
1.24 (6H, m), 1.40 (6H, m), 5.48 (2H, br), 7.79 (1H, s), 7.25 (m, 2H), 7.34
(m, 3H), 7.79 (1H, s). IR (KBr) cmꢀ1: 3400, 3200, 1630, 1600. MS m/z: 436
(Mꢁ). Anal. Calcd for C21H35NOSn: C, 57.82; H, 8.09; N, 3.21. Found: C,
57.39; H, 8.13; N, 3.28.
Methyl 3-(3,4,5-Trimethoxyphenyl)-propiolate (18) To a solution of
17 (10 g, 28 mmol) in dry THF (100 ml) was added n-butyllithium (1.6 M in
hexane) (39 ml, 63 mmol) below ꢀ50 °C under nitrogen and the mixture was
stirred at room temperature for 1 h. Then methyl chloroformate (2.6 ml,
34 mmol) in dry THF (20 ml) was added below ꢀ50 °C and the resulting
mixture was stirred at room temperature for 30 min. The reaction was
quenched by addition of saturated aqueous NH4Cl and the reaction mixture
was extracted with AcOEt. The organic layer was washed with brine, dried
(MgSO4), and concentrated in vacuo. The residue was chromatographed on
silica gel (hexane : AcOEtꢂ3 : 1) to give 18 (6.3 g, 88%); mp 97—98 °C. 1H-
NMR (CDCl3) d: 3.85 (3H, s), 3.86 (6H, s), 3.88 (6H, s), 6.84 (2H, s). IR
(KBr) cmꢀ1: 2220, 1705, 1580, 1505, 1240. MS m/z: 250 (Mꢁ). Anal. Calcd
for C13H14O5: C, 62.39; H, 5.64. Found: C, 62.26; H, 5.56.
1
Methyl (2E,3Z)-3-Carbamoyl-4-phenyl-2-(3,4,5-trimethoxybenzyli-
dene)-but-3-enoate (9) A solution of 22 (5.4 g, 12.4 mmol), 25 (4.1 g,
12.4 mmol) and PdCl2(PPh3)2 (0.43 g, 0.62 mmol) in DMF (25 ml) was
stirred under nitrogen at 60 °C for 14 h. Solvent was removed in vacuo.
AcOEt and aqueous KF was added to the residue and the mixture was stirred
for 1 h. The insoluble material was filtered off and the filtrate was extracted
with AcOEt. The organic layer was washed with brine, dried (MgSO4), and
concentrated in vacuo. The residue was chromatographed on silica gel
Methyl (E)-2-(Tributylstannyl)-3-(3,4,5-trimethoxyphenyl)-acrylate
(19) To a solution of 18 (15.0 g, 60 mmol) and Pd(PPh3)4 (1.4 g, 1.2 mmol)
in dry THF (75 ml) was added dropwise Bu3SnH (16.2 ml, 60 mmol) in dry
THF (50 ml) over 2 h under nitrogen and stirred at room temperature for
3.5 h. Solvent was removed in vacuo and the residue was diluted with
hexane. The resulting precipitate was filtered off and the filtrate was concen-
trated in vacuo. The residue was chromatographed on silica gel (hexane :
1
(CHCl3 : acetoneꢂ5 : 1) to give 9 (3.1 g, 63%); mp 146—147 °C. H-NMR
(CDCl3) d: 3.81 (6H, s), 3.84 (3H, s), 3.86 (3H, s), 5.64 (1H, bs), 6.48 (1H,
bs), 6.60 (1H, s), 7.23 (2H, s), 7.31 (3H, m), 7.46 (2H, m), 7.79 (1H, s). IR
(KBr) cmꢀ1: 3470, 3200, 1690, 1660, 1580. MS m/z: 397 (Mꢁ). Anal. Calcd
for C22H23NO6: C, 66.49; H, 5.83; N, 3.52. Found: C, 66.41; H, 5.77; N,
3.31.
(3Z,4E)-3-Benzylidene-4-(3,4,5-trimethoxybenzylidene)-pyrrolidine-
2,5-dione (6) To a solution of 9 (2.0 g, 5.0 mmol) in THF (20 ml) was
added 2 N NaOH (5 ml) and the mixture was stirreded for 30 min. To this so-
lution, 2 N HCl (5 ml) was added and the mixture was extracted with CHCl3
and dried (MgSO4), and concentrated in vacuo. The residue was chro-
matographed on silica gel (CHCl3 : acetoneꢂ10 : 1) to give 6 (1.7 g, 93%);
mp 176—178 °C. 1H-NMR (CDCl3) d: 3.80 (6H, s), 3.92 (3H, s), 6.88 (2H,
s), 7.40 (3H, m), 7.62 (1H, s), 7.84 (2H, m), 7.86 (1H, s), 8.35 (1H, bs). IR
(KBr) cmꢀ1: 3160, 1750, 1700, 1640, 1610, 1500. MS m/z: 365 (Mꢁ). Anal.
1
AcOEtꢂ5 : 1) to give 19 (22.2 g, 73%) as an oil. H-NMR (CDCl3) d: 0.91
(9H, t, Jꢂ7.1 Hz), 1.03 (6H, t, Jꢂ7.8 Hz), 1.20—1.70 (12H, m), 3.71 (3H,
s), 3.84 (9H, s), 6.58 (2H, s), 6.59 (1H, s). IR (film) cmꢀ1: 2955, 1705, 1580,
1510, 1240. MS (SI-MS) m/z: 542 (Mꢁꢁ1).
Methyl (Z)-2-(Tributylstannyl)-3-(3,4,5-trimethoxyphenyl)-acrylate
(20) To a solution of 18 (4.0 g, 16 mmol) and Bu3SnH (4.3 ml, 16 mmol) in
toluene (80 ml) was added AIBN (40 mg, 0.24 mmol) under nitrogen and the
mixture was stirred at room temperature for 1 h. Solvent was removed in
vacuo. The residue was chromatographed on silica gel (hexane : AcOEtꢂ

December 2006
1693
Calcd for C21H19NO5: C, 69.03; H, 5.24; N, 3.83. Found: C, 69.00; H, 5.19;
N, 3.90.
Antithrombotic Activity in a Rat Model of Venous Thrombosis The
oral antithrombotic activity of test compounds was evaluated in a rat model
Methyl (2Z,3E)-3-Carbamoyl-4-phenyl-2-(3,4,5-trimethoxybenzyli- of venous thrombosis induced by the intravenous injection of thromboplastin
dene)-but-3-enoate (10) This compound was prepared in 65% yield from
followed by stasis of the inferior vena cava.19) Test compounds were sus-
pended in 0.1% Nikkol HCO-60 solution at concentrations of 1 and
21 and 26 by a method similar to that described for 9. mp 186—187 °C. 1H-
NMR (CDCl3) d: 3.74 (3H, s), 3.84 (6H, s), 3.87 (3H, s), 5.74 (1H, bs), 6.38 10 mg/ml. Each solution of the test compounds was orally administered to
(1H, bs), 6.61 (2H, s), 6.71 (1H, s), 7.33 (3H, m), 7.65 (2H, m), 7.81 (1H, s). rats in a volume of 10 ml/kg for 8 consecutive days. Control groups were
IR (KBr) cmꢀ1: 3500, 3360, 1705, 1670, 1580. MS m/z: 397 (Mꢁ). Anal.
treated with 0.1% Nikkol HCO-60 solution only. Two hours after the last ad-
Calcd for C22H23NO6: C, 66.49; H, 5.83; N, 3.52. Found: C, 66.47; H, 5.84; ministration of each compound, the thrombus was induced as described
N, 3.50. above. The thrombus formed was removed and its dry weight was measured.
(3E,4Z)-3-Benzylidene-4-(3,4,5-trimethoxybenzylidene)-pyrrolidine- The percentage decrease in thrombus weight for each treatment group com-
2,5-dione (7) This compound was prepared in 95% yield from 10 by a
method similar to that described for 6. mp 197—198 °C. H-NMR (CDCl3)
pared to the control group (vehicle) was estimated.
1
d: 3.87 (6H, s), 3.91 (3H, s), 7.25 (2H, s), 7.42 (3H, m), 7.56 (1H, s), 7.61 References and Notes
(2H, m), 7.69 (1H, s), 8.65 (1H, bs). IR (KBr) cmꢀ1: 3170, 1750, 1710,
1575, 1510. MS m/z: 365 (Mꢁ). Anal. Calcd for C21H19NO5: C, 69.03; H,
5.24; N, 3.83. Found: C, 68.90; H, 5.26; N, 3.72.
1) Sprengers E. D., Kluft C., Blood, 69, 381—387 (1987).
2) Schneiderman J., Loskutoff D. J., Trends Cardiovasc. Med., 1, 99—
102 (1991).
Methyl (2Z,3Z)-3-Carbamoyl-4-phenyl-2-(3,4,5-trimethoxybenzyli-
dene)-but-3-enoate (11) This compound was prepared in 68% yield from
21 and 25 by a method similar to that described for 9. mp 158—160 °C. 1H-
NMR (CDCl3) d: 3.82 (3H, s), 3.85 (6H, s), 3.87 (3H, s), 5.70 (2H, bs), 6.60
(2H, s), 6.64 (1H, s), 6.92 (1H, s), 7.29—7.41 (3H, m), 7.47—7.53 (2H, m).
IR (KBr) cmꢀ1: 3455, 3345, 1730, 1670, 1575, 1510, 1250. MS m/z: 397
(Mꢁ). Anal. Calcd for C22H23NO6: C, 66.49; H, 5.83; N, 3.52. Found: C,
66.35; H, 5.76; N, 3.64.
3) Schleef R. R., Higgins D. L., Pillemer E., Levitt L. J., J. Clin. Invest.,
83, 1747—1752 (1989).
4) Kooistra T., Lansink M., Emeis J. J., Drug Future, 21, 291—299
(1996).
5) Levin E. G., Marzec U., Anderson J., Harker L. A., J. Clin. Invest., 74,
33—39 (1990).
6) Van Hinsberg V. W. M., Sprengers E. D., Kooistra T., Thromb.
Haemost., 57, 148—153 (1987).
(3Z,4Z)-3-Benzylidene-4-(3,4,5-trimethoxybenzylidene)-pyrrolidine-
2,5-dione (8) This compound was prepared in 93% yield from 11 by a
method similar to that described for 6. mp 190—192 °C. H-NMR (CDCl3)
d: 3.95 (9H, s), 7.28 (1H, s), 7.37 (1H, s), 7.44 (3H, m), 7.54 (2H, s), 8.00
(2H, m), 8.16 (1H, bs). IR (KBr) cmꢀ1: 3180, 1745, 1700, 1575, 1505. MS
m/z: 365 (Mꢁ). Anal. Calcd for C21H19NO5: C, 69.03; H, 5.24; N, 3.83.
Found: C, 69.03; H, 5.20; N, 3.91.
7) Kooistra T., Van den Berg J., Tons A., Platenberg G., Rijken D. C., Van
den Berg E., Biochem. J., 247, 605—612 (1987).
8) Bulens F., Nelles L., Van den Panhuyzen N., Collen D., J. Cardiovasc.
Pharmacol., 19, 508—514 (1992).
9) Kojima S., Hagiwara H., Shimonaka M., Saito Y., Inada Y., Biomed.
Res., 7, 155—159 (1986).
1
10) Johnson W. S., Daube G. H., Org. React., 6, 1—73 (1951).
Plasminogen Activator Activity in Conditioned Medium from Bovine 11) The stereochemistry was decided by NMR date.
Endothelial Cells Endothelial cells from bovine carotid artery were grown 12) Sai H., Ogiku T., Nishitani T., Hiramatsu H., Horikawa H., Iwasaki T.,
to confluence on 24-well microplates in E’MEM supplemented with ꢁ10%
fetal bovine serum (FBS) and 2 mM L-glutamine. The cell monolayer was
washed twice with FBS-free E’MEM and then further incubated in fresh
FBS-free MEM containing the test compound at a concentration of 3 mM for
24 h. The test compound was added as an ethanol (final 0.5%) solution and
Synthesis, 1995, 582—586 (1995).
13) Corey E. J., Fuchs P. L., Tetrahedron Lett., 13, 3769—3772 (1972).
14) Ichinose Y., Oda H., Oshima K., Utimoto K., Bull. Chem. Soc. Jpn.,
60, 3468—3470 (1987).
15) Rossi R., Carpita A., Cossi P., Tetrahedron, 48, 8801—8824 (1992).
therefore control cells were incubated in the presence of 0.5% ethanol only. 16) Corey E. J., Ulrich P., Fitzpatrick J. M., J. Am. Chem. Soc., 98, 222—
After the incubation, the conditioned medium was collected and centrifuged
at 3000 rpm at 4 °C for 10 min to remove cellular debris. The conditioned
medium was stored at ꢀ80 °C until measurement of the activity of plas-
224 (1976).
17) Baekelmans P., Gielen M., Malfroid P., Nasieski J., Bull. Soc. Chem.
Belg., 77, 85—90 (1968).
minogen activator. Plasminogen activator (PA) activity in the conditioned 18) Chen C., Cox P. B., Roberts S. M., J. Chem. Soc., Chem. Commun.,
medium was measured by the spectrophotometric method using a commer- 1988, 971—973 (1988).
cial kit (SpectrolyseTM/fibrin, Biopool AB, Umea, Sweden). The relative PA 19) Vogel G. M. T., Mueleman D. G., Bourgondien F. G. M., Hobbelen P.
activity in the cells treated with the test compounds was estimated on the as-
sumption that the PA activity in the absence of any test compound is 100%.
M. J., Thromb. Res., 54, 399—410 (1989).