Preparation and spectral properties of the nitrogen analogs of (E)- 5,5'-diaryl-3,3'-bifuranylidene-2,2'-diones and their derivatives

Article abstract of DOI:10.3987/COM-99-8741

(E)-5,5'-bis(2-methylphenyl)- and (E)-5,5'-bis(2,4,6-trimethylphenyl)- 3,3'-bifuranylidene-2,2'-diones and their isomeric pyrano[4,3-c]pyran-1,5- diones were converted into the nitrogen analogs, in which the aryl groups were twisted relative to the parent

Full text of DOI:10.3987/COM-99-8741

HETEROCYCLES, Vol. 53, No. 1, 2000, pp. 135 - 142, Received, 25th August, 1999
PREPARATION AND SPECTRAL PROPERTIES OF THE NITROGEN
ANALOGS OF (E)- 5,5’-DIARYL-3, 3’-BIFURANYLIDENE-2,2'-DIONES
AND THEIR DERIVATIVES
Hajime Irikawa* and Norihide Adachi
Department of Chemistry, Faculty of Science, Shizuoka University, Ohya,
Shizuoka 422-8529, Japan
Abstract- (E)-5,5’-bis(2-methylphenyl)- and (E)-5,5’-bis(2,4,6-trimethyl-
phenyl)-3,3’-bifuranylidene-2,2’-diones and their isomeric pyrano[4,3-c]pyran-
1,5-diones were converted into the nitrogen analogs, in which the aryl groups
were twisted relative to the parent skeletons, and had small conjugation effect.
Another nitrogen analogs bearing coplanar aryl rings were prepared, and their UV-
VIS and NMR spectral data were compared with those of the analogs having
twisted aryl groups. Conjugation effect of the 2-alkylphenyl group is
bathochromic shift by 24 nm. Steric compression due to coplanarity of the aryl
rings causes a deshielding of a 1H NMR signal by ~ 0.6 ppm, and a shielding of a
13C NMR signal by ~ 5 ppm.
It is well known that two aromatic rings in biphenyls are twisted as the o,o- and o’,o’-substituents become
bulky, and that in ultraviolet spectrum λmax of such biphenyl derivatives comes close to that of
a-c
monophenyl analogs.1
In a previous paper, we have reported the absorption spectrum of the nitrogen
analog (1a) derived from a Pechmann dye, 5,5’-diphenyl-3,3’-bifuranylidene-2,2’-dione (2a), and of the
analog (3a) obtained from an isomeric pyrano[4,3-c]pyran-1,5-dione (4a).2a Calculation using MOPAC
AM1 suggested that the phenyl groups in 1a were twisted by 38° relative to the parent skeleton. The X-
Ray analysis of 3a showed that the phenyl groups were twisted by 51.8° and 61.5°.2b Presence of methyl
groups in the o, o-positions of the phenyl groups in 1a and 3 a seemed to make the aryl groups more
1
H
O
O
2
5 X
Ar
H
O
O
1
7
2 O
N
Ar
N
1
N
X
4
H
3
3
Ar
4
3'
H
X
3
H
H
3
N
H
5
4
5'
4
H
O
O
O5
2'
Ar
H
X
1'
H
3a-c X=NMe
4a-c X=O
1a-c X=NMe
2a-c X=O
5
6
a : Ar = C H b : Ar = 2-MeC H c : Ar = 2,4,6-Me C H
3 6 2
6
5
6
4

twisted, and the λmax of such analogs (1b, c and 3b, c) seemed to come close to that of the parent
chromophores, respectively, because of small conjugation effect of the aryl groups. Comparison of the
λmax of these analogs (1b, c and 3b, c) with that of another nitrogen analogs (5 and 6) bearing coplanar
aryl rings seemed to indicate conjugation effect of the aryl rings. Coplanarity of the aryl rings and the
1
13
parent skeletons in 5 and 6 seemed to affect chemical shifts of the H-4 and C-4 in the H and C NMR
1
spectra. This paper deals with comparisons of the spectral data (UV-VIS, H and 13C NMR) of the
nitrogen analogs (1b,c and 3b), derived from (E)-5,5’-bis(2-methylphenyl)- and (E)-5,5’-bis(2,4,6-
trimethylphenyl)-3,3’-bifuranylidene-2,2’-diones (2b and 2c), with those of another analogs (5 and 6)
derived from 2a and 4a.
Preparatio n
The compound (2 b) was prepared from 4-(2-methylphenyl)-4-oxo-2-butenoic acid according to
the literature procedure.3 Reaction of 2 b with MeNH2 in CH2 Cl2 gave complicated products,
a
Me
Me
N
Me
Ar
O
O
Ar
NH
O
O
N
Ar
O
Ar
O
O
b or c
a
＋
b
O
Ar
O
Ar
O
Ar
N
O
O
Ar
O
Me
HN
Me
a'
2a-c
9b,c
7b,c
1b,c
Cl
d
e, f, g
N
O
O
N
O
h
Ar
H
O
H
4
H
O
a: Ar = C6H5
Ar
O
N
b: Ar= 2-MeC6H4
c: Ar = 2,4,6-Me3C6H2
O
O
N
12
4a-c
5
Cl
a
a
O
O
O
O
H
Me
Ar
MeN
Ar
Me
Ar
Ar
Ar
N
NMe
Ar
N
c
a, c
NMe
Ar
O
O
O
Ar
OH
O
O
O
O
O
8b,c
3b
10a,b
11b,c
H
O
N
O
O
H
R
Cl
N
N
f, g
h
c
e
Ph
N
X
O
4a
d
4
H
O
O
Ph
O
c'
H
N
H
R
O
13 X = O
14 X = CH2CH2Cl
6
15 R = CH2CH2OH
a) MeNH2 / CH2Cl2 ; b) Ac2O / AcOH ; c) PO Cl3 / CH2Cl2 ; d) ∆ / 1,3-propanediol ;
e) 2-aminoethanol / CH2Cl3 f) 5% HCl ; g) PPh3 / CCl4 / CH2Cl2 ; h) AlCl3 / C6H5Cl
;

which were treated with a mixture of acetic anhydride and acetic acid to give 7b (7%) and 1b (13%).
Calculation using MOPAC AM1 showed that the 2-methylphenyl groups in 1b were twisted by 48°
relative to the parent skeleton. In order to obtain an analog bearing more twisted aryl groups, the
compound (2c) was used.4 On aminolysis with MeNH2, 2c gave complicated products, which
were treated with POCl3 in CH2Cl2 to give 7c (44%) and 1c (1%), along with a fluorescent
compound (8c, 1%). Under conditions used for the preparation of 1b, 2c did not yield 1c.
The formation of 7b,c and 1b,c is explained by cyclization via routes a - b and a - a’ shown in the
structure of 9b,c, respectively.
A low yield of 1c reflects bulkiness of the 2,4,6-
trimethylphenyl (common name, mesityl) groups.
The compound (2b) was isomerized into 4b by heating in 1,3-propanediol. On aminolysis with
MeNH2, followed by treatment with POCl3, 4b gave 8b (71%), which was converted into 3b
(60%) by repeating the aminolysis and POCl3 treatment. The compound (3b) might contain both
1
atrop isomers, because the H NMR spectrum of 3b showed two singlet signals (assigned to the
methyl groups on the aryl groups) at 2.19 and 2.20 ppm. In a previous paper, we reported that
reaction of 4a with MeNH2 gave a ring tautomer (10a) of the ring-chain tautomerism.2a,5 On the
contrary, a chain tautomer (11c) was obtained almost quantitatively by aminolysis of 4c6 with
MeNH2. The aminolysis products of 4b contained both ring-chain tautomers (10b and 11b) in a
1
ratio of 1.0 : 1.6 (determined by H NMR). On heating above 300 °C, 11c changed into 4c
almost quantitatively, while on treatment with POCl3, 11c yielded 8c (19%), along with 4c (60%).
The compound (3c) was not obtained from 8c by repeating the aminolysis and POCl3 treatment.
The λmax of 9,10-dihydrophenanthrene, a two-atom-bridged biphenyl, is observed at considerably
longer wavelength than that of biphenyl because of planarity of the structure (interplanar angle =
20°).1b In order to prevent twisting of the phenyl groups in 1a and 3a, another nitrogen analogs
(5 and 6) were derived from 2a and 4a. On aminolysis with 2-aminoethanol, cyclization with
5% HCl, and chlorination with Ph3P and CCl4, 2a gave a violet compound (12, 41%) as a main
product.
Under similar conditions, 4a yielded fluorescent compounds (13, 25%; 14, 9%),
along and 12 (11%). Formation of 13 and 14 is explained by cyclization via c -d, and c - c’
shown in the structure of 15, respectively, and that of 12 by cyclization similar to that (a - a’)
shown in 9b,c. Friedel-Crafts reaction of 12 and 14 with anhydrous AlCl3 in chlorobenzene
yielded 5 (36%) and 6 (72%), respectively.
Absorption Spectra
In a previous paper, we reported that replacement of the lactone-oxygen atoms in 2a with N-methyl groups
caused bathochromic shift.2a The λmax of 2b was observed at 505 nm (shoulder at 530 nm), and that of
7b and 1b was found at 532 and 533 nm, respectively. In general, twisting of the benzene rings relative
to the chromophore causes hypsochromic shift. In 7b and 1b, the bathochromic and hypsochromic shifts
mentioned above might be compensated each other. Comparison of the λmax of 2c (468 nm) with that of
7c (510 nm) and 1c (522 nm) showed bathochromic shifts as the lactone-oxygen atoms in 2c were replaced
with N-methyl groups. X-Ray analysis shows that 2c exists in two forms and the mesityl groups are

twisted by 39° and 56°.4 Also in X-Ray analysis of 1c the mesityl groups were shown to be twisted by
71°.2c In 7c and 1c, bathochromic shifts caused by introduction of the N-methyl groups might exceed
hypsochromic shifts due to twisting of the mesityl groups, since the mesityl groups in 2c are already
twisted largely.
The λmax of biphenyls with four alkyl substituents in the o-, o’-positions is observed almost at the same
wavelength as that of their corresponding monophenyl analogs.1c In o,o’-dimethylbiphenyl, two benzene
rings are twisted by 70°, and the conjugation is hindered.1a So, in 3b the 2-methylphenyl groups are
suggested to be similarly twisted, and the conjugation effect of the 2-methylphenyl groups seems small.
Twisting angle (71°) of the mesityl groups in 1c is similar to that (70°) of o,o’-dimethylbiphenyl.
Accordingly, the λmax of 1c (522 nm) and 3b (390 nm) is estimated to be close to that of the parent
chromophores of compounds (1a and 3a), respectively.
The absorption spectra of 1c and 5, and those of 3 b and 6 are shown in Figures 1 and 2, respectively.
The λmax of 3b is found at 390 nm, and that of 6 is observed at 438 nm, which is longer than that of 3b
by 48 nm. In 6, two 2-alkylphenyl groups are conjugated with the parent chromophore. Therefore, the
conjugation effect of the 2-alkylphenyl group in 6 is bathochromic shift by 24 nm. The planar derivative
(5) shows two peaks at 632 and 587 nm, while 1c indicates one peak at 522 nm. So, the conjugation
effect of the 2-alkylphenyl group in 5 can not be calculated, but is bathochromic shift similar to that
observed in 6, as shown in Figure. 1.
1 H and 1 3C NMR Spectra
Coplanarity of the aryl rings and the parent skeletons in 5 and 6 seemed to cause steric interactions around
the hydrogen on C-4, as shown in the structures of 5 and 6. Chemical shifts of the H-4 and C-4 in the
analogs (1b and 3b) and in the planar analogs (5 and 6) were summarized in Table 1. The H-4 signal of
5 and 6 was deshielded compared with that of 1c and 3b by 0.5 ~ 0.6 ppm. On the other hand, the C-4
signal of 5 and 6 was shielded compared with that of 1c and 3b by 4 ~ 5 ppm. The characteristics are
rationalized by steric interactions around the hydrogen on C-4 in 5 and 6, respectively, because it is well
known that steric interactions arising from overlapping of van der Waals radii of closely spaced hydrogens
cause a deshielding of the hydrogens and a shielding of the carbons attached to those hydrogens.7 The N -

methyl signal in 1a-c (1a, δ = 3.19 ppm; 1b, δ = 2.91 ; 1c, δ = 2.80) shows increase of the shielding, as
methyl groups are introduced on the o, o-positions, and twisting of the 5,5’-aryl groups becomes larger.
This trend might be in line with decrease of the deshielding due to anisotropic effect of the aryl rings.
Table 1. 1H and 13C NMR spectral data of the analogs (1b, 3b, 5, and 6)
Compounds
δH-4
6.78
7.27
δC-4
102.5
97.7
Compounds
δH-4
6.97
7.61
δC-4
104.0
100.2
1b
5
3b
6
The results presented in this paper is an example of substituent effects of the twisted and coplanar
aryl rings.
EXPERIMEN TAL
All melting points are measured on a Yanaco MP-J3, and are uncorrected. Absorption spectra
were measured on a Hitachi U3000 in CHCl3 . 1 H and 1 3C NMR spectra were measured on a
Bruker AC300 (300 MHz, 75 MHz) in CDCl3 , using a CHCl3 signal (δ=7.26) and a CDCl3 signal
(δ=77. 0) as an internal standard. MS spectra were obtained on a JEOL-DX303. Column
chromatography was performed with silica gel 60 (70－230 mesh, Merck). TLC was carried out
on Kieselgel 60F2 54 plates (Art. 5744, Merck).
Preparation of 2b. A mixture of 4-(2-methylphenyl)-4-oxo- 2-butenoic acid (4.5 g, 24 mmol), cuprous
chloride (0.84 g, 8.5 mmol), ammonium chloride (0.93 g, 17 mmol), and acetic anhydride (30 mL) was
heated under reflux for 2 h. The mixture was cooled, and the solid was collected and washed with acetic
acid and ethanol. The crude product was then extracted with boiling toluene to give 2b (2.7 g, 66%): mp
215 - 217 °C (CHCl3); UV-VIS λmax 283 (ε 20400), 505 (37600), and 530 nm (sh, 34300); 1H NMR δ =
2.62 (6H, s, 2×Me), 7.29 - 7.39 (6H, m), 7.42 (2H, s), and 7.85 (2H, dd, J=7.7 and 2.2 Hz); 13C NMR
δ = 22.6, 107.0, 126.5, 126.8, 126.9, 128.6, 131.3, 132.1, 138.2, 160.4, and 167.0. Anal. Calcd for
C22H16O4: C, 76.73; H, 4.68. Found: C,76.57; H, 4.71.
Preparation of 7b and 1b. A mixture of 2b (52 mg, 0.15 mmol), 40% methanolic MeNH2 (0.1 mL, 1
mmol), and CH 2Cl2 (5 mL) was allowed to stand at rt overnight. The mixture was concentrated under
reduced pressure to give a residue, which was dissolved in a mixture of acetic anhydride (1 mL) and acetic
acid (1 mL). The solution was heated under reflux for 5 min, and concentrated under reduced pressure.
The residue was separated with column chromatography (CHCl3) and with TLC (AcOEt:hexane 1:4) to give
7b (4 mg, 7%) and 1b (7 mg, 13%). 7b: mp 162 - 164 °C (CHCl3 - hexane); UV-VIS λmax 281 (ε
1
13200), 437 (8700), and 532 nm (13700); H NMR δ = 2.35 (3H, s), 2.62 (3H, s), 2.95 (3H, s), 6.64
13
(1H, s), 7.25 - 7.41 (7H, m), 7.57 (1H, s), and 7.83 (1H, m); C NMR δ = 20.0, 22.6, 27.4, 102.6,
107.1, 125.1, 126.1, 126.4, 127.3, 128.3, 129.2, 130.1, 130.2, 130.7, 131.0, 131.9, 136.9, 137.8,
154.0, 159.4, 167.9, and 169.8. High resolution MS Calcd for C23H19NO3: M, 357.1365. Found:
357.1366. 1b: mp 210 - 213 °C (CHCl3 - MeOH); UV-VIS λmax 288 (ε 15200) and 533 nm (12900);

1H NMR δ = 2.33 (6H, s, 2×Me), 2.91 (6H, s), 6.78 (2H, s), and 7.25 - 7.39 (8H, m); 13C NMR δ =
19.9, 27.3, 102.5, 126.0, 129.3, 129.7, 130.6, 130.7, 137.0, 152.5, and 170.6; MS m/z 370 (M+).
Anal. Calcd for C24H22N2O2: C, 77.81; H, 5.99; N, 7.56. Found: C, 77.48; H, 6.01; N, 7.48.
Preparation of 7c and 1c. A mixture of 2c (200 mg, 0.5 mmol), 40% methanolicMeNH2 (0.2 mL, 2
mmol), and CH2Cl2 (15 mL) was stirred at rt for 1 h, and concentrated under reduced pressure. To a
mixture of the residue and CH2Cl2 (15 mL) was added POCl3 (0.3 mL, 3 mmol). The mixture was stirred at
rt for 2d. After dilution with CHCl3, the mixture was washed (saturated aq. NaHCO3 and saturated aq.
NaCl), dried (Na2SO4), and concentrated under reduced pressure. The residue was separated with column
chromatography (CHCl3 : hexane 3:2) and with TLC (CHCl3 : hexane 2:1) to give 7c (85 mg, 41%), 1c (2
mg, 1%), and 8c as an oil (2 mg, 1%), along with 2c (17 mg, 8%). 7c:mp 217 - 219 °C (EtOH);UV-VIS
λmax 419 (ε 9100) and 510 nm (13300); 1H NMR δ = 2.21 (6H, s), 2.32 (3H, s), 2.33 (3H, s), 2.36 (6H,
s), 2.82 (3H, s), 6.56 (1H, s), 6.94 (2H, s), 6.96 (2H, s), and 7.24 (1H, s); 13C NMR δ = 19.9, 20.8, 21.2,
21.3, 26.5, 101.9, 108.6, 124.4, 125.8, 127.0, 128.5, 128.9, 131.4, 136.8, 138.0, 139.6, 140.2, 153.6,
160.3, 168.6, and 169.4; MS m/z 413 (M+). Anal. Calcd for C27H27NO3: C, 78.42; H, 6.58; N, 3.39.
Found: C, 78.27; H, 6.64; N, 3.50. 1c: mp > 300 °C (CHCl3 - EtOH); UV-VIS λmax 274 (ε 12400) and
522 nm (12100); 1H NMR δ = 2.21 (12H, s, 4×Me), 2.34 (6H, s), 2.80 (6H, s), 6.72 (2H, s), and 6.96
13
(4H, s); C NMR δ = 19.9, 21.2, 26.3, 102.0, 127.5, 128.3, 129.3, 137.0, 139.2, 151.7, and 170.4
High resolution MS Calcd for C28H30N2O2: M, 426.2307. Found: 426.2300. 8c was identical with that
described below.
Isomerization of 2b into 4b. A mixture of 2b (532 mg) and 1,3-propanediol (15 mL) was heated
under reflux for 1.5 h. The solution was cooled, and diluted with MeOH. The solid was collected and
washed with MeOH to give 4b (345 mg, 65%): mp 201 - 203 °C (CHCl3 - hexane); UV-VIS λmax 292 (ε
1
13
18400) and 409 nm (24000); H NMR δ = 2.54 (6H, s, 2×Me), 7.02 (2H, s), 7.26 - 7.58 (8H, m); C
NMR δ = 21.0, 101.7, 126.4, 127.4, 129.2, 130.7, 131.5, 131.6, 136.9, 160.1, and 160.4. Anal.
Calcd for C22H16O4: C, 76.73; H, 4.68. Found: C, 76.54; H, 4.75.
Preparation of 8b. A mixture of 4b (75 mg, 0.22 mmol), 40% methanolic MeNH2 (0.4 mL, 4 mmol),
1
and CH2Cl2 (10 mL) was stirred at rt for 1d, and concentrated under reduced pressure. The H NMR
1
spectrum of the residue showed the presence of 10b and 11b in a ratio of 1.0 : 1.6. 10b: H NMR δ =
2.37 (3H, s), 2.45 (3H, s), 2.83 (3H, s), 3.29 (2H, AB-q, J=19.5 Hz), 7.03 (1H, s), 7.22 - 7.72 (8H, m).
11b: 1H NMR δ = 2.50 (3H, s), 2.51 (3H, s), 2.94 (3H, d, J=4.8 Hz), 4.22 (2H, s), 6.53 (1H, s), 7.22 -
8.06 (8H, m). To a mixture of the residue and CH2Cl2 (3 mL) was added POCl3 (1.5 mL, 16 mmol).
The mixture was stirred at rt for 1d, and worked up as described above to give 8b as an oil (55 mg, 71%):
1H NMR δ = 2.19 (3H, s), 2.54 (3H, s), 3.33 (3H, s), 6.80 (1H, s), 7.19 (1H, s), and 7.21 - 7.59 (8H,
13
m); C NMR δ = 19.4, 21.0, 33.8, 102.3, 103.9, 125.2, 126.2, 126.5, 128.9, 129.2, 129.9, 130.1,
130.4, 130.6, 131.3,132.3, 134.5, 136.2, 136.7, 147.7, 157.9, 160.8, and 161.5. High resolution MS
Calcd for C23H19NO3: M, 357.1365. Found: 357.1364.
Preparation of 3b. A mixture of 8b (55 mg, 0.15 mmol), 40% methanolic MeNH2 (0.3 mL, 3 mmol),
and CH2Cl2 (5 mL) was stirred at rt for 3 d, and concentrated under reduced pressure. To a mixture of the
residue and CH2Cl2 (2 mL) was added POCl3 (1 mL, 11 mmol). The mixture was stirred at rt for 1 d, and

worked up as described above to give 3b (34 mg, 60%): mp >300 °C (CHCl3 - hexane); UV-VIS λmax
294 (ε 12400), 306 (11700), 371 (19100), and 390 nm (16300); 1H NMR δ = 2.19 (3H, s), 2.20 (3H, s),
13
3.31 (6H, s), 6.97 (2H, s), and 7.21 - 7.43 (8H, m); C NMR δ = 19.5, 33.5, 104.0, 126.3, 128.9,
129.2*, 129.3*, 129.6, 130.5, 135.3, 136.5, 145.2, and 161.9; MS m/z 370 (M+). Anal. Calcd for
C24H22N2O2: C, 77.81; H, 5.99; N, 7.56. Found: C, 77.90; H, 6.08; N, 7.60. * These signals might
be assigned to the C-6 in the 2-methylphenyl groups of the atrop isomers.
Preparation of 11c. A mixture of 4c6 (60 mg, 0.15 mmol), 40% methanolic MeNH2 (0.1 mL, 1
mmol) and CH2Cl2 (2 mL) was allowed to stand at rt for 2 h, and concentrated under reduced pressure.
1
Crystallization of the residue from CHCl3 - hexane gave 11c (59 mg, 91%): H NMR δ = 2.27 (6H, s),
2.31 (3H, s), 2.32 (9H, s), 2.94 (3H, d, J=4.8 Hz), 4.10 (2H, s), 6.28 (1H, s), 6.82 (1H, br s), 6.89
(2H, s) and 6.92 (2H, s); 13C NMR δ = 19.2, 20.1, 21.1, 21.2, 26.4, 43.7, 105.8, 116.2, 128.6, 128.8,
129.1, 133.1, 137.0, 138.5, 139.2, 140.0, 149.3, 161.2, 163.5, 166.5, and 208.4; MS m/z 431 (M+).
Anal. Calcd for C27H29NO4: C, 75.15; H, 6.77; N, 3.25. Found: C, 74.97; H, 6.82; N, 3.21. The
compound (11c) did not melted above 300 °C. After keeping above 300 °C for 10 min in a mp apparatus,
1
the sample was examined by H NMR, and the spectrum was in agreement with that of 4c almost
completely.
Preparation of 8c. Aminolysis of 4c (120 mg, 0.3 mmol) as mentioned above gave 11c almost
quantitatively, which was used without further purification. A mixture of 11c (129 mg), POCl3 (0.5 mL, 5
mmol) and CH2Cl2 (5 mL) was stirred at rt for 3d, and worked up as described above. Separation of the
products with column chromatography (CHCl3:hexane 2:1) and with TLC (CHCl 3:hexane 2:1) gave 8c (23
mg, 19%), along with 4c (72 mg, 60%). 8c: mp 239 - 242 °C (CHCl3 - MeOH); UV-VIS λmax 283 (ε
15800), 383 (18000), and 400 nm (sh, 14400); 1H NMR δ = 2.11 (6H, s), 2.29 (6H, s), 2.33 (3H, s), 2.36
(3H, s), 3.30 (3H, s), 6.78 (1H, s), 6.95 (2H, s), 6.99 (1H, s), and 7.00 (2H, s); 13C NMR δ = 19.8, 20.1,
21.1, 21.2, 32.9, 103.7, 103.8, 125.5, 128.5, 128.7, 129.7, 130.0, 131.3, 136.1, 137.3, 139.5, 139.7,
147.1, 156.8, 161.1, and 162.2. High resolution MS Calcd for C27H27NO3: M, 413.1990. Found:
413.1960.
Preparation of 12. A mixture of 2a (147 mg, 0.47 mmol), 2-aminoethanol (0.2 mL, 3.3 mmol), and
CH2Cl2 (10 mL) was allowed to stand at rt for 2 d, and then diluted with AcOEt. The mixture was shaken
with 5% HCl for 10 min, washed (water and saturated aq. NaCl), dried (Na2SO4), and concentrated under
reduced pressure. To the solution of the residue in CCl4 (15 mL) and CH2Cl2 (15 mL) was added Ph3P
(508 mg, 1.96 mmol).
The mixture was stirred at rt overnight, and concentrated under reduced pressure.
The residue was separated with column chromatography (CHCl3) to give 12 (84 mg, 41%): mp 206 - 207
°C (CHCl3 - hexane); UV-VIS λmax 299 (ε 20900) and 548 nm (17500); 1H NMR δ = 3.56 (4H, t, J=6.7
13
Hz, 2×CH2), 4.02 (4H, t, J=6.7 Hz), 6.92 (2H, s), and 7.47 - 7.50 (10H, m); C NMR δ = 41.0, 42.5,
103.8, 127.8, 128.8, 129.1, 130.2, 130.7, 152.3, and 171.3. High resolution MS Calcd for
C24H20N2O2Cl2: M, 438.0902. Found: 438.0896.
Preparation of 13 and 14 As described above, 4a (191 mg, 0.60 mmol) was reacted with 2-
aminoethanol (0.3 mmol) in CH2Cl2 (15 mL). The reaction mixture was shaken with 5% HCl, and then
treated with Ph3P (777 mg, 3.0 mmol) and CCl4 (15 mL) in CH2Cl2 (15 mL). Separation of the products

with column chromatography (CHCl3) and crystallization from CHCl3 - hexane gave 1 3 (56 mg, 25%) and
1 4 (25 mg, 9%), along with 1 2 (30 mg, 11%). 1 3: mp 236 - 239 °C; UV-VIS λmax 309 (ε 14700), 404
(24600), and 425 nm (20300); 1H NMR δ = 3.74 (2H, t, J=6.6 Hz)), 4.35 (2H, t, J=6.6 Hz), 6.84 (1H,
s), 7.37 - 7.52 (9H, m), and 7.91 - 7.94 (2H, m); 13C NMR δ = 39.9, 47.7, 98.0, 105.2, 125.4, 128.9,
129.0, 129.1, 129.9, 130.6, 131.1, 131.5, 134.6, 147.9, 156.4, 160.5, and 161.0 High resolution MS
Calcd for C22H16NO3Cl: M, 377.0819. Found: 377.0826. 14: mp 241 - 243 °C; UV-VIS λmax 305 (ε
1
11900), 378 (19700), and 395 nm (17200); H NMR δ = 3.71 (4H, t, J=6.7 Hz, 2×CH2), 4.32 (4H, t,
J=6.7 Hz), 6.96 (2H, s), and 7.38 - 7.51 (10H, m); 13C NMR δ = 40.1, 47.4, 105.1, 128.8, 129.2, 129.5,
135.1, 146.0, and 161.5. High resolution MS Calcd for C24H20N2O2Cl2: M, 438.0902. Found:
438.0916.
Preparation of 5. A mixture of 12 (33 mg, 0.075 mmol), AlCl3 (194 mg, 1.46 mmol), and chlorobenzene
(5 mL) was heated under reflux for 1.5 h. To the reaction mixture was added water, and then CHCl3.
The mixture was washed (5% HCl, water, and saturated aq. NaCl), dried (Na2SO4), and concentrated under
reduced pressure. Theresiduewas separated with column chromatography (CHCl3) and with TLC (CHCl3) to
give 5 (10 mg, 36%): mp 296 - 300 °C (CHCl3 - hexane);UV-VIS λmax 314 (ε 25800), 587 (26600), and 632
nm (22000);1H NMR δ = 3.06 (4H, t, J=6.3 Hz, 2×CH2), 3.85 (4H, t, J=6.3 Hz), 7.24 - 7.37 (6H, m), 7.27
(2H, s), and 7.81 (2H, m);13C NMR δ = 28.7, 36.4, 97.7, 125.8, 126.5, 127.4, 128.7, 129.9, 130.3, 135.0,
145.1, and 169.4. High resolution MS Calcd for C24H18N2O2: M, 366.1368. Found: 366.1359.
Preparation of 6. A mixture of 14 (22 mg, 0.05 mmol), AlCl3 (160 mg, 1.2 mmol), and chlorobenzene (5
mL) was heated under reflux for 1.5 h, and worked up as described above to give 6 (10 mg, 56%): mp >300 °C
(CHCl3 - MeOH);UV-VIS λmax 334 (ε 9400), 349 (9100), 391 (17200), 412 (32100), and 438 nm (36800);
1H NMR δ = 3.05 (4H, t, J=6.3 Hz, 2×CH2), 4.40 (4H, t, J=6.3 Hz), 7.28 - 7.40 (6H, m), 7.61 (2H, s), and
7.93 (2H, m);13C NMR δ = 28.2, 40.2, 100.2, 125.6, 127.8, 128.0, 129.0, 129.8, 129.9, 134.9, 139.2, and
161.0. High resolution MS Calcd for C24H18N2O2: M, 366.1368. Found: 366.1371.
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