Synthesis and crystal structures of 2,3,12,13-tetraalkoxy-21,23- dithiaporphyrins and 2,3-dialkoxy-21-monothiaporphyrins

Article abstract of DOI:10.1016/j.tet.2004.09.008

The tetraalkoxy and dialkoxy substituted 21,23-dithiaporphyrins and 21-monothiaporphyrins, respectively, having methoxy, butoxy, octyloxy and dodecyloxy substituents at β-thiophene carbons were synthesized and characterized. The X-ray structure was solved for tetrabutoxy substituted 21,23-dithiaporphyrin and it exhibited a more planar structure compared with unsubstituted S₂TPP, whereas the dimethoxy substituted 21-monothiaporphyrin showed a saddle shaped structure similar to unsubstituted STPPH. A series of 21,23-dithia and 21-monothiaporphyrins having methoxy, butoxy, octyloxy and dodecyloxy substituents at β-thiophene carbons were synthesized and characterized.

Full text of DOI:10.1016/j.tet.2004.09.008

Tetrahedron 60 (2004) 10671–10680
Synthesis and crystal structures of
2,3,12,13-tetraalkoxy-21,23-dithiaporphyrins and
2,3-dialkoxy-21-monothiaporphyrins
Neeraj Agarwal,a C.-H. Hungb and Mangalampalli Ravikantha,
*
aDepartment of Chemistry, Indian Institute of Technology, Powai, Mumbai 400076, India
bDepartment of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan, ROC
Received 21 April 2004; revised 12 August 2004; accepted 2 September 2004
Available online 1 October 2004
Abstract—The tetraalkoxy and dialkoxy substituted 21,23-dithiaporphyrins and 21-monothiaporphyrins, respectively, having methoxy,
butoxy, octyloxy and dodecyloxy substituents at b-thiophene carbons were synthesized and characterized. The X-ray structure was solved for
tetrabutoxy substituted 21,23-dithiaporphyrin and it exhibited a more planar structure compared with unsubstituted S2TPP, whereas the
dimethoxy substituted 21-monothiaporphyrin showed a saddle shaped structure similar to unsubstituted STPPH.
q 2004 Elsevier Ltd. All rights reserved.
1. Introduction
thiaporphyrins. In our recent communication, we reported
the preliminary details of the synthesis of 2,3,12,13-
tetraalkoxy-21,23-dithiaporphyrins with methoxy, butoxy,
octyloxy and dodecyloxy substituents at b-thiophene
carbons.5 In this paper, we report the detailed synthesis of
series of 21,23-dithiaporphyrins and 21-monothiapor-
phyrins having alkoxy substituents at b-thiophene carbons.
The b-substituted porphyrins synthesised were (Chart 1)
2,3,12,13-tetramethoxy-5,10,15,20-tetraphenyl-21,23-
dithiaporphyrin (1), 2,3,12,13-tetrabutoxy-5,10,15,20-tetra-
phenyl-21,23-dithiaporphyrin (2), 2,3,12,13-tetraoctyloxy-
5,10,15,20-tetraphenyl-21,23-dithiaporphyrin (3),
2,3,12,13-tetradodecyloxy-5,10,15,20-tetraphenyl-21,23-
dithiaporphyrin (4), 2,3-dimethoxy-5,10,15,20-tetraphenyl-
21-monothiaporphyrin (5), 2,3-dibutoxy-5,10,15,20-tetra-
phenyl-21-monothiaporphyrin (6), 2,3-dioctyloxy-
5,10,15,20-tetraphenyl-21-monothiaporphyrin (7) and 2,3-
didodecyloxy-5,10,15,20-tetraphenyl-21-monothia-
porphyrin (8). The X-ray structure was solved for 2 and
indicates that it is more planar than parent 5,10,15,20-
tetraphenyl-21,23-dithiaporphyrin (S2TPP)1 whereas the
structure solved for 5 is almost saddle-shaped similar
to that of 5,10,15,20-tetraphenyl-21-monothiaporphyrin
(STPPH).1
Thiaporphyrins are a class of compounds in which one or
two inner nitrogens of the porphyrin ring are replaced by
sulfur atoms (N3S and N2S2 cores).1,2 The physico-chemical
properties and metal coordination chemistry of thiapor-
phyrins are quite different from normal porphyrins (N4
core). One of the interesting feature of thiaporphyrins is that
they stabilize metals in unusual oxidation states such as
copper and nickel in the C1 oxidation state, which is not
possible with N4 porphyrins.1 Porphyrins have two reactive
positions—the b- and meso-positions at which suitable
substituent(s) can be introduced to tune the electronic
properties of the porphyrin for specific applications. The
b-functionalization of porphyrins is of considerable chemi-
cal interest since the b-substituents are in direct conjugation
with the porphyrin ring and small changes in the
substituents at b-positions alters the properties of porphyrin
macrocycle. There are several reports on both electron
releasing and electron withdrawing substituents at b-pyrrole
carbons of N4 porphyrin systems.3 Porphyrins with electron
withdrawing substituents at b-pyrrole carbons are found to
be robust catalysts for alkene epoxidation and alkane
hydroxylation reactions.4 Interestingly, reports on b-sub-
stituted thiaporphyrins rarely exploit their potential for
various applications. Thiaporphyrins possess two reactive
b-positions: b-thiophenes and b-pyrroles at which sub-
stituents can be introduced to alter the properties of
2. Results and discussion
2.1. Thiophenes (13–16) and thiophene diols 17–20
Keywords: Monothiaporphyrin; Dithiaporphyrin; STPPH.
* Corresponding author. Fax: C91 22 576 7152;
e-mail: ravikanth@chem.iitb.ac.in
The required thiophenes were prepared according to the
literature6 with some modifications as outlined in Scheme 1.
0040–4020/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2004.09.008

10672
N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
Chart 1.
The thiodiglycolic acid was first esterified and afforded
dimethylthiodiglycollate 9 as a yellow liquid. Compound 9
was condensed with diethyloxalate in the presence of
sodium methoxide and the resultant precipitate of disodium
salt 10 was filtered and dried. The disodium salt 10 was then
refluxed with dimethyl sulfate at 100 8C for 1 h. The excess
dimethylsulfate was removed in vacuo and gave 11 as white
solid in 64% yield. The demethylation of 11 was carried out
by refluxing with 10% NaOH for 1 h followed by work-up,
which resulted in product 12 as a white solid in 84% yield.
The decarboxylation of 12 proceeded smoothly with copper
chromite at 180 8C for 4 h. The brown coloured crude liquid
obtained after standard work up was purified by column
chromatography and afforded 3,4-dimethoxythiophene 13
as a colourless liquid in 56% yield. 3,4-Dibutoxy 14, 3,4-
dioctyloxy 15, and 3,4-didodecyloxy 16 substituted
thiophenes were prepared under trans-etherification
conditions in w67% yields by treating 13 with 1-butanol,
1-octanol and 1-dodecanol, respectively, in the presence of
p-toluenesulfonic acid in toluene.6b

N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
10673
Scheme 1. Synthetic scheme for thiophenes 13–16.
The diol reaction mixtures were purified by silica gel
column chromatography using petroleum ether/ethyl acetate
mixture as eluant and afforded pure diols 17–20 as white
soft solids in 23–33% yields. The diols 17–20 were
characterized by NMR, IR, mass and elemental analysis.
All four diols showed a broad peak at w2.80 ppm for OH
1
and a sharp peak at w6.00 ppm for –CH in H NMR and
broad peak of OH at w3300 cmK1 in IR confirmed the
compounds.
Scheme 2. General synthetic scheme for diols 17–20.
2.2. 21,23-Dithiaporphyrins with alkoxy substituents at
b-thiophene carbons 1–4
The unknown thiophene diols 17–20 were prepared
according to the method of Ulman and Manassen.7 One
equivalent of 3,4-disubstituted-2,5-dilithiothiophene was
condensed with 2.5 equiv of benzaldehyde in ice cold dry
THF (Scheme 2). The TLC analysis showed the formation
of required diol with some amount of mono-ol (18–21%).
21,23-Dithiaporphyrins 1, 2, 3 and 4 were synthesized by
condensing 1 equiv of corresponding diol 17, 18, 19 and 20,
respectively, with 1 equiv of pyrrole in CH2Cl2 in the
presence of a catalytic amount of BF3$OEt2 followed by
Scheme 3. Synthetic scheme for N2S2 porphyrin 4.

10674
N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
Table 1. 1H NMR chemical shifts (d in ppm) of selected protons of
porphyrins 1–8 recorded in CDCl3
oxidation with DDQ (Scheme 3). TLC analysis showed a
single yellow spot for the required 21,23-dithiaporphyrin
with small amount of polymeric compound (2–5%) on the
baseline. The crude porphyrins were purified by silica gel
column chromatography using petroleum ether/CH2Cl2
(1:1) and afforded the porphyrins 1–4 in 8–14% yields.
Porphyrins 1 and 2 are purple crystalline solids and 3 and 4
were waxy purple solids. The b-alkoxy 21,23-dithia-
porphyrins 1–4 were characterized by NMR, mass, absorp-
tion, emission and elemental analysis. The 1H NMR data of
selected protons compared with unsubstituted 5,10,15,20-
tetraphenyl-21,23-dithiaporphyrin (S2TPP) is presented in
Table 1. The b-thiophene protons which usually appear at
Porphyrin
NH
Pyrrole
S2TPP
1
2
—
—
—
—
—
8.67 (s)
8.38 (s)
8.30 (s)
8.30 (s)
8.30 (s)
8.61 (d), 8.72 (d), 8.88 (s)
8.47(d), 8.52 (d), 8.85 (s)
8.41 (d), 8.50 (d), 8.85 (s)
8.40 (d), 8.48 (d), 8.83 (s)
8.42 (d), 8.50 (d), 8.84 (s)
3
4
STPPH
5
6
7
8
K2.66(s)
K2.58 (s)
K2.57 (s)
K2.59 (s)
K2.58 (s)
Table 2. Absorption and emission data of porphyrins 1–8 in toluene
Porphyrin
Soret band l, nm (log 3)
Q-bands l, nm (log 3)
lem.
IV
III
II
I
Q(0,0)
Q(0,1)
fa
S2TPP
1
2
435 (5.40)
439 (5.40)
441 (5.04)
441 (5.14)
441 (5.24)
429 (5.27)
430 (5.49)
431 (5.36)
431 (5.30)
431 (5.50)
514 (4.41)
517 (4.31)
519 (4.22)
519 (4.53)
519 (4.41)
513 (4.23)
513 (4.49)
514 (4.39)
515 (4.39)
515 (4.54)
547 (3.84)
552 (sh)
555 (sh)
557 (sh)
553 (sh)
547 (3.64)
546 (sh)
547 (sh)
551 (sh)
549 (sh)
633 (3.34)
639 (3.28)
639 (3.40)
640 (3.28)
640 (2.71)
618 (3.27)
617 (3.56)
617 (3.48)
620 (3.43)
618 (3.60)
696 (3.65)
703 (3.61)
705 (3.58)
705 (3.74)
705 (3.78)
675 (3.47)
677 (3.78)
678 (3.68)
680 (3.61)
678 (3.84)
706
711
713
713
713
678
684
685
684
685
781
788
787
787
789
760
750
752
752
752
0.0076
0.0107
0.0133
0.0094
0.0080
0.0168
0.0042
0.0047
0.0036
0.0035
3
4
STPPH
5
6
7
8
a The fluorescence quantum yields were estimated by taking 5,10,15,20-tetraphenyl porphyrin fZ0.11 as the standard.
Scheme 4. Synthetic scheme of N3S porphyrin 8.

N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
10675
shifts compared to S2TPP. However, the quantum yields of
1–4 were slightly increased with alkoxy substituents at
b-thiophene carbons compared to S2TPP (Table 2).
2.3. 21-Monothiaporphyrins with alkoxy substituents at
b-thiophene carbons 5–8
21-Monothiaporphyrins 5–8 were prepared using the same
diols 17–20. One equivalent of corresponding diol 17–20
was condensed with 2 equiv of benzaldehyde and 3 equiv of
pyrrole in the presence of a catalytic amount of BF3$OEt2
followed by oxidation with DDQ (Scheme 4). The
condensation resulted in the formation of a mixture of
three porphyrins with three different porphyrin cores:8 N4,
N3S and N2S2. The mixture of three porphyrins was
separated by silica gel column chromatography using
petroleum ether/dichloromethane mixture as eluant. The
desired N3S porphyrin 5–8 always moved as the second
band and afforded 5–8 in 8–15% yields. Porphyrins 5 and 6
are purple crystalline solids and 7 and 8 are soft brownish
solids. The presence of corresponding strong molecular ion
peaks in the mass spectra confirmed the porphyrins 5–8. The
1H NMR spectra of porphyrins 5 and 8 are presented in
Figure 1 and data of selected protons are tabulated in
1
Table 1. In H NMR, the thiophene protons which usually
appear at 9.81 ppm as a singlet in STPPH were absent due to
substitution of thiophene protons by alkoxy groups. The
three pyrroles in 5–8 appeared as three separate doublets
like STPPH, indicating the less symmetric nature of
porphyrins 5–8. However, the pyrrole protons of 5–8 were
upfield shifted compared to STPPH (Table 1). The NH
proton of 5–8 appeared as a singlet and slightly downfield
shifted compared to STPPH. Absorption and emission bands
were also slightly red shifted compared to STPPH.1
Figure 1. 1H NMR spectra of N3S porphyrin 5 (top) and 8 (bottom)
recorded in CDCl3.
9.68 ppm in S2TPP1were absent in 1–4 due to the
substitution of alkoxy groups at b-thiophene carbons. The
pyrrole protons appeared as singlet indicating the symmetric
nature of porphyrins 1–4. However, the proton signal of
pyrrole which appears at w8.30 ppm in S2TPP1 was upfield
shifted in 1–4 by 0.35 ppm. The mass spectra of 1–4 showed
corresponding molecular ion peaks confirming the products.
The absorption spectra of 1–4 showed three clear Q-bands
and a strong Soret band, which were bathochromically
shifted (8–10 nm) compared to the parent S2TPP (Table 2).
The fluorescence bands of 1–4 also experienced similar red
2.4. Crystal-structure analysis of N2S2 porphyrin 2 and
N3S porphyrin 5
The structures of 2 (CCDC No. 191919) and 5 (CCDC No.
221893) were elucidated by single crystal X-ray diffraction
analysis. A single crystal of 2 suitable for X-ray analysis
was obtained by slow evaporation of CH2Cl2 solution over a
period of one week and crystallized in a triclinic P-1 unit
cell. The aerial and side views of 2 are presented in Figure 2
and the selected parameters and bond lengths and bond
Figure 2. X-ray structure of (a) N2S2 porphyrin 2 and (b) N3S porphyrin 5. Top: aerial view; bottom: side view.

10676
N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
Table 3. Crystal data and collection parameters for 2 and 5
organization between the dithiaporphyrin rings was clearly
evident from the packing diagram.
Parameters
2
5
Empirical formula
Formula weight
Dimensions (mm3)
Crystal system
C30H30NO2S
468.61
C46H33N3O2S
691.81
Porphyrin 5 with two methoxy substituents at b-thiophene
carbons crystallized in a triclinic P-1 unit cell with two
molecules in the unit cell. The crystal was obtained by slow
evaporation of CH2Cl2/CH3OH solution over a period of 10
days. The structure of 5 was slightly saddle-shaped similar
to that of b-unsubstituted 5,10,15,20-tetraphenyl-21-thia-
porphyrin (STPPH) suggesting that the two methoxy groups
at b-thiophene carbons did not alter the structure of the
porphyrin (Fig. 2). The average bond distance of 1.741(3) is
in the normal range of carbon–sulfur bond distances. One of
the methoxy groups on the b-thiophene carbon was tilted
upward and the other methoxy group was tilted downward.
The porphyrin core is saddle-shaped with a mean deviation
of 0.16 A for the atoms in the porphyrin core. The packing
of 5 showed a twisted layer structure with a distance of
˚
3.464 A between N(1) of one molecule and C(21) of the
neighbouring molecule. The Ca–S, Cb–Cb distances of 5 is
almost similar to that of STPPH. The important feature of
the structure is the presence of intramolecular hydrogen-
bonded interactions in the cavity (Table 5).
0.47!0.18!0.12
Triclinic
8.6153(9)
12.0456(13)
12.2567(14)
97.985(2)
90.840(2)
97.106(2)
1249.3(2)
P-1
0.25!0.20!0.18
Triclinic
10.4122(7)
12.5830(9)
14.3020(10)
78.568(2)
75.1600(10)
84.1140(10)
3375(5)
˚
a (A)
˚
b (A)
˚
c (A)
a (deg)
b (deg)
g (deg)
3
˚
V (A )
Space group
Z value
Residuals: R1
T (K)
P-1
2
0.0694
150(2)
2
0.0543
150(2)
˚
angles are presented in Tables 3 and 4. The ORTEP
structure of 2 is perfectly symmetrical but slightly
disordered and half of the molecules are observed with the
other half generated from symmetry. Disorder was noted
with the butoxy groups, which were placed into two
positions in a ratio of 74/26. Interestingly, porphyrin 2 is
more planar compared to S2TPP indicating that the presence
of the butoxy substituents at b-thiophene carbons induced
more planarity in 2 compared to the parent S2TPP. In the
structure of S2TPP, the four five-membered rings are
slightly deviated from the plane of the four meso carbons
whereas in the structure of 2, the four five membered rings
were in the same plane with four meso carbons with
negligible deviation. The non-bonded S/S0 distance was
slightly increased and the N/N0 distance was decreased in
2 compared to S2TPP.1 Furthermore, the presence of
substituents at b-positions also resulted in the decrease of
the Ca–Cb and Cb–Cb distances of the thiophene rings in 2
compared to S2TPP.1 The average distance between the
3. Conclusions
In conclusion, we synthesized and characterized 2,3,12,13-
tetraalkoxy substituted 21,23-dithiaporphyrins and 2,3-
dialkoxy substituted 21-monothiaporphyrins. The spectral
properties were moderately altered by introducing alkoxy
substituents at b-thiophene carbons. Interestingly, the
crystal structure solved for the butoxy substituted 21,23-
dithiaporphyrin is more planar than the unsubstituted parent
S2TPP. However, the crystal structure solved for methoxy
substituted 21-monothiaporphyrin exhibited a saddle-
shaped structure as shown by the unsubstituted parent
STPPH (Fig. 2). Porphyrins bearing long chain alkoxy
groups have been shown to be good liquid crystalline
˚
porphyrin cores in the layered packing structure is 4.702 A.
There was no complete organized overlap packing on the
n-butoxy chain for the b-substituents but the tail-to-tail
Table 4. Selected X-ray structural data for porphyrins 2 and 5
˚
Bond angles (A)
˚
Non-bonded distances (A)
Compound
Bond lengths
1.741(3)
2
S1–C12
C9–C10–C11
113.5(3)
113.6(3)
109.5(2)
110.5(2)
126.7(3)
92.89(15)
105.9(3)
110.9(3)
122.5(3)
125.7(3)
123.4(3)
107.0(3)
S1/S1A
3.100
4.574
C11–C12
C10–C11
N1–C20
C20–C21
C21–C22
1.438(4)
1.383(4)
1.357(4)
1.450(5)
1.339(5)
C10–C11–C12
C11–C12–S1
S1–C9–C10
N1/N1A
C11–C12–C13
C9–S1–C12
C20–N1–C1A
N1–C20–C21
C12–C13–C20
C13–C20–C21
N1–C20–C13
C21–C22–C1A
5
S1–C18
1.738(3)
1.429(4)
1.380(5)
1.350(4)
1.455(5)
1.337(4)
1.422(4)
1.400(5)
C1–S1–C18
92.69(15)
110.3(3)
113.3 (3)
114.0(3)
109.7(3)
121.8(5)
111.2 (3)
106.5 (3)
105.9 (3)
111.4 (2)
104.9 (3)
125.8 (3)
S1/N2
N1/N3
3.598
4.343
C18–C19
C19–C20
N3–C16
C16–C15
C15–C14
C16–C17
C17–C18
S1–C18–C19
C18–C19–C20
C19–C20–C1
S1–C1–C20
C16–C17–C18
N3–C16–C15
C16–C15–C14
C15–C14–C13
C14–C13–N3
C13–N3–C16
C13–C12–C11

N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
Table 5. Intramolecular hydrogen bonding data for N3S porphyrin 5
10677
˚
Distance (A)
Angle (deg)
N2/H2A/S1
N2/H2A/N1
N2/H2A/N3
0.8600
0.8600
0.8600
2.7650
2.4927
2.4771
3.598(2)
2.985(4)
2.971(3)
163.48
117.18
117.28
materials9 and the porphyrins reported in this paper are
potential liquid crystalline materials.
quinoline (30 ml). The mixture was heated at 160 8C for 4 h
under argon atmosphere. The reaction mixture was vacuum
distilled and the pink liquid obtained was dissolved in 50 ml
of ethyl acetate and washed repeatedly with 5% HCl and
water. The organic layer was dried over anhydrous Na2SO4,
filtered and the solvent was evaporated to give a crude
brown coloured liquid. The crude compound was purified by
silica gel column chromatography using ethyl acetate/
petroleum ether mixture (5:95) to afford 13 as colourless
liquid (3.1 g, 56%). 1H NMR (CDCl3, d, ppm): 3.8 (s, 6H),
6.2 (s, 2H); Anal. Calcd: C, 49.98; H, 5.59; S, 22.24. Found:
C, 50.15; H, 5.45; S, 22.47.
4. Experimental
4.1. General
4.1.1. Dimethyl thiodiglycollate 9. In a 500 ml round
bottom flask, thiodiglycolic acid (100 g, 0.666 mol) was
dissolved in dry methanol (250 ml) and conc. sulphuric acid
(10 ml) was added drop wise to it. The resulting mixture was
refluxed for 24 h. The excess methanol was evaporated and
the residue was taken in ethyl acetate, washed with saturated
sodium bicarbonate solution until the aqueous layer was
neutral. The organic layer wad dried over sodium sulfate
and the solvent was removed on a rotary evaporator to afford
4.1.5. 3,4-Dibutoxythiophene 14. In a 100 ml dry three-
necked round bottom flask, 13 (2.0 g, 13.8 mmol) was taken
with 50 ml of dry toluene. To this solution n-butanol (3.5 g,
47.29 mmol) was added along with 0.20 g p-toluenesulfonic
acid. The mixture was allowed to stir at 90 8C for 28 h.
Excess solvent was evaporated and the crude compound was
purified by column chromatography using petroleum ether
as eluent. 2.0 g (66%) of pure compound 14 was obtained as
a yellow oil. 1H NMR (CDCl3, d, ppm): 6.10 (s, 2H), 3.90 (t,
JZ7.99 Hz 4H), 1.80 (m, 4H), 1.46 (m, 4H), 0.96 (t, JZ
6.39 Hz, 6H); Anal. Calcd: C, 63.12; H, 8.83; S, 14.04.
Found: C, 63.39; H, 8.67; S, 14.17.
1
a light yellow liquid (106 g, 89%). H NMR (CDCl3, d,
ppm): 3.4 (s, 4H), 3.7 (s, 6H); Anal. Calcd: C, 40.44; H,
5.66; S, 17.99. Found: C, 40.32; H, 5.85; S, 17.88.
4.1.2. 3,4-Dimethoxy-2,5-dimethoxycarboxy thiophene
11. A solution of 10.5 g of sodium metal in 100 ml of dry
methanol was cooled at 0–5 8C. To this a solution of 26.7 g
of 9 and 26.7 g of diethyloxalate was added and stirred. The
temperature was maintained below 30 8C. The sodium salt
was precipitated as a yellow solid. The reaction was
completed by warming the reaction mixture to reflux for
2 h. After cooling, the solid was filtered and dried. The
sodium salt of diol diester 10 (15 g, 54.3 mmol) was taken in
65 ml of freshly distilled dimethyl sulfate and the mixture
was heated at 100 8C for 1 h. The excess dimethyl sulfate
was distilled at low pressure and the crude product was
dissolved in ethyl acetate (100 ml) and washed with cold 5%
NaOH solution (50 ml). The organic layer was dried over
sodium sulfate and solvent was evaporated to afford
compound 11 as a pure light yellow solid (9.1 g, 64%).
4.1.6. 3,4-Dioctyloxythiophene 15. Stirring of 13 (2.0 g,
13.8 mmol) in 50 ml of dry toluene, n-Octanol (3.9 g,
30 mmol) and p-toluenesulfonic acid (0.20 g) under same
reaction conditions mentioned for 14 yielded 15 as yellow
oil in 67% yield (3.1 g). 1H NMR (CDCl3, d, ppm): 6.10 (s,
2H), 3.9 (t, JZ5.94 Hz, 4H), 1.80 (m, 4H), 1.30 (m, 20H),
0.80 (t, JZ3.99 Hz, 6H); Anal. Calcd: C, 70.53; H, 10.65; S,
9.42. Found: C, 70.92; H, 10.87; S, 9.58.
4.1.7. 3,4-Didodecyloxythiophene 16. Compound 16 was
synthesized under similar reaction conditions mentioned for
14 by stirring 13 (2.0 g, 13.8 mmol) in 50 ml of dry toluene
with n-dodecanol (5.6 g, 30.36 mmol) and p-toluene-
sulfonic acid (0.20 g) at 90 8C. Column chromatography
of crude compound afforded 16 as yellow oil (4.2 g, 67%).
1H NMR (CDCl3, d, ppm): 6.10 (s, 2H), 3.98 (t, JZ5.99 Hz,
4H), 1.80 (m, 4H), 1.15 (m, 36H), 0.80 (t, JZ4.23 Hz, 6H);
Anal. Calcd: C, 74.27; H, 11.58; S, 7.08. Found: C, 74.53;
H, 11.79; S, 7.20.
1
Mp: 85 8C; H NMR (CDCl3, d, ppm): 3.9 (s, 6H), 4.1 (s,
6H); Anal. Calcd: C, 46.15; H, 4.65; S, 12.32. Found: C,
46.46; H, 4.42; S, 12.51.
4.1.3. 3,4-Dimethoxy thiophene-2,5-dicarboxylic acid 12.
In a 100 ml round bottom flask 11 (9 g, 34.6 mmol) was
taken and 10% NaOH (50 ml) was added to it. The mixture
was refluxed for 1 h. The reaction mixture was cooled to
room temperature and conc. HCl was added to it with
stirring. The precipitate thus formed was collected in a
Buchner funnel and dried in a oven to give 12 as a white
solid (6.8 g, 84%). Mp: O250 8C (lit. value6a: decomposed
above 250 8C); 1H NMR (CDCl3, d, ppm): 3.9 (s, 6H); Anal.
Calcd: C, 41.38; H, 3.47; S, 13.81. Found: C, 41.59; H, 3.52,
S, 13.94, (lit. value6a: S, 13.79).
4.1.8. 2,5-Bis-(phenylhydroxymethyl)-3,4-dimethoxy-
thiophene 17. In a 100 ml three-necked round bottom
flask fitted with a gas inlet tube, a reflux condenser and a
rubber septum, d0ry and distilled n-hexane (25 ml) was
placed. N, N0,N0,N -Tetramethylethylenediamine (TMEDA)
(1.40 ml, 9.45 mmol) and n-BuLi (7.0 ml 15% solution in
hexane) were injected and stirred for 10 min. A sample of 13
(540 mg, 3.75 mmol) was then added and solution was
refluxed gently for 1 h. A white curdy solution of 2,5-
dilithiated salt of 13 was formed. In another three-necked
4.1.4. 3,4-Dimethoxythiophene 13. A 100 ml dry three-
necked round bottom flask was charged with 12 (9 g,
43.3 mmol), copper chromite (0.56 g, 4% mol) and dry

10678
N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
round bottom flask, fitted with a gas inlet, outlet and rubber
septum, benzaldehyde (1.1 ml, 10.7 mmol) was dissolved in
15 ml dry THF. The solution was cooled in an ice bath and
nitrogen was bubbled for 15 min. The 2,5-dilithiated salt of
13 was added slowly to benzaldehyde solution in THF
through siphon apparatus over 15 min. After addition was
complete, the mixture was allowed to reach the room
temperature. An ice-cooled saturated NH4Cl solution was
added and extracted with ether (3!50 ml). The organic
layers were combined and washed with brine and dried over
anhydrous Na2SO4. The solvent was removed on a rotary
evaporator to obtain a crude brown oil. TLC analysis
indicated the formation of the required diol 17 and small
amounts of mono-ol. The crude diol was subjected to silica
gel column chromatography using petroleum ether/ethyl
acetate mixture as eluent. The mono-ol was collected first as
oily compound using petroleum ether/ethyl acetate (8:2) in
21% yield (0.210 g) and the diol 17 was collected as white
crystalline compound using petroleum ether/ethyl acetate
(7:3) in 23% yield (0.295 g). Mp: 126–127 8C; IR (KBr,
cmK1): 3310 (OH); 1H NMR (CDCl3, d in ppm): 0.88 (t, JZ
6.89 Hz, 6H, CH3), 1.27 (s, 24H, CH2), 2.68 (s, 2H, OH),
3.83–3.93 (m, 4H, OCH2), 6.03 (s, 2H, CH), 7.26–7.43 (m,
10H, phenyl); FAB-MS: C34H48O4S calcd av. mass, 552.8.
Obsd m/z 552 (MC); Anal. Calcd: C, 73.87; H, 8.75; S, 5.80.
Found: C, 73.45; H, 9.01; S, 5.95.
4.1.11. 2,5-Bis-(phenylhydroxymethyl)-3,4-bis-(didode-
cyloxy)thiophene 20. The 2,5-Dilithiated salt of 16 was
prepared by refluxing TMEDA (0.56 ml, 3.80 mmol),
n-BuLi (3.0 ml 15% solution in hexane) and 16 (0.680 g,
1.5 mmol) in n-hexane (6 ml). Benzaldehyde, (0.40 ml,
3.92 mmol) in dry THF (10 ml) was added slowly to the 2,5-
dilithiated salt of 16 and refluxed for 1 h. After standard
work-up, the crude diol was purified by colomn chroma-
tography using petroleum ether/ethyl acetate mixture as
eluent. The oily mono-ol (18%) was collected as the first
band with petroleum ether/ethyl acetate (9:1) and white
crystalline solid diol 20 was collected in 9:1 petroleum
ether/ethyl acetate solvent mixture (0.345 g, 33%). Mp: 54–
56 8C; IR (KBr, cmK1): 3308 (OH); 1H NMR (CDCl3, d in
ppm): 0.88 (t, JZ6.92 Hz, 6H, CH3), 1.26 (s, 36H, CH2),
1.65 (q, JZ7.62 Hz, 4H, CH2), 2.65 (d, JZ3.66 Hz, 2H,
OH), 3.90 (q, JZ6.67 Hz, 4H, OCH2,), 6.03 (d, JZ3.66 Hz,
2H, CH), 7.28–7.43 (m, 10H, phenyl); FAB-MS:
C42H64O4S calcd av. mass, 665.02. Obsd m/z 665 (MC);
Anal. Calcd: C, 75.85; H, 9.70; S, 4.82. Found: C, 75.63; H,
9.87; S, 4.75.
1
cmK1): 3299 (OH); H NMR (CDCl3, d in ppm): 2.60 (s,
2H, OH), 3.77 (s, 6H, OCH3), 6.11 (s, 2H, CH), 7.27–7.43
(m, 10H, phenyls); FAB-MS: C20H20O4S calcd av. mass,
356.10. Obsd m/z 356 (MC); Anal. Calcd: C, 67.39, H, 5.66.
S, 9.00. Found: C, 67.58; H, 5.79, S, 9.25.
4.1.9. 2,5-Bis-(phenylhydroxymethyl)-3,4-dibutyloxy-
thiophene 18. The 2,5-dilithiated salt of 14 was prepared
by refluxing the mixture of TMEDA (0.35 ml, 2.3 mmol),
n-Buli (2.2 ml of 15% solution in n-hexane) and 14
(0.230 mg, 1 mmol) in n-hexane (15 ml). The 2,5-dilithiated
salt of 14 was then added slowly to the ice-cooled solution
of benzaldehyde (0.270 ml, 2.65 mmol) in dry THF (5 ml)
and refluxed for 1 h. After standard work-up as mentioned
for diol 17, the crude compound was purified by silica gel
column chromatography. The fast moving mono-ol was
collected as the first band with petroleum ether/ethyl acetate
(9:1) in 21% yield (0.210 g) and the desired diol 18 was
obtained as white crystalline solid in 28% yield (0.125 g).
Mp: 92–94 8C; IR (KBr, cmK1): 3313(OH); 1H NMR
(CDCl3, d in ppm): 0.94 (t, JZ7.34 Hz, 6H, CH3), 1.45 (q,
JZ7.71 Hz, 4H, CH2), 1.60–1.67 (m, 4H, CH2), 2.61 (d, JZ
3.2 Hz, 2H, OH), 3.90–3.94 (m, 4H, OCH2), 6.03 (d, JZ
3.0 Hz, 2H, CH), 7.28–7.43 (m, 10H, phenyl); 13C NMR
(CDCl3, d in ppm): 13.91, 14.26, 18.95, 19.23, 19.34, 31.90,
69.62, 72.71, 73.26, 74.36, 126.23, 127.26, 128.32, 142.4,
145.7; FAB-MS: C26H32O4S calcd av. mass, 440.5. Obsd
m/z 440 (MC); Anal. Calcd: C, 70.88; H, 7.32; S, 7.28.
Found: C, 71.23; H, 7.47; S, 7.36.
4.1.12. 2,3,12,13-Tetramethoxy-5,10,15,20-tetraphenyl-
21,23-dithiaporphyrin 1. A solution of 1 equiv of diol 17
(0.50 g, 1.41 mmol) and 1 equiv of pyrrole (0.15 ml,
2.16 mmol) were condensed in CH2Cl2 (140 ml) in the
presence of catalytic amount of BF3$OEt2 (50 ml of 2.5 M
solution in CH2Cl2). The reaction mixture was stirred for 1 h
under nitrogen. The progress of the reaction was monitored
with UV–visible spectroscopy at regular intervals by taking
aliquots of the reaction mixture and oxidised with DDQ.
After completion of the reaction, DDQ (0.250 g,
1.10 mmol) was added as an oxidant and the reaction
stirred at room temperature for 1 h in air. A few drops of
triethylamine were added to neutralize the reaction mixture.
TLC analysis showed the formation the required compound
as the sole product. The solvent was removed under vacuo
and the crude reaction mixture was purified by silica gel
column chromatography using petroleum ether/CH2Cl2
(2:8) and afforded 1 as a purple solid in 14% yield
(0.150 g). Mp: O300 8C; IR (KBr, cmK1): 701, 2867, 2952,
1
3425; H NMR (CDCl3, d in ppm): 3.86 (s, 12H, OCH3),
7.69–7.77 (m, 12H, m,p-phenyl), 8.12 (q, JZ3.66 Hz, 8H,
o-phenyl), 8.38 (s, 4H, pyrrole); FAB-MS calcd av. for
C48H36N2O4S2: 768.9. Obsd m/z: 769. Anal. Calcd: C,
74.97; H, 4.72; N, 3.64; S, 8.34. Found: C, 75.26; H, 4.92;
N, 3.71; S, 7.98.
4.1.10. 2,5-Bis-(phenylhydroxymethyl)-3,4-dioctyloxy-
thiophene 19. A mixture of 15 (0.420 g, 1.2 mmol),
TMEDA (0.450 ml, 3.03 mmol) and n-BuLi (2.5 ml,
1.6 M solution in hexane) in n-hexane (10 ml) was refluxed
to afford the 2,5-dilithiated salt of 15. The dilithiated salt of
15 was added slowly to an ice-cooled solution of
benzaldehyde (0.33 ml, 3.23 mmol) in dry THF (10 ml).
The crude compound was subjected to silica gel column
chromatography using petroleum ether/ethyl acetate mix-
ture as eluent. The mono-ol was obtained as oil in 21% yield
(0.130 g) using petroleum ether/ethyl acetate (8:2) and diol
19 as white solid in 28% yield (0.190 g) using petroleum
ether/ethyl acetate mixture (8:2). Mp: 128–129 8C; IR (KBr,
4.1.13. 2,3,12,13-Tetrabutyloxy-5,10,15,20-tetraphenyl-
21,23-dithiaporphyrin 2. Samples of diol 18 (0.650 g,
1.47 mmol) and pyrrole (0.15 ml, 2.16 mmol) were dis-
solved in 150 ml dichloromethane taken in a 250 ml one-
necked round bottom flask and stirred under an argon
atmosphere for 15 min. BF3$OEt2 (50 ml of 2.5 M solution)
was added to initiate the condensation. After 1 h DDQ
(0.260 g, 1.14 mmol) was added and the reaction mixture

N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
10679
stirred for 1 h in air. After standard work up, the crude
compound was purified by silica gel column chromato-
graphy using petroleum ether/CH2Cl2 (2:8) as eluent to
afford purple compound 2 in 8% yield (0.110 g). Mp: O
benzaldehyde (0.120 ml, 1.17 mmol) and pyrrole (0.120 ml,
1.73 mmol) were dissolved in dichloromethane (50 ml) and
stirred at room temperature for 15 min. BF3$OEt2 (30 ml of
2.5 M stock solution in dichloromethane) was added to
initiate the reaction. After 1.5 h stirring DDQ (0.095 g,
0.42 mmol) was added to oxidise the porphyrinogen. The
TLC analysis of the crude porphyrin showed the formation
of three porphyrins as expected. The mixture of three
porphyrins were separated by silica gel column chromato-
graphy using petroleum ether/dichloromethane as solvent
mixture. The desired N3S porphyrin 5 moved as the second
band with petroleum ether/CH2Cl2 (1:1). Removal of
solvent under reduced pressure gave 5 as purple solid in
10% yield (0.039 g). Mp: O 300 8C; IR (KBr, cmK1): 701,
1
250 8C; IR (KBr, cmK1): 701, 2866, 2955, 3414; H NMR
(CDCl3, d in ppm): 0.87 (t, JZ6.59 Hz, 12H, CH3), 1.20–
1.25 (m, 16H, CH2), 4.11 (t, JZ6.22 Hz, 8H, OCH2), 7.67–
7.69 (m, 12H, m,p-phenyl), 8.13 (q, JZ3.66 Hz, 8H, o-
phenyl), 8.30 (s, 4H, pyrrole); 13C NMR (CDCl3, d in ppm):
13.89, 14.14, 19.12, 29.76, 31.68, 53.48, 74.39, 120.18,
126.46, 127.34, 128.47, 133.22, 134.04, 137.57, 142.40,
153.92, 157.46; LD-MS C60H60N2O4S2 calcd av. mass:
937.26. Obsd m/z: 937.64; Anal. Calcd: C, 76.89; H, 6.45;
N, 2.99; S, 6.84. Found: C, 76.69; H, 6.58; N, 3.10; S, 6.95.
1
2854, 2927, 3463; H NMR (CDCl3, d in ppm): K2.58 (s,
1H, NH), 3.92 (s, 6H, OCH3), 7.70–7.74 (m, 12H, m,p-
phenyl), 8.11–8.18 (m, 8H, o-phenyl), 8.47 (d, JZ4.76 Hz,
2H, pyrrole), 8.52 (d, JZ4.76 Hz, 2H, pyrrole), 8.85 (s, 2H,
pyrrole); FAB-MS: C46H33N3O2S calcd 691.84. Obsd m/z:
692; Anal. Calcd: C, 79.86; H, 4.81; N, 6.07; S, 4.63. Found:
C, 79.51; H, 5.06; N, 6.47; S, 4.92.
4.1.14. 2,3,12,13-Tetraoctyloxy-5,10,15,20-tetraphenyl-
21,23-dithiaporphyrin 3. In a one-necked 250 ml round
bottom flask, samples of diol 19 (0.50 g, 0.91 mmol) and
pyrrole (0.090 ml, 1.3 mmol) were dissolved in 100 ml
CH2Cl2 and stirred at room temperature under an inert
atmosphere. BF3$OEt2 (40 ml of 2.5 M solution in dichloro-
methane) was added to start the cyclization. After stirring
for 1.5 h DDQ (154 mg, 0.678 mmol) was added and stirred
for additional 1 h in air. A few drops of triethylamine were
added to neutralize the reaction mixture. Column chroma-
tography on silica gel, using petroleum ether/CH2Cl2 (1:2)
as an eluent afforded the desired porphyrin 3 as purple waxy
solid (13%, 0.13 g). Mp: 216–217 8C; IR (KBr, cmK1): 701,
2856, 2923, 3434; 1H NMR (CDCl3, d in ppm): 0.91 (t, JZ
6.95 Hz, 12H, CH3), 1.25 (m, 48H, CH2), 4.11 (q, JZ
6.22 Hz, 8H, OCH2), 7.67–7.69 (m, 12H, m,p-phenyl), 8.11
(q, JZ3.29 Hz, 8H, o-phenyl),), 8.30 (s, 4H, pyrrole); 13C
NMR (CDCl3, d in ppm): 14.21, 22.79, 25.94, 29.36, 29.78,
31.93, 74.68, 126.46, 127.37, 131.45, 132.15, 133.05,
133.21, 134.05, 142.43, 153.96, 157.28; LDMS
C76H92N2O4S2 calcd mass 1161.6. Obsd m/z 1162.5; Anal.
Calcd: C, 78.58; H, 7.98; N, 2.41; S, 5.52. Found: C, 78.46;
H, 8.06; N, 2.58; S, 5.69.
4.1.17. 2,3-Dibutoxy-5,10,15,20-tetraphenyl-21-mono-
thiaporphyrin 6. A solution of diol 18 (0.30 g,
0.68 mmol), benzaldehyde (0.15 ml, 1.47 mmol) and
pyrrole (0.14 ml, 2.02 mmol) in dichloromethane (80 ml)
was treated with BF3$OEt2 (50 ml of 2.5 M solution of
dichloromethane). After 1 h, DDQ (0.120 g, 0.528 mmol)
was added and stirring was continued for another 1 h.
Column chromatography on silica gel using with petroleum
ether and CH2Cl2 (1:1) gave the desired compound 6 as the
second band (0.042 g, 8%). Mp: O300 8C; IR (KBr, cmK1):
709, 2861, 2927, 3460; 1H NMR (CDCl3, d in ppm): K2.57
(s, 1H, NH), 1.27 (s, 14H, CH2CH3), 4.21–4.24 (s, 4H,
OCH2), 7.70–7.76 (m, 12H, m,p-phenyl), 8.11–8.18
(m, 8H, o-phenyl), 8.41 (d, JZ4.76 Hz, 2H, pyrrole), 8.50
(d, JZ4.39 Hz, 2H, pyrrole), 8.85 (s, 2H, pyrrole); FAB-
MS: C52H45N3O2S calcd 776.84. Obsd m/z: 776; Anal.
Calcd: C, 80.48; H, 5.85; N, 5.41; S, 4.13. Found: C, 80.83;
H, 6.02; N, 5.77; S, 4.43.
4.1.15. 2,3,12,13-Tetradodecyloxy-5,10,15,20-tetra-
phenyl-21,23-dithiaporphyrin 4. A solution of diol 20
(0.400 g, 0.58 mmol) and pyrrole (0.050 ml, 0.73 mmol) in
CH2Cl2 was stirred under an inert atmosphere. After 15 min,
BF3$OEt2 (30 ml of 2.5 M solution in dichloromethane) was
added and the reaction was stirred for 1 h. DDQ (0.102 g,
0.45 mmol) was added and stirred for an additional 1 h in
air. After work up, the crude porphyrin was purified by
column chromatography using petroleum ether/CH2Cl2
(6:4) as eluent and afforded a waxy purple solid of 4 in
13% yield (0.260 g). Mp: 195–196 8C; IR (KBr, cmK1):
702, 2860, 2927, 3442; 1H NMR (CDCl3, d in ppm): 0.90 (t,
JZ6.59 Hz, 12H, CH3), 1.25–1.28 (m, 80H, CH2), 4.11 (t,
JZ6.22 Hz, 8H, OCH2), 7.67–7.69 (m, 12H, m, p-phenyl),
8.10–8.13 (m, 8H, o-phenyl), 8.30 (s, 4H, pyrrole); 13C
NMR (CDCl3, d in ppm): 14.22, 22.80, 25.97, 29.50, 29.74,
32.05, 74.70, 126.47, 127.39, 131.47, 133.07, 133.22,
134.07, 142.45, 153.98, 157.30; LD-MS C92H124N2O4S2
calcd mass 1386.1. Obsd m/z: 1386.0; Anal. Calcd: C,
79.72; H, 9.02; N, 2.02; S, 4.63. Found: C, 79.96; H, 8.93;
N, 2.23; S, 4.84.
4.1.18. 2,3-Dioctyloxy-5,10,15,20-tetraphenyl-21-mono-
thiaporphyrin 7. A mixture of 19 (0.200 g, 0.362 mmol),
benzaldehyde (0.090 ml, 0.797 mmol) and pyrrole
(0.080 ml, 1.21 mmol) in dry CH2Cl2 (40 ml) was con-
densed in the presence of BF3$OEt2 (30 ml of 2.5 M solution
in dichloromethane) followed by oxidation with DDQ
(0.062 g, 0.27 mmol). Purification was achieved by silica
gel column chromatography using petroleum ether/CH2Cl2
mixture (1:1) giving the desired N3S as second band. The
solvent was removed in vacuo to afford 7 as soft purple solid
(0.032 g, 9.9%). Mp: O225 8C; IR (KBr, cmK1): 703, 2852,
2923, 3434; 1H NMR (CDCl3, d in ppm): and K2.59 (s, 1H,
NH), 1.42 (s, 30H, CH2CH3), 4.2 (s, 4H, OCH2), 7.68–7.73
(m, 12H, m,p-phenyl), 8.11–8.29 (m, 8H, o-phenyl), 8.40 (d,
JZ4.88 Hz, 2H, pyrrole), 8.48 (d, JZ3.66 Hz, 2H, pyrrole),
8.83 (s, 2H, pyrrole); FAB-MS: C60H61N3O2S calcd 888.21.
Obsd m/z: 889; Anal. Calcd: C, 80.13; H, 6.92; N, 4.73; S,
3.61. Found: C, 80.38; H, 6.74; N, 4.98; S, 3.45.
4.1.19. 2,3-Didodecyloxy-5,10,15,20-tetraphenyl-21-
monothia porphyrin 8. A solution of diol 20 (0.210 g,
0.304 mmol), benzaldehyde (0.065 ml, 0.637 mmol) and
4.1.16. 2,3-Dimethoxy-5,10,15,20-tetraphenyl-21-mono-
thiaporphyrin 5. A mixture of 17 (0.200 g, 0.560 mmol),

10680
N. Agarwal et al. / Tetrahedron 60 (2004) 10671–10680
Eds.; The Porphyrin Handbook; Academic: New York, 2000;
Vol. 2, pp 361–416; and references cited therein.
pyrrole (0.070 ml, 1.01 mmol) in CH2Cl2 (30 ml) was
treated with BF3$OEt2 (25 ml of 2.5 M solution). After 1 h
stirring, DDQ (0.060 g, 0.26 mmol) was added and stirring
was continued for another hour. Chromatography on silica
gel using petroleum ether/CH2Cl2 (7:3) gave the desired
N3S porphyrin 8 as a waxy purple solid in 15% yield
(0.450 g). Mp: O225 8C; IR (KBr, cmK1): 704, 2853, 2923,
2. Ravikanth, M.; Chandrashekar, T. K. Struct. Bonding 1995, 82,
105–188 and references cited therein.
3. (a) Hariprasad, G.; Dahal, S.; Maiya, B. G. J. Chem. Soc.,
Dalton Trans. 1996, 3429–3436. (b) Ellis, P. E.; Lyons, J. E.
Coord. Chem. Rev. 1990, 105, 181–193. (c) Bhyrappa, P.;
Krishanan, V. Inorg. Chem. 1991, 30, 239–245. (d) Crossley,
M. J.; Burn, P. L.; Chew, S. S.; Cuttance, F. B.; Newton, I. A.
J. Chem. Soc., Chem. Commun. 1991, 1564–1566. (e) D’Souza,
F.; Villard, A.; Camelbecke, E. V.; Franzen, M.; Boschi, T.;
Tagliatesti, P.; Kadish, K. M. Inorg. Chem. 1993, 32,
4042–4048. (f) Ochsenbein, P.; Mandon, D.; Fischer, J.;
Weiss, R.; Austin, R. N.; Jayaraj, K.; Gold, A.; Terner, J.;
Bill, E.; Muther, M.; Trautwein, A. X. J. Angew. Chem., Int. Ed.
Engl. 1993, 32, 1437–1439. (g) D’Souza, F.; Deviprasad, G. R.;
Zandler, M. E. J. Chem. Soc., Dalton Trans. 1997, 3699–3704.
4. (a) Dolphin, D.; Traylor, T. G.; Xie, L. L. Acc. Chem. Res. 1997,
30, 251–259. (b) Ellis, P. E. Jr.; Lyons, J. E. Catal. Lett. 1989, 3,
389–393. (c) Grinstaff, M. W.; Hill, M. G.; Labinger, J. A.;
Gray, H. B. Science 1994, 264, 1311–1313.
1
3453; H NMR (CDCl3, d in ppm): K2.58 (s, 1H, NH),
0.90 (s, 6H, CH3), 1.27 (s, 40H, CH2), 4.19 (s, 4H, OCH2),
7.67–7.73 (m, 12H, m,p-phenyl), 8.10–8.15 (m, 8H,
o-phenyl), 8.42 (d, JZ4.76 Hz, 2H, pyrrole), 8.50 (d, JZ
4.76 Hz, 2H, pyrrole), 8.84 (s, 2H, pyrrole); 13C NMR
(CDCl3, d in ppm): 14.2, 22.78, 26.00, 29.74, 32.04, 74.73,
123.96, 126.45, 127.30, 127.86, 128.43, 133.06, 133.38,
134.42, 134.84, 138.71, 142.25, 142.50, 153.53, 154.18,
158.71; FAB-MS: C68H77N3O2S calcd 1000.42. Obsd m/z:
1001; Anal. Calcd: C, 81.64; H, 7.76; N, 4.20; S, 3.21.
Found: C, 81.76; H, 7.52; N, 4.60; S, 3.53.
Acknowledgements
5. Agarwal, N.; Mishra, S. P.; Kumar, A.; Hung, C.-H.; Ravikanth,
M. Chem. Commun. 2002, 2642–2643.
This research was supported by Department of Atomic
Energy (No. 2001/37/21/BRNS/797) and Council of
Scientific and Industrial Research, Govt. of India. Mass
and NMR spectra were obtained at Department of
Chemistry, IIT-Bombay.
6. (a) Fager, E. W. J. Am. Chem. Soc. 1945, 67, 2217–2218.
(b) Krishnamoorthy, K.; Ambade, A. V.; Kanungo, M.;
Contractor, A. Q.; Kumar, A. J. Mater. Chem. 2001, 11,
2909–2911.
7. Ulman, A.; Manassen, J. J. Am. Chem. Soc. 1975, 97,
6540–6544.
8. (a) Kumaresan, D.; Agarwal, N.; Gupta, I.; Ravikanth, M.
Tetrahedron 2002, 58, 5347–5356. (b) Santra, S.; Kumaresan,
D.; Agarwal, N.; Ravikanth, M. Tetrahedron 2003, 59,
2353–2362.
Supplementary data
Supplementary data associated with this article can be found
at doi:10.1016/j.tet.2004.09.008
9. (a) Patel, B. R.; Suslick, K. S. J. Am. Chem. Soc. 1998, 120,
11802–11803. (b) Bhyrappa, P.; Young, J. K.; Moore, J. S.;
Suslick, K. S. J. Am. Chem. Soc. 1996, 118, 5708–5711.
(c) Gaspard, S.; Maillard, P.; Billard, J. Mol. Cryst. Liq. Cryst.
1985, 123, 369–375. (d) Nakai, T.; Ban, K.; Ohta, K.; Kimura,
M. J. Mater. Chem. 2002, 844–850 and references cited therein.
References and notes
1. Latos-Grazynski, L. Kadish, K. M., Smith, K. M., Guilard, R.,