Efficient method for the synthesis of hetarenoindanones based on 3-arylhetarenes and their conversion into hetarenoindenes

Article abstract of DOI:10.1021/jo049504w

A series of hetarenoindanones have been prepared by direct double metalation of the appropriate 3-phenylhetarene with butyllithium in the presence of TMEDA followed by treatment of the resulting dilithium compound with ethyl N ,N-dimethylcarbamate. All hetarenoindanones were reduced according to Wolff-Kishner by hydrazine in the presence of KOH to the corresponding hetarenoindenes.

Full text of DOI:10.1021/jo049504w

sibility of these benzoic acids, sometimes unpredictable
reaction route,8 and relatively low yields in the case of
furan derivatives.5 According to some known methods for
the synthesis of cyclic ketones, the carbonyl group is
introduced by direct carbonylation. For example, a num-
ber of hetarenoindanones with various heteroatoms have
been prepared by palladium-catalyzed cyclocarbonylation
of phenylhetarenes containing a halogen (Br or I) either
in the heterocycle or in the phenyl group9 (eq 2) (Scheme
1).
We developed a new, efficient method for the synthesis
of ketones in which readily available 3-arylhetarenes are
involved in cyclocarbonylation. The essence of this method
is direct double metalation of 3-arylhetarene with butyl-
lithium in the presence of TMEDA, similar to the reaction
reported for biphenyl,10 and treatment of the resulting
dilithium salt with ethyl N,N-dimethylcarbamate as a
carbonylating reagent (Scheme 2). This reagent, like
other N,N-disubstituted carbamates, is also employed
successfully for the synthesis of acyclic dithienyl ketenes.11
Since monometalation is apparently the rate-determining
step in the preparation of the dilithium derivative of
biphenyl and the heterocycle is metalated more readily
than benzene,12 we expected that the yields of the
dilithium derivatives would be higher in the case of
3-phenylhetarenes than with biphenyl.
Efficien t Meth od for th e Syn th esis of
Heta r en oin d a n on es Ba sed on
3-Ar ylh eta r en es a n d Th eir Con ver sion in to
Heta r en oin d en es
Igor A. Kashulin and Ilya E. Nifant’ev*
Department of Chemistry, Moscow State University,
Moscow 119992, Russia
inif@org.chem.msu.ru
Received March 26, 2004
Abstr a ct: A series of hetarenoindanones have been pre-
pared by direct double metalation of the appropriate 3-phen-
ylhetarene with butyllithium in the presence of TMEDA
followed by treatment of the resulting dilithium compound
with ethyl N,N-dimethylcarbamate. All hetarenoindanones
were reduced according to Wolff-Kishner by hydrazine in
the presence of ΚOH to the corresponding hetarenoindenes.
In recent years, indene derivatives in which the cyclo-
pentadienyl ring is annelated to a five-membered het-
erocycle (hetarenoindenes)1 have found increasing appli-
cation in the synthesis of ligands for transition metal
complexes.2,3
The dilithium derivatives of phenylhetarenes were
prepared in situ by treatment of compounds 1a -e in
ether with 2 equiv of BuLi in hexane in the presence of
2 equiv of TMEDA. Treatment of a part of the reaction
mixture with D2O has shown that bimetalation of phen-
ylhetarenes proceeds in a quantitative yield (according
to 1H and 13C NMR), whereas the bimetalation of biphen-
yl (1f) and 4,4′-di-tert-butyl-1,1′-biphenyl (1g) according
to a known procedure,10 namely, by refluxing a mixture
of the substrate and 2 equiv of TMEDA in a hexane
solution of BuLi, occurs in a yield of only 50-60%.
The reaction of dilithium derivatives 1a -e with ethyl
N,N-dimethylcarbamate (eqs 3, 4) gave rise to the
required hetarenoindanones 2a -e (Scheme 3). The yields
of ketones 2a -e were 42-90%. The starting compound
1a was synthesized by cyclization of ω-phenoxyacetophe-
none;13 compounds 1b-e were prepared by cross-coupling
of 3-bromo-heterocycles with Grignard reagents in the
presence of NiCl2dppp as the catalyst.
A general method for the synthesis of hetarenoindenes
is reduction of the corresponding hetarenoindanones,
which usually proceeds rather smoothly and gives prod-
ucts in good yields. However, the main method for the
synthesis of the starting hetarenoindanones consisting
of intramolecular cyclization of 2-hetarylbenzoic acids
and their derivatives under various conditions4-7 (eq 1)
suffers from a number of drawbacks such as low acces-
* Phone/Fax: +7(095) 939 4523.
(1) Laishevtsev, I. P.; Kashulin, I. A.; Taidakov, I. V.; Bagrov, V.
V.; Nifant’ev I. E. Chem. Heterocycl. Compd. 2003, 39, 553.
(2) For heterocyclic analogues of fluorene, see: (a) Nifant’ev, I. E.;
Bagrov, V. V. PCT WO 99/24446. (b) Resconi, L.; Guidotti, S.; Baruzzi,
G.; Grandini, C.; Kashulin, I. A.; Ivchenko, P. V.; Nifant’ev, I. E. PCT
WO 01/53360. (c) J ohnson, K. W.; Merrick-Mack, J . A.; Mack, M. P.;
Nagy, S.; Wang, S.; Lee, C. C.; Lynch, M. W.; Mutchler, J . A.; Tsuie,
B. M.; Neal-Hawkins, K. L. PCT WO 03/089485. (d) Grandini, C.;
Camurati, I.; Guidotti, S.; Mascellani, N.; Resconi, L.; Nifant’ev, I. E.;
Kashulin, I. A.; Ivchenko, P. V.; Mercandelli, P.; Sironi, A. Organo-
metallics 2004, 23, No. 3, 344. (e) Mack, M. P.; Nagy, S.; Wang, S.;
Lee, C. C.; Tsuie, B. M.; Hlatky, G. G.; Meverden, C. C. PCT WO 2004/
013194.
The developed procedure was used to convert biphenyls
1f,g into fluorenones 2f,g (eq 5). The dilithium salt of
biphenyl is quantitatively converted into the ketone, the
yield of the product (50-60%) being determined only by
the degree of bimetalation of the starting hydrocarbon
(Scheme 3).
(3) For heterocyclic analogues of indene, see: (a) J ones, R. L. J .;
Dubitsky, Y. A.; Elder, M. J .; Ewen, J . A. PCT WO 98/22486. (b) Ewen,
J . A.; J ones, R. L.; Elder, M. J .; Rheingold, A. L.; Liable-Sands, L. M.
J . Am. Chem. Soc. 1998, 120, 10786. (c) Resconi, L.; Guidotti, S.;
Laishevtsev, I. P.; Nifant’ev, I. E. EP 1157027, 2001. (d) Dall’oco, T.;
Fusco, O.; Galimberti, M.; Nifant’ev, I. E.; Laishevtsev, I. P. EP
1157046, 2001. (e) Ewen, J . A.; Elder, M. J .; J ones, R. L.; Rheingold,
A. L.; Liable-Sands, L. M.; Sommer, R. D. J . Am. Chem. Soc. 2001,
123, 4763. (f) Dall’oco, T.; Fusco, O.; Laishevtsev, I. P.; Nifant’ev, I. E.
EP1226193, 2002. (g) Ryabov, A. N.; Izmer, V. V.; Borisenko, A. A.;
Canich, J . A. M.; Kuz’mina, L. G.; Howard, J . A. K.; Voskoboynikov,
A. Z. J . Chem. Soc., Dalton Trans. 2002, 15, 2995. (h) Temme, R. B.;
Fisher, R. A. U.S. Patent 6451938, 2002. (i) Ryabov, A. N.; Gribkov,
D. V.; Izmer, V. V.; Voskoboynikov A. Z. Organometallics 2002, 21,
2842
(8) Gattermann, L. Leibigs Ann. Chem. 1912, 393, 113.
(9) Campo, M. A.; Larock, R. C. J . Org. Chem. 2002, 67, 5616.
(10) Neugebauer, W.; Kos, A. J .; Schleyer, P. R. J . Organomet. Chem.
1982, 228, 107.
(11) Michael, U.; Hornfeldt, A.-B. Tetrahedron Lett. 1970, 60, 5219.
(12) Talalaeva, T. V.; Kocheshkov, K. A. In Metody Elementorgan-
icheskoi Khimii. Litii, Natrii, Kalii, Rubidii, Tsezii [Methods of
Organoelement Chemistry. Lithium, Sodium, Potassium, Rubidium,
Cesium]; Nesmeyanov, A. N., Kocheshkov, K. A., Eds.; Nauka, Moscow,
1971; Book 1, p 295.
(4) MacDowell, D. W. H.; Patrick, T. B. J . Org. Chem. 1967, 32, 2441.
(5) Guillaumel, J .; Boccara, N.; Demerseman, P. J . Heterocycl. Chem.
1990, 27, 1047.
(6) Sauter, F.; Dzerovicz, A. Monatsh. Chem. 1969, 100, 913.
(7) Sauter, F.; Deinhammer, W. Monatsh. Chem. 1970, 101, 544.
(13) Davies W.; Middleton S. J . Chem. Soc. 1958, 822
10.1021/jo049504w CCC: $27.50 © 2004 American Chemical Society
Published on Web 07/08/2004
5476
J . Org. Chem. 2004, 69, 5476-5479

SCHEME 1
SCHEME 2
SCHEME 3
We demonstrated that our approach can be extended
to N-arylpyrroles. 9H-Pyrrolo[1,2-a]indol-9-one (2h ) was
prepared from 1-phenyl-1H-pyrrole (1h ) by the standard
procedure (eq 6) (Scheme 3) .The bimetalation14 of the
latter and the reactions of its dilithium derivative15 have
been studied in detail previously.
The key method for the transformation of hetareno-
indanones into hetarenoindenes is either Wolff-Kishner
reduction of cyclic ketones by hydrazine in the presence
of ΚOH4 or reduction with the LiAlH4/AlCl3 system in
ether.16 We used both approaches; however, only the
Wolff-Kishner reduction by hydrazine in the presence
of ΚOH resulted in the desired hetarenoindenes 3a -h
(14) Faigl, F.; Schlosser, M. Tetrahedron 1993, 49, 10271.
(15) Cheeseman, G. W. H.; Greenberg, S. G. J . Organomet. Chem.
1979, 166, 139.
(16) Boberg, F.; Czogalla, C.-D.; Torges, K.-F.; Wentrup, G.-J . Liebigs
Ann. Chem. 1983, 1598.
J . Org. Chem, Vol. 69, No. 16, 2004 5477

was 0.84 g (86%) of a greenish solid. 1H NMR (CDC13, 25 °C), δ:
7.88 (m, 1H); 7.55 (d, 1H J ) 7.4 Hz); 7.36 (m, 1H); 7.26 (m,
3H); 7.18 (d, 1H J ) 7.4 Hz); 3.77 (s, 3H); 3.64 (s, 2H); 2.44 (s,
3H). 13C NMR (CDC13, 25 °C), δ: 148.2, 142.4, 141.0, 137.5,
131.4, 127.4, 125.7, 121.8, 120.6, 119.8, 119.7, 119.1, 117.8, 109.7,
31.0, 29.9, 21.3. Anal. Calcd for C17H15N (%): 87.52 C; 6.48 H;
6.00 N. Found (%): 87.48 C; 6.49 H; 6.03 N. Mp: 142-143 °C.
3-P h en yl-1-ben zofu r a n (1a ). 1H NMR (CDCl3, 25 °C) δ:
7.93 (d, 1H J ) 7.4 Hz); 7.85 (s, 1H); 7.72 (d, 2H J ) 6.9 Hz);
7.63 (d, 1H J ) 7.4 Hz); 7.55 (t, 2H J ) 6.9 Hz); 7.42-7.35 (m,
3H). Anal. Calcd for C14H10O (%): 86.57 C; 5.19 H. Found (%):
86.52 C; 5.23 H. Taken from ref 1 in Supporting Information.
(Scheme 3). The LiAlH4/AlCl3 reduction yielded the
corresponding carbinol, which can further be converted
into hetarenoindene by ionic hydrogenation, but only in
a low yield; thus, this method is not expedient for the
synthesis.
In conclusion, we have developed a general method for
the synthesis of ketones, which allows one to prepare both
hetarenoindanones with various heteroatoms (O, N, S)
and fluorenones. All these can be easily reduced to
hetarenoindenes or fluorenes. By using various Grignard
reagents in the synthesis of the starting phenylhetarenes
1, one can prepare ketones 2 (and, hence, hetarenoin-
denes 3) with required substituents.
1
3-P h en yl-1-ben zoth iop h en e (1c). H NMR (CDCl3, 30 °C)
δ: 7.37-7.42 (4H, m); 7.48 (2H, t, J ) 7.5 Hz); 7.58 (2H, d, J )
7.8 Hz); 7.90-7.92 (2H, m). 13C NMR (CDCl3, 30 °C) δ: 140.7.
138.1, 137.9, 136.0, 128.7, 127.5, 124.4, 124.3, 123.4, 122.9. Anal.
Calcd for C14H10S (%): 79.69 C; 4.79 H. Found (%): 79.66 C;
4.81 H. Taken from ref 2 in Supporting Information.
Exp er im en ta l Section
2-Meth yl-4-p h en ylth iop h en e (1d ). 1H NMR (CDCl3, 30 °C)
δ: 7.66 (d, 2H, J ) 7.5 Hz), 7.47 (t, 2H, J ) 7.5 Hz), 7.37 (t, 1H,
J ) 7.5 Hz), 7.28 (d, 1H J ) 7.5 Hz), 7.16 (s, 1H), 2.61 (s, 3H,
CH3). 13C NMR (CDCl3, 30 °C) δ: 141.9, 140.3, 136.0, 128.6,
126.8, 126.1, 124.5, 117.9, 15.3. Anal. Calcd for C11H10S (%):
75.82 C; 5.78 H. Found (%): 75.84 C; 5.79 H. Mp: 75-77 °C.
4-(4-ter t-Bu tylp h en yl)-2-m eth ylth iop h en e (1e). 1H NMR
(CDCl3, 30 °C) δ: 7.55 (d, 2H, J ) 8.1 Hz), 7.46 (d, 2H, J ) 8.1
Hz), 7.21 (s, 1H), 7.10 (s, 1H), 2.57 (s, 3H), 1.40 (s, 9H). 13C NMR
(CDCl3, 30 °C) δ: 149.8, 141.9, 140.1, 133.3, 125.8, 125.5, 124.6,
117.4, 34.4, 31.2, 15.3. Anal. Calcd for C15H18S (%): 78.21 C;
7.88 H. Found (%): 78.29 C; 7.92 H. Mp: 58-59 °C.
Typ ica l P r oced u r e for Cr oss-Cou p lin g of 3-Br om o-
h eter ocycle w ith Gr ign a r d Rea gen t Exem p lified by th e
Syn th esis of 1-Meth yl-3-(4-m eth ylp h en yl)-1H-in d ole (1b).
A solution of (4-methylphenyl)magnesiumbromide in ether
(prepared from 0.6 g of Mg (0.025 mol) and 4.21 g of 1-bromo-
4-methylbenzene (0.024 mol) in 40 mL of ether) was added with
stirring to a mixture of 4.31 g (0.02 mol) of 3-bromo-l-methyl-
l-H-indole and 0.22 g (0.0004 mol) of NiCl2dppp in 20 mL of
ether. The reaction mixture was stirred overnight and then
treated with 10% aqueous NH4Cl. The organic layer was
separated, washed with 10% aqueous NH4Cl, and dried over
anhydrous Na2SO4. The solution was concentrated to give an
oil that crystallized. The product was washed with methanol and
dried. The yield was 2.2 g (49%) of a colorless crysalline solid.
1H NMR (CDC13, 25 °C), δ: 8.14 (d, 1H, J ) 8.2 Hz); 7.75 (d,
2H, J ) 7.8 Hz); 7.50 (t, 1H, J ) 8.2 Hz); 7.46-7.42 (m, 3H);
7.38 (t, 1H, J ) 8.2 Hz); 7.31 (s, 1H); 3.90 (s, 3H); 2.58 (s, 3H).
13C NMR (CDC13, 25 °C), δ: 137.3, 135.1, 132.6, 129.3, 127.1,
126.6, 126.1, 121.7, 119.8, 119.6, 116.5, 109.3, 32.5, 21.0. Anal.
Calcd for C16H15N (%): 86.84 C; 6.83 H; 6.33 N. Found (%): 86.75
C; 6.77 H; 6.48 N. Mp: 65-68 °C (lit.17 63 °C).
Typ ica l P r oced u r e of Ca r bon yla tion of 3-P h en yl-h et-
er ocycle Exem p lified by th e Syn th esis of 5,8-Dim eth ylin -
d en o[2,l-b]in d ol-6(5H)-on e (2b). A solution of 2.19 g (0.00991
mol) of l-methyl-3-(4-methylphenyl)-1-H-indole 1b and 3.24 mL
(0.0218 mol) of TMEDA in 30 mL of ether was treated with 13.6
mL (0.0218 mol) of 1.6 M BuLi in hexane under stirring at -40
°C. Then, the reaction mixture was allowed to warm to room
temperature, stirred for 4 h, cooled to -70 °C, and treated with
1.16 g (0.00991 mol) of ethyl N,N-dimethylcarbamate in 5 mL
of ether. Then, the reaction mixture was allowed to warm to
room temperature and stirred overnight. The resulting mixture
was treated with 50 mL of 10% aqueous NH4Cl The violet
precipitate was separated, washed twice with water, and dried.
The yield was 1.04 g (42%). 1H NMR (CDC13, 25 °C), δ: 7.58 (d,
1H J ) 8.2 Hz); 7.27 (t, 1H J ) 8.2 Hz); 7.22 (d, 1H J ) 8.2 Hz);
7.14 (t, 1H J ) 8.2 Hz); 7.09 (s, 1H); 6.98 (d, 1H J ) 7.5 Hz);
6.92 (d, 1H J ) 7.5 Hz); 3.80 (s, 3H); 2.26 (s, 3H). 13C NMR
(CDC13, 25 °C), δ: 184.7, 143.7, 137.3, 137.2, 136.7, 136.0, 133.6,
133.3, 125.6, 124.5, 121.5, 121.5, 120.9, 118.6, 111.2, 30.3, 21.1.
Anal. Calcd for C17H13N (%): 82.57 C; 5.30 H; 5.66 N. Found
(%): 82.50 C; 5.41 H; 5.69 N. Mp: 145 °C.
6H-In den o[2,1-b][1]ben zofu r an -6-on e (2a). 1H NMR (CDCl3,
25 °C) δ: 7.73 (d, 1H, J ) 7.8 Hz); 7.55 (d, 1H, J ) 7.8 Hz); 7.46
(t, 1H, J ) 7.8 Hz); 7.41-4.29 (m, 3H); 7.21-7.14 (m, 2H). 13C
NMR (CDCl3, 25 °C) δ: 180.4, 161.4, 154.5, 141.2, 135.9, 134.8,
133.7, 128.5, 128.5, 124.6, 123.9, 121.9, 121.9, 120.1, 113.64.
Anal. Calcd for C15H8O2 (%): 81.81 C; 3.66 H. Found (%): 81.78
C; 3.55 H. Mp: 105-106 °C (lit. 109-110 °C (from ref 3 in
Supporting Information)).
6H-In d en o[2,1-b][1]ben zoth iop h en -6-on e (2c). 1H NMR
(CDCl3, 25 °C) δ: 7.87 (m, 1H); 7.81 (m, 1H); 7.76-7.38 (m, 3H);
7.34 (m, 2H); 7.16 (m, 1H). 13C NMR (CDCl3, 25 °C) δ: 186.9,
152.7, 148.2, 140.1, 137.0, 136.9, 133.6, 131.8, 127.98, 127.4,
125.7, 124.4, 123.8, 123.7, 119.5. Anal. Calcd for C15H8OS (%):
76.25 C; 3.41 H. Found (%): 76.11 C; 3.49 H. Mp: 198-199 °C
(lit. 194-196 °C (from ref 4 in Supporting Information)).
2-Meth yl-8H-in d en o[2,1-b]th iop h en -8-on e (2d ). 1H NMR
(CDCl3, 30 °C) δ: 7.44 (d, 1H, J ) 7.5 Hz), 7.29 (t, 1H, J ) 7.5
Hz), 7.14 (t, 1H, J ) 7.5 Hz), 7.07 (d, 1H, J ) 7.5 Hz), 6.79 (d,
1H, J ) 1.0 Hz), 2.55 (d, 3H, J ) 1.0 Hz). 13C NMR (CDCl3, 30
°C) δ: 185.2, 159.0, 156.1, 139.6, 137.4, 134.1, 133.1, 127.8, 123.3,
119.1, 118.9, 16.4. Anal. Calcd for C12H8OS (%): 71.97 C; 4.03
H. Found (%): 72.88 C; 4.00 H. Mp: 125-126 °C.
6-ter t-Bu t yl-2-m et h yl-8H -in d en o[2,1-b]t h iop h en -8-on e
(2e). 1H NMR (CDCl3, 30 °C) δ: 7.53 (d, 1H, J ) 1.9 Hz), 7.29
(dd, 1H, J ) 7.5 and 1.9 Hz), 7.01 (d, 1H, J ) 7.5 Hz), 6.80 (d,
1H, J ) 0.9 Hz), 2.55 (d, 3H, J ) 0.9 Hz), 1.33 (s, 9H). 13C NMR
(CDCl3, 30 °C) δ: 185.8, 159.1, 156.0, 151.5, 137.6, 136.8, 134.0,
129.2, 121.3, 118.9, 118.8, 34.8, 30.9, 16.5. Anal. Calcd for C16H16
OS (%): 74.96 C; 6.29 H. Found (%): 75.02 C; 6.39 H.
-
9H-P yr r olo[1,2-a ]in d ol-9-on e (2h ). 1H NMR (CDCl3, 30 °C)
δ: 7.58 (d, 1H, J ) 6.8 Hz), 7.44 (dt, 1H, J ) 6.8 Hz, and 1.3
Hz), 7.16-7.08 (m, 3H), 6.78 (d, 1H, J ) 3.7 Hz), 6.32 (dd, 1H,
J ) 3.7 and 2.6 Hz). 13C NMR (CDCl3, 30 °C) δ: 179.4, 143.6,
133.9, 131.8, 130.1, 125.2, 124.3, 119.3, 115.7, 113.7, 110.1. Anal.
Calcd for C11H7NO (%): 78.09 C; 4.17 H; 8.28 N. Found (%):
78.18 C; 4.06 H; 8.21 N. Mp: 121-122 °C (lit. 121-122 °C (from
ref 3 in Supporting Information)).
Typ ica l P r oced u r e of Red u ction of Heta r en oin d a n on e
to Heta r en oin d en e Exem p lified by th e Syn th esis of 5,8-
Dim eth yl-5,6-d ih yd r oin d en o[2,l-b]in d ole (3b). A mixture of
1.04 g (0.0042 mol) of 5,8-dimethylindeno[2,l-b]indol-6(5H)-one
2b and 1.12 mL (0.0224 mol) of hydrazine monohydrate in 20
mL of diethylene glycol was stirred at 80 °C for 1 h and then
refluxed for 1 h. The resulting mixture was cooled to room
temperature, treated with a solution of 1.2 g (0.0214 mol) of KOH
in 5 mL of water, and refluxed for 2 h. The resulting mixture
was poured into 100 mL of water, and the precipitate was filtered
off, washed five times with 50 mL of water, and dried. The yield
1
6H-In d en o[2,1-b][1]ben zofu r a n (3a ). H NMR (CDCl3, 25
°C) δ: 7.83 (d, 1H, J ) 7.4 Hz); 7.67 (d, 1H, J ) 7.4 Hz); 7.60 (d,
1H, J ) 7.4 Hz); 7.50 (d, 1H, J ) 7.4 Hz); 7.39 (m, 3H); 7.24 (t,
1H, J ) 7.4 Hz); 3.81 (s, 2H). 13C NMR (CDCl3, 25 °C) δ: 165.4,
160.2, 141.6, 137.3, 127.0, 124.9, 124.1, 124.0, 123.6, 123.3, 123.1,
119.5, 119.3, 112.1, 31.2. Anal. Calcd for C15H10O (%): 87.36 C;
4.89 H. Found (%): 87.25 C; 4.80 H. Mp: 95-98 °C.
(17) Brown, F.; Mann, F. G. J . Chem. Soc. 1948, 847.
5478 J . Org. Chem., Vol. 69, No. 16, 2004

6H-In d en o[2,1-b][1]ben zoth iop h en e (3c). 1H (CDCl3, 25
°C) δ: 8.20 (d, 1H, J ) 7.8 Hz); 7.92 (d, 1H, J ) 7.8 Hz); 7.88 (d,
1H, J ) 7.8 Hz); 7.56 (d, 1H, J ) 7.8 Hz); 7.52 (t, 1H, J ) 7.8
Hz); 7.44 (t, 1H, J ) 7.8 Hz); 7.39 (t, 1H, J ) 7.8 Hz); 7.27 (t,
1H, J ) 7.8 Hz); 3.97 (s, 2H). 13C NMR (CDCl3, 25°) δ: 146.2,
145.6, 144.8, 140.9, 139.5, 133.0, 126.7, 124.5, 124.5, 124.2, 123.7,
123.5, 121.7, 118.9, 35.2. Anal. Calcd for C15H10S (%): 81.04 C;
4.53 H. Found (%): 80.91 C; 4.58 H. Mp: 112-113 °C (lit. 111-
112 °C (from ref 5 in Supporting Information)).
1H), 3.82 (s, 2H), 2.62 (s, 3H), 1.44 (s, 9H). Anal. Calcd for
16H18S (%): 79.29 C; 7.49 H. Found (%): 79.21 C; 7.37 H. Mp:
139-141 °C.
C
9H-P yr r olo[1,2-a ]in d ole (3h ). 1H NMR (CDCl3, 30 °C) δ:
7.47 (d, 1H, J ) 6.8 Hz), 7.41-7.32 (m, 2H), 7.22-7.12 (m, 2H),
6.54 (t, 1H, J ) 3.2 Hz), 6.25 (m, 1H), 3.91 (s, 2H). 13C NMR
(CDCl3, 30 °C) δ: 141.0, 135.2, 134.8, 128.2, 127.2, 125.6, 122.8,
113.0, 109.5, 101.5, 28.8. Anal. Calcd for C11H9N (%): 85.13 C;
5.85 H; 9.03 N. Found (%): 86.02 C; 5.80 H; 8.94 N. Mp: 91-92
°C (lit. 90-91 °C (from ref 6 in Supporting Information)).
2-Meth yl-8H-in den o[2,1-b]th ioph en e (3d). 1H NMR (CDCl3,
30 °C) δ: 7.51 (m, 2H), 7.37 (t, 1H, J ) 7.9 Hz), 7.23 (t, 1H, J )
7.9 Hz), 7.01 (m, 1H), 3.81 (s, 2H), 2.61 (d, 3H, J ) 0.8 Hz). 13C
NMR (CDCl3, 30 °C) δ: 146.8, 146.2, 143.4, 141.3, 139.5, 126.5,
Su p p or tin g In for m a tion Ava ila ble: Spectral and ana-
lytical data and literature references for 1a , 1c-e, 2a , 2c-e,
2h , 3a , 3c-e, and 3h . This material is available free of charge
via the Internet at http://pubs.acs.org.
124.5, 123.9, 118.7, 116.6, 34.6, 16.0. Anal. Calcd for C12H10
S
(%): 77.37 C; 5.41 H. Found (%): 77.26 C; 5.36 H. Mp: 77-78
°C.
6-ter t-Bu tyl-2-m eth yl-8H-in d en o[2,1-b]th iop h en e (3e). 1H
NMR (CDCl3, 30 °C) δ: 7.58 (s, 1H), 7.46-7.37 (m, 2H), 6.98 (s,
J O049504W
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