I
Synlett
S. M. Rafiq, A. K. Mohanakrishnan
Letter
(
15) Bapat, D. S.; Subba Rao, B. C.; Unni, M. K.; Venkataraman, K. Tet-
7.50 (m, 2 H), 7.49–7.44 (m, 3 H), 4.38 (t, J = 6.9 Hz, 2 H, CH2),
1.88 (t, J = 6.9 Hz, 2 H, CH ), 1.30–1.25 (m, 6 H, CH ), 0.87–0.82
rahedron Lett. 1960,26 : 15.
2
2
13
(16) Clar, E. Polycyclic Hydrocarbons; Vols. I and II; Academic: New
York, 1964.
(m, 3 H, CH3). C NMR (75.4 MHz, CDCl ): δ = 138.8, 137.3,
3
132.5, 129.6, 128.7, 128.3, 128.0, 127.9 (2 C), 125.7, 124.3,
123.9, 123.5, 121.8, 120.7, 120.4, 120.1, 113.2, 112.4, 109.6,
43.2, 31.6, 29.8, 27.0, 22.6, 14.0. DEPT-135 NMR (75.4 MHz,
(
(
17) Gilman, H.; Diehl, J. J. Org. Chem. 1961, 26, 4817.
18) (a) Platt, K. L.; Oesch, F. J. Org. Chem. 1981, 46, 2601. (b) Harvey,
R. G.; Leyba, C.; Konieczny, M.; Fu, P. P.; Sukumaran, K. B. J. Org.
Chem. 1978, 43, 3423.
CDCl ): δ = 128.3, 128.0, 127.9 (2 C), 125.7, 124.3, 123.5, 121.8,
3
120.7, 120.1, 112.4, 109.6, 43.2, 31.6, 29.8, 27.0, 22.6, 14.0.
+
(19) (a) Graebe, C.; Liebermann, C. Justus Liebigs Ann. Chem. 1870,
HRMS (EI): m/z [M ] calcd for C26H25N: 351.1987; found:
155, 257. (b) Liebermann, C. Justus Liebigs Ann. Chem. 1871, 158,
351.1980.
2
99. (c) Schmidt, E. J. Prakt. Chem. 1874, 9, 241.
8
4c
1
(
20) (a) Meakins, G. D.; Swindells, R. J. Chem. Soc. 1959, 1044. (b) Ho,
T.-L.; Wong, C. M. Synthesis 1975, 161.
21) Guerrero, T. H.; Deulofeu, V. Chem. Ber. 1937, 70, 947.
22) Giebe, G. Chem. Ber. 1896, 29, 2533.
23) Clar, E. Polycyclic Hydrocarbons; Vol. 1; Academic Press: New
York, 1964, 171.
24) Miller, G. P.; Briggs, J. Org. Lett. 2003, 5, 4203.
25) Aprahamian, I.; Preda, D. V.; Bancu, M.; Belanger, A. P.;
Sheradsky, T.; Scott, L. T.; Rabinovitz, M. J. Org. Chem. 2006, 71,
Mp 124–126 °C (Lit. 122–124 °C). H NMR (300 MHz, CDCl ):
3
δ = 8.73 (s, 1 H), 8.66 (s, 1 H), 8.54 (s, 1 H), 8.23 (d, J = 7.5 Hz, 1
H), 8.02 (t, J = 8.9 Hz, 2 H), 7.78 (s, 1 H), 7.54 (t, J = 7.7 Hz, 1 H),
7.44 (t, J = 6.4 Hz, 2 H), 7.35 (t, J = 7.4 Hz, 1 H), 7.24–7.22 (m, 1
H), 4.32 (t, J = 7.4 Hz, 2 H, CH ), 1.95 (t, J = 6.8 Hz, 2 H, CH ),
1.51–1.38 (m, 2 H, CH ), 1.36–1.25 (m, 4 H, CH ), 0.88 (t, J = 6.9
Hz, 3 H, CH3). C NMR (75.4 MHz, CDCl ): δ = 144.2, 141.0,
131.4 (2 C), 129.6, 128.2, 127.9, 127.6, 127.6, 127.0, 126.7,
124.9, 124.1, 123.8, 122.8, 121.2, 118.8, 118.6, 108.0, 101.2,
43.3, 31.7, 28.3, 27.1, 22.6, 14.0. DEPT-135 NMR (75.4 MHz,
(
(
(
2
2
2
3
13
(
(
3
290.
(26) Sivasakthikumaran,
R.;
Rafiq,
S.
M.;
Sankar,
E.;
CDCl ): δ = 128.2, 127.9, 127.6, 126.7, 124.9, 124.1, 123.8, 121.2,
3
Mohanakrishnan, A. K. Eur. J. Org. Chem. 2015, 7816.
27) Kotha, S.; Ghosh, A. K. Synlett 2002, 451.
28) Reductive Cyclization of Keto Acid 6: Typical Procedure
118.8, 118.6, 108.0, 101.2, 43.3, 31.7, 28.3, 27.1, 22.6, 14.0.
HRMS (EI): m/z [M ] calcd for C26H25N: 351.1987; found:
351.1979.
+
(
(
5
7% aq HI (2.49 mL, 20 mmol) and red phosphorus (0.37 g, 12
Anthra[2,1-b]benzo[d]thiophene (11); Typical Procedure
57% aq HI (2.37 mL, 18.98 mmol) and red phosphorus (0.31 g,
10.1 mmol) were added to a solution of phthalide 13 (0.4 g, 1.26
mmol) in glacial AcOH (30 mL), and the mixture was refluxed
for 12 h. After workup similar to that for 7, column chromatog-
raphy (silica gel, 1% EtOAc–hexane) gave anthra[2,1-b]benzo[d]-
thiophene 11 as a pale green solid; yield: 0.307 g (90%); mp
mmol) were added to a solution of keto acid 6 (0.4 g, 1.0 mmol)
in glacial AcOH (30 mL), and the mixture was refluxed for 24 h.
The red phosphorus was then removed by filtration. The filtrate
was mixed with ice–water (100 mL), and the precipitated solid
was collected by filtration, washed successively with 10% aq
Na S O (30 mL) and H O (60 mL), and air-dried. The crude
2
2
3
2
4c
1
product was purified by column chromatography (silica gel,
hexane) to afford 5-hexylnaphtho[2,3-c]carbazole (7) as
yellow solid; yield: 0.144 g (41%). Further elution of the column
silica gel, 1% EtOAc–hexane) gave 5-hexyl-5H-naphtho[2,3-
168 °C (Lit. 168–170 °C). H NMR (300 MHz, CDCl ): δ = 9.40
3
a
(s, 1 H), 8.95 (d, J = 8.4 Hz, 1 H), 8.47 (s, 1 H), 8.11 (d, J = 8.1 Hz, 1
H), 7.99–7.90 (m, 3 H), 7.75 (d, J = 9.0 Hz, 1 H), 7.60 (t, J = 7.7 Hz,
13
(
1 H), 7.53–7.42 (m, 3 H). C NMR (75.4 MHz, CDCl ): δ = 139.7,
3
b]carbazole (8) as a yellow solid; yield: 0.127 g (36%).
138.5, 137.1, 132.3, 130.7, 130.6, 128.9, 128.5, 128.4, 128.2,
128.0, 127.9, 126.1, 125.5, 125.1, 125.0, 124.5, 123.3, 121.7,
7
Mp 104–106 °C (Lit. 104 °C). 1H NMR (300 MHz, CDCl ):
4
c
120.9. DEPT-135 (75.4 MHz, CDCl ): δ = 128.5, 128.4, 128.0 (2C),
3
3
δ = 9.22 (s, 1 H), 8.74 (d, J = 7.2 Hz, 1 H), 8.51 (s, 1 H), 8.15 (d, J =
126.1, 125.6, 125.1, 125.0, 124.5, 123.3, 121.7, 121.0. HRMS (EI):
m/z [M ] calcd for C20H12S: 284.0660; found: 284.0654.
+
8.4 Hz, 1 H), 8.05–7.95 (m, 2 H), 7.62 (d, J = 9.3 Hz, 1 H), 7.57–
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2016, 27, A–I