References
1a
Lee JH.
Park JW.
Chot SK.
Synth. Met.
1997,
88:
31
1b
Cho CS.
Wang WT.
Macromol. Chem. Phys.
2001,
202:
2864
1c
Thomas JKR.
Jian LT.
J. Am. Chem. Soc.
2001,
123:
9404
2a
Romeo DB.
Schaer M.
Leclerc M.
Ades D.
Siove A.
Zuppiroli L.
Synth. Met.
1996,
80:
271
2b
Morin J.-F.
Leclerc M.
Macromolecules
2002,
35:
8413 ; and references cited therein
3
McClenaghan ND.
Passalacqua R.
Loiseau F.
Campagna S.
Verheyde B.
Hameurlaine A.
Dehaen W.
J. Am. Chem. Soc.
2003,
125:
5356
4 For a recent review about the synthesis of biologically active carbazole alkaloids, see: Knölker H.-J.
Reddy KR.
Chem. Rev.
2002,
102:
4303
5a
Cao R.
Chen Q.
Hou X.
Chen H.
Guan H.
Ma Y.
Peng W.
Xu A.
Bioorg. Med. Chem.
2004,
12:
4613
5b
Kanekiyo N.
Kuwada T.
Choshi T.
Nobuhiro J.
Hibino S.
J. Org. Chem.
2001,
66:
8793
5c
Hino T.
Nakagawa M.
J. Heterocycl. Chem.
2000,
37:
567
5d Beria I, Cozzi P, Baraldi PG, Spalluto G, and Geroni MC. inventors; Brit. UK Pat. Appl. GB 2344818 CAN 133:321873.
5e Jakobsen P, Kanstrup A, Faarup P, Olesen PH, and Lundbech JM. inventors; U.S. 5,536,721.
5f
Olesen PH.
Hansen JB.
Engelstoft M.
J. Heterocycl. Chem.
1995,
32:
1641
6a
Joshi BS.
Gawad DH.
Indian J. Chem.
1974,
12:
437
6b
Bhattacharyya P.
Chakraborty A.
Phytochemistry
1984,
23:
471
6c
Chakraborty DP.
Das AP.
Sci. Cult. (India)
1966,
32:
181
6d
Ruangrungsi N.
Ariyaprayoon J.
Lange GL.
Organ MG.
J. Nat. Prod.
1990,
53:
946
6e
Jash SS.
Biswas GK.
Bhattacharyya SK.
Bhattacharyya P.
Chakraborty A.
Choudhury BK.
Phytochemistry
1992,
31:
2503
7a
Cadogan GIJ.
Carmen-Wood M.
Proc. Chem. Soc.
1962,
361
7b
Cadogan GIJ.
Carmen-Wood M.
Makie RK.
Searle RJG.
J. Chem. Soc.
1965,
4831
7c
Cadogan GIJ.
Organophosphorus Reagents in Organic Synthesis
Academic Press Inc.;
London:
1979.
p.279
8a
Akermark B.
Eberson L.
Jonsson E.
Patterson E.
J. Org. Chem.
1975,
40:
1365
8b
Ames DE.
Bull D.
Tetrahedron
1982,
38:
383
8c
Ames DE.
Opalko A.
Tetrahedron
1984,
40:
1919
8d
Hegedus LS.
Angew. Chem., Int. Ed. Engl.
1988,
27:
1113 ; Angew. Chem. 1988, 100, 1147
9a
Pizzotti M.
Cenini S.
Quici S.
Tollari S.
J. Chem. Soc., Perkin Trans. 2
1994,
913
9b
Smitrovich JH.
Davies IW.
Org. Lett.
2004,
6:
533
10a
Adam D.
Nature
2003,
421:
571
10b
Kaval N.
Van der Eycken J.
Caroen J.
Dehaen W.
Strohmeier GA.
Kappe CO.
Van der Eycken E.
J. Comb. Chem.
2003,
5:
560
10c
Lew A.
Krutzik PO.
Hart ME.
Chamberlin AR.
J. Comb. Chem.
2002,
2:
95
10d
Kappe CO.
Curr. Opin. Chem. Biol.
2002,
6:
314
10e
Lidström P.
Westman J.
Lewis A.
Comb. Chem. High Throughput Screening
2002,
5:
441
10f
Van der Eycken E.
Appukkuttan P.
De Borggraeve W.
Dehaen W.
Dallinger D.
Kappe CO.
J. Org. Chem.
2002,
67:
7904
11a
Bouchard J.
Wakim S.
Leclerc M.
J. Org. Chem.
2004,
69:
5705
11b
Morin J.-F.
Leclerc M.
Macromolecules
2001,
34:
4680
11c
Holzapfel CW.
Dwyer C.
Heterocycles
1998,
48:
1513
12
Monovich LG.
Le Huérou Y.
Rönn M.
Molander GA.
J. Am. Chem. Soc.
2000,
122:
52 ; and references cited therein
13a
Wright SW.
Hageman DL.
McClure LD.
J. Org. Chem.
1994,
59:
6095
13b
Gronowitz S.
Hörnfledt A.-B.
Yang Y.-H.
Chem. Scr.
1986,
26:
383
13c
Watanabe T.
Miyaura N.
Suzuki A.
Synlett
1992,
207
14
Appukkuttan P.
Orts AB.
Chandran RP.
Goeman JL.
Van der Eycken J.
Dehaen W.
Van der Eycken E.
Eur. J. Org. Chem.
2004,
3277
15
Seaman W.
J. Am. Chem. Soc.
1931,
53:
711
16 CEM-Discover, CEM Corporation P.O. Box 200 Matthews, NC 28106.
17a
Kikugawa Y.
Aoki Y.
Sakamoto T.
J. Org. Chem.
2001,
66:
8612
17b
Hewlins MJE.
Jackson AH.
Long A.
Campos A.-O.
Shannon PVR.
J. Chem. Res., Synop.
1986,
8:
292
17c
Patel BPJ.
J. Ind. Chem. Soc.
1985,
62:
534
17d
Clancy MG.
Hesabi MM.
Otto M.-C.
J. Chem. Soc., Perkin Trans. 1
1984,
3:
429
18
General Procedure for the Microwave-Enhanced Suzuki Reaction and Cadogan Cyclization - Synthesis of 8
H
-Thieno[2,3-
b
]indole (
4q): 3-Bromothiophene (2q, 0.041 g, 0.25 mmol), 2-nitrophenylboronic acid (0.054 g, 0.325 mmol), NaHCO3 (0.063 g, 0.75 mmol) and tetrakis(triphenylphosphine)palladium(0) (0.015 g, 5 mol%) were suspended in DMF (1.5 mL) and H2O (1.5 mL) in a 10 mL glass vial equipped with a small stirring magnet. The vial was sealed tightly with an aluminium-Teflon® crimp top and the mixture was irradiated in the cavity of a mono-mode CEM®-Discover machine for 15 min at a pre-selected temperature of 150 °C, using a maximum irradiation power of 100 W. After the reaction, the vial was cooled to 50 °C by gas jet cooling. The crude mixture was partitioned between Et2O and H2O (25 mL each) and the aqueous layer was extracted with Et2O (3 × 20 mL). The combined organic layers were dried on MgSO4 and solvents were removed under vacuum to yield the crude product as yellow oil. Column chromatography [silica gel, heptane-EtOAc (9:1)] afforded the biaryl compound 3q (0.046 g, 890%) as yellowish oily material.
The nitro compound 3q was suspended in triethyl phosphate (3 mL) in a tightly sealed 10 mL glass vial and was irradiated at a maximum irradiation power of 300 W for 15 min at a pre-selected temperature of 210 °C. After the reaction, the vial was cooled to 50 °C by gas jet cooling and the contents were transferred to a 50 mL flask with the help of EtOAc (10 mL). This mixture was then heated to 80 °C with an excess of HCl (6 N, 10 mL) and maintained at the temperature for 3 h. After cooling to r.t., the mixture was partitioned between H2O and EtOAc (20 mL each) and the aqueous layer was further extracted with EtOAc (3 × 10 mL). The combined organic layers were dried over MgSO4 and solvents were removed under reduced pressure, and further purification by column chromatography (silica gel, heptane-EtOAc, 9:1) afforded the thieno-indole 4q (0.0296 g, 76%). 1H NMR (300 MHz, CDCl3): δ = 6.92 (d, 1 H, J = 5.2 Hz), 7.19-7.27 (m, 2 H), 7.36 (d, 1 H, J = 5.2 Hz), 7.41 (d, 1 H, J = 8.0 Hz), 7.81 (dd, 1 H, J = 7.6, 0.8 Hz), 8.22 (br s, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 111.2, 117.1, 117.6, 119.3, 119.9, 122.2, 122.5, 125.6, 141.2, 142.2 ppm. DEPT-NMR (75 MHz, CDCl3): δ = 111.2, 117.1, 117.6, 119.3, 122.5, 125.6 ppm. MS (EI): 173 [M+]. HRMS (EI): m/z calcd for C10H07NS [M+]: 173.02992; found: 173.02986.
