Abstract
A simple protocol to achieve the aromatisation of Hantzsch dihydropyridines in high yield was established using p-toluenesulfonic acid in acetic acid and yields of 90% were obtained at room temperature. With regards to the Hantzsch 1,4-dihydropyridines derived from alkyl aldehydes bearing one or more á-hydrogens, dealkylation products were obtained through a proposed autoxidation mechanism.
References
1.
Hantzsch A.
, Eur. J. Org. Chem. , 1882 , 215 , 1 .
2.
Ogawa A.K.
,
Willoughby C.A.
,
Bergeron R.
,
Ellsworth K.P.
,
Geissler W.M.
,
Myers R.W.
,
Yao J.
,
Harris G.
and
Chapman K.T.
, Bioorg. Med. Chem. Lett. , 2003 , 13 , 3405 .
3.
Mitchell P.
, Science , 1979 , 206 , 1148 .
4.
Fukuzumi S.
,
Koumitsu S.
,
Hironaka K.
and
Tanaka T.
, J. Am. Chem. Soc. , 1987 , 109 , 305 .
5.
Singer A.
and
McElvain S.M.
, Org. Synth. , 1934 , 14 , 30 .
6.
Fister P.
and
Jürg R.
, Synthesis , 1990 , 8 , 689 .
7.
Eynde J.J.V.
,
Mayence A.
and
Maquestiau A.
, Tetrahedron , 1992 , 48 , 463 .
8.
Love B.
and
Snader K.M.
, J. Org. Chem. , 1965 , 30 , 1914 .
9.
Eynde J.J.V.
,
Delfosse F.
,
Mayence A.
and
Haverbeke Y.V.
, Tetrahedron , 1995 , 51 , 6511 .
10.
Mashraqui S.H.
and
Karnik M.A.
, Tetrahedron Lett. , 1998 , 39 , 4895 .
11.
Nakamichi N.
,
Kawashita Y.
and
Hayashi M.
, Org. Lett , 2002 , 4 , 3955 .
12.
Nakamichi N.
,
Kawabata H.
and
Hayashi M.
, J. Org. Chem. , 2003 , 68 , 8272 .
13.
Heravi M.M.
,
Behbahani F.K.
,
Oskooie H.A.
and
Shoar R.H.
, Tetrahedron Lett , 2005 , 46 , 2775 .
14.
Han B.
,
Liu Z.
,
Liu Q.
,
Yang L.
,
Liu Z.L.
and
Yu W.
, Tetrahedron , 2006 , 62 , 2492 .
15.
Fang X.
,
Liu Y.-C.
and
Li C.
, J. Org. Chem. , 2007 , 72 , 8608 .
16.
Saini A.
,
Kumar S.
and
Sandhu J.S.
, J. Sci. Ind. Res. India , 2008 , 67 , 95 .
17.
Kumar P.
, J. Heterocyclic. Chem. , 2010 , 47 , 1429 .
18.
Anuradha V.
,
Srinivas P.V.
,
Aparna P.
and
Rao J.M.
, Tetrahedron Lett. , 2006 , 47 , 4933 .
19.
Milas N.A.
, Chem. Rev. , 1932 , 10 , 295 .
20.
Pintér A.
,
Sud A.
,
Sureshkumar D.
and
Klussmann M.
, Angew. Chem. Int. Ed. , 2010 , 49 , 5004 .
21.
Partenheimer W.
, Adv. Synth. Catal. , 2005 , 347 , 580 .
22.
Hayakawa K.
,
Yodo M.
,
Ohsuki S.
and
Kanemats K.
, J. Am. Chem. Soc. , 1984 , 106 , 6735 .
23.
Goverdhan M.
and
Paras P.N.
, Synthesis , 1975 , 6 , 404 .
24.
Chen Z.Y.
and
Zhang W.
, Chin. Chem. Lett. , 2007 , 18 , 1443 .
25.
Paolis O.D.
,
Baffoe J.
,
Landge S.M.
and
Török B.
, Synthesis , 2008 , 21 , 3423 .