Abstract
A general and practical route for the synthesis of dihydropyrimidines by the one-pot cyclocondensation of aldehydes, β-ketoesters and urea is described using NH2SO3H as catalyst. Yields and selectivities are significantly better than under classical Biginelli reaction conditions.
References
1.
Biginelli P.
, Gazz, Chim. Ital. , 1893 , 23 , 360 .
2.
Kappe C.O.
, Tetrahedron , 1993 , 49 , 6937 .
3.
(a)
Atwal K.S.
,
Rovnyak G.C.
,
O'Reilly B.C.
and
Schwartz J.
, J. Org. Chem. , 1989 , 54 , 5898
4.
Atwal K.S.
,
Swanson B.N.
,
Unger S.E.
,
Floyd D.M.
,
Moreland S.
,
Hedberg A.
and
O'Reilly B.C.
, J. Med. Chem. , 1991 , 34 , 806
5.
Rovnyak G.C.
,
Atwal K.S.
,
Hedberg A.
,
Kimball S.D.
,
Moreland S.
,
Gougoutas J.Z.
,
O'Reilly B.C.
,
Schwartz J.
and
Malley M.F.
, J. Med. Chem. , 1992 , 35 , 3254
6.
Kappe C.O.
and
Fabian W.M.F.
, Tetrahedron , 1997 , 53 , 2803 .
7.
Folker K.
,
Harwood H.J.
and
Johnson T.B.
, J. Am. Chem. Soc , 1932 , 54 , 3751 .
8.
Kappe C.O.
, J. Org. Chem. , 1997 , 62 , 7201 .
9.
Atwal K.S.
,
O'Reilly B.C.
,
Gougoutas J.Z.
and
Malley M.F.
, Heterocycles , 1987 , 26 , 1189 .
10.
Tomas B.M.
,
Rubio V.
and
Gotor V.
, J. Chem. Soc. Chem. Commun. , 1979 , 675.
11.
Wipf P.
and
Cunningham A.
, Tetrahedron Lett. , 1995 , 36 , 7819 .
12.
Hu E.H.
,
Sidler D.R.
and
Dolling U.H.
, J. Org. Chem. , 1998 , 63 , 3454 .
13.
Kappe C.O.
and
Falsone S.F.
, Synlett. , 1998 , 718.
14.
Bigi F.
,
Carloni S.
,
Frullanti B.
,
Maggi R.
and
Sartori G.
, Tetrahedron Lett. , 1999 , 40 , 3465 .
15.
Lu J.
and
Ma H.
, Synlett. , 2000 , 63.
16.
Yadav J.S.
,
Subba Reddy B.V.
,
Reddy E. Jagan
and
Ramalingam T.
, J. Chem. Res. , 2000 , 354.
17.
(a)
Studer A.
,
Hadida S.
,
Territto R.
,
Kim S.Y.
,
Jeger P.
,
Wipf P.
and
Curran D.P.
, Science , 1997 , 275 , 823
18.
Studer A.
,
Jeger P.
and
Curran D.P.
, J. Org. Chem. , 1997 , 62 , 2917 .
19.
Eynde J. Vanden
,
Audiart N.
,
Canonne V.
,
Michel S.
,
van Haverbeke Y.
and
Kapple C.O.
, Heterocycles , 1997 , 45 , 1967 .
20.
(a)
O'Reilly B.C.
and
Atwal K.S.
, Heterocycles , 1987 , 26 , 1185
21.
Gupta R.
,
Gupta A.K.
,
Paul S.
and
Kachroo PL
., Ind. J. Chem. , 1995 , 34B , 151 .
22.
Lu J.
and
Ma H.
, Chin. Org. Chem. , 2000 , 20 , 815 .
23.
Folkers K.
and
Johnson T.B.
, J. Am. Chem. Soc , 1933 , 55 , 2886 .