Process to prepare dihydropyridine and derivatives thereof

Details Process to prepare dihydropyridine and derivatives thereof Process to prepare dihydropyridine and derivatives thereof

1995-12-28

1999-11-02

Fan, Jane

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C07D21186

Patent

active

059773693

ABSTRACT:
A novel process is disclosed for the preparation of dihydropyridine compounds and derivatives thereof, and more particularly felodipine. The process to prepare felodipine involves a two step procedure condensing 2,3-dichlorobenzaldehyde with methyl acetoacetate in the presence of a catalyst system. The resultant benzylidine intermediate is sequentially reacted with ethyl aminocrotonate to provide felodipine. The novelty of the present invention resides in part on (1) a new catalyst system not previously disclosed for the preparation of felodipine, (2) the absence of acid(s), (3) the control of reaction conditions to yield lower amounts of unreacted aldehyde compared to known reactions, (4) a simplified purification process, and (5) formation of negligible quantities of symmetrical diester byproducts.

REFERENCES:
patent: 4600778 (1986-07-01), Teller et al.
patent: 5310917 (1994-05-01), Auerbach
patent: 5403849 (1995-04-01), Schohe-Loop et al.
CA 116:59220 Serra et al, 1992.
CA 114:122068 Serra et al, 1991.
CA 89:109132 Sato et al., 1978.

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