Pharmaceutical pyridine derivatives, processes for preparing the same and intermediates therefor

摘要

A pyridine derivative of the formula (I): <CHEM> wherein A is group of the following formulae: <CHEM> R<1> and R<2> are each H, or protected or unprotected OH, R<31>, R<41> and R<42> are protected or unprotected hydroxymethyl, R<32> is H, lower alkyl, or protected or unprotected hydroxymethyl, R<33> is substituted or unsubstituted lower alkyl, and the dotted line means the presence or absence of a double bond' R<5> and R<6> are H, or protected or unprotected amino, or both combine together with the adjacent nitrogen to form substituted or unsubstituted heterocycle, or a pharmaceutically acceptable salt thereof, show excellent bronchoconstriction inhibitory activity and/or anti-inflammatory activity of airways, and are , useful in the prophylaxis or treatment of asthma.