| abstract |
A process for the manufacture of bipyridyls which comprises reacting the corresponding substituted pyridine with ammonia in the vapour phase, the substituted pyridine being a 2(pyridyl)tetrahydropyran or tetrahydrothiopyran, a 4(pyridyl)tetrahydropyran or tetrahydrothiopyran, or a substituted pyridine wherein the substituent is a group of the structural formula - C(R)(R1)(R2) wherein R represents a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group or an amino group, and R1 and R2 each represents a group of the general formula CHn(XR3)2 nCHm(XR4)3 m wherein X represents an atom of sulphur or oxygen, n is 0, 1 or 2 and m is 1 or 2, and R3 and R4 each represents a hydrogen atom or an alkyl, alkene, alkaryl, aralkyl or cyclo-aliphatic group. |