PROCESS FOR PRODUCING BIPYRIDYLS

• Main Author: BOWDEN R,GB
• Format: Patent
• Language: English
• Published: 07.08.1973
• Subjects: CHEMISTRY; HETEROCYCLIC COMPOUNDS; METALLURGY; ORGANIC CHEMISTRY

1310516 Pyridine derivatives IMPERIAL CHEMICAL INDUSTRIES Ltd 22 June 1970 [8 July 1969] 34414/69 Heading C2C The invention comprises 4-(2-pyridyl)-piperidine and also a process for making bipyridyls by reacting a substituted pyridine in the liquid phase at 200-450‹ C. with ammonia and converting any pyridyl piperidine so formed into a bipyridyl, the substituted pyridine being a 2- (pyridyl)-tetrahydropyran or a 2-(pyridyl)- tetrahydrothiopyran, a 4-(pyridyl)-tetrahydropyran or a 4-(pyridyl)-tetrahydrothiopyran, or a substituted pyridine having a substituent -C(R)(R 1 )(R 2 ) in which R is hydrogen, halogen, hydroxy, alkoxy or amino and R 1 and R 2 each represents a group in which X is oxygen or sulphur, n is 0, 1 or 2 and m is 1 or 2 and R 3 and R 4 are each hydrogen, or an alkyl, alkenyl, aryl, alkaryl, aralkyl or cycloaliphatic group. Examples describe the reaction of (a) 3-(4-pyridyl)-pentane-1,5 diol with ammonia to give 4-(4-piperidyl)-pyridine and/or 4,41-bipyridyl; (b) 3-(2-pyridyl)-pentane- 1,5-diol with ammonia to give 2-(4-piperidyl)- pyridine and/or 2,31-bipyridyl; (c) 3-(4-pyridyl)- pentane-1,5-diethyl ether with ammonia to give 4,41-bipyridyl; (d) gamma-picoline with sodium amide and ethylene oxide to give 4-(4-pyridyl)- tetrahydropyran which is acted with ammonia to give 4,41-bipyridyl along with some 3-(4- pyridyl)-propanol and 3-(4-pyridyl)propyl-1- amine. In all cases any piperidyl pyridine formed is converted to bipyridyl.