[Lactones. 24. "Gamma-lactonized" neuroleptics--synthesis, stereochemistry and affinity at the D2 receptor]

Addition of piperidines 15a-d to methylene lactones 8,14a gives the "gamma-lactonized" diphenylbutylpiperidine-type neuroleptics 3a,b,d,4a-d. 8 can be produced by cyclization or--as well as 14--from the corresponding alpha-carboxylactone. 1H- and 13C-nmr data give evidence for the equatorial position of the aminomethyl group in all derivatives of 3 and 4 and bisequatorial-trans-configuration in 4a-d. 3H-spiroperidole displacement at the D2 receptor in rat brain by 3,4 and the "gamma-lactonized" butyrophenone neuroleptics 1,2a-c was investigated. Some compounds show moderate up to high (3b) activity.