By diastereoselective aldol-type reaction of 2-chlorobenzaldehyde with
methyl thiotetronate 4, racemic thiolactone 3a, an analogue of losiga
mone 2, was synthesized along with its (R,R*)-isomer 3b and its dehyd
ration product 5. In contrast to the lead compound, thiolosigamone 3a
displayed weak anticonvulsant activity only at high doses in the MES-t
est. The other newly synthesized compounds did not protect mice agains
t seizures induced by maximal electroshock. (C) Elsevier, Paris.