3-Carboxy-3, 4dehydropyrrolidine was found to bind with affinity equal to that of glycine in a [3H] strychnine binding assay. Simple substitution of the 1-, 2-, 4-, or 5-position resulted in marked loss of affinity. A decline in affinity was also found upon enlargement, contraction, or saturation of the &membered ring. However,@-proline and azetidine-3-carboxylic acid retained significant binding affinity. Despite its good affinity in [3H] strychnine binding, 3- ...
