In the present study, compounds derived from the anticonvulsant drug valproic acid (VPA, 2- n-propylpentanoic acid) and analogues known to be teratogenic were synthesized with an additional carbon-branching in one of the side chains. The substances were tested for their ability to induce anticonvulsant activity and sedation in adult mice, and neural tube defects (exencephaly) in the offspring of pregnant animals (Han: NMRI mice). In all cases, the ...