A new dipeptide, Nα-(4-aminobutyryl)-L-cystathionine (10), has been identified in human brain and cerebrospinal fluid by Perry et al. (1977). The compound (10) and analogous compounds, (R)-Nα-(4-amino-3-hydroxybutyryl)-L-cystathionine (11), (S)-Nα-(4-amino-3-hydroxybutyryl)-L-cystathionine (12) and (S)-Nα-(4-amino-4-carboxybutyryl)-L-cystathionine (13), were prepared in the overall yields of 66.1%, 21.7%, 18.5% and 23.2% respectively, from Nα'-benzyloxycarbonyl-L-cystathionine (1) by mixed anhydride method. When compound (10) (30 mg) was injected into lateral ventricle of cats, spike discharge appeared in thalamus, globus pallidus, amygdala, substantia nigra and motor cortex after ten or more minutes and was observed repeatedly for some hours.
