NEW MATERIAL:A compound of formula I or II (R1 is H or organic residual group combined with the ring through C; R2 is H or N-protecting group; CO-R3 is carboxyl group which may be esterified or amidized; R4 and R5 are H, acyl or linear or alicyclic hydrocarbon residual group which can have an aryl group; R6 is NOH or O; n' is 0-3; R4 and R5 together form a ring through N, or R4 and R5 together form benzylideneamino; but when R1, R2, R4, R5 are H; CO-R3 is carboxyl; and the stearic configuration of an asymmetric carbon bonded to -amino is H, n' is 0, 2 or 3) or a salt thereof.
USE: A cerebral function-improving agent.
PREPARATION: For example, a microorganism belonging to the genus Streptomyces, e.g. Streptomyces.platensis, is cultured in a medium to prepare a compound of formula II wherein R3 is OH; R1 and R4 are H; R6 is NOH and n' is 1.
NAGAOKA AKINOBU
ITO KATSUMI
TERAO SHINJI
