PURPOSE: To obtain a new synthetic intermediate useful for producing an amino acid derivative having renin inhibiting activity in good yield at a reduced cost.
CONSTITUTION: The compound of formula I [R1 is lower alkyl which may be substituted with a substituent group selected from acyl, OH, lower alkoxy, aryl, lower alkylthio and formula II (R6 is H or acyl; R7 is H or lower alkyl), aryl or amino which may be substituted with lower alkyl or acyl; R2 is H or lower alkyl or R1 and R2, together with the adjacent N atom, form a heterocyclic group which may be substituted (with alkyl, hydroxyalkyl, acyl, etc.); R3 is H or lower alkyl; R4 is H or N-protecting group; R5 is H or carboxy- protecting group]. This compound is obtained by reacting a compound of formula III with a compound of formula IV. The objective amino acid derivative of formula VI is prepared by reacting the compound of formula I or a reactive derivative at the carboxyl group thereof with a compound of formula V (R10 is lower alkyl) and, as necessary, releasing the N-protecting group.
KAWAI NOBUTAKA
MACHITANI KOJI
KODERA TETSUO
NAKAMURA TAKASHI
