Depsipeptide derivative, process for production thereof, and novel intermediate therefor

A compound of the following formula or a salt thereof:

• ##STR17## wherein R.sub.1 represents hydrogen or an amino-protecting group, R.sub.2 represents carboxy or protected carboxy, R.sub.3 and R.sub.4 independently represent hydrogen, lower alkyl, or an amino-protecting group, with at least either R.sub.3 or R.sub.4 being an amino-protecting group.

A process for producing a depsipeptide derivative or a salt thereof which comprises subjecting a compound of the formula:

• ##STR18## (wherein R.sub.3 and R.sub.4 independently represent hydrogen, lower alkyl, or an amino-protecting group, with at least either R.sub.3 or R.sub.4 being an amino-protecting group) or a salt thereof to a deprotection reaction for elimination of the amino-protecting group to provide a compound of the formula:
• ##STR19## or a salt thereof.

A process for producing a depsipeptide derivative or a salt thereof which comprises subjecting a compound of the formula:

• ##STR20## (wherein R.sub.3 and R.sub.4 independently represent hydrogen, lower alkyl, or an amino-protecting group, with at least either R.sub.3 or R.sub.4 being an amino-protecting group) or a salt thereof to a deprotection reaction for elimination of the amino-protecting group to provide a compound of the formula:
• ##STR21## or a salt thereof and reacting the compound or salt thus obtained with a compound of the formula (XCH.sub.2 CH.sub.2).sub.2 O (wherein X represents a leaving group) to provide a compound of the formula:
• ##STR22## or a salt thereof.