N.sup.2 -substituted-L-arginine derivatives and the pharmaceutically acceptable acid addition salts thereof

A method for inhibiting activity and suppressing activation of thrombin in vivo, which comprises administering to a patient a pharmaceutically effective amount of an N.sup.2 -substituted-L-arginine ester or amide having the formula:

• ##STR154## or a pharmaceutically acceptable acid addition salt thereof, wherein R is selected from the group consisting of (1) --OR.sub.1, wherein R.sub.1 is selected from the group consisting of C.sub.1 -C.sub.10 alkyl, C.sub.3 -C.sub.10 cycloalkyl, C.sub.1 -C.sub.10 haloalkyl, C.sub.2 -C.sub.10 alkoxyalkyl, C.sub.2 -C.sub.10 alkenyl, C.sub.2 -C.sub.10 alkynyl and C.sub.7 -C.sub.15 aralkyl;
• ##STR155## wherein R.sub.2 and R.sub.3 are selected from the group consisting of hydrogen, C.sub.1 -C.sub.10 alkyl, C.sub.7 -C.sub.15 aralkyl, and C.sub.1 -C.sub.10 alkyl substituted with a group selected from C.sub.1 -C.sub.10 alkoxy, C.sub.2 -C.sub.10 alkoxycarbonyl and carboxy;
• and (3) -N Z, wherein Z is a divalent group which consists of at least two groups selected from the group consisting of methylene --CH.sub.2 -- and monosubstituted ##STR156## wherein R.sub.4 is selected from the group consisting of C.sub.1 -C.sub.10 alkyl and C.sub.1 -C.sub.10 alkoxy, which are combined in an arbitraary order, the number of the combined groups being up to 20;
• and R' is selected from the group consisting of ##STR157## wherein R" and R'" when considered separately are C.sub.1 -C.sub.10 alkyl, or R" and R'" when taken together are C.sub.1 -C.sub.10 alkylene;
• ##STR158## wherein R"" is C.sub.1 -C.sub.10 alkoxy;
• ##STR159##