There are provided according to the invention novel compounds of formula (I) ##STR1## wherein R.sup.1 represents C.sub.1-4 alkyl or C.sub.3-8 cycloalkyl, R.sup.2 represents C.sub.1-4 alkyl or C.sub.3-4 alkenyl, R.sup.3 represents hydrogen, C.sub.1-3 alkyl or halogen, and R.sup.4 represents C.sub.1-6 alkyl, processes for preparing them, pharmaceutical formulations containing them and their use in therapy particularly as thrombin inhibitors.

É fornecido de acordo com os compostos da novela da invenção do ## do ## STR1 da fórmula (I) wherein R.sup.1 representa o alkyl C.sub.1-4 ou o cycloalkyl C.sub.3-8, R.sup.2 representa o alkyl C.sub.1-4 ou o alkenyl C.sub.3-4, R.sup.3 representa o hidrogênio, o alkyl C.sub.1-3 ou o halogênio, e R.sup.4 representa o alkyl C.sub.1-6, os processos para prepará-los, os formulations pharmaceutical que contêm os e seu uso na terapia particularmente como inibidores do thrombin.