There is provided a compound of formula (I) wherein R<1>, R<2a>, R<2b>, R<3a>, R<3b>, R<4>, R<5>, R<6>, A, G and L have meanings given in the description, which compounds are useful as, or are useful as prodrugs of, competetive inhibitors of trypsin-like proteases, such as trombin, and thus, in particular, in the treatment of conditions where inhibition of thrombin is beneficial (e,g. conditions, such as thrombo-embolisms, where inhibition of trombin is required or desired, and/or conditions wherea anticoagulant thererapy is indicated).