The present application describes 1,1-disubstitutedcycloalkyl-, glycinamidyl-, sulfonyl-amidino-, and tetrahydropyrimidinyl-containing diaminoalkyl, .beta.-aminoacids, .alpha.-aminoacids and derivatives thereof of Formula I: P-M-M.sub.1I or a stereoisomer or pharmaceutically acceptable salt or solvate form thereof, wherein M is a linear core. Compounds of the present invention are useful as inhibitors of trypsin-like serine proteases, specifically factor Xa.