n , n - di cyclic urea derivatives , such as the compounds of the following formula : ## str1 ## wherein r 1 is -- cnh 2 , -- cnor 11 , -- cncr 9 , or -- cncor 11 ; r 2 and r 3 are independently hydrogen , halo , lower alkyl , lower haloalkyl , aryl , -- or 11 , -- cor 11 , -- cnr 12 , -- nr 12 , -- ncr 11 , or -- ns 2 r 11 ; r 4 is halo , lower haloalkyl , imidazolyl , -- cnh 2 , -- cnhor 11 , -- n cor 11 , -- cnr 12 , or -- nr 12 ; r 7 and r 8 are independently hydrogen , lower alkyl , lower haloalkyl , 4 - pyridinyl , -- cor 11 , -- cnr 12 , or aryl r 12 ); r 11 and r 12 are independently hydrogen , lower alkyl , aryl or lower aralkyl ; or r 13 is pyrrolidinyl , 4 - morpholinyl , piperazinyl , n - methylpiperazinyl , or piperidinyl ; or a pharmaceutically acceptable salt thereof , are disclosed herein as being inhibitors of factor xa and thereby being useful as anticoagulants .