monosubstituted

adjective

mono·​sub·​sti·​tut·​ed -ˈsəb-stə-ˌt(y)üt-əd 

: having one substituent atom or group in a molecule

monosubstituted acetylenes

monosubstitution

-ˌsəb-stə-ˈt(y)ü-shən 

noun