I have been wondering whether these (eg ClCc1n(H)ccn1 with substituents) would be viable covalent binders to Cysteine or if they are too easily hydrolysed? Would this also be the case for ClCc1n(H)cco1, ClCc1n(H)ccs1 etc? (I havent done any lab chemistry for over 40 years and even then heterocyclic chemistry was at the periphery of “advanced organic chemistry”.

PS It appears that such compounds are not usually present in commercial HTS compound libraries.