Abstract: A method of conversion of thioimidates into amidines includes reacting a starting material compound including a thioimidate with a nitrogen-containing reagent to form a product compound including an amidine in place of the thioimidate in the starting material compound. The nitrogen-containing reagent includes a primary amine, a secondary amine, an ammonium salt, or a combination thereof. The thioimidate includes —S—R1, wherein R1 is substituted or unsubstituted (C1-C20)hydrocarbyl. A method of forming a cyclized product includes intramolecularly reacting an amidine with a carbonyl carbon to form the cyclized product including a 4H-imidazolone and/or a derivative thereof.

Abstract: Provided herein are proteins comprising a novel antigen binding domain. Said antigen binding domain, and proteins comprising it, are able to bind to osteosarcoma cells under physiological conditions. The antigen binding domain comprises an antibody light chain variable domain (VL) and an antibody heavy chain variable domain (VH), each comprising three complementarity determining regions (CDRs) flanked by human framework sequences. The human framework sequences reduces the risk of triggering unwanted immunogenic responses against the antigen binding domain. This may be especially important in a therapeutic setting wherein a drug is administered repeatedly to a human osteosarcoma patient.