2s 2 4 1rs 1 2 4 diaminopteridin 6 yl methyl but 3 ynyl benzoyl amino pentanedioic acid, 2s 2 4 1 2 4 diaminopteridin 6 yl pent 4 yn 2 yl benzoyl amino pentanedioic acid, 10 propargyl 10 deazaaminopterin