A series of chiral lactam carboxamides of aminomethylpiperidine were synthesized and investigated for the collagen induced in vitro anti-platelet efficacy and collagen plus epinephrine induced in vivo pulmonary thromboembolism. The compound 31a (30 μM/kg) displayed a remarkable antithrombotic efficacy (60% protection) which was sustained for more than 24 h and points to its excellent bioavailability. The compounds 31a (IC50 = 6.6 μM) and 32a (IC50 = 37 μM), as well as their racemic mixture 28i (IC50 = 16 μM) significantly inhibited collagen-induced human platelet aggregation in vitro. Compound 34c displayed dual mechanism of action against both collagen (IC50 = 3.3 μM) and U46619 (IC50 = 2.7 μM) induced platelet aggregation. The pharmacokinetic study of 31a indicated very faster absorption, prolonged and constant systemic exposure and thereby exhibiting better therapeutic response.