142373-60-2

Tirofiban was launched as Aggrastat in Switzerland and the US for patients with unstable angina or non-Q-wave myocardial infarction to prevent cardiac ischemic events. Tirofiban is synthesized from (S)-tyrosine by a fourstep process. Tirofiban is a novel highly potent antiplatelet agent that inhibits the interaction of fibrinogen with GPⅡb/Ⅲa, an activated platelet membrane-bound glycoprotein complex. It prevents arterial thrombus formation in a dosedependent manner. Clinical efficacy was highly significant with an absolute and relative risk reduction. In these studies, treatment with tirofiban was well tolerated, without significant adverse effects.

Sibutramine (Sibutramine)

Aggrastat (Millot Laboratories, France).

The synthesis of tirofiban starts by reaction of tyrosine with bis-trimethylsilyl trifluoraceramide to give a derivative in which both functions -OH and COOH_x0002_are protected. Treatment of this intermediate with butylsulfonyl chloride gives the corresponding sulfonamide derivative; the quite labile silyl groups are then removed under mildly acidic conditions to give N-butylsulfonyl-tyrosine. In a parallel scheme, 4-picoline is converted to its anion by means of butyl lithium; this gives 4-(4-chlorobutyl)-pyridine on alkylation with 1-bromo-3- chloropropane. The reaction of this compound with N-butylsulfonyl-tyrosine in presence of NaOH gives the ether 2-butylsulfonyaminol-3-[4-pyridin-4-ylbutoxy-phenyl]propionic acid. Hydrogenation over palladium on charcoal then reduce the pyridine ring to a piperidine to afford the fibrinogen receptor antagonist tirofiban.

Tirofiban is INN and BAN.

Fibrinogen receptor antagonist