Synthesis of Metallacyclobutenes of Late Transition Metals via Nucleophilic Addition of Allenyl or Propargyl Complexes

The regioselective addition of NEt3, PPh3, or pyridine to the central carbon of a cationic η3-allenyl/propargyl complex of platinum, {Pt(PPh3)2(η3-C3H3)}(BF4) (1), leads to the formation of the new cationic = NEt3 (2a), PPh3 (2b), C5H5N (2c)) via formation of a C−N or C−P bond, respectively. Complex 2c can transform into {cis-Pt(PPh3)2(Py)(η1-CHCCH2)}(BF4) (3). The reverse reaction has not been observed. It is suggested that nucleophilic addition of 1 likely involves external attack at the central carbon of the η3-allenyl/propargyl ligand. Protonation of 2b yields {Pt(PPh3)2[η3-CH2C(PPh3)CH2]}(BF4)2 (7). Addition of PPh3 to a labile η1-allenyliridium complex, (OC-6-42)-Ir(Cl)(PPh3)2(OTf)(CO)(η1-CHCCH2) (4), results in the The single-crystal X-ray structure of 5 has been determined

Synthesis of 1-Benzyl-3-(5‘-hydroxymethyl-2‘-furyl)indazole Analogues as Novel Antiplatelet Agents

1-Benzyl-3-(5‘-hydroxymethyl-2‘-furyl)indazole (28, YC-1) was selected as the lead compound for systemic structural modification. After screening for antiplatelet activity, SARs of YC-1 analogues were established. Among these potent active derivatives, compounds 29, 30, 31, 44, and 45 functioned as potent activators of sGC and inhibitors of PDE5 with potency comparable to that of YC-1. In addition, compound 58 was found to be a selective and potent inhibitor of protease-activated receptor type 4 (PAR4)-dependent platelet activation