R. D. Larsen

Learn More
alpha-Aryl ketones react with vinamidinium hexafluorophosphate salts to give access to the corresponding 3-arylpyridines. The annulation reactions proceed in good to excellent yields with vinamidinium salts containing electron-withdrawing groups at the beta-position (R(2)). The reaction was applied to the preparation of the COX-2 specific inhibitor(More)
A number of synthetic strategies to the Cox-2 specific inhibitor 1 have been described. These studies have led to the identification of a novel pyridine construction using annulation of ketone 2 using a vinamidinium species 29 and ammonia in 97% assay yield. Three approaches to the synthesis of ketone 2 are described that allow for its preparation in large(More)
  • R. D. Larsen
  • Current opinion in drug discovery & development
  • 1999
Palladium-catalyzed reactions are having a great impact on the synthesis of medicinal agents due to their ability to form carbon-carbon and carbon-heteroatom bonds effectively. Quite often the palladium-catalyzed step(s) in a synthesis is key to the overall strategy for preparing a drug candidate. The diversity of the coupling processes is being broadened(More)
We have used two methods to evaluate the level of expression of Gb3Cer in several human leukaemia/lymphoma cell lines representative of the myeloid (K562, KG-1, HL-60, and THP-1) and lymphoid (Reh, Daudi, Raji, RPMI 8226, CCRF-CEM, MOLT-4) lineages blocked at varied stages of differentiation. TLC immunostaining of glycolipid extracts with a monoclonal(More)
[reaction: see text] New air-stable PdCl(2){P(t)Bu(2)(p-R-Ph)}(2) (R = H, NMe(2), CF(3),) complexes represent simple, general, and efficient catalysts for the Suzuki-Miyaura cross-coupling reactions of aryl halides including five-membered heteroaryl halides and heteroatom-substituted six-membered heteroaryl chlorides with a diverse range of arylboronic(More)
An efficient and convenient method for the synthesis of [1,2,4]triazolo[4,3-a]pyridines was exemplified by the synthesis of 20 analogues bearing a variety of substituents at the 3-position. The methodology involves a palladium-catalyzed addition of hydrazides to 2-chloropyridine, which occurs chemoselectively at the terminal nitrogen atom of the hydrazide,(More)