Synthesis of a TRPV1 Receptor Antagonist

Abstract

A five-step synthesis of a TRPV1 receptor antagonist 1 is described. The key step involves a novel palladium-catalyzed amidation reaction of 4-chloro-1-methylindazole 8 with the benzyl urea 9 to form the unsymmetrically substituted urea 1.

Iodoindazoles with Selective Magnesiation at Position 3: A Route to Highly Functionalized Indazoles

“…The direct functionalization of the indazole ring using cross‐coupling reactions or metal–halogen exchange from variously substituted N‐protected haloindazoles is an attractive alternative to cyclization reactions to obtain functionalized indazoles . However, in the case of direct metalation at position 3 of 1‐substituted indazoles, ring‐opening issues remain a strong limitation .…”

“…The direct functionalizationo ft he indazoler ing using crosscoupling reactions or metal-halogen exchange from variously substituted N-protected haloindazoles is an attractive alternative to cyclization reactions to obtain functionalized indazoles. [29][30][31][32][33][34][35] However,i nt he case of direct metalation at position 3o f1 -substitutedi ndazoles, ring-openingi ssues remain as trong limitation. [36,37] Recently,t wo methods in the literature describing the selectivef unctionalization of substituted indazoles at position 3u sing direct metalation reactionsh ave attractedo ur attention.…”

Synthesis and applications of bipyrazole systems

“…[170][171][172] The bipyrazole derivatives (bippyphos) 57 were applied as efficient ligands in the palladium-catalyzed C-O and C-N cross-coupling reactions of aryl halides with primary alcohols and with urea derivatives, respectively. 46,[173][174][175][176] 5,5'-Dihydroxy-4,4'-bipyrazoles 356 were reported as useful medicines for treatment of cerebral ischemia, heart diseases, gastrointestinal diseases, cancer, aging and inflammation. These medicines are useful for effectively capturing active oxygen and free radicals which cause adult diseases where singlet oxygen generated in a photo-excited hematoporphyrin system was reacted with 5,5'-dihydroxy-4,4'-bipyrazoles 356 to give ESR signal indicating production of stable free radical.…”

Synthesis of ethynylated biaryls and asymmetric diethynylated benzene via sequential Sonogashira and Suzuki couplings in water

“…[3][4][5][6][7][8] In addition, Suzuki-Miyaura cross-coupling reaction is one of the most versatile and utilized reactions for carbon-carbon bond formation in the synthesis of natural products and pharmaceuticals. [9][10][11][12][13] Water as an available, cheap, renewable, safe and green solvent and allows easy work up and separation, has been exploited in several catalytic C-C bond formation reactions and was reported as an important partner in improving the catalyst activity.…”