Solid-phase synthesis of functionalized 1,2,4-triazin-6-ones

Published in: Journal, Volume : 43, Issue : 45, Pages : 8165-8167

DOI : 10.1016/s0040-4039(02)01956-1

Author : Blass, Benjamin E.; Coburn, Keith R.; Faulkner, Amy L.; Liu, Song; Ogden, Adam; Portlock, David E.; Srivastava, Anil

Abstract : The solid supported synthesis of functionalized 1,2,4-triazin-6-ones from resin bound amino acids and acid chlorides is described. A thioamide intermediate is generated with Lawesson’s reagent, and the final products are cyclized and cleaved from resin with hydrazine. The products are obtained in good yield and purity.

Petasis boronic acid-Mannich reactions of substituted hydrazines: synthesis of α-hydrazino carboxylic acids

Published in: Journal, Volume : 43, Issue : 38, Pages : 6845-6847

DOI : 10.1016/s0040-4039(02)01511-3

Author : Portlock, David E.; Naskar, Dinabandhu; West, Laura; Li, Min

Abstract : R1CONHNHR2 [R1 = OCMe3, OCH2Ph, NH2; R2 = cyclohexylmethyl, Me2CHCH2, MeO2CCH2, PhCH2, Ph, 4-MeC6H4, 4-O2NC6H4,2-pyridyl, H, EtO2CCH2] can serve as amine substrates for the Petasis boronic acid-Mannich reaction with R3B(OH)2 [R3 = 4-MeOC6H4, 4-MeC6H4, PhCH:CH, Ph, 2-benzothienyl, 1-naphthyl] and OCHCO2H, providing a practical synthetic route for the preparation of α-hydrazinocarboxylic acids R1CONHNR2CHR3CO2H. The scope and limitations of this method have been examined

Solution phase synthesis of imidazo[1,2-b]pyrazol-2-one, an interesting 5,5-fused heterocyclic ring system

Published in: Journal, Volume : 45, Issue : 3, Pages : 619-621

DOI : 10.1016/j.tetlet.2003.10.177

Author : Blass, Benjamin E.; Srivastava, Anil; Coburn, Keith R.; Faulkner, Amy L.; Janusz, John J.; Ridgeway, James M.; Seibel, William L.

Abstract : The solution phase synthesis of a series of imidazo[1,2-b]pyrazol-2-ones, e.g., I, a fused 5,5-ring system, is described. The heterocyclization of α-hydrazino acids with α-cyano ketones gave 5-aminopyrazoles, e.g., II, which underwent an intramol. cyclodehydration to give the corresponding imidazo[1,2-b]pyrazol-2-ones.