Borane complexes of 2‐(1‐Methyl‐1,2,5,6‐tetra‐hydropyridin‐3‐yl)benzoxazoles

Abstract

2‐Pyridin‐3‐ylbenzoxazoles were synthesized by the reaction between 3‐pyridinecarboxaldehyde and substituted o‐aminophenols in the presence of iodobenzene diacetate. The resulting benzoxazoles 3 were treated with methyl iodide to give the corresponding pyridinium salts 4 which underwent the hydride reduction with sodium borohydride or sodium cyanoborohydride to produce 2‐(1‐methyl‐1,2,5,6‐tetrahy‐dropyridin‐3‐yl)benzoxazole borane complex derivatives.

Synthesis, characterization and crystal structures of boron-containing intermediates in the reductive amination of ferrocenecarboxaldehyde to a bis(ferrocenylmethyl) amine

“…Initial attempts to form the cyanoborane 6 by thermolysis of solid 4 at 80°C and Loss of H 2 was confirmed by mass spectrometry (M + = 466) as well as X-ray crystallographic analysis. Similar amine-borane adducts have pharmaceutical applications, displaying anti-cancer, anti-inflammatory, and anti-osteoporotic properties [36][37][38][39]. Scheme 4 depicts a mechanism for the formation of 4-6, based in part on the work of Boga et al [40] and Biot and co-workers [14].…”

Synthesis of 5-(4-Alkylsulfanyl-[1, 2, 5]Thiadiazol-3-yl)-3-Methyl-1, 2, 3, 4-Tetrahydropyrimidine Oxalate Salts and their Evaluation as Muscarinic Receptor Agonists

“…The sodium borohydride reduction of 6 in methanol at low temperature furnished 5-(4-alkylsulfanyl-[1,2,5]thiadiazol-3-yl)-3-methyl-1,2,3,4-tetrahydropyrimidine as the sole product.To enhance their stability and purity, the product was further treated with oxalic acid in methanol to give the oxalate salts 7. The structure of 7 can be deduced from X-ray crystallographic data of pyrimidinylbenzoxazole which was previously obtained via identical chemical pathway [15].1 H-NMR spectra of the final compound 7 showed singlets at 7.52-7.63 ppm corresponding to the C6-H, and the signals of the two protons at C4 were observed at 3.92-4.02 ppm as singlets. …”