SingaCycle^TM‐A1‐Catalyzed Successive Suzuki‐Miyaura and Buchwald Couplings for the Synthesis of Various New Pyridine Analogues

Abstract

A new diversified, rapid and easily accessible, N‐heterocyclic carbene based palladacycle, SingaCycleTM‐A1 exploited for the cross coupling reactions on heterocyclic amines. This Pd‐NHC catalyst is considered to be merely stable and takes part in dynamic conversion of various organic functionalities. Herein, we report its first time use in the synthesis of C‐ and N‐ diaryl/ heteroaryl pyridine analogues from the less active parent 5‐bromopyridine‐2‐amine via sequential Suzuki‐Miyaura and Buchwald couplings. Surprisingly, both the coupling reactions proceed very smoothly and efficiently under mild reaction conditions in green solvent system (ethanol:water) at a faster rate. Moreover 1 mol% of the catalyst is sufficient to proceed the reactions and obtain comparatively better results.

Highly Efficient N‐Heterocyclic Carbene Precursor from Sterically Hindered Benzimidazolium Salt for Benzoin Condensation

“…TON=Ratio of moles of reactant to ratio of moles of catalyst used multiplies with percentage of yield. TOF=Turnover number per hour [18b,c] …”

Structure controlled Au@Pd NPs/rGO as robust heterogeneous catalyst for Suzuki coupling in biowaste‐derived water extract of pomegranate ash

“…The present method has been found to be highly efficient for the heteroaryl bromides including 2‐bromothiophene, 2‐bromopyridine, and 2‐amino‐5‐bromopyridine to provide excellent yields of coupling products in short reaction times (20–30 min) (Table 2, products 3ac – 3ae ). Moreover, high degree of chemoselectivity was observed in the reaction of 4‐bromoaniline and phenylboronic acid or 2‐amino‐5‐bromopyridine and 2,4‐fluorophenylboronic acid, [ 61 ] that is, the selective reactivity of halogen attached position over free –NH 2 (Table 2, products 3q and 3ae ), which may usually results the Chan‐Lam coupling. Furthermore, the sensitive functional groups, formyl, keto, carboxyl, ester, nitro, cyano, amino, and chloro, present on both the aryl halides and ABAs were unaffected in these reactions.…”

Synthesis of novel cytotoxic tetracyclic acridone derivatives and study of their molecular docking, ADMET, QSAR, bioactivity and protein binding properties

“…This kind of construction has evolved some triazolo-, imidazolo-and pyrimidino-fused acridones so far, this piperazine fused acridone frame linking alkyl/ aryl moieties with amide linker is a novel accomplishment to the existing array of acridones. As Pd(OAc) 2 -Xantphos is used as a potential catalyst-ligand system for C-N coupling 44 , here we have extended the use of Cs 2 CO 3 -Pd(OAc) 2 -Xantphos system in producing the acridone ring by forming a C-N linkage through N-arylation process. The chemical structures of the synthesized compounds (7a-s) of the study were confirmed by IR, 1 H, 13 C and mass spectrometry analyses and all the spectral responses were observed in their expected standard range, and cor- 7r, 7l, 7o, 7a, 7d, 7b, 7e, 7i and 7q having the substitutions like p-hydroxybenzoyl, p-fluorobenzoyl, benzoyl, p-(trifluoromethyl)benzoyl, picolinoyl, cyclopropyl-acetyl, 3-nicotinoyl, 6-methylpicolinoyl, trifluoromethylpicolinyl and 3-fluorobenzoyl groups on acridone fused piperazine moiety.…”