Organocatalytic Enantioselective Aminoalkylation of 5‐Aminopyrazole Derivatives with Cyclic Imines

Abstract

In this communication, an efficient asymmetric aminoalkylation of 5‐aminopyrazole derivatives with cyclic benzoxathiazine 2,2‐dioxides catalyzed by a quinine‐derived squaramide in dichloromethane has been established. This is the first example of 5‐aminopyrazole derivatives in asymmetric catalysis. A variety of chiral sulfamidates bearing an aminopyrazole moiety were obtained in good yields (up to 98 %) and moderate to excellent enantioselectivities (up to 99 %ee).

Photocatalytic Functionalization of Dihydroquinoxalin‐2‐Ones with Pyrazolones

“…However, the use of this class of nitrogen heterocycles is underdeveloped. We decided to study the performance of 5‐aminopyrazoles [27] as nucleophiles under the optimized reaction conditions. Delightfully, the corresponding amino‐pyrazolone‐quinoxalin‐2‐one adducts 7 , were obtained with good yields (60–95%).…”

Chiral Phosphoric Acid‐Catalyzed Enantioselective Synthesis of Pyrazole‐Based Unnatural α‐Amino Acid Derivatives

“…In addition, this motif is also widely found in insecticidal agents, [18b] supramolecular and polymer chemistry, food industry and as cosmetic dyes and UV stabilizers [18c] . Pyrazoles have recently attracted considerable attention from chemists [19–21] . We therefore hypothesize that the fusion of alkynyl‐α‐amino acid and pyrazole scaffolds may lead to promising multi‐target compounds and provide new compound libraries for protein engineering studies.…”

“…[18c] Pyrazoles have recently attracted considerable attention from chemists. [19][20][21] We therefore hypothesize that the fusion of alkynyl-αamino acid and pyrazole scaffolds may lead to promising multi-target compounds and provide new compound libraries for protein engineering studies. To continue our efforts [22] on the advancement of chiral phosphoric acid catalysis, in this context, we envisioned that a variety of pyrazole based α-chiral amino acid derivatives bearing a tetrasubstituted carbon stereocenter could be obtained via direct chiral phosphoric acid-catalyzed α-addition of N-aryl-5amino pyrazoles to β,γ-alkynyl-α-imino esters in high yields with excellent regioselectivity and enantioselectivity (Scheme 1).…”

Nickel-catalyzed multicomponent reaction of dinitriles and hydrazine hydrochlorides with boronic acids: access to 1,3-diaryl-1H-pyrazol-5-amines and 4,5-dihydropyridazin-3(2H)-ones

“…(Scheme 1, top). 2 Meanwhile, it could be used to synthesize photoluminescent and electroluminescent materials. 3 On account of the ubiquitous nature of this scaffold, the development of diverse channels to assemble 1,3-diaryl-1 H -pyrazol-5-amine has received considerable attention from academia and industry.…”