Eco-friendly synthesis of amidochloroalkylnaphthols and its related oxazepinones with biological evaluation

Abstract

A general mild and efficient protocol for the synthesis of amidochloroalkylnaphthol libraries was achieved utilizing SiO 2 -ZnCl 2 (silzic) as a reusable heterogeneous catalyst via Ritter-type reaction, through one-pot, three-component condensation of various aldehydes, chloroacetonitrile, and b-naphthol under solventfree reaction conditions. The amidochloroalkylnaphthols were cyclized to its related oxazepinones, and their anticancer and antioxidant activities were studied. Graphical Abstract

An Efficient and Facile Synthesis of Functionalized Indole‐3‐yl Pyrazole Derivatives Starting from 3‐Cyanoacetylindole

“…The formation of the target compounds (13) and (14) was illustrated through elimination of two HCl molecules in case of compound (13) and elimination of HBr molecule followed by cyclization through elimination of a water molecule in case of compound (14). Moreover, cyclocondensation of (4) with diethyl oxalate in glacial acetic acid at reflux afforded the corresponding imidazo[1,2-b]pyrazole derivative (15), through elimination of two ethanol molecules (Scheme 4).…”

“…We have recently reviewed the methods of preparation and the chemical reactivity of 3‐cyanoacetylindole as building block for the synthesis of polyfunctionalized 3‐substituted indole derivatives with pharmacological interest . As a consequence of our recent work aimed at synthesis of new heterocyclic systems with remarkable biological importance , it was planned to present an efficient regioselective synthesis of some novel biologically active heterocycles such as pyrazolo[1,5‐ a ]pyrimidines, imidazo[1,2‐ b ]pyrazoles, pyrazolo[1,5‐ a ][1,3]diazepine and pyrazolo[1,5‐ c ][1,3,5]thiadiazine bearing indole ring system, which have not been reported hitherto. The results of screening of their biological activity will be reported in due course.…”

Recent Applications of Ritter Reactions in Organic Syntheses

“…[80] In 2016, Soliman and co-workers developed an environmentally friendly multicomponent Ritter reaction of chloroacetonitrile 79, various aldehydes 37 and naphthol 214 in the presence of inexpensive SiO 2 -ZnCl 2 as catalyst under solventfree conditions to yield amido-chloroalkyl naphthol 215, which was converted to the oxazapinones 216 in the presence of K 2 CO 3 in dimethylformamide (DMF) (Scheme 86). [81] In 2018, Wei et al developed a new approach to synthesize fluorinated cyclobuta[b]indoline derivatives 218 and multifluorinated polycycles 219 through the Ritter reaction of acetonitrile 47 and amide derivatives 217 in the presence of selectfluor (Scheme 87). [82] The mechanism of this reaction is created by selectfluor two single electron transfer (SET) processes for the synthesis of the fluorinated cyclopropylcarbinyl cation 221, which produces…”

V2O5/SiO2 as an efficient catalyst in the synthesis of 5-amino- pyrazole derivatives under solvent free condition

“…Catalysts contain silicon element attracted our attention and play an important role in our group [24][25][26], and we forward are the aim of investigation new methods for design and synthesis of heterocyclic compounds by efficient and simple reaction. This work presented the synthesis of 5-aminopyrazole derivatives using V 2 O 5 /SiO 2 as a heterogeneous catalyst under solvent free condition.…”