CuSO₄–d-glucose, an inexpensive and eco-efficient catalytic system: direct access to diverse quinolines through modified Friedländer approach involving S_NAr/reduction/annulation cascade in one pot

Abstract

A one-pot, efficient approach to quinoline synthesis, directly from 2-bromoaromatic aldehydes/ketones in a H2O–EtOH mixture involving a sequence of SNAr/reduction/annulation cascade using CuSO4-d-glucose, is devised.

d‐Glucose: An Efficient Reducing Agent for a Copper(II)‐Mediated Arylation of Primary Amines in Water

“…To the best of our knowledge, d ‐glucose has been used rarely as a reducing agent in organic chemistry. It has been reported for the one‐pot assembly of N‐fused imidazoles, the reductive homocoupling of aryl halides, and the formation of quinolines involving a three‐steps cascade . Therefore, this seems to be the first report of the use of d ‐glucose as a reducing agent in a copper‐catalyzed reaction in an aqueous medium.…”

Synthesis of 2‐(1,2,3‐Triazolyl)benzamide Derivatives by a Copper(I)‐Catalyzed Multicomponent Reaction

“…For example, Li, Chen, and co‐workers used this phenomenon to synthesize quinazolinones from 2‐iodobenzamide, NaN 3 , and aldehydes. Singh and co‐workers utilized the in situ generated 2‐aminobenzaldehydes, from 2‐bromobenzaldehydes and NaN 3 , in a condensation reaction to prepare the corresponding quinolines in a multicomponent manner Our findings emphasize one of the great features of multicomponent reactions, that is, the utilization of an unstable intermediate.…”

Efficient one pot multi-component domino Aldol condensation–Michael addition–Suzuki coupling reaction for the highly functionalized quinolines

“…It is noteworthy that when water was added to ethanol, the desired product 4a was obtained with an increased yield to 45% at 6h (entry 10). In the like manner, with the reaction improved condition, the catalyst loading and base variation were explored (entries [10][11][12][13][14][15][16]. Accordingly, among the tested bases, for instance, Na 2 CO 3 , NaOH, TEA, K 2 HPO 4 , Cs 2 CO 3 and K 3 PO 4 , NaOH and K 2 HPO 4 gave 80 and 82 % (entries 13 and 14), while K 3 PO 4 gave excellent yield of 92% (entry 16) while Cs 2 CO 3 , Na 2 CO 3 gave poor yields.…”

“…The parallel reactions are helpful to minimize the cost reasonably and could be done under same reaction conditions (Scheme 1, Eq. 1-5) without isolating the reaction intermediates [7][8][9][10][11][12][13][14][15][16][17][18][19][20] . The expense and mass production conditions of this strategy could be handled through parallel robotized syntheses and by precise investigation of the chemical reactions.…”