Tandem cyclocondensation-Knoevenagel–Michael reaction of phenyl hydrazine, acetoacetate derivatives and arylaldehydes

Abstract

In this work, a novel N-bromo sulfonamide reagent, namely N,2-dibromo-6-chloro-3,4-dihydro-2Hbenzo[e][1,2,4]thiadiazine-7-sulfonamide 1,1-dioxide (DCDBTSD), is synthesized and fully characterized by IR, UV, 1 H and 13 C NMR, XRD, TG/DTG as well as mass spectra. The presented N-bromo sulfonamide is used as a new and highly efficient catalyst for the synthesis of 4,4 0 -(arylmethylene)-bis(3-methyl-1phenyl-1H-pyrazol-5-ol)s via one-pot pseudo five component condensation reaction of phenylhydrazine, acetoacetate derivatives and arylaldehydes. Mechanistically, Br + ions, which are generated by the catalyst, can catalyze this reaction in neutral media. This methodology offers several advantages, such as use of non-toxic and inexpensive materials, high yields, short reaction times and clean workup.

N,2-Dibromo-6-chloro-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazine-7-sulfonamide 1,1-dioxide: an efficient and homogeneous catalyst for one-pot synthesis of 4H-pyran, pyranopyrazole and pyrazolo[1,2-b]phthalazine derivatives under aqueous media

“…2 The preparation of tetrahydrobenzo [b]pyrans are important due to their significant anti-coagulant, diuretic, spasmolytic, anti-cancer, antihypertensive, calcium antagonists spasmolytic, pharmaceuticals and anti-anaphylactic properties. [10][11][12] Having above facts and in continuation of our previous studies on the applications of N-halo reagents in organic synthesis, [13][14][15][16][17][18][19][20][21] we [1,2,4]thiadiazine-7-sulfonamide 1,1-dioxide (DCDBTSD) (Figure 1) as an efficient and homogeneous catalyst for the synthesis of 4H-pyran and pyrazolo [1,2-b] phthalazine and pyranopyrazole derivatives. However, some reported methods for the synthesis of mentioned compounds suffer from one or more of disadvantages such as using toxic, corrosive, expensive and/or large amount of catalysts, long reaction time, toxic and corrosive solvents and strong acidic media.…”

One-pot synthesis of 4,4ʹ-(arylmethylene)-bis-(3-methyl-1-phenyl-1H-pyrazol-5-ols) catalyzed by Brönsted acidic ionic liquid supported on nanoporous Na+-montmorillonite

“…The main synthetic method for the preparation of this type of compounds is based on the condensation of aldehydes with 3-methyl-1-phenyl-5-pyrazolone. Therefore, a variety of catalysts and reagents have been used to facilitate this reaction [13][14][15][16][17][18][19][20][21][22]. Although these procedures provide an improvement in the synthesis of these heterocyclic compounds, many of them suffer from disadvantages such as long reaction times, harsh reaction conditions, the need of excess amounts of the reagent, the use of organic solvents, the use of toxic reagents and non-recoverability of the catalyst.…”

Silica-bonded 1,4-diaza-bicyclo[2.2.2]octane-sulfonic acid chloride catalyzed synthesis of spiropyran derivatives

“…Additionally, MCRs increase simplicity and synthetic efficiency on the conventional organic transformations [1][2][3][4][5].…”