Molecular diversity of cycloaddition reactions of the functionalized pyridinium salts with 3-phenacylideneoxindoles

Formation of diverse polycyclic spirooxindoles via three-component reaction of isoquinolinium salts, isatins and malononitrile

“…On the other hand, when N -phenacylisoquinolinum bromides were employed in the three-component reaction, we were very disappointed to find that the reaction resulted in complex mixtures, which were unable to be separated out. It has been known that N -phenacylisoquinolinum bromides usually have higher reactivity than that of N-p -nitrobenzyl- and N -ethoxycarbonylmethylisoquinolinium bromides495051525354555657. In order to get good results, we carefully examined the reaction conditions for N -phenacylisoquinolinum bromides and did not get the expected products.…”

“…In order to explain the formation mechanism of the spiro compounds 1 and 2 , a plausible reaction mechanism was proposed on the basis of the known 1,3-dipolar cycloaddition reactions of the cyclic nitrogen ylides49505152535455565758 (Fig. 6).…”

“…In the past few years, we investigated the multicomponent reactions by employing easily generated cyclic nitrogen ylides as the main substrates and have successfully developed a number of highly efficient protocols for synthesis of some biologically important nitrogen-containing heterocyclic compounds404142434445464748. Recently, we successfully found that the cycloaddition reaction of the cyclic nitrogen N -ylides with reactive 3-phenacylideneoxindoles resulted in diverse spirooxindole systems including spiro[indoline-3,1′-pyrrolo[2,1-a]isoquinolines], spiro[cyclopropane-1,3′-indolines], 3-furan-3(2 H)-ylidene)indolin-2-ones, spiro[benzo[d]pyrrolo[2,1-b]thiazole-3,3′-indolines], and complex cyclopentyl dispiroxindoles495051525354555657. We also found that three-component reactions of N -benzylbenzimidazolium salts, isatins and malononitrile or ethyl cyanoacetate gave a series of the novel zwitterionic salts and the unexpected products with opening of the imidazole ring58.…”

Diastereoselective Sonochemical Synthesis of Spirocyclopropaneoxindoles and Evaluation of Their Antioxidant and Cytotoxic Activities

“…[15 -17] Reaction between 3-chlorooxindole and α,β-unsaturated olefins has been provided an operationally simple, stepwise pathway to construct functionalized spirocyclopropyl oxindoles. [18 -20] The cycloaddition of arsonium, [21] sulfonium, [22] phosphrous [23] and ammonium ylides [24] with electrondeficient olefins has been attempted by many researchers for the synthesis of cyclopropane-containing frameworks. Although this strategy provides highly diverse spirocyclic cyclopropanes, but suffer from formation of byproducts such as furan derivatives and often harsh reaction conditions.…”

Synthesis of functionalized pyridinium salts bearing a free amino group

“…1 Introduction of functional groups that can participate in hydride transfer reactions offers the potential to induce new reactivity and selectivity patterns. However, the development of methods for the preparation of such analogues is hampered by the relatively high electrophilicity of pyridines and pyridinium salts, [2][3][4] which significantly complicates attempts to functionalize these structures. This contribution describes our efforts in the synthesis of pyridinium salts 1 bearing free tertiary amine functionalities, which could serve as mediators in hydride transfer reactions.…”