A general and efficient one-pot synthesis of spiro[2-amino-4H-pyrans] via tandem multi-component reactions catalyzed by Dabco-based ionic liquids

Synthesis of heterocyclic compounds via Michael and Hantzsch reactions

“…Spiro tetrahydrobenzo[ b ]pyrans 75 and 76 were prepared by a three‐component reaction of isatin 5 or acenaphthequinone 6 , malononitrile or ethyl cyanoacetate 2a,b , and dimidone or cyclohexa‐1,3‐dione in different media (Methods A‐C, Scheme , Table ) …”

“…One‐pot, three‐components reaction of 4‐hydroxycoumarin 100 , malononitrile or methyl 2‐cyanoacetate, and isatin 5 , ninhydrin 138 , or acenaphthenequinone 6 in the presence of different catalysts and solvents afforded spiro(indoline‐3,4′‐pyrano[3,2‐ c ]chromene) derivatives 139‐141 (Methods A‐E, Scheme ) …”

Synthesis and evaluation of antimicrobial activity, cytotoxic and pro-apoptotic effects of novel spiro-4H-pyran derivatives

“…21 In recent years, a variety of synthetic approaches for constructing spiro-fused pyran derivatives via multicomponent reactions have been reported, particularly involving a threecomponent reaction of 1,3-diketones, aldehydes and malononitrile/ethyl cyanoacetate in the presence of various homo-and heterogeneous catalysts. [22][23][24][25][26][27][28][29] Drug resistance is always a great challenge for researchers to encourage them to explore and design new drugs with the potential effectiveness in treatment of diseases including infectious diseases and cancer. To do so, we focused on derivatives of spiro-fused-pyran compounds.…”

A Facile and Green Pathway for One‐Pot Multicomponent Synthesis of Functionalized Spiroxyindoles using Caffeinium Hydrogen Sulfate as a Catalyst.

“…Recently, MCR's have become an excellent strategy for the construction of C−C bonds and are extensively utilized for the synthesis of a vast library of functionally diverse organic molecules and drug candidates . These reactions offer several advantages like superior atom economy, high productivity, excellent selectivity, facile execution and are perfectly susceptible to automation for combinatorial synthesis . Isatin, as a core structure in the synthesis of a library of heterocyclic compounds possess a wide range of biological and pharmacological properties such as antidepressant, anti‐inflammatory and antimicrobial properties ,.…”

“…These heterocyclic pyran ring system exhibit various pharmacological properties like antileshmanial, antioxidant, antitumor, anti‐allergic, antibacterial and antipoliferative properties . Also spiropyrans serve as key ingredients of many dyes, pigments, cosmetics, biodegradable agrochemicals, can be used as fluorescence markers and in laser technologies ,. The conventional method for the preparation of spiropyran derivatives involve the one pot three component condensation of isatin, active methylenes (malononitrile or ethyl cyanoacetate) and various C−H activated carbonyl compounds such as dimedone, barbituric acid, thiobarbituric acid, α and β naphthol and 4‐hydroxycoumarin.…”