Eco-friendly polyethylene glycol (PEG-400): a green reaction medium for one-pot, four-component synthesis of novel asymmetrical bis-spirooxindole derivatives at room temperature

Abstract

PEG-400 has been used for the synthesis of novel asymmetrical bis-spirooxindoles by the reaction of N-alkyl isatin, isatin derivatives, alkylmalonates and C–H activated carbonyl compounds in the presence of K2CO3 at room temperature.

I2‐Catalyzed Oxidative N−P Cross‐Coupling of Diarylphosphine Oxides and Sulfoximines

“…It seems that PEG400 stablizes the active catalytic intermediate or transition state and thus benefits this reaction. Fortunately, PEG400 is a well-known green solvent, [15] and also an essential solvent for this reaction, so it is perfect for this reaction.…”

“…As we known, PEG400 is considered as an inexpensive, safe, recyclable, degradable, non-flammable, facile, environmentally benign and abundantly available green solvent. [15]…”

CsF promoted rapid synthesis of spirooxindole‐pyran annulated heterocycles at room temperature in ethanol

“…After the successful synthesis of spiro‐4 H ‐pyran derivatives 4a–4aa , the scope of this methodology was further extended toward bis‐spiro‐4 H isatin derivatives. The biological activities were usually enhanced when different substitutions are present on the two heterocyclic moieties in the bis‐compound . However, the extreme steric conjugation in bis‐heterocycles makes the construction of all‐carbon quaternary centers a formidable challenge for synthetic organic chemists .…”

Synthesis of carboxamide and sulfonyl carboxamide linked heterocycles under green conditions

“…In recent years, the use of green reaction solvents such as ionic liquids and polyethylene glycol (PEG-400) has gained importance. [22][23][24] Though phase transfer catalysis is an alternative technique, it is not always possible because of sensitivity of the reactants to aqueous conditions. 25 In this context, PEG-400 has become an alternative reaction media to perform organic synthesis due to its inherent advantages over toxic solvents.…”