Abstract
Synthesis of carboxamide and sulfonyl carboxamide linked heterocycles under green conditions
Highlights
Amide moiety represents a privileged structural motif and it plays an important role in the composition of polymers, proteins, natural products and pharmaceuticals.[1,2] Various approaches were explored for efficient construction of this significant skeleton.[3,4] The most common synthetic route relies on the reactions of activated carboxylic acids and their derivatives with amines.[5,6,7] this method has innate drawbacks, for instance, a large amount of byproducts are generated leading to lower yields
We have reported the reaction between heteroaryl acids and heteroaryl amines to develop amide linkage using 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate (TBTU)/ N,N-diisopropylethylamine (DIPEA)/ N,N-dimethylformamide (DMF),[16] N,N'dicyclohexylcarbodiimide (DCC)/ 4-dimethylaminopyridine (DMAP)/ Dioxane,17,18 1-[bis(dimethylamino)methylene]1H-1,2,3-triazolo[4,5-b]pyridinium-3-oxidehexafluorophosphate (HATU)/ DIPEA/DMF.[19]
The resultant N-(5(chlorosulfonyl)-4-phenyl-1H-imidazol-2-yl)benzamide on further treatment with 25% NH4OH gave 4.21 Initially, in our attempt to develop amide linkage directly from aldehydes and amines, we have chosen 1a and 2a to carry out the pilot reaction in the presence of different oxidants viz., m-CPBA in dichloromethane, H2O2 in dimethyl carbonate (DMC) and CCl3CN/H2O2 in dichloromethane
Summary
Amide moiety represents a privileged structural motif and it plays an important role in the composition of polymers, proteins, natural products and pharmaceuticals.[1,2] Various approaches were explored for efficient construction of this significant skeleton.[3,4] The most common synthetic route relies on the reactions of activated carboxylic acids and their derivatives with amines.[5,6,7] this method has innate drawbacks, for instance, a large amount of byproducts are generated leading to lower yields. In continuation of our interest on green-reaction conditions for organic transformations[15] we report a simple and efficient protocol for the synthesis of carboxamide and sulfonyl carboxamide linked heterocycles using PEG-400 in the presence of an oxidant CCl3CN/H2O2 as eco-friendly and recyclable medium. The resultant N-(5(chlorosulfonyl)-4-phenyl-1H-imidazol-2-yl)benzamide on further treatment with 25% NH4OH gave 4.21 Initially, in our attempt to develop amide linkage directly from aldehydes and amines, we have chosen 1a and 2a to carry out the pilot reaction in the presence of different oxidants viz., m-CPBA in dichloromethane, H2O2 in dimethyl carbonate (DMC) and CCl3CN/H2O2 in dichloromethane.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callSimilar Papers
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
