Squaric acid: an impressive organocatalyst for the synthesis of biologically relevant 2,3-dihydro-1H-perimidines in water
作者:Sushil Khopkar、Ganapati Shankarling
DOI:10.1007/s12039-019-1735-1
日期:2020.12
Abstract Squaricacid, a green, metal-free and eco-friendly organocatalyst, has been exploited for the synthesis of biologically interesting 2,3-dihydro-1H-perimidines. The reaction was performed using water as a green reaction medium and the organocatalyst can be easily recovered and reused up to four consecutive cycles without much decrease in catalytic activity. Several advantages of the present
Chitosan hydrochloride mediated efficient, green catalysis for the synthesis of perimidine derivatives
作者:Premchand B. Shelke、Suraj N. Mali、Hemchandra K. Chaudhari、Amit P. Pratap
DOI:10.1002/jhet.3700
日期:2019.11
Chitosan hydrochloride as biopolymer‐based, renewable, and recyclable heterogeneous catalyst was used for efficient one‐pot synthesis of perimidine derivatives. This newly developed greener methodology provides a very simple and greener route for the synthesis of perimidines in short time with excellent yield.
Near-infrared-absorbing squaraine dyes containing 2,3-dihydroperimidine terminal groups
作者:Kasali A. Bello、S. Nigel Corns、John Griffiths
DOI:10.1039/c39930000452
日期:——
Condensation of 2,3-dihydroperimidines with squaric acid under conditions of azeotropic removal of water affords a new class of diarylsquaraine dyes with intense absorption bands at ca. 800nm.
In a photographic photothermographic material comprising a organic silver salt, a silver halide, and a reducing agent on a transparent support, a specific hydrazine derivative and a specific squarylium dye are contained in suitable photosensitive or non-photosensitive layers on the support. The material is improved in Dmax, contrast, resolution, and residual color after processing.