A highly efficient and recyclable photocatalyst Cu/Pd-N-TiO2 was developed and used successfully for a one-pot synthesis of twenty 2-substituted and 2,3-disubstituted quinoxaline derivatives by the reaction of various alpha-hydroxyketones with ortho-phenylenediamines. The composition and crystal phase of the catalyst were determined by p-XRD studies, and its morphological and surface characteristics were ascertained by SEM and HRTEM studies. All the synthesized compounds were appropriately identified by spectroscopic studies ( IR, 1H and 13C NMR, MS)
D-Luciferin is the cornerstone of modern bioluminescence technologies, with applications spanning molecular biology, chemical biology, medical imaging, and diagnostics. Since its structural elucidation and first total synthesis in the early 1960s, sustained synthetic innovation has transformed D-luciferin from a rare natural product into a widely accessible and broadly used chemical tool. This review presents a comprehensive and chronological account of the chemical syntheses of D-luciferin, with particular emphasis on how successive synthetic strategies developed over time. The evolution of benzothiazole construction, and the now canonical 1,2-aminothiol click reaction with D-cysteine is traced in detail. We show that despite the many different syntheses reported, they all employ 2-cyanobenzothiazoles (2-CBTs) as common intermediates, to achieve the synthesis of the various luciferins. We further demonstrate that the progress made in accessing D-luciferin, stemmed largely from effective synthetic efforts to forging 2-CBTs. The emergence of C6-modified luciferins is also highlighted, notably D-aminoluciferin and D-thioluciferin, and how improved synthetic access to these 2-CBT analogues enabled new bioluminescence technologies.
