Synthesis of Substituted Quinones Using a Greener Approach

Abstract

In Chapter 1, we described the importance of quinones and existing synthetic strategy newlinefor substituted quinones. In Chapter 2, we have presented a one-step procedure (isolated yield newlineof and#8805;75%) for thiolation of substituted 1,4- naphthoquinones using Eosin Y as a photoredox newlinecatalyst with various aromatic and aliphatic thiols at room temperature (RT). In this process, newlinethe rate-determining step is the formation of thiyl radical, which was trapped by a radical newlinescavenger TEMPO and characterized by high-resolution mass spectrometry (HRMS). In newlineChapter 3, one step approach for C-H arylation of substituted 1,4-Napthoquinones (1,4-SNQ) newlineand 1,2-Napthoquinone (1,2-NQ) with diazonium salt in presence of green light using Eosin Y newlineat RT (isolated yield of and#8805;75%) was described. The rate-determining step of the reaction is aryl newlineradical generation, which was trapped by HRMS. In Chapter 4, we gave a brief description of newlinean environmentally friendly approach for synthesizing arylated phenothiazine-5-one newlinederivatives (isolated yield: 68-90%) using Eosin Y in the presence of a Green LED. Thiyl and newlinearyl radicals were captured as TEMPO adduct in HRMS. In Chapter 5, we described reagentfree newlinesynthesis of 4-Aryl/alkylamino-1,2-naphthoquinones in water and iprOH (1:1) mixture at newlineRT (isolated yield of and#8805;65%). Our finding suggested that molecular oxygen and water have newlineimportant roles in the synthesis process. newline