Reactions And Synthesis Of N-heterocyclic Compounds Via C-H Functionalization

C-H Functionalization have attracted much attention because of their atom economy, simple reaction steps. Nitrogen-containing heterocyclic compounds are ubiquitous subunits of natural prodcts, drugs, biologically active molecules. Recently, many chemists have developed the methods of constructing N-heterocycles via C-H Functionalization. These methods are very important for pharmaceutical and nature products chemistry. The contents were listed as below:1. Manganese catalysed sulfenylation of N-methyl amides with arenesulfonyl hydrazidesWe have developed a convenient oxidative sulfenylation method for the formation of various sulfenyl amides has been reported. Arenesulfonyl hydrazine as a sulfur source in the presence of a manganese salt can activate the sp3 C-H bond of N-methyl amides through a freeradical pathway using di-tert-butyl peroxide (DTBP). This study has investigated the role of the metal catalyst in the sulphonyl hydrazide decomposition process and has broadened the scope of sulphonyl hydrazides as electrophilic sulfenylation reagents in the free-radicalinitiated C-H bond activation pathway.2. Metal-free catalytic approach for allylic C-H Animation using N-heterocycles via sp3 C-H bond activation.A versatile metal-free synthesis of allylic N-heterocycles has been developed using a TBAI/TBHP oxidation system. This general protocol could be applied for the C-N bond formation of electrondeficient phthalimides, imidazoles, triazoles, and sulfonamides with cyclic and acylic olefins. The practical use of the method is demonstrated by the amidation of functionalized biologically active substrates. This metal-free amination pathway presents a direct access to a variety of allyl-substituted heterocycles as useful synthetic intermediates and important bioactive agents.3. Metal-free tandem oxidative coupling of primary alcohols with azoles for the synthesis of hemiaminal ethers via C-H bond functionalization.We have demonstrated a general protocol for the oxidative coupling of azoles with primary alcohols via sp3 C-H bond activation. This metal-free amination pathway presents a direct access to a variety of hemiacetal ethers as useful synthetic intermediates and important bioactive agents. A novel metal-free [2+1] tandem oxidative coupling process for the synthesis of hemiaminal ethers has been developed. This general protocol could be applied for the C-N bond formation of electron-deficient trizoles, tetrazoles, carbazoles and indazoles with primary alcohols.4. Metal-free oxidative amination of primary alcohols with aminobenzamides for the synthesis of quinazolinones via C-H bond Functionalization.We have developed a metal-free oxidative amination protocol for the synthesis of N-heterocycles from the cyclization of primary alcohols with aminobenzamides. This simple method shows good functional group compatibility and both aromatic and alkyl primary alcohols were tolerant. The present results provided a feasible pathway to prepare bioactive quinazolinones, quinazolines and benzothiadiazine derivatives.5. Copper(Ⅱ)-promoted four-component reactions for the synthesis of 1,2,3-triacylindolizines.An efficient one-pot synthesis of 1,2,3-triaroylindolizines was described via the reaction of three molecular of acyl bromides and one molecular of pyridine using copper(Ⅱ) chloride as oxidant. In this reaction process, three C-C bonds and one C-O bond were formed in one pot. This multi-components reaction provides a convenient synthetic route to indolizine skeleton presented in many biologically interesting compounds.