One-pot Synthesis Of Methylthio Arylethynes

Methylthio arylethynes(MAT) are widely applied in the field of organic synthesis due to their unique chemical properties. What's more prominent is that MAT can are very important terminal blocks in the synthesis of multidentate organosuifur compounds which can self-assemble on gold surface. In a word, the study of MAT's synthesis is very important both in theory and application.In our previous research, MAT had been synthesized throgh a one-pot reaction of double elimination where methylthiomethyl phenyl sulfone (MP-S) used as a nucleophile reacts with aromatic aldehydes; and then a series of methylthio aryldiynes were successfully synthesized based on the previous resaerch. This method is of high yield, good versatile, high efficiency and handled easily.Basing on the previous research, after reviewing and studying a plenty of literatures, we designed a new one-pot reaction of phosphate elimination, and achieved satifactory results. This new method uses aryl ketone as starting material to synthesize MAT, and the substrates was synthesized throgh bromination and nucleophilic substitution processes.In the synthesis of substrates,β-naphthyl ketone was synthesized through Friedel-Crafts acylation reation catalyzed by AlC13 in the solution of nitrobenzene using naphthalene as substrate, acetic anhydride as acylation reagent, meanswhile, 4-iodine acetophenone and 4-bromine acetophenone were synthesized through Sandmeyer reaction using 4-amino acetophenone as substrate. And then,α-bromide aryl ketones were prepared through bromination reaction using CuBr of 2 eqiuvalence as bromination reagent, and the selectivity was achieved through the control of reaction time decided by the trace of TLC. At last, The substrates of this new one-pot reaction was prepared through the nucleophilic substitution reaction between a-bromide aryl ketones and CH3SNa.This new one-pot reaction advanced in this article includes three processes and involves two reagents. At first, Lithum hexamethyl disilazine(LiHMDS) of 1.2 eqiuvalence was added into the reaction system to get oxygen ions of enol, following this, Cl(O)P(OEt)2 of 1.2 eqiuvalence was added into the reaction system, and then the crucial intermediate enolated phosphate was obtained, at last, LiHMDS of 2.5 eqiuvalence was added to trigger the elimination reaction, and finally the MAT was synthesized successfully throgh this one-pot reaction.Compared with the previous method, the new one-pot reation uses less substrates and can be handled more easily with good versatile. In this papper, a reaction mechanism of enolation-phosphation-phosphate elimination was proposed, and also been discussed pilotly as well as the influent factors of the reaction.All the compounds in this papper have been determinated by 1H NMR,13C NMR, IR and MS.