?-Ketophosphonates And Benzoxazoles Research Of New Synthesis Method

Alkyne containing a carbon-carbon triple bond is a kind of important organic compound, which is commercial available, cheap and easy to obtain. Therefore, they have been widespread applied in organic synthesis and were involved in important organic transformation including the formation of C-C, C-X, C-O, C-N bonds. At the same time, they have been highly favored by chemists in organic synthesis, which applied to all directions in the field of organic synthesis. Therefore, deeply studies and development concerning on carbon-carbon triple bond-related learning still remained desrible. ?-ketophosphonates are greatly important chemicals that present a variety of biological activities and act as important components in organic synthesis. Currently, a variety of efficient methods for the synthesis of ?-ketophosphonates have been reported. However, these methods are associated with several shortcomings:harsh conditions, complicated experimental manipulations, and the use of hazardous and expensive reagents. Heterocyclic compounds are the most important kind of compounds in the pharmaceutical and agrochemical industries, which exist in 60% of all drugs. ?-carbonyl-benzoxazole?benzothiazole?compounds are found in numerous biologically active natural products and pharmacologically relevant therapeutic agents. Currently, there are a variety of synthetic methods for the synthesis of ?-carbonyl-benzoxazole?benzothiazole?compounds, but these methods have harsh reaction conditions, complicated operations, narrow scope of substrates and are environmentally unfriendly.In this paper, alkynes were chosen as raw materials to the synthesis of alkynyl phosphonates and 2,2-halo ketones, and further synthesis of ?-ketophosphonates and ?-carbonyl benzoxazole heterocycles. The main works are as following:1. A new method to synthesize ?-ketophosphonates from alkynylphosphonates was described in this paper, in the ionic liquid system of H₂SO₄ ?7.0 equiv? at 60? for 20 h. This method provides a simple and effective method to prepare the ?-ketophosphonates, with the advantages of good yields, functional group compatibility, recyclable ionic liquid solvent and no metal catalysts.2. Author develops a new method to synthesize a-carbonyl-benzoxazole ?benzothiazole?compounds from 2,2-haloketones and 2-amino?thio?phenol compounds by a base promoted cyclization reaction without metal catalyst. The desired product can be obtaind in good yield under the conditions of diethylamine ?4.0 equiv? and DMF solvent at 90? for 5 h, with the advantages of easily preparing of substrate, good functional group compatibility and mild solvent. ???R₁=H, alKyl, Halo R₂=aryl, heterocyclic...