Mmm, a reaction sandwich…︁ Using an immunoassay‐based technique able to monitor any kind of cross‐coupling reaction, a systematic and rapid evaluation of a large panel of random reactions was carried out. This approach led to the discovery of two new copper‐promoted reactions: a desulfurization reaction of thioureas leading to isoureas and a cyclization reaction leading to thiazole derivatives from
A convenient oxidative cyclodesulfurization method toward the synthesis of benzofused nitrogen heterocycles using inexpensive and readily available potassium periodate as an oxidant was developed. Upon treating isothiocyanates with ortho-substituted anilines bearing N,N-, N,O-, and N,S-bis-nucleophiles, followed by an intramolecular cyclization of the in situ generated monothioureas, substituted 2-aminobenzazole
A sonochemical method for the synthesis of 2-aminobenzimidazoles and 2-aminobenzoxazoles, as well as chiral aminooxazolines and a chiral substituted quinazolin-5-one is reported. Using the Ph3P–I2 system in the presence of triethylamine as a desulfurization agent, monothioureas prepared in situ from the reaction of bis-nucleophiles with isothiocyanates underwent rapid cyclization to afford a variety
Desulfurization Mediated by Hypervalent Iodine(III): A Novel Strategy for the Construction of Heterocycles
作者:Harisadhan Ghosh、Ramesh Yella、Jayashree Nath、Bhisma K. Patel
DOI:10.1002/ejoc.200800901
日期:2008.12
The desulfurization ability of diacetoxyiodobenzene (DIB) has been explored in the preparation of isothiocyanates from the corresponding dithiocarbamate salts. The in situ generated isothiocyanates reacted with o-phenylenediamine and o-aminophenol to form monothioureas, which, on treatment with a further equivalent of DIB in one pot, gave benzimidazoles and aminobenzoxazoles, respectively. Aliphatic
Iodide catalyzed synthesis of 2-aminobenzoxazoles via oxidative cyclodesulfurization of phenolic thioureas with hydrogen peroxide
作者:Vinod K. Yadav、Vishnu P. Srivastava、Lal Dhar S. Yadav
DOI:10.1016/j.tetlet.2017.12.019
日期:2018.1
A convenient and efficient oxidative cyclodesulfurization of o-phenolic thioureas to 2-aminobenzoxazoles employing TBAI (tetrabutylammonium iodide)/H2O2 catalyst/reagent system is reported. The protocol utilizes and offers a number of desired features such as metal-free, base-free, simple operation, room temperature, low cost catalyst/reagent, no need for anhydrous and inert conditions. The approach
报道了使用TBAI(碘化四丁铵)/ H 2 O 2催化剂/试剂系统将邻苯酚硫脲方便且有效地氧化成2-氨基苯并恶唑的氧化环脱硫。该方案利用并提供了许多所需的功能,例如无金属,无碱,操作简单,室温,低成本的催化剂/试剂,不需要无水和惰性条件。该方法还适用于直接从邻氨基苯酚和异硫氰酸芳基酯开始的一锅合成2-氨基苯并恶唑,产率高。