Reagent-Controlled Divergent Synthesis of 2-Amino-1,3-Benzoxazines and 2-Amino-1,3-Benzothiazines
作者:V. P. Rama Kishore Putta、Nagaraju Vodnala、Raghuram Gujjarappa、Ujjawal Tyagi、Aakriti Garg、Sreya Gupta、Prasad Pralhad Pujar、Chandi C. Malakar
DOI:10.1021/acs.joc.9b02384
日期:2020.1.17
devised for the synthesis of 4H-1,3-benzoxazines and related biologically important heterocycles in high yields under mild conditions. These scaffolds could be efficiently constructed using two different chemoselective reactions that rely on the choice of reagents and reaction conditions. The treatment of various 2-amino-arylalkyl alcohols with isothiocyanates afforded thiourea intermediates, which were
A facile and environmentally benign access to N-aryl/alkyl-4H-benzoxazin-2-amines is achieved from 1-[2-(hydroxymethyl)phenyl/alkyl]-3-phenylthioureas under transition-metal-free conditions. The conversions occur smoothly in the presence of a catalytic amount of molecular iodine and hydrogen peroxide as the oxidant in tetrahydrofuran at room temperature to afford moderate to good yields (28–90%) of
One-Pot Synthesis of Five and Six Membered N, O, S-Heterocycles Using a Ditribromide Reagent
作者:Ramesh Yella、Bhisma K. Patel
DOI:10.1021/cc100124q
日期:2010.9.13
In a one-pot procedure, bromine less brominating reagent 1,1′-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) has been utilized as an efficient desulfurizing agent for the construction of a library of heterocycles containing N, O, and S starting from aryl/alkyl isothiocyanates. In this approach, aryl/alkyl isothiocyanate reacts with o-phenylenediamine (o-PD), o-aminophenol, and o-aminothiophenol