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
P(III)‐Mediated Cascade C‐N/C‐S Bond Formation: A Protocol towards the Synthesis of
<i>N</i>
,
<i>S</i>
‐Heterocycles and Spiro Compounds
作者:Saibabu Polina、V. P. Rama Kishore Putta、Raghuram Gujjarappa、Virender Singh、Prasad Pralhad Pujar、Chandi C. Malakar
DOI:10.1002/adsc.202001149
日期:2021.1.19
of C−N/C−S bond has been devised. The developed heterocyclization method was exercised for the synthesis of a diverse range of N,S‐heterocycles and related spiro molecules. P(NMe2)3 revealed the maximum efficacies under the aerobic reaction conditions and a spectrum of bis‐nucleophiles, and isothiocyanates were tolerated well to serve the access of manifold immense molecules.
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