HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Special Issue
Somsak Ruchirawat's Special Issues, Vol. 105, No. 1, 2022
Published online: 8th March, 2022
■ Synthesis of N3-Substituted Quinazoline-2,4-diones via C-4 Amination-Cyclization of Isatoic Anhydrides
Nittaya Wiriya, Dolnapa Yamano, Surat Hongsibsong, Mookda Pattarawarapan, and Wong Phakhodee*
*Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
Abstract
A direct approach for the synthesis of N3-substituted quinazoline-2,4-diones via condensation of isatoic anhydrides with amines mediated by Ph3P-I2 was reported. Instead of the expected benzoxazinones, the reaction proceeds with an amine attack at the C-4 position of isatoic anhydrides leading to quinazoline-2,4-diones upon heating in the presence of base. This one-pot process enables a rapid construction of a broad range of quinazoline-2,4-dione derivatives using simple, readily available, and low-cost reagents with no extra carbonylating agent needed.
Published online: 1st April, 2022
■ Asymmetric Intramolecular Aldol Reactions Mediated by Chiral Triamines Bearing a Pyrrolidine Scaffold to Provide a Wieland–Miescher Ketone
Yuichi Akahane and Kohei Inomata*
*Department of Pharmaceutical Sciences, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara 324-8501, Japan
Abstract
We established a new asymmetric route to provide (R)-Wieland–Miescher ketone [(R)-2] using a combination of trifluoroacetic acid (TFA) and known or new chiral triamines (7) bearing a pyrrolidine scaffold. Although the intramolecular aldol reaction of trione (1) mediated by chiral prrolidine (7) resulted in the production of 2 with low enantioselectivities, a remarkably increased enantioselectivity with a combination of 7b or 7c and TFA was observed. We also found that a secondary amine motif existing in the middle of the side chain was important in defining the enantioselectivity.
Published online: 7th April, 2022
■ Synthesis and Cytotoxic Activity of Wrightiadione and Its Derivatives
Sanit Thongnest and Jutatip Boonsombat*
*Chulabhorn Research Institute, Bangkok 10210, Thailand
Abstract
A synthetic method for generating the tetracyclic isoflavone wrightiadione was developed through a Friedel-Crafts acylation of isoflavone-2-carboxylic acid. A series of wrightiadione derivatives was conveniently synthesized by this approach and evaluated for cancer cytotoxic, cancer chemopreventive, and antimalarial properties. Some derivatives exhibited potent cancer cytotoxic activity at the single-digit micromolar level.
Published online: 23rd May, 2022
■ Synthesis of Penicolinates A, C and D
Angela Qi Yun Chiu, Krishna Ramesh, Ma Yadanar Phyo, Patcharaporn Sae-Lao, and Roderick Wayland Bates*
*Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
Abstract
Penicolinates A, C and D are synthesized using the Sonogashira coupling reaction as a key step. By comparison of the optical rotation, the stereochemistry of penicolinate D is determined to be (S).