Molecular Design Group
We design and synthesize molecules that reveal new functions, reactivity, and architectures at the intersection of organic chemistry, coordination chemistry, and molecular recognition.
Designing Molecules with Shape, Motion, and Function
The Kumagai Laboratory explores how carefully designed molecular frameworks create new behavior. Our work spans nitrogen-containing macrocycles, heteroaromatic architectures, catalytic transformations, and fluorescent molecular systems.
By combining synthesis, structural analysis, and mechanistic insight, we develop molecules that bind protons, organize space, respond to stimuli, and drive useful chemical reactions.
Research Focus
Our research centers on molecular design as a way to build function from structure. We create original molecular skeletons and study how their geometry, rigidity, and electronic properties control reactivity and recognition.
Highlights
Exotic Heterocycles
Non-standard heterocycles, including DATB, turn unusual atom arrangements into clean catalytic reactivity.
Fluorescent Materials
C4N4 fluorophores provide modular platforms for emission, imaging, sensing, and responsive molecular design.
Quinoline Oligomers
Quinoline-based cyclic systems create compact cavities for proton dynamics and molecular recognition.
Latest News
The paper by Yusuke Kinase and Prof. Ryosuke Tsutsumi was accepted in Synlett.
Catalyst-Controlled Chemoselective Transformation of Cyanopyridines over Cyanoarenes Enabled by a DATB-Phenothiazine Hybrid Photocatalyst
Yusuke Kinase, Ryosuke Tsutsumi, and Naoya Kumagai*
Synlett, in press.
Mai Yamashita was awarded a Poster Award at the International Symposium on Macrocyclic and Supramolecular Chemistry 2026 (ISMSC2026) in Bordeaux, France.
Shogo Tashiro was awarded a Student Lecture Award at the 90th Kanto Branch Symposium of the Society of Synthetic Organic Chemistry, Japan.
The paper by Prof. Wei Xu and Ayami Takeda was accepted in JACS Au.
Quinoline-Directed Folding in AnilideQuinoline Hybrids: Length-Controlled Three-Dimensional Conformational Diversity
Wei Xu, Ayami Takeda, and Naoya Kumagai*
Takuya Sakurai was awarded a Student Presentation Award for an English oral presentation at the 106th CSJ Annual Meeting.
The paper by Miki Kohei and Go Kawamura, in collaboration with ICReDD, was accepted in Chemistry – A European Journal.
Revisiting C4N4 Fluorophore: Theoretical Elucidation of the Origin of Fluorescent Properties of 2,5-Diaminopyrimidines and Strategic Applications to Pd Detection
Miki Kohei, Itsuki Kondo, Go Kawamura, Yu Harabuchi, Satoshi Maeda, and Naoya Kumagai*
The paper by Takuya Sakurai and Prof. Ryosuke Tsutsumi was accepted in Chemistry of Materials.
TriQuinazoline and Related Quinoline/Quinazoline Cyclic Trimers: Unified Synthesis, Planar Discotic Architecture, and Proton Dynamics in an Atomic-Scale Cavity
Takuya Sakurai, Ryosuke Tsutsumi, and Naoya Kumagai*
The review by Prof. Toi Kobayashi and Takuya Sakurai was accepted in Chemistry Letters.
Insights into Coordination and (Semi-)Rigidity in the Molecular Design of Bicyclic Heterocycle Frameworks
Toi Kobayashi, Takuya Sakurai, and Naoya Kumagai*
Takuya Sakurai was awarded an Excellent Presentation Award, Chemical Science Award, at the 52nd Symposium on Main Group Element Chemistry.
Mai Yamashita was awarded a Poster Award, Chemistry – An Asian Journal Award, at the 54th Congress of Heterocyclic Chemistry.
Shogo Tashiro was awarded a Poster Award at the 56th Young Researchers Meeting on Structural Organic Chemistry.
The paper by Mai Yamashita, Prof. Ryosuke Tsutsumi, and Prof. Toi Kobayashi was accepted in Chemistry – An Asian Journal.
Enlarged-TriQuinoline (Enl-TQ): Disparity in Chemical Behaviors by Geometric Scaling of the Trimeric Quinoline Ring System
Mai Yamashita, Ryosuke Tsutsumi, Toi Kobayashi, and Naoya Kumagai*
The paper by Ryota Yagami, Prof. Wei Xu, and Prof. Toi Kobayashi was accepted in Chemical Science.
iso-TEtraQuinoline (i-TEQ): An Inherently Chiral N4 Macrocyclic Quinoline Tetramer
Ryota Yagami, Wei Xu, Toi Kobayashi, Yuuya Nagata, and Naoya Kumagai*
The review by Prof. Toi Kobayashi and Prof. Wei Xu was published in the Journal of Synthetic Organic Chemistry, Japan.
Development of Unique Quinoline-Based Macrocyclic Systems and Strategic Applications in Versatile Chemistry
Toi Kobayashi, Wei Xu, and Naoya Kumagai*
We won the badminton tournament.
The paper by Taiga Karimata and Prof. Wei Xu was accepted in Chemistry – A European Journal.
DiQuinoline-MonoQuinazoline: A Flat Proton Binder and Its Application as a Polyaromatic Hydrocarbon Scavenger and G4 Ligand
Taiga Karimata, Wei Xu, and Naoya Kumagai*
Chem. Eur. J. 2025, 31, e202404335.
Selected as a Hot Paper
An interview with Toi Kobayashi was posted on the website of the Faculty of Pharmacy, Keio University.
TEtraQuinoline (TEQ) was selected for Chem-Station’s Molecule of the Year 2023.
Toi Kobayashi was awarded a Poster Award at the 33rd Symposium on Physical Organic Chemistry.
Latest published work.
Oxa-TriQuinoline: A New Entry to Aza-Oxa-Crown Architectures
Toi Kobayashi and Naoya Kumagai*
Kotaro Tsuruoka was awarded an Excellent Presentation Award at the 84th Kanto Branch Symposium of the Society of Synthetic Organic Chemistry, Japan.
Toi Kobayashi was awarded an Excellent Presentation Award at the 21st Symposium for Young Organic Chemists.
Toi Kobayashi was awarded a Student Excellent Presentation Award at the 143rd Annual Meeting of the Pharmaceutical Society of Japan.
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Kumagai Laboratory is located at the Faculty of Pharmacy, Keio University, in Shibakoen, Minato-ku, Tokyo.
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