Naoko Mizuyama

Synthesis, solid-state fluorescence properties, and computational analysis of novel 2-aminobenzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxides

Summary New fluorescent compounds, benzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxides (3a–g), 2-amino-4-methylsulfanylbenzo[4,5]thieno[3,2-d]pyrimidine (6), and 2-amino-4-methylsulfanyl-7-methoxybenzo[4,5]furo[3,2-d]pyrimidine (7), were synthesized in good yields from heterocyclic ketene dithioacetals (1a–c) and guanidine carbonate (2a) or (S)-methylisothiourea sulfate (2b) in pyridine under reflux. Among the fused pyrimidine derivatives, compound 3c, which has an amino group at the 2-position and a benzylamino group at the 4-position of the pyrimidine ring, showed the strongest solid-state fluorescence. The absorption and emission properties of the compounds were quantitatively reproduced by a series of ab initio quantum-chemical calculations.

DEVELOPMENT OF FLUORESCENT 2-PYRONE DERIVATIVES USING KETENE DITHIOACETALS FOR ORGANIC EL DEVICES

In recent years, organic electro luminescent (EL) materials have received considerable attention due to their potential application in next-generation display devices with high brightness levels, wide color ranges, and wide viewing angles. Fluorescent 2-pyrone derivatives have been synthesized using a convenient method involving ketene dithioacetals, which emit fluorescence (red, green, and blue) in both solution (dichloromethane and ethanol) and solid state. The structure-activity relationships of various 2-pyrone derivatives have been clarified.

Synthesis of Quinolizino[3,2-a]quinolizine Derivatives and Their Fluorescence

Polycyclic quinolizine derivatives, quinolizino[3,2-a]quinolizines (4a-c), were synthesized in moderate yields by a one-pot method using ketene dithioacetal, methyl bis(methylsulfanyl)methylene-cyanoacetate (2), alkyl 2-pyridylacetates (1a, b), and 2-pyridylacetonitrile (1c). Compounds 4a, b exhibited red fluorescence (Em max: 576 nm) in solid state.

One-Pot Synthesis of 6-Substituted Amino-2,4-diaminopyrimidine Derivatives Using Ketene Dithioacetals with Amines and Guanidine Carbonate

6-Substituted amino-2,4-diaminopyrimidine derivatives were prepared by one-pot synthesis using ketene dithioacetals, amine compounds, and guanidine carbonate in pyridine. These pyrimidine products displayed blue fluorescence in the solid state.

Synthesis and fluorescence of 4-methylsulfanyl-6-pyridyl-2H-pyran-2-ones in solid state

Various 4-methylsulfanyl-6-pyridyl-2H-pyran-2-one derivatives were synthesized by the reaction of ketene dithioacetals with active methyl or methylene compounds in the presence of powdered sodium hydroxide in dimethyl sulfoxide (DMSO). Among these 2-pyrone derivatives, 3-aryl-4-methylsulfanyl-6-pyrid-2-yl-2H-pyran-2-ones show strong fluorescence in the solid state.

Synthesis and TDDFT Investigation of New Maleimide Derivatives Bearing Pyrrole and Indole Ring

A novel series of heterocycles were obtained through the condensation reaction of 4-methylthiomaleimides with pyrroles and indoles. The newly synthesized compounds exhibit their major electronic absorption peaks ranging 435–504 nm in solution at room temperature. Time-dependent density-functional theory (TDDFT) calculations were systematically performed in order to elucidate their structure-color relationships, using a set of exchange-correlation (XC) functionals. The TDDFT computational scheme employing PCM-TDDFT/6-31