METHOD FOR PREPARATION OF 4,7-DIBROMO[1,2,5]THIADIAZOLO[3,4-D]PYRIDAZINE Russian patent published in 2018 - IPC C07D513/04 

FIELD: chemistry.

SUBSTANCE: invention relates to the field of organic chemistry, namely to a process for the preparation of 4,7-dibromo[1,2,5]thiadiazolo[3,4-d]pyridazine (1), which comprises treating diaminomaleotonitrile with thionyl chloride in acetonitrile in the presence of pyridine at a lower temperature, then the prepared 1,2,5-thiadiazole-3,4-dicarbonitrile is boiled in dilute hydrochloric acid, the resulting 1,2,5-thiadiazole-3,4-dicarboxylic acid is treated with methanol in the presence of thionyl chloride to form dimethyl ether 1,2,5-thiadiazole-3,4-dicarboxylic acid, which is treated with hydrazine hydrate in isopropanol, the resulting 1,2,5-thiadiazole-3,4-dicarbohydrazide is heated in dilute hydrochloric acid to form 5,6-dihydro [1,2,5]thiadiazolo[3,4-d]pyridazine-4,7-dione followed by treatment with a mixture of phosphorus tribromide and bromine or phosphorus oxobromide in dimethylformamide at a temperature of 0 to 105 °C.

EFFECT: process for the preparation of 4,7-dibromo[1,2,5]thiadiazolo[3,4-d]pyridazine, which can be useful as a starting material to obtain components of solar cells with improved values of the band gap, the short-circuit current density and the duty cycle and, ultimately, the photovoltaic efficiency of the solar cell.

1 cl, 2 ex