A method for synthesizing pyrrolo[3,4-c]pyrazole-4,6(1h,5h)dione derivatives
A 4-c and derivative technology, applied in the direction of organic chemistry, can solve the problems of low conversion rate and yield, unfavorable industrialization, and many side reactions, and achieve high conversion rate and yield, good applicability, and side reactions little effect
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Embodiment 1
[0066] Example 1, Synthesis of 3-bromo-1-methyl-5-phenylpyrrole[3,4-c]pyrazole-4,6(1H,5H)-dione (Formula A-a)
[0067]
[0068] Step 1. Add an aqueous solution of sodium formate (4.4g sodium formate dissolved in 25mL of purified water) to the ethanol (25mL) solution of raw material compound A-1 (1.0g), then drop the temperature in an ice bath to 0°C and add bromine (4.8g ), the reaction solution was stirred for 3 hours; after the reaction was completed, the reaction system was added with water (30mL) to extract it and extracted with ethyl acetate, the organic phase was collected and washed with saturated brine, dried over anhydrous sodium sulfate, filtered, the filtrate was concentrated to remove the solvent, and the residue Separation and purification by column chromatography gave compound A-2 (1.2 g, yield 81%) as a yellow solid;
[0069] Step 2. Add toluene (20mL) solvent to aniline (compound A-3a) (0.9g), cool down to 0°C in an ice bath, add 2N trimethylaluminum toluene...
Embodiment 2
[0074] Example 2, 3-bromo-5-(3-chloro-4-fluorophenyl)-1-methylpyrrole[3,4-c]pyrazole-4,6(1H,5H)-dione (formula Synthesis of A-b)
[0075]
[0076] Step 1. Add the aqueous solution of sodium acetate (4g sodium acetate dissolved in 35mL pure water) to the ethanol (25mL) solution of raw material compound A-1 (1.0g), then cool down to 0°C in an ice bath and add bromine (4g ), the reaction solution was stirred for 5 hours; after the reaction was completed, the reaction system was added with water (30mL) to extract it and extracted with ethyl acetate, the organic phase was collected and washed with saturated brine, dried over anhydrous sodium sulfate, filtered, the filtrate was concentrated to remove the solvent, and the residue Separation and purification by column chromatography gave compound A-2 (1.3 g, yield 85%) as a yellow solid;
[0077] Step 2. Add benzene (29mL) solvent to 3-chloro-4-fluoroaniline (compound A-3b) (1.2g), cool to 0°C in an ice bath and add 2N trimethylal...
Embodiment 3
[0082] Example 3, Synthesis of 3-bromo-5-(4-methylphenyl)-1-methylpyrrole[3,4-c]pyrazole-4,6(1H,5H)-dione (Formula A-c)
[0083]
[0084] Synthesized by an operation similar to that of Example 1 to obtain the target product compound 3-bromo-5-(4-methylphenyl)-1-methylpyrrole[3,4-c]pyrazole-4,6(1H, 5H) - diketones (formulas A-c).
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