Method for synthesizing persantine intermediate 2,4,6,8-tetrahydroxy pyrimido[5,4-d] pyrimidine
A technology for hydroxypyrimidine and intermediates, which is applied in the field of synthesizing dipyridamole intermediates, can solve problems such as long production cycle, high reaction temperature, and difficult stirring, and achieve the effects of saving time and labor, mild reaction conditions, and shortened reaction time
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Embodiment 1
[0030] The existing "urea method" process.
[0031] The synthetic route of urea method is illustrated as follows:
[0032]
[0033] Specific steps are as follows:
[0034] 1. Add 50g of nitroorotic acid into 500ml of aqueous solution of 15g of sodium hydroxide, and stir until completely dissolved. Transfer this solution to the hydrogenation kettle, add 10g Raney nickel, the average nickel contact area of Raney nickel is 100m 2 / g, hydrogenation at 80°C and 0.8MPa for 8 hours, no hydrogen absorption. Cool to 35°C and filter off the catalyst. Slowly add 35g of industrial hydrochloric acid to the filtrate to obtain a thick slurry. The crude product of aminoorotic acid was obtained by filtering with a plate and frame filter press.
[0035] 2. Mix the obtained aminoorotic acid crude product, 20ml diethylene glycol, and 145g urea, heat to 120-140°C for 2 hours, evaporate a small amount of water, and continue to heat the obtained viscous product to 190°C for 10 hours.
[0...
Embodiment 2
[0044] A method for synthesizing dipyridamole intermediates—2,4,6,8-tetrahydroxypyrimido[5,4-d]pyrimidine,
[0045] The synthetic route is illustrated as follows:
[0046]
[0047] Specific steps are as follows:
[0048] 1. Dissolve 50g of nitroorotic acid in 500ml of aqueous solution of 35g of sodium hydroxide, transfer the resulting solution into a hydrogenation kettle, add 10g of Raney nickel, and the average nickel contact area of Raney nickel is 100m 2 / g, hydrogenated at 80°C and 0.8MPa for 8 hours, no more hydrogen was absorbed.
[0049] Cool to 35°C and filter off the catalyst. The filtrate was directly used in the next reaction without separation.
[0050] 2. Add concentrated hydrochloric acid dropwise to the obtained filtrate to adjust the pH value to 3.
[0051] Raise the temperature to 70°C, add sodium cyanate in batches, and add 55g of 90% sodium cyanate in about 1 hour. Insulate at 70°C and continue to incubate for 1.0 hour.
[0052] Add sodium hydroxi...
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