Novel valganciclovir hydrochloride synthesis method
A technology of valganciclovir hydrochloride and ganciclovir, which is applied in the chemical field, can solve the problems of low purity of valganciclovir hydrochloride and low purity of intermediates, and achieve controllable quality, high product purity and cost reduction Effect
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Embodiment 1
[0018] Example 1 Preparation of monoformyl ganciclovir
[0019] Put 100 grams of ganciclovir, 350 milliliters of DMF, and 75 grams of triethyl orthoformate into the reaction flask, stir, add 1 milliliter of trifluoroacetic acid, heat up to 55-65 ° C for 3 hours, and cool to 0-5 ° C , add water, heat up to 60°C and stir for 15 minutes, then cool to 0-5°C, filter to obtain a wet product. Put the wet product into a reaction bottle, add 130 ml of DMSO, heat up to 65°C, stir to dissolve, add 90 ml of methanol, cool and crystallize, filter at room temperature, and dry at 85°C to obtain 85 grams with a purity of more than 95%.
Embodiment 2
[0020] Example 2 Preparation of Monoacetylganciclovir
[0021] Put 100 grams of ganciclovir, 350 milliliters of DMF, and 70 grams of trimethyl orthoacetate into the reaction flask, stir, add 1 milliliter of trifluoroacetic acid, heat up to 55-65 ° C for 3 hours, and cool to 0-5 ° C , add water, heat up to 60°C and stir for 15 minutes, then cool to 0-5°C, filter to obtain a wet product. Put the wet product into a reaction bottle, add 130 ml of DMSO, heat up to 65°C, stir to dissolve, add 90 ml of methanol, cool and crystallize, filter at room temperature, and dry at 85°C to obtain 82 grams. The purity is above 94%.
Embodiment 3
[0022] The preparation of embodiment 3 N-benzyloxycarbonyl valganciclovir
[0023] Put 96 grams of monoformylganciclovir, 480 milliliters of DMF and 96 grams of DCC into the reaction flask, stir, then add 102 grams of CBZ-L-valine and 6.72 grams of DMAP, and react at a temperature below 10°C for 24 hours , then add 500 milliliters of ethyl acetate and 480 milliliters of water, filter, wash with 300 milliliters of ethyl acetate, combine the filtrate and washings, separate the organic layer, wash with saturated brine, concentrate under reduced pressure, add 288 milliliters of water and 72 milliliters of hydrochloric acid, stirred at room temperature for 5 hours, added 864 milliliters of water, adjusted the pH value to 6 with ammonia water, filtered, put the obtained solid into the reaction flask, added 324 grams of acetic acid, stirred and dissolved, added 800 milliliters of hot water at 50°C, cooled to room temperature, filtered, and dried at 70°C to obtain 83 grams with a puri...
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