Preparation method of N, N-dimethylacetamide
A technology of dimethylacetamide and methylpyrimidine, which is applied in the field of preparation of 2--N,N-dimethylacetamide, can solve the problems of complicated post-treatment process, poor atom economy and high reaction cost, and achieve the goal of reaction And the effect of simple post-processing, low cost and high atom economy
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[0029] The invention provides a preparation method of 2-(2-n-butyl-4-hydroxyl-6-methylpyrimidin-5-yl)-N,N-dimethylacetamide, comprising the following steps:
[0030] 1) Make pentamidine hydrochloride and dimethyl acetylsuccinate react under the effect of organic amine to obtain 2-(2-n-butyl-4-hydroxyl-6-methylpyrimidin-5-yl)-acetic acid methyl Esters, wherein the pKa of the organic amine is 8-11.5;
[0031] 2) Reaction of 2-(2-n-butyl-4-hydroxyl-6-methylpyrimidin-5-yl)-acetic acid methyl ester with dimethylamine to obtain 2-(2-n-butyl-4-hydroxyl -6-methylpyrimidin-5-yl)-N,N-dimethylacetamide.
[0032] Above-mentioned preparation method can be represented by following chemical reaction formula:
[0033]
[0034] In the reaction of pentamidine hydrochloride and dimethyl acetylsuccinate, it is necessary to use alkali to neutralize the HCl in pentamidine hydrochloride, so that the nitrogen atom in the carbon-nitrogen double bond in pentamidine hydrochloride It has nucleophil...
Embodiment 1
[0052] The preparation method of the present embodiment 2-(2-n-butyl-4-hydroxyl-6-methylpyrimidin-5-yl)-N,N-dimethylacetamide is as follows:
[0053] 1) Preparation of 2-(2-n-butyl-4-hydroxyl-6-methylpyrimidin-5-yl)-acetic acid methyl ester
[0054] At room temperature, 13.7 g (0.1 mol) of pentamidine hydrochloride and 20.7 g (0.11 mol, 1.1 equiv) of dimethyl acetylsuccinate were added to a 250 mL four-necked flask, and 70 mL of methanol was added to dissolve the reactant completely. Under stirring state, use the constant pressure dropping funnel to add dropwise N,N-diisopropylethylamine 25.8g (0.2mol, 2.0equiv, pKa value is 10.98), control dropping time to be 0.5h, dropwise add The system was heated to reflux for 4 hours.
[0055] After cooling the reaction system to room temperature, concentrate under reduced pressure to remove methanol to obtain a concentrate, add 100 mL of water to the concentrate, add 13 g of concentrated hydrochloric acid under stirring to adjust the pH...
Embodiment 2
[0063] The preparation method of the present embodiment 2-(2-n-butyl-4-hydroxyl-6-methylpyrimidin-5-yl)-N,N-dimethylacetamide is as follows:
[0064] 1) Preparation of 2-(2-n-butyl-4-hydroxyl-6-methylpyrimidin-5-yl)-acetic acid methyl ester
[0065] At room temperature, add 27.4g (0.2mol) of pentamidine hydrochloride and 41.4g (0.22mol, 1.1equiv) of dimethyl acetylsuccinate into a 500mL four-neck flask, add 70mL of methanol to completely dissolve the reactants, and stir 51.6g (0.4mol, 2.0equiv) of N, N-diisopropylethylamine was added dropwise using a constant pressure dropping funnel, and the dropping time was controlled to be 1h. After the dropping was completed, the system was heated to reflux for 4 hours .
[0066] After cooling the reaction system to room temperature, concentrate under reduced pressure to remove methanol to obtain a concentrate, add 200 mL of water to the concentrate, add 26 g of concentrated hydrochloric acid under stirring to adjust the pH to 3, and use...
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