The synthetic method of 2-amino-3-hydroxyl-5-chloropyridine
Technical field
The invention belongs to organic synthesis field, particularly a kind of synthetic method of 2-amino-3-hydroxyl-5-chloropyridine.
Background technology
The derivative of pyridine is as chemical industry, and particularly the important source material of fine chemistry industry, is of wide application.Relate to new drug development, medicine intermediate, pharmaceutical products, agricultural chemicals research and development, pesticide intermediate, agricultural chemicals, feed and feedstuff raw material and other multinomial field.The pyridine derivate that polyfunctional group replaces has even more important using value.2-amino-3-hydroxyl-5-chloropyridine You Sige functional group for example, they are respectively-Cl ,-OH ,-NH
2with the nitrogen on pyridine ring.For example, 2-amino-3-hydroxyl-5-chloropyridine reacts with methylating reagent and generates 2-amino-3-methoxyl group-5-chloropyridine, then with the chloro-8-methoxyl group of corresponding alpha-bromo ketogenesis 6-imidazo [1,2-a] derivative of pyridine, the latter is used to research (the PCT Int. Appl. of kinases PIK3,2012007345,19 Jan 2012).The product that 2-amino-3-methoxyl group-5-chloropyridine reacts with oxine etc. has been used to the development research (U.S. Pat. Appl. Publ., 20110301193,08 Dec 2011) of medicine.2-amino-3-hydroxyl-5-chloropyridine reacts and generates 2-amino-3-phenyl-5-chloropyridine and 2-amino-3-benzyl-5-chloropyridine with corresponding halobenzene or cylite, and they have been respectively used to the activation of glucokinase and the research that selectivity is secreted plasma urokinase-type plasminogen activator.
Summary of the invention
The present invention, in order to make up the defect of prior art, provides a kind of synthetic method that is suitable for the synthetic 2-amino-3-hydroxyl-5-chloropyridine of industrialization
The present invention is achieved through the following technical solutions:
A synthetic method for 2-amino-3-hydroxyl-5-chloropyridine, is characterized in that, comprises the following steps:
(1). with oxazole [4,5-b] pyridine-2 (3H)-one and N-chlorosuccinimide be raw material, in solvent, in 10 ~ 120 ℃ of thermotonuses, within 1 ~ 36 hour, generates also [4,5-b] pyridin-2-ones of the chloro-3H-oxazole of 6-, after purifying, obtain also [4,5-b] pyridin-2-ones of the chloro-3H-oxazole of sterling 6-;
(2). ketone heating hydrolysis under suitable alkali effect in 6-chlorine oxazole [4,5-b] pyridine-2 (3H) generates 2-amino-3-hydroxyl-5-chloropyridine sodium salt, obtains product 2-amino-3-hydroxyl-5-chloropyridine after purifying.
In described step (1), solvent is methylene dichloride, the mixture of acetonitrile and Glacial acetic acid, tetrahydrofuran (THF), N, N-dimethylformamide (DMF), N, any one material in N-dimethyl acetyl ammonia (DMA) or N-Methyl pyrrolidone (NMP).
In described step (1), the charging capacity of reactant and solvent is oxazole [4,5-b] pyridine-2 (3H)-one: N-chlorosuccinimide: solvent=5:6 ~ 6.3:30 ~ 34 are more than weight ratio.
In described step (1), reaction conditions is at 20 ~ 90 ℃, to react 6 ~ 24 hours.
In described step (1), purification step comprises successively and adds moisture liquid, filters washing, desiccant dryness, evaporation concentration, solvent recrystallization.
In described step (1), recrystallization solvent is ethyl acetate, ethanol, methylene dichloride, chloroform, any one in normal hexane or two kinds of materials.
In described step (2), alkali is lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, any one material in magnesium hydroxide.
In described step (2), heating hydrolysis temperature of reaction is 25 ℃ ~ 100 ℃.
In described step (2), purification step comprises acidifying, filter, and washing, dry.
In described step (2), the acid that acidifying is used refers to hydrochloric acid, sulfuric acid, phosphoric acid.
The invention has the beneficial effects as follows: raw material of the present invention is easy to get, and be solid, transportation, it is convenient to store; In simultaneous reactions, do not use heavy metal and corrosive gases, reaction temperature and, conversion unit is not had to particular requirement, common erosion resistance equipment can be produced; In addition the reaction times of the present invention moderate, reaction is easy to control, aftertreatment is simple, product purity is high, and production cost is low, is easy to apply.
Embodiment
Embodiment 1:
In three mouthfuls of round-bottomed flasks of one 250 mL, add methylene dichloride (200 mL).On there-necked flask, add a reflux condensing tube, start magnetic stirring apparatus and add oxazole [4,5-b] pyridine-2 (3H)-one (4.1 g).After oxazole [4,5-b] pyridine-2 (3H)-one is all dissolved, will add in batches N-chlorosuccinimide (4.7 g).10 ℃ of stirring reactions 4 hours, then heating reflux reaction was 12 hours.TLC and GC are definite to have reacted.Revolve and steam except desolventizing.Thick product obtains straight product 6-chlorinated oxazoline [4,5-b] pyridine-2 (3H)-one (3.14 g), productive rate 61%, purity 97.3%(GC from methylene dichloride and re-crystallizing in ethyl acetate).182 ℃ ~ 185 ℃ of fusing points (183 ℃ ~ 186 ℃, document).Nuclear magnetic resonance spectroscopy, 1H NMR (DMSO-d6) 300 MHz: δ 8.107ppm (d, J=4Hz, 1H); 7.815ppm (d, J=4Hz, 1H).
In the single necked round bottom flask of one 50 mL, add sodium hydroxide (1.68 grams, 0.042 mole) and water (20 mL).Starting magnetic stirring apparatus all dissolves sodium hydroxide.Above-mentioned gained 6-chlorinated oxazoline [4,5-b] pyridine-2 (3H)-one (3.14 grams, 0.018 mole) is joined and in reaction flask and on reaction flask, adds a reflux condensing tube.Reaction mixture is heated and refluxes 8 hours.TLC and gas chromatographic analysis show to react completely.With 12 mol/L hydrochloric acid, regulate the pH value of reaction mixture to have a large amount of precipitations to generate to 8().Filter, filter cake washes (5 milliliters) with water.Dry to obtain 1.99 grams of product 2-amino-3-hydroxyl-5-chloropyridines, productive rate 74.8%, purity 99.9% (GC).197 ℃ ~ 200 ℃ of fusing points (198 ℃ ~ 201 ℃, document).
Embodiment 2:
In three mouthfuls of round-bottomed flasks of one 10 L, add DMF(2000 mL).On there-necked flask, add a reflux condensing tube.Start mechanical stirrer and add oxazole [4,5-b] pyridine-2 (3H)-one (497g).Stirring is all dissolved oxazole [4,5-b] pyridine-2 (3H)-one.N-chlorosuccinimide (608 g) is dissolved in DMF(2500 mL) in.Then be transferred to a constant pressure funnel, slowly drip N-chlorosuccinimide in reaction flask, control temperature of reaction and be no more than 40 ℃ (use if desired frozen water cooling).After dripping, remove ice-water bath, under room temperature, stir and spend the night.With TLC and GC, follow the tracks of reaction.After question response completes, under frozen water is cooling, slowly add water 4000 mL.Stirred reaction mixture 30 minutes, filters.Filter cake washes twice with water, and vacuum-drying obtains crude product 530 g.Thick product obtains straight product 6-chlorinated oxazoline [4,5-b] pyridine-2 (3H)-one (505 g), productive rate 81%, purity 99.1%(GC from methylene dichloride and re-crystallizing in ethyl acetate).184 ℃ ~ 187 ℃ of fusing points (183 ℃ ~ 186 ℃, document).
In the single necked round bottom flask of one 5 L, add sodium hydroxide (355 grams, 8.883 moles) and water (3.5 L).Starting magnetic stirring apparatus all dissolves sodium hydroxide.Above-mentioned gained 6-chlorinated oxazoline [4,5-b] pyridine-2 (3H)-one (505 grams, 2.961 moles) is joined and in reaction flask and on reaction flask, adds a reflux condensing tube.Reaction mixture is heated and refluxes 10 hours.With TLC and GC, following the tracks of reaction shows to react completely.With 12 mol/L hydrochloric acid, regulate the pH value of reaction mixture to have a large amount of precipitations to generate to 8().Filter, filter cake washes (400 milliliters) with water.Dry to obtain 420 grams of product 2-amino-3-hydroxyl-5-chloropyridines, productive rate 98%, purity 97.9% (GC).197 ℃ ~ 202 ℃ of fusing points (198 ℃ ~ 201 ℃, document).
Embodiment 3:
In the reactor of one 50 L, add DMF(4 L).Start mechanical stirrer and add oxazole [4,5-b] pyridine-2 (3H)-one (4.97 kg).Stirring is all dissolved oxazole [4,5-b] pyridine-2 (3H)-one.N-chlorosuccinimide (6.08 kg) is dissolved in DMF(25 L) in.Then slowly drip N-chlorosuccinimide in reactor, control temperature of reaction and be no more than 40 ℃ (use if desired circulating condensing pump cooling).After dripping, under room temperature, stir and spend the night.With TLC and GC, follow the tracks of reaction.After question response completes, reaction solution is shifted in the reactor of one 100 L, under cooling, slowly add water 35 L.Stirred reaction mixture 60 minutes, filters.Filter cake washes twice with water, and vacuum-drying obtains crude product 4.95 kg.Thick product recrystallization from methylene dichloride and ethyl acetate obtains straight product 6-chlorinated oxazoline [4,5-b] pyridine-2 (3H)-one (4.76 kg), productive rate 76%, purity 99.4%(GC).183 ℃ ~ 185 ℃ of fusing points (183 ℃ ~ 186 ℃, document).
In the reactor of one 50 L, add sodium hydroxide (3.348 kilograms, 83.7 moles) and water (35 L).Starting magnetic stirring apparatus all dissolves sodium hydroxide.Above-mentioned gained 6-chlorinated oxazoline [4,5-b] pyridine-2 (3H)-one (4.76 kilograms, 27.9 moles) is joined and in reaction flask and on reaction flask, adds a reflux condensing tube.Reaction mixture is heated and refluxes 12 hours.With TLC and GC, following the tracks of reaction shows to react completely.With 12 mol/L hydrochloric acid, regulate the pH value of reaction mixture to have a large amount of precipitations to generate to 8().Filter, filter cake washes (10 liters) with water.Dry to obtain 3.90 kilograms of product 2-amino-3-hydroxyl-5-chloropyridines, productive rate 96%, purity 98.6% (GC).199 ℃ ~ 202 ℃ of fusing points (198 ℃ ~ 201 ℃, document).