阅读说明：本技术 一种酶促在线合成3-（吡啶-2-氨基）丙羟肟酸的方法 (Method for enzymatic on-line synthesis of 3- (pyridine-2-amino) propylhydroxamic acid ) 是由 杜理华 薛苗 龙瑞杰 杨梦婕 罗锡平 夏晓丹 罗旭凌 徐筱颖 于 2020-05-19 设计创作，主要内容包括：本发明提供了一种酶促在线合成3-(吡啶-2-氨基)丙羟肟酸(V)的方法,首先2-氨基吡啶(I)和丙烯酸酯(II)在微流控通道反应器中利用脂肪酶Lipozyme RM IM催化在线合成3-(吡啶-2-氨基)丙酸酯衍生物(III),接着3-(吡啶-2-氨基)丙酸酯衍生物(III)和盐酸羟胺(IV)在微流控通道反应器中经甲醇钠催化在线合成3-(吡啶-2-氨基)丙羟肟酸(V)；该法不仅大大地缩短了反应时间,而且具有高的转化率；同时首次利用经济的脂肪酶Lipozyme RM IM催化氨基吡啶与丙烯酸酯的迈克尔加成反应,降低了反应成本,具有经济高效的优势；<Image he="217" wi="700" file="DDA0002498341590000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The invention provides a method for enzymatically synthesizing 3- (pyridine-2-amino) propylhydroxamic acid (V) on line, which comprises the steps of firstly, utilizing lipase Lipozyme RM IM to catalyze and synthesize 3- (pyridine-2-amino) propionate derivatives (III) on line by 2-aminopyridine (I) and acrylate (II) in a microfluidic channel reactor, and then catalyzing and synthesizing 3- (pyridine-2-amino) propionate derivatives (III) and hydroxylamine hydrochloride (IV) on line by sodium methoxide in the microfluidic channel reactor; the method not only greatly shortens the reaction time, but also has high conversion rate; meanwhile, the Michael addition reaction of aminopyridine and acrylic ester is catalyzed by using the economic lipase Lipozyme RM IM for the first time, so that the reaction cost is reduced, and the method has the advantages of economy and high efficiency;)

1. a method for the enzymatic on-line synthesis of 3- (pyridin-2-amino) propylhydroxamic acid (V), comprising:

(1) methanol is taken as a reaction solvent, 2-aminopyridine (I) and acrylic ester (II) are taken as raw materials, and lipase Lipozyme RMIM is taken as a catalyst; dissolving raw materials 2-aminopyridine (I) and acrylate (II) by using a solvent methanol respectively, then placing the raw materials into an injector respectively, uniformly filling a lipase Lipozyme RM IM in a reaction channel of a microfluidic channel reactor, continuously introducing a 2-aminopyridine (I) solution and an acrylate (II) solution in the injector into the reaction channel under the push of an injection pump to perform Michael addition reaction, controlling the reaction temperature to be 30-55 ℃, controlling the reaction time of the continuous flow of the reaction liquid in the reaction channel to be 10-50 min, collecting the reaction liquid flowing out of the reaction channel on line by a product collector, and performing aftertreatment to obtain a product 3- (pyridine-2-amino) propionate derivative (III);

and in the reaction liquid introduced into the reaction channel, the mass ratio of the 2-aminopyridine (I) to the acrylate (II) is 1: 0.5 to 8;

(2) methanol is taken as a reaction solvent, the 3- (pyridine-2-amino) propionate derivative (III) obtained in the step (1) and hydroxylamine hydrochloride (IV) are taken as raw materials, and sodium methoxide is taken as a catalyst; dissolving a 3- (pyridine-2-amino) propionate derivative (III) in methanol and placing the methanol into an injector, dissolving hydroxylamine hydrochloride (IV) and sodium methoxide in methanol and placing the methanol into another injector, continuously introducing feed liquid in the two injectors into a reaction channel under the driving of an injection pump to perform hydroxylamine condensation reaction, controlling the reaction temperature to be 0 ℃, continuously flowing the reaction liquid in the reaction channel for 10min, collecting the reaction liquid flowing out of the reaction channel on line through a product collector, and performing post-treatment to obtain a product, namely 3- (pyridine-2-amino) propylhydroxamic acid (V);

and (2) introducing the 3- (pyridine-2-amino) propionate derivative (III), hydroxylamine hydrochloride (IV) and sodium methoxide into the mixed reaction liquid in the reaction channel, wherein the mass ratio of the 3- (pyridine-2-amino) propionate derivative (III), the hydroxylamine hydrochloride (IV) and the sodium methoxide is 1: 1: 2;

in the formula (II) or (III), R₁＝CH₃Or C (CH)₃)₃。

2. The method for the enzymatic on-line synthesis of 3- (pyridine-2-amino) propylhydroxamic acid (V) according to claim 1, wherein in step (1), after the 2-aminopyridine (I) and the acrylate (II) are respectively dissolved by the solvent methanol, the concentration of the obtained 2-aminopyridine (I) solution is 0.5mmol/mL, and the concentration of the acrylate (II) solution is 0.25-4 mmol/mL.

3. The process for the enzymatic on-line synthesis of 3- (pyridin-2-amino) propionhydroxamic acid (V) according to claim 1, wherein in step (1), the amount of the catalyst lipase Lipozyme RM IM added is 0.043g/mL based on the volume of the reaction medium.

4. The process for the enzymatic on-line synthesis of 3- (pyridin-2-amino) propylhydroxamic acid (V) according to claim 1, wherein in step (1), the post-treatment process is: and (3) distilling the reaction solution under reduced pressure to remove the solvent, carrying out silica gel column chromatography separation, and filling the column by using a 200-mesh and 300-mesh silica gel wet method, wherein an elution reagent is petroleum ether: ethyl acetate volume ratio of 1:2, tracking the elution process by TLC, collecting the eluent containing the target compound, evaporating the solvent and drying to obtain the product 3- (pyridine-2-amino) propionate derivative (III).

5. The process for the enzymatic on-line synthesis of 3- (pyridin-2-amino) propylhydroxamic acid (V) according to claim 1, wherein in step (1), the reaction solution is introduced into the reaction channel in such a manner that the ratio of the amounts of 2-aminopyridine (I) to acrylate (II) is 1: 4.

6. the process for the enzymatic on-line synthesis of 3- (pyridine-2-amino) propionic acid (V) according to claim 1, wherein in step (2), the 3- (pyridine-2-amino) propionic acid ester derivative (III) is dissolved in methanol to give a solution having a concentration of 0.1 mmol/mL; after the hydroxylamine hydrochloride (IV) and sodium methoxide are dissolved in methanol, the concentration of the hydroxylamine hydrochloride (IV) in the obtained solution is 0.1mmol/mL, and the concentration of the sodium methoxide is 0.2 mmol/mL.

7. The process for the enzymatic on-line synthesis of 3- (pyridin-2-amino) propionhydroxamic acid (V) according to claim 1, wherein in step (2), the post-treatment is carried out by: and (3) distilling the reaction solution under reduced pressure to remove the solvent, performing silica gel column chromatography, and performing wet column packing by using 200-mesh and 300-mesh silica gel, wherein an elution reagent is methanol: dichloromethane volume ratio ═ 1:20, tracking the elution process by TLC, collecting the eluent containing the target compound, evaporating the solvent and drying to obtain the product 3- (pyridine-2-amino) propionic hydroxamic acid (V).

Technical Field

The invention relates to a method for synthesizing 3- (pyridine-2-amino) propylhydroxamic acid on line.

Background

Hydroxamic acids are a very important class of organic ligands with a variety of biological activities due to the ability to chelate with metal ions to form strong hydrogen bonds. They interact with a variety of metal-containing enzymes such as matrix metalloproteinases, TNF-a convertases, angiotensin converting enzymes, lipoxygenase, LTA4 hydrolase, urease, peptide deformylase, histone deacetylase, procollagen C-protease, and the like. Through targeting with these metalloenzymes, hydroxamic acid drugs are used to treat a variety of diseases such as cancer, cardiovascular disease, aids, alzheimer, malaria, allergic disease, hypertension, tuberculosis, glaucoma, ulcers, metal poisoning, and the like. It has been found that aromatic amine based beta-amino hydroxamic acids are useful as urease inhibitors for the treatment of helicobacter pylori infection. Therefore, the exploration of a green synthesis technology for synthesizing the aromatic ammonia beta-amino hydroxamic acid has important significance.

The beta-amino acid ester derivative is an important intermediate for synthesizing aromatic ammonia beta-amino hydroxamic acid. And is the basic structural unit of many amino acids and natural products. The beta-amino acid ester has wide application in drug synthesis, and can be used as synthetic base stones of a plurality of bioactive molecules, such as antibiotics, antitumor drugs, antiviral drugs, antipsychotic drugs, medical intermediates and the like. Meanwhile, the beta-amino acid ester is used for constructing the beta-amino acid ester polymer, and is widely applied to biomedicine, such as serving as a drug carrier of an anti-cancer drug and an antibacterial drug, protein delivery, tissue repair and the like, which has important significance in pharmaceutical chemistry and material science. In 2004, Thomas et al synthesized a series of pyridodiazepinone derivatives using 3- (pyridin-2-amino) propionate derivatives as intermediates and investigated their selectivity for dopamine D4 receptor. Therefore, the exploration of the green synthesis technology for synthesizing the beta-amino acid ester compounds has important significance.

(a)H₂,Pd-C(5％),EtOH,1500hPa；(b)AcOH(96％),reflux,4h

Synthesis of pyridodiazepinone derivatives

The michael addition of ammonia to α, β -unsaturated ester compounds is one of the simplest and most efficient methods for preparing β -amino acid esters with high atom economy. At present, the catalysts commonly used for the Michael addition reaction of ammonia compounds mainly include acids, bases, metal ligands and the like. Acid and base catalyzed michael addition reactions are prone to side reactions and are not suitable for substrates sensitive to acids and bases. Although the transition metal ligand catalyst has the advantages of high catalytic activity, small dosage and the like, the defects are obvious, and firstly, the preparation is difficult; secondly, the transition metal is mostly noble metal, so the cost is higher; thirdly, the stability is poor, the separation and the recycling are not easy to apply, and the product and the environment can be polluted. Aromatic amines are less prone to michael addition due to their weak nucleophilicity and greater steric hindrance. In past studies, complexes of trifluoromethanesulfonic acid, potassium tert-butoxide, magnetic nanoparticles, ionic liquids, and metals such as copper, cobalt, aluminum, and iron were used as catalysts to catalyze the michael addition reaction of aromatic amines to synthesize β -amino acid esters. The preparation process of the reaction catalyst is complicated, the production cost is high, and the reaction catalyst is not easy to prepare in large quantity and is suitable for industrial production. Therefore, the research on the green synthesis method of the aromatic ammonia beta-amino acid ester becomes a hot research field in organic synthesis.

The enzyme catalysis reaction is a key point of green chemical research due to high efficiency, green and strong specificity. The enzymatic reaction has been widely used in the fields of industrial biosynthesis, medical care and food industry because of its mild reaction conditions, high selectivity and good product stability. However, the enzymatic reaction has the restriction of solvent to substrate dissolution, solvent polarity to enzyme activity inhibition and the like, the reaction time is often long (24-96 h), and the conversion rate of a specific substrate is not very high, so that the development of a novel synthesis technology of the enzymatic aromatic ammonia beta-amino acid ester compound based on the micro-fluidic technology based on the traditional enzymatic reaction becomes the research target of the people.

Compared with the conventional chemical reactor, the microfluidic reactor has the characteristics of high mixing efficiency, fast mass and heat transfer, accurate parameter control, high reaction selectivity, good safety and the like, and is widely applied to organic synthesis reaction. In a continuous flow micro-reactor, a plurality of reactions can realize rapid screening of the conditions of micro-reactions, and safe reactions can be carried out even under harsh experimental conditions, so that reaction raw materials are greatly saved, the screening efficiency is improved, and the concept of green chemistry is more attached.

To date, relatively few studies have been conducted on the synthesis of beta-amino acid esters by enzymatic aromatic amine Michael addition. Candida rugosa lipase CAL-B (Lipase B from Candida antarctica) effectively catalyzes the reaction, but the method requires a long reaction time (72h) and the conversion rate for a specific substrate reaction is not high. In order to develop a new technology for synthesizing aromatic ammonia beta-amino hydroxamic acid with high efficiency and green. We research a method for synthesizing 3- (pyridine-2-amino) propionic acid ester derivatives on line by lipase catalysis in a microfluidic channel reactor, and further synthesize 3- (pyridine-2-amino) propionic acid oxime acid by taking the 3- (pyridine-2-amino) propionic acid ester derivatives as raw materials in the microfluidic channel reactor, aiming at finding a new technology for synthesizing the 3- (pyridine-2-amino) propionic acid with high efficiency and environmental protection.

Disclosure of Invention

The invention aims to provide a novel process method for synthesizing 3- (pyridine-2-amino) propylhydroxamic acid on line in a microfluidic channel reactor, which has the advantages of short reaction time and high yield.

The technical scheme of the invention is as follows:

a method for the enzymatic on-line synthesis of 3- (pyridin-2-amino) propylhydroxamic acid (V), said method comprising:

(1) methanol is taken as a reaction solvent, 2-aminopyridine (I) and acrylic ester (II) are taken as raw materials, and lipase lipozyme RM IM is taken as a catalyst; dissolving raw materials 2-aminopyridine (I) and acrylic ester (II) by using a solvent methanol respectively, then placing the raw materials into an injector respectively, uniformly filling a reaction channel of a microfluidic channel reactor with lipase Lipozyme RM IM, continuously introducing a 2-aminopyridine (I) solution and an acrylic ester (II) solution in the injector into the reaction channel under the driving of an injection pump to perform Michael addition reaction, controlling the reaction temperature to be 30-55 ℃ (preferably 35 ℃), continuously flowing the reaction liquid in the reaction channel for 10-50 min (preferably 30min), collecting the reaction liquid flowing out of the reaction channel on line by a product collector, and performing aftertreatment to obtain a product 3- (pyridine-2-amino) propionate derivative (III);

and in the reaction liquid introduced into the reaction channel, the mass ratio of the 2-aminopyridine (I) to the acrylate (II) is 1: 0.5 to 8, particularly preferably 1: 4;

after the 2-aminopyridine (I) and the acrylic ester (II) are respectively dissolved by using a solvent methanol, the concentration of the obtained 2-aminopyridine (I) solution is recommended to be 0.5mmol/mL, and the concentration of the acrylic ester (II) solution is recommended to be 0.25-4 mmol/mL;

the lipase Lipozyme RM IM is a preparation prepared by microorganisms using Novozymes (novozymes) Inc., a 1, 3-site specific, food grade lipase (EC 3.1.1.3) on granular silica gel, which is produced by submerged fermentation using a genetically modified Aspergillus oryzae (Aspergillus oryzae) microorganism, obtained from Rhizomucor miehei; the lipase Lipozyme RM IM can be obtained by directly and uniformly fixing a granular catalyst in a reaction channel by a physical method; the catalyst was added in an amount of 0.043g/mL based on the volume of the reaction medium, to the maximum extent that the reaction channel could accommodate the packed catalyst;

specifically, the post-treatment method comprises the following steps: and (3) distilling the reaction solution under reduced pressure to remove the solvent, carrying out silica gel column chromatography separation, and filling the column by using a 200-mesh and 300-mesh silica gel wet method, wherein an elution reagent is petroleum ether: ethyl acetate volume ratio of 1:2, tracking the elution process by TLC, collecting the eluent containing the target compound, evaporating the solvent and drying to obtain a product 3- (pyridine-2-amino) propionate derivative (III);

(2) methanol is taken as a reaction solvent, the 3- (pyridine-2-amino) propionate derivative (III) obtained in the step (1) and hydroxylamine hydrochloride (IV) are taken as raw materials, and sodium methoxide is taken as a catalyst; dissolving a 3- (pyridine-2-amino) propionate derivative (III) in methanol and placing the methanol into an injector, dissolving hydroxylamine hydrochloride (IV) and sodium methoxide in methanol and placing the methanol into another injector, continuously introducing feed liquid in the two injectors into a reaction channel under the driving of an injection pump to perform hydroxylamine condensation reaction, controlling the reaction temperature to be 0 ℃, continuously flowing the reaction liquid in the reaction channel for 10min, collecting the reaction liquid flowing out of the reaction channel on line through a product collector, and performing post-treatment to obtain a product, namely 3- (pyridine-2-amino) propylhydroxamic acid (V);

and (2) introducing the 3- (pyridine-2-amino) propionate derivative (III), hydroxylamine hydrochloride (IV) and sodium methoxide into the mixed reaction liquid in the reaction channel, wherein the mass ratio of the 3- (pyridine-2-amino) propionate derivative (III), the hydroxylamine hydrochloride (IV) and the sodium methoxide is 1: 1: 2;

preferably, after the 3- (pyridine-2-amino) propionate derivative (III) is dissolved in methanol, the concentration of the obtained solution is 0.1 mmol/mL; after the hydroxylamine hydrochloride (IV) and the sodium methoxide are dissolved in methanol, the concentration of the hydroxylamine hydrochloride (IV) in the obtained solution is 0.1mmol/mL, and the concentration of the sodium methoxide is 0.2 mmol/mL;

the post-treatment method specifically comprises the following steps: and (3) distilling the reaction solution under reduced pressure to remove the solvent, performing silica gel column chromatography, and performing wet column packing by using 200-mesh and 300-mesh silica gel, wherein an elution reagent is methanol: dichloromethane volume ratio ═ 1:20, tracking the elution process by TLC, collecting the eluent containing the target compound, evaporating the solvent and drying to obtain a product, namely 3- (pyridine-2-amino) propionic hydroxamic acid (V);

in the formula (II) or (III), R₁＝CH₃Or C (CH)₃)₃。

The method adopts a microfluidic channel reactor, and the microfluidic channel reactor comprises the following steps: the device comprises a first injector, a second injector, a reaction channel and a product collector; the first injector and the second injector are connected with the inlet of the reaction channel through a Y-shaped or T-shaped pipeline, and the product collector is connected with the outlet of the reaction channel through a pipeline;

in particular, the method comprises the following steps of,

the first injector and the second injector are arranged in the injection pump and are synchronously pushed by the injection pump;

the inner diameter of the reaction channel is 2.0mm, and the length of the reaction channel is 1.0 m; the material of the reaction channel is not limited, and green and environment-friendly materials such as a silicone tube are recommended; the shape of the reaction channel is preferably curved, so that the reaction liquid can stably pass through the reaction channel at a constant speed;

the microfluidic channel reactor can also comprise a thermostat, the reaction channel is arranged in the thermostat, so that the reaction temperature can be effectively controlled, and the thermostat can be selected automatically according to the reaction temperature requirement, such as a water bath thermostat and the like.

Compared with the prior art, the invention has the beneficial effects that:

the 3- (pyridine-2-amino) propionic hydroxamic acid (V) is synthesized on line in the microfluidic channel reactor, and the method not only greatly shortens the reaction time, but also has high conversion rate; meanwhile, the economical lipase Lipozyme RMIM is used for catalyzing the Michael addition reaction of the aminopyridine and the acrylic ester for the first time, so that the reaction cost is reduced, and the method has the advantages of economy and high efficiency.

Drawings

Fig. 1 is a schematic structural diagram of a microfluidic channel reactor used in an embodiment of the present invention.

In the figure, 1-first injector, 2-second injector, 3-reaction channel, 4-product collector, 5-water bath incubator.

Detailed Description

The invention is further illustrated by the following specific examples, without limiting the scope of the invention thereto:

referring to fig. 1, a microfluidic channel reactor used in an embodiment of the present invention includes a syringe pump (not shown), two syringes 1 and 2, a reaction channel 3, a water bath incubator (5, only a schematic plan view thereof is shown), and a product collector 4; two injectors 1 and 2 are installed in the injection pump and are connected with an inlet of a reaction channel 3 through a Y-shaped interface, the reaction channel 3 is arranged in a water bath thermostat 5, the reaction temperature is controlled through the water bath thermostat 5, the inner diameter of the reaction channel 3 is 2.0mm, the length of a tube is 1.0m, and an outlet of the reaction channel 3 is connected with a product collector 4 through an interface.