阅读说明：本技术 一种罗沙司他关键中间体的制备方法 (Preparation method of key intermediate of roxasistat ) 是由 李坚军 周嘉第 张其伟 胡思雅 于 2020-07-02 设计创作，主要内容包括：本发明提供了一种罗沙司他关键中间体的制备方法,该中间体Ⅰ为4-羟基-1-甲基-7-苯氧基异喹啉-3-羧酸酯。所述制备方法为：以酪氨酸为起始原料,依次经酯化、酰化、醚化、环化、芳构化和氧化重排反应制得罗沙司他关键中间体。该制备方法原料廉价易得,环境友好,如本发明的环合反应避免使用了三氯氧磷、多聚磷酸等环境不友好试剂,其工艺简单,操作简便,反应条件温和；三废少,产物收率和纯度较高,适用于工业化生产。(The invention provides a preparation method of a key intermediate of roxasistat, wherein the intermediate I is 4-hydroxy-1-methyl-7-phenoxy isoquinoline-3-carboxylic ester. The preparation method comprises the following steps: tyrosine is taken as a starting raw material, and the key intermediate of the Rosemastat is prepared by esterification, acylation, etherification, cyclization, aromatization and oxidation rearrangement reaction in sequence. The preparation method has the advantages of cheap and easily-obtained raw materials and environmental friendliness, and the cyclization reaction avoids using environmentally-unfriendly reagents such as phosphorus oxychloride and polyphosphoric acid, and the preparation method has the advantages of simple process, simple and convenient operation and mild reaction conditions; less three wastes, higher product yield and purity, and suitability for industrial production.)

1. A preparation method of a key intermediate of Rosemastat is disclosed, wherein the key intermediate is 4-hydroxy-1-methyl-7-phenoxyisoquinoline-3-carboxylic ester shown in formula (I), tyrosine shown in formula (II) is used as a starting raw material, and the key intermediate is obtained by esterification, acylation, etherification, cyclization, aromatization and oxidative rearrangement reactions in sequence, and is characterized by specifically comprising the following steps:

(1) carrying out esterification reaction on tyrosine shown in an initial raw material formula (II) and alcohol A at a reflux temperature in the presence of a catalyst, cooling and concentrating to remove the alcohol A after the reaction is finished, sequentially adding a saturated sodium bicarbonate solution for neutralization, alkalifying with ammonia water until the pH value is 8-9, filtering and drying to obtain tyrosine ester shown in a formula (III);

(2) adding tyrosine ester shown in a formula (III) and an acylation reagent into a solvent A, heating to reflux for acylation reaction, concentrating to remove the solvent A after the reaction is finished, washing with water, filtering, and drying to obtain a compound shown in a formula (IV);

(3) adding a compound shown as a formula (IV) into a solvent B, carrying out etherification reaction with halobenzene PhX under the action of a ligand, a copper catalyst and alkali A, filtering after the reaction is finished, adding water and an extracting agent A into filtrate, washing an organic phase with water, drying, filtering and concentrating to obtain a compound shown as a formula (V);

(4) adding a compound shown as a formula (V) into a solvent C, adding oxalyl chloride and Lewis acid to react at a reflux temperature, after the reaction is finished, washing with water, drying, filtering, concentrating, dissolving in alcohol B, heating under an acidic condition, carrying out reflux reaction, after the reaction is finished, concentrating to remove the alcohol B, adding water and the solvent D, alkalifying a water phase, extracting with an extractant B, drying an organic phase, filtering, and concentrating to obtain a compound shown as a formula (VI);

(5) carrying out aromatization reaction on a compound shown as a formula (VI) and an aromatization catalyst in a solvent E, washing with water after the reaction is finished, drying, filtering and concentrating to obtain a compound shown as a formula (VII);

(6) carrying out oxidation reaction on a compound shown as a formula (VII) and an oxidant in a solvent F, after the reaction is finished, quenching the compound by using a saturated sodium thiosulfate solution, washing the compound by using saturated salt water, drying, filtering and concentrating the solution, dissolving the compound in a mixed solution of acetic acid and acetic anhydride, adding acetate to react, after the reaction is finished, concentrating the solution, adding water and alkalifying the solution by using ammonia water, extracting the solution by using an extracting agent C, washing an organic phase by using water, drying, filtering and concentrating the organic phase, refluxing the organic phase under an acidic condition, after the reaction is finished, adjusting the pH to be neutral, filtering, and recrystallizing by using isopropanol to obtain a key intermediate of a target compound, namely 4-hydroxy-1-methyl-7-phenoxyisoquinoline-3-carboxylate shown as a formula (I);

wherein R is C1-C4 alkyl.

2. The method for preparing the key intermediate of the rosmarinic acid as claimed in claim 1, wherein the catalyst in the step (1) is concentrated sulfuric acid, phosphoric acid, thionyl chloride, hydrogen chloride, preferably thionyl chloride, and the amount ratio of the catalyst to the tyrosine represented by the formula (II) is 1.5-2.5: 1, preferably 1.7-2.2: 1; the alcohol A is C1-C4 alkyl alcohol, preferably methanol.

3. The process for the preparation of key intermediates of rosmarinic acid according to claim 1, characterized in that the acylating agent in step (2) is acetyl chloride or acetic anhydride, preferably acetyl chloride; the solvent A is ethyl acetate, tetrahydrofuran, methyl acetate, chloroform, dichloromethane or 1, 2-dichloroethane, preferably tetrahydrofuran, and the mass ratio of the acylating agent to the compound represented by the formula (III) is 1.0-1.5: 1, preferably 1.05-1.2: 1.

4. The method for preparing key intermediates of rosmarinic acid according to claim 1, wherein the ligand in step (3) is 1, 10-phenanthroline, L-proline, N-dimethylglycine, N' -dimethyl-1, 2-ethylenediamine, 2,6, 6-tetramethylhepta-3, 5-dione, 2-isobutyrylcyclohexanone, salicylaldoxime or 8-hydroxyquinoline, preferably 1, 10-phenanthroline, and the mass ratio of the ligand to the compound represented by formula (IV) is 0.05-0.25: 1; preferably 0.1-0.2: 1; the copper catalyst is copper powder, cuprous oxide, cuprous chloride, cuprous bromide or cuprous iodide, preferably cuprous chloride, and the mass ratio of the copper catalyst to the compound shown in the formula (IV) is 0.05-0.25: 1, preferably 0.1-0.2: 1; the alkali A is sodium carbonate, potassium carbonate, cesium carbonate, potassium phosphate, sodium hydroxide, potassium hydroxide or potassium tert-butoxide, preferably sodium carbonate, and the mass ratio of the alkali A to the compound shown in the formula (IV) is 1.0-2.0: 1, preferably 1.5-1.8: 1; the solvent B is N, N-dimethylformamide, dimethyl sulfoxide, 1, 4-dioxane, N-methylpyrrolidone or acetonitrile, and preferably is N, N-dimethylformamide; the halobenzene is iodobenzene and bromobenzene, preferably bromobenzene, and the mass ratio of the halobenzene to the compound shown in the formula (IV) is 1.0-1.5: 1, preferably 1.1-1.3: 1; the extractant A is dichloromethane, chloroform, 1, 2-dichloroethane, ethyl acetate or methyl acetate, preferably dichloromethane.

5. The process for preparing key intermediates of rosmarinic acid according to claim 1, wherein the temperature of the etherification reaction in step (3) is 60 to 150 ℃, preferably 80 to 120 ℃.

6. The process for the preparation of key intermediates of rosxastat according to claim 1, characterized in that the solvent C in step (4) is ethyl acetate, chloroform, dichloromethane, 1, 2-dichloroethane, tetrahydrofuran, acetonitrile or 2-methyltetrahydrofuran, preferably ethyl acetate; the Lewis acid is anhydrous aluminum chloride, anhydrous ferric chloride, stannic chloride, titanium tetrachloride, zinc chloride or boron trifluoride diethyl etherate, and is preferably anhydrous aluminum chloride; the mass ratio of oxalyl chloride to the compound represented by the formula (V) is 1.0-2.0: 1, preferably 1.1-1.6: 1; the mass ratio of the Lewis acid to the compound represented by the formula (V) is 1.1-3.0: 1, preferably 1.2-2.0: 1; the alcohol B is methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol or tert-butanol; the acid used in the acidic condition is concentrated sulfuric acid, trifluoroacetic acid, acetic acid, concentrated hydrochloric acid or phosphoric acid, preferably trifluoroacetic acid, and the mass ratio of the acid used to the compound shown in the formula (V) is 0.5-1.5: 1, preferably 0.8-1.2: 1; the solvent D is isopropyl acetate, ethyl acetate, methyl acetate, dichloromethane or chloroform, preferably isopropyl acetate; the extractant B is ethyl acetate, dichloromethane, methyl acetate or chloroform, and dichloromethane is preferred.

7. The method for preparing key intermediates of rosmarinic acid according to claim 1, wherein the aromatization catalyst in step (5) is hydrogen peroxide, tert-butyl hydroperoxide and potassium iodide, tert-butyl hydroperoxide and sodium iodide, potassium hydrogen persulfate, ferric chloride hexahydrate, manganese dioxide or potassium permanganate, preferably ferric chloride hexahydrate, and the mass ratio of the aromatization catalyst to the compound represented by formula (VI) is 0.5-5.0: 1, preferably 1.0-3.0: 1; the solvent E is acetic acid, ethyl acetate, chloroform, dichloromethane, 1, 2-dichloroethane, tetrahydrofuran, acetonitrile, 2-methyltetrahydrofuran or pyridine, preferably dichloromethane.

8. The process for the preparation of key intermediates of rosxastat according to claim 1, characterized in that the temperature of aromatization reaction in step (5) is 25-100 ℃, preferably 30-75 ℃.

9. The preparation method of key intermediate of rosmarinic acid according to claim 1, wherein the oxidant in step (6) is hydrogen peroxide, perbenzoic acid, m-chloroperoxybenzoic acid, peracetic acid, preferably m-chloroperoxybenzoic acid, and the amount ratio of the oxidant to the feeding substance of the compound represented by formula (VII) is 1.2-4.0: 1, preferably 1.4-3.5: 1; the solvent F is dichloromethane, acetic acid, chloroform or 1, 2-dichloroethane, preferably dichloromethane; the acetate is sodium acetate, potassium acetate or ammonium acetate, preferably sodium acetate, and the amount ratio of the acetate to the feeding substance of the compound shown in the formula (VII) is 1.2-3.0: 1, preferably 1.5-2.5: 1; the extractant C is ethyl acetate, dichloromethane, methyl acetate or chloroform, preferably ethyl acetate; the acidic condition is hydrochloric acid methanol mixed solution, hydrochloric acid ethanol mixed solution, sulfuric acid methanol mixed solution and sulfuric acid ethanol mixed solution, and the acidity is 2-10%, preferably 3-7%.

10. The process for preparing key intermediates of rosmarinic acid according to claim 1, wherein the temperature of the oxidative rearrangement reaction in step (6) is 25-100 ℃, preferably 40-85 ℃.

Technical Field

The invention belongs to the technical field of synthesis of medical intermediates, and particularly relates to a preparation method of a key intermediate of a medicine rosisastat for treating renal anemia.

Background

Renal anemia (CKD) is a long-term progressive disease characterized by loss of renal function, ultimately leading to end-stage renal disease. While anemia is a common complication in CKD patients. The main drugs for treating anemia associated with chronic kidney disease are Erythropoiesis Stimulating Agents (ESAs) and recombinant Erythropoietin (EPO). However, ESAs increase the risk of cardiovascular adverse reactions, and control of EPO content by regulating the expression of Hypoxia Inducible Factor (HIF) in vivo can increase the formation of hemoglobin in blood and increase the content of blood cells in vivo. Thus, therapeutic approaches to oral HIF inhibitors have potential. Currently prominent HIF inhibitors are rosxastat, dapipristal, and valdoxetal, among others.

Rosxastat (Roxadustat), chemical name N- [ (4-hydroxy-1-methyl-7-phenoxy-3-isoquinoline) carbonyl ] glycine, is a small molecule inhibitor developed by Fabricius Advanc (FibroGen) company to inhibit the activity of hypoxia inducible factor prolyl hydroxylase (HIF-PH), can stabilize HIF-2 and simultaneously induce the expression of EPO, and is clinically used for treating anemia. In 2018, 12 and 17 months, the national drug administration approves a new class 1 medicine of the roxasistat capsule (trade name: erethipine) to be sold on the market, and the structural formula of the roxasistat is shown as follows:

4-hydroxy-1-methyl-7-phenoxyisoquinoline-3-carboxylate is a key intermediate for synthesizing the roxasistat, and the structural formula is shown as the following formula (I):

at present, the synthesis route of the rasagiline mainly comprises the following steps:

in 2004, the company FibroGen in the original research reported a synthetic route for preparing Rosemastat from 4-nitrophthalonitrile (US 20040254215). The method has a route of 8 steps, and the core steps are the construction of an isoquinoline ring and a methylation reaction at the C-1 position. Wherein the construction of the isoquinoline ring adopts Gabriel-Colman rearrangement reaction. The alkylation reaction of the 1-site isoquinoline ring needs to use a lithium metal reagent, the reaction temperature is ultralow at-78 ℃, and the energy consumption is very high. The operation is complicated and the reaction conditions are severe.

In 2013, the Zhejiang Beida pharmaceutical industry also disclosed a synthetic route using 4-nitrophthalonitrile as a starting material (WO 2013013609). The total yield of the route is lower than 14 percent, toxic reagents such as phosphorus oxychloride and the like are used in the methylation reaction of the C-1 position, and the used palladium reagent is expensive.

In 2014, the company FibroGen in the original research reported an improved route using 5-bromoisobenzofuran-1 (3H) -one as a raw material (WO 2014014835). The route does not need chromatography separation, the total yield is about 26%, and the main innovation point of the method is that an isoquinoline ring is constructed by Claisen ester condensation and the methyl substitution of the 1-position of the isoquinoline ring. But the steps are more, the raw materials are expensive, and the production cost is higher.

In 2017, Zentiva reported a synthetic route using methyl 2-bromo-4-fluorobenzoate as a raw material (EP, 3305769). The method has the advantages that C-1 methylation and C-4 hydroxylation are simultaneously completed while an isoquinoline ring is constructed, the steps are short, the total yield is about 13%, but raw materials are not easy to prepare, and the used reagent (Pd (OAc))₂DPEPhos, etc.) are expensive.

Aiming at the problems of lower yield, complicated steps, difficult separation, environment-friendliness and the like in the synthetic method. The invention develops a synthesis process of the key intermediate of the roxasistat, which has the advantages of easily obtained raw materials, simple process, economy and environmental protection.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a method for preparing the key intermediate 4-hydroxy-1-methyl-7-phenoxyisoquinoline-3-carboxylic ester of the Rosemasite by taking tyrosine as a starting raw material, and the method has the characteristics of simple process, convenient operation, higher yield, lower cost and the like.

The preparation method of the key intermediate of the Rosesastat is characterized in that the key intermediate is 4-hydroxy-1-methyl-7-phenoxy isoquinoline-3-carboxylic ester shown in a formula (I), tyrosine shown in a formula (II) is used as a starting raw material, and the tyrosine is obtained through esterification, acylation, etherification, cyclization, aromatization and oxidation rearrangement reactions in turn, and the preparation method is characterized by specifically comprising the following steps:

(1) carrying out esterification reaction on tyrosine shown in an initial raw material formula (II) and alcohol A at a reflux temperature in the presence of a catalyst, cooling and concentrating to remove the alcohol A after the reaction is finished, sequentially adding a saturated sodium bicarbonate solution for neutralization, alkalifying with ammonia water until the pH value is 8-9, filtering and drying to obtain tyrosine ester shown in a formula (III);

(2) adding a compound shown as a formula (III) and an acylating agent into a solvent A, heating to reflux for acylation reaction, concentrating to remove the solvent A after the reaction is finished, washing with water, filtering, and drying to obtain a compound shown as a formula (IV);

(3) adding a compound shown as a formula (IV) into a solvent B, carrying out etherification reaction with halobenzene PhX under the action of a ligand, a copper catalyst and alkali A, filtering after the reaction is finished, adding water and an extracting agent A into filtrate, washing an organic phase with water, drying, filtering and concentrating to obtain a compound shown as a formula (V);

(4) adding a compound shown as a formula (V) into a solvent C, adding oxalyl chloride and Lewis acid to react at a reflux temperature, after the reaction is finished, washing with water, drying, filtering, concentrating, dissolving in alcohol B, heating under an acidic condition, carrying out reflux reaction, after the reaction is finished, concentrating to remove the alcohol B, adding water and the solvent D, alkalifying a water phase, extracting with an extractant B, drying an organic phase, filtering, and concentrating to obtain a compound shown as a formula (VI);

(5) carrying out aromatization reaction on a compound shown as a formula (VI) and an aromatization catalyst in a solvent E, washing with water after the reaction is finished, drying, filtering and concentrating to obtain a compound shown as a formula (VII);

(6) carrying out oxidation reaction on a compound shown as a formula (VII) and an oxidant in a solvent F, after the reaction is finished, quenching the compound by using a saturated sodium thiosulfate solution, washing the compound by using saturated salt water, drying, filtering and concentrating the solution, dissolving the compound in a mixed solution of acetic acid and acetic anhydride, adding acetate to react, after the reaction is finished, concentrating the solution, adding water and alkalifying the solution by using ammonia water, extracting the solution by using an extracting agent C, washing an organic phase by using water, drying, filtering and concentrating the organic phase, refluxing the organic phase under an acidic condition, after the reaction is finished, adjusting the pH to be neutral, filtering, and recrystallizing by using isopropanol to obtain a key intermediate of a target compound, namely 4-hydroxy-1-methyl-7-phenoxyisoquinoline-3-carboxylate shown as a formula (I);

wherein R is C1-C4 alkyl.

The preparation method of the key intermediate of the roxasistat is characterized in that the catalyst in the step (1) is concentrated sulfuric acid, phosphoric acid, thionyl chloride and hydrogen chloride, preferably thionyl chloride, and the mass ratio of the catalyst to the tyrosine shown in the formula (II) is 1.5-2.5: 1, preferably 1.7-2.2: 1; the alcohol A is C1-C4 alkyl alcohol, preferably methanol.

The preparation method of the key intermediate of the roxasistat is characterized in that an acylating reagent in the step (2) is acetyl chloride or acetic anhydride, preferably acetyl chloride; the solvent A is ethyl acetate, tetrahydrofuran, methyl acetate, chloroform, dichloromethane or 1, 2-dichloroethane, preferably tetrahydrofuran, and the mass ratio of the acylating agent to the compound represented by the formula (III) is 1.0-1.5: 1, preferably 1.05-1.2: 1.

The preparation method of the key intermediate of the rosmarintat is characterized in that the ligand in the step (3) is 1, 10-phenanthroline, L-proline, N-dimethylglycine, N' -dimethyl-1, 2-ethylenediamine, 2,6, 6-tetramethylhepta-3, 5-dione, 2-isobutyrylcyclohexanone, salicylaldoxime or 8-hydroxyquinoline, preferably 1, 10-phenanthroline, and the mass ratio of the ligand to the compound shown in the formula (IV) is 0.05-0.25: 1; preferably 0.1-0.2: 1; the copper catalyst is copper powder, cuprous oxide, cuprous chloride, cuprous bromide or cuprous iodide, preferably cuprous chloride, and the mass ratio of the copper catalyst to the compound shown in the formula (IV) is 0.05-0.25: 1, preferably 0.1-0.2: 1; the alkali A is sodium carbonate, potassium carbonate, cesium carbonate, potassium phosphate, sodium hydroxide, potassium hydroxide or potassium tert-butoxide, preferably sodium carbonate, and the mass ratio of the alkali A to the compound shown in the formula (IV) is 1.0-2.0: 1, preferably 1.5-1.8: 1; the solvent B is N, N-dimethylformamide, dimethyl sulfoxide, 1, 4-dioxane, N-methylpyrrolidone or acetonitrile, and preferably is N, N-dimethylformamide; the halobenzene is iodobenzene and bromobenzene, preferably bromobenzene, and the mass ratio of the halobenzene to the compound shown in the formula (IV) is 1.0-1.5: 1, preferably 1.1-1.3: 1; the extractant A is dichloromethane, chloroform, 1, 2-dichloroethane, ethyl acetate or methyl acetate, preferably dichloromethane.

The preparation method of the key intermediate of the roxasistat is characterized in that the temperature of the etherification reaction in the step (3) is 60-150 ℃, and preferably 80-120 ℃.

The preparation method of the key intermediate of the roxasistat is characterized in that the solvent C in the step (4) is ethyl acetate, chloroform, dichloromethane, 1, 2-dichloroethane, tetrahydrofuran, acetonitrile or 2-methyltetrahydrofuran, and preferably ethyl acetate; the Lewis acid is anhydrous aluminum chloride, anhydrous ferric chloride, stannic chloride, titanium tetrachloride, zinc chloride or boron trifluoride diethyl etherate, and is preferably anhydrous aluminum chloride; the mass ratio of oxalyl chloride to the compound represented by the formula (V) is 1.0-2.0: 1, preferably 1.1-1.6: 1; the mass ratio of the Lewis acid to the compound represented by the formula (V) is 1.1-3.0: 1, preferably 1.2-2.0: 1; the alcohol B is methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol or tert-butanol; the acid used in the acidic condition is concentrated sulfuric acid, trifluoroacetic acid, acetic acid, concentrated hydrochloric acid or phosphoric acid, preferably trifluoroacetic acid, and the mass ratio of the acid used to the compound shown in the formula (V) is 0.5-1.5: 1, preferably 0.8-1.2: 1; the solvent D is isopropyl acetate, ethyl acetate, methyl acetate, dichloromethane or chloroform, preferably isopropyl acetate; the extractant B is ethyl acetate, dichloromethane, methyl acetate or chloroform, and dichloromethane is preferred.

The preparation method of the key intermediate of the roxasistat is characterized in that the aromatization catalyst in the step (5) is hydrogen peroxide, tert-butyl hydroperoxide and potassium iodide, tert-butyl hydroperoxide and sodium iodide, potassium hydrogen persulfate, ferric chloride hexahydrate, manganese dioxide or potassium permanganate, preferably ferric chloride hexahydrate, and the mass ratio of the aromatization catalyst to the compound shown in the formula (VI) is 0.5-5.0: 1, preferably 1.0-3.0: 1; the solvent E is acetic acid, ethyl acetate, chloroform, dichloromethane, 1, 2-dichloroethane, tetrahydrofuran, acetonitrile, 2-methyltetrahydrofuran or pyridine, preferably dichloromethane.

The preparation method of the key intermediate of the roxasistat is characterized in that the temperature of aromatization reaction in the step (5) is 25-100 ℃, and preferably 30-75 ℃.

The preparation method of the key intermediate of the roxasistat is characterized in that the oxidant in the step (6) is hydrogen peroxide, perbenzoic acid, m-chloroperoxybenzoic acid and peracetic acid, preferably m-chloroperoxybenzoic acid, and the amount ratio of the oxidant to the feeding substance of the compound shown in the formula (VII) is 1.2-4.0: 1, preferably 1.4-3.5: 1; the solvent F is dichloromethane, acetic acid, chloroform or 1, 2-dichloroethane, preferably dichloromethane; the acetate is sodium acetate, potassium acetate or ammonium acetate, preferably sodium acetate, and the amount ratio of the acetate to the feeding substance of the compound shown in the formula (VII) is 1.2-3.0: 1, preferably 1.5-2.5: 1; the extractant C is ethyl acetate, dichloromethane, methyl acetate or chloroform, preferably ethyl acetate; the acidic condition is hydrochloric acid methanol mixed solution, hydrochloric acid ethanol mixed solution, sulfuric acid methanol mixed solution and sulfuric acid ethanol mixed solution, and the acidity is 2-10%, preferably 3-7%.

The preparation method of the key intermediate of the roxasistat is characterized in that the temperature of the oxidation rearrangement reaction in the step (6) is 25-100 ℃, and preferably 40-85 ℃.

By adopting the technology, compared with the prior art, the invention has the beneficial effects that:

(1) the process is simple, the operation is simple and convenient, and the reaction condition is mild;

(2) the raw materials are cheap and environment-friendly;

(3) compared with the traditional process, the method avoids the use of expensive catalysts, has less three wastes and higher product yield and purity, and is suitable for industrial production.

Detailed Description

The technical solution of the present invention is illustrated by the following specific examples, but the scope of the present invention is not limited thereto.

The technical solution of the present invention is illustrated by the following specific examples, but the scope of the present invention is not limited thereto.

Typical synthetic procedures for the preparation of key intermediate (I) of rosmarintat in the examples of the invention are shown in the following synthetic schemes: