ACETYLSALICYLIC ACID DERIVATIVE AND APPLICATION THEREOF

Abstract

An acetylsalicylic acid derivative and an application thereof. The present disclosure relates to the field of chemical pharmaceuticals, and in particular, to a compound shown in formula (I) or pharmaceutically acceptable salts thereof.

##STR00001##

Claims

1. A compound represented by Formula (1) or a pharmaceutically acceptable salt thereof, ##STR00006## wherein R.sub.1 and R.sub.2 each independently represent H, substituted or unsubstituted C.sub.1-C.sub.30 alkyl, substituted or unsubstituted C.sub.1-C.sub.30 alkoxy, substituted or unsubstituted C.sub.2-C.sub.30 alkenyl, substituted or unsubstituted C.sub.6-C.sub.30 aryl, substituted or unsubstituted C.sub.7-C.sub.30 aralkyl, or substituted or unsubstituted C.sub.3-C.sub.30 cycloalkyl, or R.sub.1 and R.sub.2 form 4-, 5-, 6- or 7-membered heterocycle, together with the N to which they are linked; R.sub.3 represents substituted or unsubstituted C.sub.1-C.sub.12 alkyl; n represents an integer of 0-20.

2. The compound or the pharmaceutically acceptable salt thereof according to claim 1, wherein R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.1-C.sub.30 alkyl, preferably substituted or unsubstituted C.sub.1-C.sub.20 alkyl, more preferably substituted or unsubstituted C.sub.1-C.sub.15 alkyl, still more preferably substituted or unsubstituted C.sub.1-C.sub.10 alkyl, most preferably substituted or unsubstituted C.sub.1-C.sub.6 alkyl (such as methyl or ethyl); or R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.1-C.sub.30 alkoxy, preferably substituted or unsubstituted C.sub.1-C.sub.20 alkoxy, more preferably substituted or unsubstituted C.sub.1-C.sub.15 alkoxy, still more preferably substituted or unsubstituted C.sub.1-C.sub.10 alkoxy, most preferably substituted or unsubstituted C.sub.1-C.sub.6 alkoxy; or R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.2-C.sub.30 alkenyl, preferably substituted or unsubstituted C.sub.2-C.sub.20 alkenyl, more preferably substituted or unsubstituted C.sub.2-C.sub.15 alkenyl, more preferably substituted or unsubstituted C.sub.2-C.sub.10 alkenyl, and most preferably substituted or unsubstituted C.sub.2-C.sub.6 alkenyl; or R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.6-C.sub.30 aryl, preferably substituted or unsubstituted C.sub.6-C.sub.20 aryl, more preferably substituted or unsubstituted C.sub.6-C.sub.15 aryl, most preferably substituted or unsubstituted C.sub.6-C.sub.10 aryl; or R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.7-C.sub.30 aralkyl, preferably substituted or unsubstituted C.sub.7-C.sub.20 aralkyl, more preferably substituted or unsubstituted C.sub.7-C.sub.15 aralkyl group, and most preferably substituted or unsubstituted C.sub.7-C.sub.10 aralkyl; or R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.3-C.sub.30 cycloalkyl, preferably substituted or unsubstituted C.sub.3-C.sub.20 cycloalkyl, more preferably substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl, most preferably substituted or unsubstituted C.sub.3-C.sub.6 cycloalkyl.

3. The compound or the pharmaceutically acceptable salt thereof according to claim 1, wherein R.sub.3 represents substituted or unsubstituted C.sub.1-C.sub.12 alkyl, preferably substituted or unsubstituted C.sub.1-C.sub.6 alkyl, more preferably substituted or unsubstituted C.sub.1-C.sub.4 alkyl, most preferably methyl.

4. The compound or the pharmaceutically acceptable salt thereof according to claim 1, wherein n is preferably an integer of 1-20, more preferably an integer of 2-15, still preferably 2-10, most preferably 1, 2, 3, 4, 5, or 6.

5. The compound or the pharmaceutically acceptable salt thereof according to claim 1, wherein the substituents in the substituted groups include deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, (C.sub.1-C.sub.30) alkyl (preferably (C.sub.1-C.sub.6) alkyl), (C.sub.2-C.sub.30) alkenyl (preferably (C.sub.2-C.sub.6) alkenyl), (C.sub.1-C.sub.30) alkoxy (preferably (C.sub.1-C.sub.6) alkoxy), (C.sub.1-C.sub.30) alkylthio (preferably (C.sub.1-C.sub.6) alkylthio), (C.sub.3-C.sub.30) cycloalkyl (preferably (C.sub.3-C.sub.6) cycloalkyl), (C.sub.6-C.sub.30) aryl (preferably (C.sub.6-C.sub.14) aryl or C.sub.6 aryl or phenyl) or amino.

6. The compound or the pharmaceutically acceptable salt thereof according to claim 1, wherein the compound represented by Formula (1) is selected from: 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide, 2-[2-(acetoxy)benzoyloxy]-N,N-dimethylacetamide, 2-[2-(acetoxy)benzoyloxy]-N-ethylacetamide, 2-[2-(acetoxy)benzoyloxy]-N-methylacetamide, 2-[2-(acetoxy)benzoyloxy]-acetylcycloethylamine, 2-[2-(acetoxy)benzoyloxy]-acetylpiperidine, 3-[2-(acetoxy)benzoyloxy]-N,N-diethylpropionamide, 3-[2-(acetoxy)benzoyloxy]-N,N-dimethylpropionamide, 4-[2-(acetoxy)benzoyloxy]-N,N-diethylbutanamide, 4-[2-(acetoxy)benzoyloxy]-N,N-dimethylbutanamide, 5-[2-(acetoxy)benzoyloxy]-N,N-diethylvaleramide, and 5-[2-(acetoxy)benzoyloxy]-N,N-dimethylvaleramide.

7. A crystal of the compound represented by Formula (1) or the pharmaceutically acceptable salt thereof according to claim 1, wherein the crystal has characteristic peaks in an X-ray powder diffraction (XRPD) pattern at the following 2θ angles: 12.2°±0.2°, 18.1°±0.2°, 21.8°±0.2°, 24.4°±0.2°, 29.4°±0.2°, 30.6°±0.2°, 31.9°±0.2°, 36.6°±0.2°; or the crystal has characteristic peaks in an X-ray powder diffraction (XRPD) pattern at the following 2θ angles: 9.4°±0.2°, 10.3°±0.2°, 12.2°±0.2°, 18.1°±0.2°, 21.8°±0.2°, 24.4°±0.2°, 29.4°±0.2°, 30.6°±0.2°, 31.9°±0.2°, 36.6°±0.2°.

8. The salt according to claim 7, wherein the crystal further has characteristic peaks in an X-ray powder diffraction (XRPD) pattern at the following 2θ angles: 20.4°±0.2°, 25.8°±0.2°, 27.0°±0.2°, 28.4°±0.2°, 28.8°±0.2°, 32.9°±0.2°.

9. A pharmaceutical composition, comprising a therapeutically effective amount of the compound represented by Formula (1) or the pharmaceutically acceptable salt thereof according to claim 1, or a crystal of the compound of Formula (1) or the pharmaceutically acceptable salt thereof according to claim 1, and a pharmaceutically acceptable carrier; preferably, the pharmaceutical composition consists of a therapeutically effective amount of the compound represented by Formula (1) or the pharmaceutically acceptable salt thereof according to claim 1, or the crystal of the compound of Formula (1) or the pharmaceutically acceptable salt thereof according to claim 1, and a pharmaceutically acceptable carrier; or a dosage form of the pharmaceutical composition is a transdermal dosage form or a transmucosal dosage form; or a dosage form of the pharmaceutical composition is selected from the group consisting of patch, suppository, drop, liniment, gel, ointment, spray, aerosol, or powder.

10. The pharmaceutical composition according to claim 9, wherein the pharmaceutical composition is used to treat acetylsalicylic acid indications; preferably, the acetylsalicylic acid indications include pain, fever, inflammation, rheumatism, arthritis, cancer, diabetes or its complications, dementia, cardiovascular diseases, cerebrovascular diseases; or the pharmaceutical composition is used for anti-platelet aggregation; or the pharmaceutical composition is used for prevention of cardiovascular and cerebrovascular diseases.

11. Use of the compound represented by Formula (1) or the pharmaceutically acceptable salt thereof according to claim 1, or a crystal of the compound of Formula (1) or the pharmaceutically acceptable salt thereof according to claim 1 in preparation of a drug for treatment of acetylsalicylic acid indications, wherein, preferably, a dosage form of the drug is a transdermal dosage form or a transmucosal dosage form; or a dosage form of the drug is selected from the group consisting of patch, suppository, drop, liniment, gel, ointment, spray, aerosol, or powder.

12. The use according to claim 11, wherein the acetylsalicylic acid indications include pain, fever, inflammation, rheumatism, arthritis, cancer, diabetes or its complications, dementia, cardiovascular diseases, cerebrovascular diseases; or the drug is an anti-platelet aggregation drug; or the drug is used to prevent cardiovascular and cerebrovascular diseases; or a subject of the use is a primate (such as a monkey or a human being), preferably a human being.

Description

DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 depicts the plasma concentrations of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide and acetylsalicylic acid in rats after transdermal administration.

[0037] FIG. 2 depicts the inhibitory effect of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide and 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride on monkey platelet aggregation.

[0038] FIG. 3 depicts the infrared absorption spectrum of a crystal of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide.

DETAILED DESCRIPTION

[0039] In this specification, unless otherwise specified particularly, the components or their preferred components involved may be combined with each other to form new technical solutions.

[0040] In this specification, unless otherwise specified particularly, all the embodiments and the preferred embodiments mentioned herein may be combined with each other to form new technical solutions.

[0041] In this specification, unless otherwise specified particularly, all the technical features and the preferred features mentioned herein may be combined with each other to form new technical solutions.

[0042] In this specification, unless otherwise specified to the contrary, a sum of the contents of the components in a composition is 100%.

[0043] In this specification, unless otherwise specified to the contrary, a sum of the parts of the components in a composition may be 100 parts by weight.

[0044] In this specification, unless otherwise specified, the numerical range “a-b” is an abbreviated representation of any combination of real numbers between a and b, wherein both a and b are real numbers. For example, the numerical range “0-5” means that all real numbers between “0-5” have been listed herein, and “0-5” is only an abbreviated representation of these numerical combinations.

[0045] In this specification, unless otherwise specified, the integer value range “a-b” is an abbreviated representation of any combination of integers between a and b, wherein both a and b are integers. For example, the integer value range “1-N” represents 1, 2 . . . N, wherein N is an integer.

[0046] In this specification, unless otherwise specified, “combination thereof” means a multi-component mixture of the respective elements, such as mixtures of two, three, four, and up to the largest possible number of components.

[0047] Unless otherwise specified, the term “a” used in this specification means “at least one”.

[0048] Unless otherwise specified, the percentages (including weight percentages) in this specification are based on the total weight of the composition.

[0049] In this specification, unless otherwise specified, the term “C.sub.n-C.sub.m” represents an organic group, wherein n and m are integers, and each group may contain n to m carbon atoms.

[0050] In this specification, unless otherwise specified, the term “alkyl” means a saturated hydrocarbon group which may be linear or branched, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, amyl and n-hexyl.

[0051] In this specification, unless otherwise specified, the term “cycloalkyl” means a saturated hydrocarbon group containing one or more cycloalkyl rings, such as cyclopentyl, cyclooctyl, and adamantyl.

[0052] In this specification, unless otherwise specified, the term “alkoxy” means a monovalent group —RO (for example, a methoxy group) composed of an alkyl group plus an oxygen atom.

[0053] In this specification, unless otherwise specified, the term “aryl” means a monovalent unsaturated hydrocarbon group containing one or more six-membered carbon rings, wherein the degree of unsaturation may be represented by three conjugate acid-base pairs, wherein one or more carbon atoms in the ring(s) of the aryl group may be substituted with hydroxyl, alkyl, alkenyl, halogen, haloalkyl, monocyclic aryl or amino, such as but not limited to phenyl, methylphenyl, methoxy phenyl, dimethylphenyl, trimethylphenyl, chlorophenyl, trichloromethylphenyl, triisobutylphenyl, tristyrylphenyl, and aminophenyl.

[0054] In this specification, unless otherwise specified, the term “aralkyl” means an alkyl group substituted with one or more aryl groups, for example, (C.sub.1-C.sub.18) alkyl substituted with one or more (C.sub.6-C.sub.14) aryl groups, such as phenylmethyl, phenylethyl and triphenylmethyl.

[0055] In this specification, unless otherwise specified, the term “alkenyl” means an unsaturated linear or branched hydrocarbon group containing one or more carbon-carbon double bonds, for example, an unsaturated linear or branched (C.sub.2-C.sub.22) hydrocarbon group, such as vinyl, n-propenyl and isopropenyl.

[0056] In this specification, unless otherwise specified, the term “substitute” or “substituted” or the like means that the group contains one or more substituents which include but are not limited to deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, (C.sub.1-C.sub.30) alkyl (preferably (C.sub.1-C.sub.6) alkyl), (C.sub.2-C.sub.30) alkenyl (preferably (C.sub.2-C.sub.6) alkenyl), (C.sub.1-C.sub.30) alkoxy (preferably (C.sub.1-C.sub.6) alkoxy), (C.sub.1-C.sub.30) alkylthio (preferably (C.sub.1-C.sub.6) alkylthio), (C.sub.3-C.sub.30) cycloalkyl (preferably (C.sub.3-C.sub.6) cycloalkyl), (C.sub.6-C.sub.30) aryl (preferably (C.sub.6-C.sub.14) aryl or C.sub.6 aryl or phenyl) or amino.

[0057] The “range” disclosed herein is formed with a lower limit and/or an upper limit. There may be one or more lower limits, and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundary of the particular range. All ranges that can be defined this way are inclusive and combinable, that is, any lower limit can be combined with any upper limit to form a range. For example, if the ranges of 60-120 and 80-110 are listed for a particular parameter, it should be appreciated that the ranges of 60-110 and 80-120 are also contemplated. In addition, if 1 and 2 are listed as the possible minimum values of a range, and if 3, 4, and 5 are listed as the possible maximum values of that range, the following ranges can all be contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0058] In particular, the present disclosure provides a compound represented by Formula (1) or a pharmaceutically acceptable salt thereof,

##STR00003##

[0059] wherein R.sub.1 and R.sub.2 each independently represent H, substituted or unsubstituted C.sub.1-C.sub.30 alkyl, substituted or unsubstituted C.sub.1-C.sub.30 alkoxy, substituted or unsubstituted C.sub.2-C.sub.30 alkenyl, substituted or unsubstituted C.sub.6-C.sub.30 aryl, substituted or unsubstituted C.sub.7-C.sub.30 aralkyl, or substituted or unsubstituted C.sub.3-C.sub.30 cycloalkyl, or R.sub.1 and R.sub.2 form 4-, 5-, 6- or 7-membered heterocycle, together with the N to which they are linked;

[0060] R.sub.3 represents substituted or unsubstituted C.sub.1-C.sub.12 alkyl;

[0061] n represents an integer of 0-20.

[0062] In an embodiment of this specification, R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.1-C.sub.30 alkyl, preferably substituted or unsubstituted C.sub.1-C.sub.20 alkyl, more preferably substituted or unsubstituted C.sub.1-C.sub.15 alkyl, still more preferably substituted or unsubstituted C.sub.1-C.sub.10 alkyl, and most preferably substituted or unsubstituted C.sub.1-C.sub.6 alkyl. In another embodiment of this specification, R.sub.1 and R.sub.2 each independently represent methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or tert-butyl.

[0063] In an embodiment of this specification, R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.1-C.sub.30 alkoxy, preferably substituted or unsubstituted C.sub.1-C.sub.20 alkoxy, more preferably substituted or unsubstituted C.sub.1-C.sub.15 alkoxy, still more preferably substituted or unsubstituted C.sub.1-C.sub.10 alkoxy, and most preferably substituted or unsubstituted C.sub.1-C.sub.6 alkoxy. In another embodiment of this specification, R.sub.1 and R.sub.2 each independently represent methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy or tert-butoxy.

[0064] In an embodiment of this specification, R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.2-C.sub.30 alkenyl, preferably substituted or unsubstituted C.sub.2-C.sub.20 alkenyl, more preferably substituted or unsubstituted C.sub.2-C.sub.15 alkenyl, still more preferably substituted or unsubstituted C.sub.2-C.sub.10 alkenyl, and most preferably substituted or unsubstituted C.sub.2-C.sub.6 alkenyl. In another embodiment of this specification, R.sub.1 and R.sub.2 each independently represent vinyl, propenyl, or butenyl.

[0065] In an embodiment of this specification, R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.6-C.sub.30 aryl, preferably substituted or unsubstituted C.sub.6-C.sub.20 aryl, more preferably substituted or unsubstituted C.sub.6-C.sub.15 aryl, most preferably substituted or unsubstituted C.sub.6-C.sub.10 aryl. In another embodiment of this specification, R.sub.1 and R.sub.2 each independently represent phenyl or naphthyl.

[0066] In an embodiment of this specification, R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.7-C.sub.30 aralkyl, preferably substituted or unsubstituted C.sub.7-C.sub.20 aralkyl, more preferably substituted or unsubstituted C.sub.7-C.sub.15 aralkyl, most preferably substituted or unsubstituted C.sub.7-C.sub.10 aralkyl. In another embodiment of this specification, R.sub.1 and R.sub.2 each independently represent phenylmethyl, phenylethyl, or naphthylmethyl.

[0067] In an embodiment of this specification, R.sub.1 and R.sub.2 each independently represent substituted or unsubstituted C.sub.3-C.sub.30 cycloalkyl, preferably substituted or unsubstituted C.sub.3-C.sub.20 cycloalkyl, more preferably substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl, most preferably substituted or unsubstituted C.sub.3-C.sub.6 cycloalkyl. In another embodiment of this specification, R.sub.1 and R.sub.2 each independently represent cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

[0068] In an embodiment of this specification, R.sub.3 represents substituted or unsubstituted C.sub.1-C.sub.12 alkyl, preferably substituted or unsubstituted C.sub.1-C.sub.6 alkyl, more preferably substituted or unsubstituted C.sub.1-C.sub.4 alkyl, most preferably methyl.

[0069] In an embodiment of this specification, n represents an integer of 0-20, preferably an integer of 1-20, more preferably an integer of 2-15, still more preferably an integer of 2-10, and most preferably an integer of 2-6. In another embodiment of this specification, n represents 1, 2, 3, 4, 5, or 6.

[0070] In an embodiment of this specification, the substituents in the substituted groups include but are not limited to deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, (C.sub.1-C.sub.30) alkyl (preferably (C.sub.1-C.sub.6) alkyl), (C.sub.2-C.sub.30) alkenyl (preferably (C.sub.2-C.sub.6) alkenyl), (C.sub.1-C.sub.30) alkoxy (preferably (C.sub.1-C.sub.6) alkoxy), (C.sub.1-C.sub.30) alkylthio (preferably (C.sub.1-C.sub.6) alkylthio), (C.sub.3-C.sub.30) cycloalkyl (preferably (C.sub.3-C.sub.6) cycloalkyl), (C.sub.6-C.sub.30) aryl (preferably (C.sub.6-C.sub.14) aryl or C.sub.6 aryl or phenyl) or amino. In another embodiment of this specification, the substituents in the substituted groups includes but are not limited to halogen, cyano, nitro, hydroxyl, amino, (C.sub.1-C.sub.6)alkoxy or preferably (C.sub.1-C.sub.6) alkyl.

[0071] In an embodiment of this specification, the compound represented by Formula (1) is selected from:

##STR00004## ##STR00005##

[0072] In this specification, unless otherwise specified, the compound represented by Formula (1) generally includes its pharmaceutically acceptable salts, including but not limited to pharmaceutically acceptable hydrochloride, sulfate, acetate or nitrate.

[0073] Acetylsalicylic acid has been proved to have anti-inflammatory, analgesic, antipyretic, anti-rheumatic, and anti-platelet aggregation effects, while salicylic acid has only anti-inflammatory, analgesic and antipyretic effects.

[0074] As mentioned above, the aspirin derivative (i.e., aspirin prodrug) described in the present application comprises two ester bonds, one of which (an acetyl group) originates from salicylic acid itself, and the other of which originates from a modifying group. Both the ester groups of the aforementioned aspirin prodrug can be rapidly cleaved by an enzyme in human plasma. As confirmed by the following examples, the modifying group in the aspirin derivative described in the present application is first removed by the enzyme in the plasma, and then the acetyl group is removed. That is, acetylsalicylic acid (aspirin) is present in the plasma. As for the aspirin prodrug disclosed in CN 101484415B, the acetyl group is first removed in the plasma, and then the modifying group is removed. That is, acetylsalicylic acid (aspirin) does not exist in the plasma, or its amount is extremely low. Therefore, the aspirin derivative described in the present application can retain all the therapeutic effects of aspirin, whereas the aspirin prodrug disclosed in CN 101484415 B can only retain the therapeutic effects of salicylic acid.

[0075] The Chinese Patent CN 101484415B mentions that, after entering the blood, the aspirin prodrug can be converted back into its parent drug, i.e. acetylsalicylic acid, instead of a salicylic acid derivative (i.e., a compound with the acetyl group removed). However, according to the test method used in this patent, the whole blood is diluted by 20 times, which reduces the activity of the enzyme in the plasma. In the case of a low dilution fold (such as 10 times described in the present application; see the following examples for details) or in vivo experiments (i.e. not diluted; see the following examples for details), after the aspirin prodrug described in CN 101484415B enters blood, there is not a large amount of aspirin (acetylsalicylic acid), or the effect of anti-platelet aggregation does not show up.

[0076] The compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof, or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof can enter blood via transdermal or transmucosal administration, and it is metabolized into acetylsalicylic acid in the plasma of a primate (e.g., a monkey, a human being). Therefore, the compound represented by Formula (1) in the present application or a pharmaceutically acceptable salt thereof really has the effects of its corresponding original drug (aspirin) as a non-steroidal anti-inflammatory drug (e.g., anti-inflammation, analgesia, antipyresis, anti-platelet aggregation). At the same time, it can avoid gastrointestinal adverse reactions caused by oral administration of a common non-steroidal anti-inflammatory drug.

[0077] The compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof, or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof can treat acetylsalicylic acid (aspirin) indications, including pain, fever, inflammation, rheumatism, arthritis, cancer, diabetes or its complications, dementia, cardiovascular diseases, cerebrovascular diseases. In particular, the compound represented by Formula (1) or a pharmaceutically acceptable salt thereof, or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof can be used as a drug to prevent platelet aggregation, because anti-platelet aggregation is exactly one of the pharmacodynamic effects of acetylsalicylic acid, not among those of salicylic acid. In addition, anti-platelet aggregation is also the key to the treatment or prevention of cardiovascular and cerebrovascular diseases.

[0078] In an embodiment of the present specification, the acetylsalicylic acid indication is selected from pain, fever, inflammation, rheumatism, arthritis, cancer, diabetes or its complications, dementia, cardiovascular diseases, and cerebrovascular diseases. In another embodiment, the treatment of the acetylsalicylic acid indication is to prevent platelet aggregation.

[0079] In another aspect of the present disclosure, there is further provided a pharmaceutical composition, comprising a therapeutically effective amount of a compound represented by Formula (1) or a pharmaceutically acceptable salt thereof, or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. Preferably, the pharmaceutical composition consists of a therapeutically effective amount of a compound represented by Formula (1) or a pharmaceutically acceptable salt thereof, or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

[0080] In this specification, unless otherwise specified, the term “comprising . . . ” means that the pharmaceutical composition may further contain any other components, and these components may be present in any amount, as long as the component present in that amount is acceptable to the human body and has no negative influence on the activity of the active ingredient in the pharmaceutical composition of the present disclosure.

[0081] In this specification, unless otherwise specified, the term “pharmaceutically acceptable carrier” shall be compatible with the active ingredient (the compound represented by Formula (1) or a pharmaceutically acceptable salt thereof) in the pharmaceutical composition of the present disclosure. That is, it can be blended with active ingredient without significantly reducing the therapeutic effect of the drug under normal circumstances. The “pharmaceutically acceptable carriers” include but are not limited to: sugars, such as lactose, glucose, sucrose, trehalose; starch, such as corn starch, potato starch; cellulose or its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose, methyl cellulose; tragacanth powder; gelatin; talc powders; vaseline; solid lubricants, such as stearic acid, magnesium stearate; calcium sulfate; vegetable oils, such as peanut oil, cottonseed oil, sesame oil, olive oil, corn oil, cocoa oil; alcohols, such as ethanol, propylene glycol, glycerin, sorbitol, mannitol, polyethylene glycol; aminocaproic acid, alginic acid; emulsifiers, such as Tween; wetting agents, such as sodium lauryl sulfate; coloring agents; flavoring agents; tableting aids; antioxidants; medicinal preservatives; pyrogen-free water; isotonic salt solutions; buffers; etc.; or combinations thereof.

[0082] In an embodiment, the pharmaceutical composition is used to treat acetylsalicylic acid indications. In another embodiment, the pharmaceutical composition is used to treat pain, fever, inflammation, rheumatism, arthritis, cancer, diabetes or its complications, dementia, cardiovascular diseases, and cerebrovascular diseases. In still another embodiment, the pharmaceutical composition is used to prevent platelet aggregation. Alternatively, the pharmaceutical composition is used to prevent cardiovascular and cerebrovascular diseases.

[0083] Preferably, the pharmaceutical composition is administered via transdermal administration or transmucosal administration. The subject to which the pharmaceutical composition is administered is a primate, more preferably a human being. The dosage form of the pharmaceutical composition is a transdermal dosage form or a transmucosal dosage form. More preferably, the dosage form of the pharmaceutical composition is selected from the group consisting of patch, suppository, drop, liniment, gel, ointment, spray, aerosol, or powder.

[0084] In a specific embodiment, the pharmaceutical composition is a 5% liniment comprising a compound represented by Formula (1) or a pharmaceutically acceptable salt thereof, or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof dissolved in 50% ethanol. When the liniment is used, a patient may apply it to the skin of the trunk or limbs, twice a day, 0.5-2 mL each time, to prevent the occurrence of cardiovascular or cerebrovascular diseases (anti-platelet aggregation effect). In yet another aspect of the present application, there is provided use of a compound represented by Formula (1) or its pharmaceutically acceptable salt or a crystal of a compound represented by Formula (1) of the present application or its pharmaceutically acceptable salt in preparation of a drug for treatment of acetylsalicylic acid indications; or there is provided use of a compound represented by Formula (1) or its pharmaceutically acceptable salt or a crystal of a compound represented by Formula (1) of the present application or its pharmaceutically acceptable salt in treatment of acetylsalicylic acid indications; or there is provided a compound represented by Formula (1) or a pharmaceutically acceptable salt thereof or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof for treatment of acetylsalicylic acid indications; or there is provided a method of using a compound represented by Formula (1) or a pharmaceutically acceptable salt thereof or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof to treat acetylsalicylic acid indications.

[0085] In an embodiment, the acetylsalicylic acid (aspirin) indication is selected from pain, fever, inflammation, rheumatism, arthritis, cancer, diabetes or its complications, dementia, cardiovascular diseases, and cerebrovascular diseases. In particular, the compound represented by Formula (1) or a pharmaceutically acceptable salt thereof, or a crystal of a compound represented by Formula (1) of the present application or a pharmaceutically acceptable salt thereof can be used as a drug to prevent platelet aggregation, because anti-platelet aggregation is exactly the pharmacodynamic effect of acetylsalicylic acid, not the pharmacodynamic effect of salicylic acid.

[0086] In an embodiment, the acetylsalicylic acid indication is selected from pain, fever, inflammation, rheumatism, arthritis, cancer, diabetes or its complications, dementia, cardiovascular diseases, and cerebrovascular diseases. In another embodiment, the treatment of the acetylsalicylic acid indication is to prevent platelet aggregation. In yet another embodiment, the drug is used to prevent cardiovascular and cerebrovascular diseases.

[0087] In an embodiment of the present application, the subject of the use or method is a primate (such as a monkey or a human being), preferably a human being.

[0088] The present application further provides a crystal form of the compound represented by Formula (1) or a pharmaceutically acceptable salt thereof. Preferably, there is provided a crystal form of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide. See Example 1 for the specific preparation method of this crystal form. In a preferred embodiment of the present application, the crystal form is obtained by recrystallizing the compound represented by Formula (1) or a pharmaceutically acceptable salt thereof in an organic solvent (preferably ethyl acetate/petroleum ether).

[0089] The present disclosure will be further described in detail with reference to the following examples. However, it should be understood that these examples are listed only for the purpose of illustration, not for limiting the scope of the present disclosure.

Example 1: Preparation of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide

[0090] Acetylsalicylic acid (360.23 g, 2.0 mol, 1.0 eq) and 2-chloro-diethylacetamide (299.89 g, 2.0 mol, 1.0 eq) were added into a 3 L three-necked flask, and dissolved in ethyl acetate (1.5 L). Triethylamine (202.34 g, 2.0 mol, 1.0 eq) and sodium iodide (30.21 g, 0.2 mol, 0.1 eq) were added, stirred and warmed up. When the oil bath temperature was raised to 80° C., refluxing was started. The stirring was continued for 4 hours. The resultant solution was cooled to room temperature, and filtered. The filtrate was washed with 2 M HCl (800 mL), a 5% aqueous solution of sodium bicarbonate (800 mL) and a saturated solution of sodium chloride (800 mL), and dried with anhydrous sodium sulfate for 4 hours. Filtration was performed, and the filtrate was concentrated to obtain a yellow solid. That is, a crude product of the target compound was obtained.

[0091] Under the heating and refluxing conditions, a mixed liquid of ethyl acetate/petroleum ether (1/1, V/V) was continuously added to the crude product of the target compound, and stirred and mixed until the crude product was completely dissolved. The final mass-volume ratio of the crude product of the target compound to the mixed liquid of ethyl acetate/petroleum ether (1/1, V/V) was 1:3. After slow cooling to 25° C., white crystals were precipitated out, and the solid was subjected to vacuum spin-drying after suction filtration.

[0092] HPLC: 99.8% (271 nm), yield: 37.2%; melting point: 76.0-77.0° C.

[0093] HNMR (CDCl3): δ(ppm): 8.15 (dd, J=8.0, 2.0 Hz, 1H), 7.58-7.54 (m, 1H), 7.31 (td, J=7.5, 1.0 Hz, 1H), 7.11 (dd, J=6.0, 2.0 Hz, 1H), 4.80 (s, 2H), 3.41 (q, J=7.0 Hz, 2H), 3.29 (q, J=7.0 Hz, 2H), 2.34 (s, 3H), 1.24 (t, J=7.0 Hz, 3H), 1.15 (t, J=7.0 Hz, 3H).

[0094] CNMR (CDCl3): δ(ppm): 169.7, 165.2, 164.0, 150.8, 134.0, 132.1, 126.0, 123.7, 122.8, 61.8, 41.0, 40.4, 19.0, 14.2, 12.9.

Example 2: Transdermal Test of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide in Rats

[0095] 12 SD rats were divided into 2 groups, namely an acetylsalicylic acid transdermal administration group and a 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide transdermal administration group. Grouping and dosing information were shown in Table 1:

TABLE-US-00001 TABLE 1 Dosing Dosage volume Group (mg/kg) Number (mL) 10% 600 6 1.2 2-[2-(acetoxy)benzoyloxy]-N,N- diethylacetamide in NMP 6.15% acetylsalicylic acid in NMP 369 6 1.2 Note 1: The weight of a rat was taken as 200 g. Note 2: NMP: N-methylpyrrolidone. Note 3: The two compounds were applied in equimolar dosages.

[0096] The test steps were as follows:

[0097] 1) Depilation and grouping: After the rats were adaptively fed, the backs of the rats were depilated with a pet depilator. After weighing, they were randomly divided into 2 groups according to body weight.

[0098] 2) Administration: A pipette was used to draw 1.2 mL of the two compound solutions, which were evenly on the depilated areas, respectively. After the administration, the rats each were raised in a single cage.

[0099] 3) Blood collection: at the time of 1, 2, 4, 6, 8, 10, and 24 hours after administration, respectively, 0.3 ml blood was collected into an anticoagulation EP tube, and centrifuged at 8000 rpm for 5 minutes to separate the plasma.

[0100] 4) HPLC analysis: 50 μl plasma was transferred into a centrifuge tube containing 300 μl acetonitrile, vortex mixed uniformly, and centrifuged at 12000 rpm for 10 minutes at 4° C. The supernatant was passed through a 0.22 m organic phase filter membrane for HPLC assay to determine the concentration of salicylic acid in the plasma (the half-life of acetylsalicylic acid in plasma in vivo was so short that it was difficult to determine the concentration of acetylsalicylic acid, so an alternative was to determine the concentration of salicylic acid in plasma).

[0101] 5) HPLC mobile phase conditions: 0.1% trifluoroacetic acid aqueous phase (1000 ml water+1 ml trifluoroacetic acid):acetonitrile=55:54 isocratic elution.

[0102] The experimental results were shown in FIG. 1. As shown by the results, after transdermal administration of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide to SD rats, the C.sub.max of salicylic acid in the plasma was 44.37 μg/mL; whereas the C.sub.max of salicylic acid in the plasma was 1.06 μg/mL after transdermal administration of equimolar dosages of acetylsalicylic acid. Therefore, the transdermal performance of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide in rats is much better than that of acetylsalicylic acid.

Example 3: Plasma Metabolic Stability Test of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide and 2-(diethylamino)-ethyl-2-acetoxybenzoate Hydrochloride

[0103] A desirable acetylsalicylic acid derivative should be able to be quickly converted back to acetylsalicylic acid in plasma. We compared 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide with another acetylsalicylic acid derivative 2-(diethylamino)ethyl-2-acetoxybenzoate hydrochloride disclosed in Chinese Patent CN 101484415B to determine the conversion rates of these two acetylsalicylic acid derivatives.

[0104] 29.30 mg 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide powder was weighed and dissolved in a 1 mL acetonitrile solution to formulate a stock solution with a concentration of 100 μM/mL for further use. 31.58 mg 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride powder was weighed and dissolved in 1 mL ddH.sub.2O to formulate a stock solution with a concentration of 100 μM/mL for further use. 50 μl of each of the 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide stock solution and the 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride stock solution (both at a concentration of 100 μM/mL) was transferred into 5 mL of a 10% monkey plasma diluent respectively. Both of the diluted drugs had a concentration of 1 μM/mL, and they were subjected to incubation reaction at 37° C. HPLC assay was performed at the time of 0 min, 5 min, 15 min, 30 min, 60 min, 120 min, 240 min after the plasma diluent was mixed with 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide uniformly. HPLC assay was performed at the time of 0 min, 10 min, 30 min, 60 min, 120 min, 240 min, 360 min, and 480 min after the plasma diluent was mixed with 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride uniformly. HPLC mobile phase conditions: 0.1% trifluoroacetic acid aqueous phase (1000 mL water+1 mL trifluoroacetic acid):acetonitrile=55:54 isocratic elution.

[0105] Upon calculation, the results showed that the initial concentration of the parent drug 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide was 221.81 μg/mL, and the concentration decreased to 179.97 μg/mL within 5 min. After 15 min, it was undetectable. The highest concentration of the metabolite, namely acetylsalicylic acid, was 141.83 μg/ml (equivalent to 0.7872 μM/mL), which appeared at the time of 30 min, and the conversion rate was 78.72%. See Table 2 for details.

Conversion rate of acetylsalicylic acid=(molar concentration of acetylsalicylic acid/initial molar concentration of drug)×100%

[0106] Note: The initial molar concentration of the drug here was 1 μM/mL.

TABLE-US-00002 TABLE 2 Acetylsalicylic acid Salicylic acid Time (μg/ml) (μg/ml)   0 min 5.32 0.27   5 min 56.74 11.45  15 min 139.88 42.15  30 min 141.83 44.60  60 min 135.97 47.59 120 min 112.72 51.64 240 min 104.85 61.89

[0107] Upon calculation, the results showed that the initial concentration of the parent drug 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride was 261.90 μg/mL, and the concentration decreased to 3.09 μg/mL after 10 min. It was undetectable at the time of 30 min. The highest concentration of the metabolite, namely acetylsalicylic acid, was 8.09 μg/mL (equivalent to 0.0449 μM/mL), which appeared at the time of 10 min, and the highest conversion rate was 4.49%. See Table 3 for details.

TABLE-US-00003 TABLE 3 Acetylsalicylic acid Salicylic acid Time (μg/ml) (μg/ml)  0 min 1.75 1.08  10 min 8.09 106.91  30 min 7.86 161.00  60 min 7.74 161.99 120 min 7.15 163.24 240 min 5.78 164.55 360 min 5.56 166.57 480 min 4.44 161.63

[0108] In addition to the investigation on the metabolism of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide and 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride in monkey plasma, the inventors also tested the metabolism of these two compounds in 10% diluted plasma of other species. The detailed results were shown in Table 4. As shown by the results, in comparison with rodents (rats, mice), dogs, etc., the conversion rate of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide into acetylsalicylic acid in the plasma of primates (including human beings) is very high, indicating that the metabolism is species-specific. In contrast, the conversion rate of 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride into acetylsalicylic acid in the plasma of all species tested is less than 6%, and it is mainly metabolized into salicylic acid in every case.

TABLE-US-00004 TABLE 4 Comparison of metabolism of the two compounds in plasma of different species Highest Time of highest Highest acetylsalicylic acetylsalicylic rate of acid acid conversion to Compound Plasma concentration in concentration acetylsalicylic name source plasma (μg/ml) in plasma (min) acid % 2-[2-(acetoxy)benzoyloxy]- human 94.68  60 min 52.55 N,N-diethylacetamide being bama pig 5.54 360 min 3.08 rabbit 4.58  60 min 2.54 beagle 1.65  60 min 0.92 rat 2.06  15 min 1.14 mouse BLOQ — — 2-(diethylamino)-ethyl- human 9.44  60 min 5.24 2-acetoxybenzoate being hydrochloride beagle 2.19  60 min 1.22 rat BLOQ — — mouse BLOQ — — Note: BLOQ means below the lower limit of quantification.

[0109] In summary, in the plasma of primates (including human beings), the compound represented by Formula (1) of the present disclosure (for example, 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide) is mainly metabolized to acetylsalicylic acid. That is, it is a genuine aspirin prodrug. In contrast, 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride is mainly metabolized to salicylic acid, and thus it can only be regarded as a prodrug of salicylic acid.

Example 4: Inhibitory Effects of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide and 2-(diethylamino)-ethyl-2-acetoxybenzoate Hydrochloride on Monkey Platelet Aggregation

[0110] 12 male cynomolgus monkeys were divided into three groups (4 per group), namely a blank group, a 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride treatment group and a 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide treatment group. 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride was dissolved in ddH.sub.2O to formulate a 200 mg/ml solution, and 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide was dissolved in a 50% ethanol solution to prepare a 50 mg/ml solution. The dosage for the 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride treatment group was 60 mg/kg, i.e. 0.3 mL/kg; and the dosage for the 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide treatment group was 70 mg/kg, i.e. 1.4 mL/kg. The dose volume for a monkey was calculated based on its weight. The hair on the monkey's back was shaved, and the drug was evenly applied to the bare skin. The drug was administered continuously every day for four weeks. Blank blood was collected before administration, and blood was collected once a week after administration to detect the platelet aggregation ability (the inducer was 1 mM arachidonic acid).

[0111] The results of the platelet aggregation ability are shown in FIG. 2. As shown by the results, after the treatment by administration of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide, the platelet aggregation rate in the blood decreased significantly since the second week, and continued until the end of the experiment, indicating that 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide had a significant inhibitory effect on platelet aggregation after transdermal administration. In contrast, the platelet aggregation rate remained at about 50% after the treatment with 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride, close to that of the blank group, indicating that 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride cannot inhibit platelet aggregation effectively.

[0112] These results are consistent with the results of Example 3. In particular, the conversion rate of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide into acetylsalicylic acid in monkey plasma was as high as 78.72%. The ester group in this compound is preferentially hydrolyzed in the plasma to generate acetylsalicylic acid, and then the acetyl group is removed so that this compound is metabolized to salicylic acid. This process is consistent with the metabolic order of acetylsalicylic acid (so this compound is a genuine acetylsalicylic acid prodrug). Therefore, this compound can inhibit platelet aggregation effectively. In contrast, the acetyl group in 2-(diethylamino)-ethyl-2-acetoxybenzoate hydrochloride is preferentially hydrolyzed in plasma (to the extent that a salicylic acid prodrug is formed), and then the transdermal group is removed so that this compound is metabolized to salicylic acid. Therefore, this compound has no anti-platelet aggregation effect (salicylic acid has no anti-platelet aggregation effect).

Example 5: X-Ray Powder Diffraction Measurement of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide Crystals

[0113] The crystal of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide obtained in Example 1 was subjected to X-ray powder diffraction. The detection instrument used was: Panalytical X' Pert Powder powder X-ray diffractometer; measurement conditions: Cu-Kα; tube pressure/tube current: 40 kV/40 mA; scanning angle: 3.0131°-59.9791°; scanning step length: 0.0260°; emission slit: 0.2177; test temperature: 25° C. The data obtained are shown in Table 5.

TABLE-US-00005 TABLE 5 Pos.[° 2θ] Height[cts] FWHM[° 2θ] d-spacing (Å) Rel.Int.[%] 9.4285 17225.46 0.1535 9.38031 28.47 10.3500 32604.38 0.0768 8.54712 53.89 10.5385 60506.98 0.1279 8.39469 100.00 12.1604 1035.88 0.2303 7.27845 1.71 16.3274 15831.89 0.2814 5.42907 26.17 18.0996 1662.92 0.1279 4.90129 2.75 18.9160 2680.04 0.1279 4.69155 4.43 20.4592 4480.91 0.2558 4.34103 7.41 21.1665 9725.47 0.3070 4.19755 16.07 21.8043 3681.10 0.2047 4.07618 6.08 22.6957 6511.42 0.2814 3.91806 10.76 24.4651 7127.69 0.2558 3.63855 11.78 25.8128 782.22 0.2047 3.45156 1.29 26.3216 868.02 0.1279 3.38598 1.43 26.9904 260.08 0.2558 3.30359 0.43 27.8508 2767.57 0.1791 3.20345 4.57 28.4536 2028.19 0.2047 3.13694 3.35 28.8459 1793.03 0.1535 3.09516 2.96 29.4468 1232.99 0.1279 3.03336 2.04 29.9437 1803.11 0.2303 2.98414 2.98 30.5841 1067.44 0.1535 2.92310 1.76 31.9930 1494.15 0.1535 2.79752 2.47 32.9487 1265.64 0.2558 2.71853 2.09 33.4855 269.87 0.2047 2.67617 0.45 34.3099 678.87 0.2047 2.61373 1.12 34.7802 513.41 0.1535 2.57945 0.85 35.3430 888.84 0.2303 2.53966 1.47 35.8309 204.07 0.1535 2.50619 0.34 36.6231 337.57 0.2558 2.45378 0.56 37.8715 1335.48 0.1791 2.37571 2.21 38.3421 559.20 0.2303 2.34763 0.92 39.0142 714.86 0.2558 2.30872 1.18 39.9471 223.26 0.3070 2.25693 0.37 40.4205 182.15 0.2047 2.23159 0.30 41.2068 542.80 0.2047 2.19080 0.90 41.5095 675.49 0.2047 2.17552 1.12 43.2239 144.41 0.6140 2.09313 0.24 45.6460 248.96 0.2558 1.98754 0.41 47.2626 342.29 0.2558 1.92326 0.57 49.3698 144.98 0.2047 1.84599 0.24 50.3891 296.83 0.2047 1.81101 0.49 52.0256 139.88 0.4093 1.75784 0.23 52.9649 67.86 0.3070 1.72885 0.11 56.3879 62.58 0.3070 1.63176 0.10 57.6414 60.55 0.7488 1.59790 0.10

Example 6: Infrared Absorption Spectrometry of a Crystal of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide

[0114] The crystal of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide obtained in Example 1 was subjected to infrared absorption spectrometry using Nicolet iZ10 Fourier Transform Infrared Spectrometer. A potassium bromide tableting method was utilized. Number of sample scanning: 32; number of background scanning: 32; resolution: 4.000; sampling gain: 1.0; moving mirror speed: 0.4747; diaphragm: 150.00. The resulting infrared absorption spectrum is shown in FIG. 3.

Example 7: Study on Stability of a Crystal of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide

[0115] The crystal of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide obtained in Example 1 was placed at 25° C.±2° C., and sampled at the time of 0 month, 3 months, 6 months, 9 months, 12 months to determine the impurities and assay thereof. The impurities and assay were determined by HPLC (external standard method). As shown by the results, the crystal of the present disclosure was very stable after stored at 25° C.±2° C. for 12 months. The detailed data were shown in Table 6.

[0116] The conditions for the HPLC determination are as follows:

[0117] Column: Inertsil ODS C18, 4.6×250 mm, 5 μm

[0118] Detection wavelength: 276 nm, 303 nm

[0119] Column temperature: 33° C.

[0120] Flow rate: 1.0 mL/min

[0121] Injection volume: 10 μL

[0122] Mobile phase: 0.1% tetrahydrofuran aqueous solution:acetonitrile=55:45

[0123] Running time: 15 min

TABLE-US-00006 TABLE 6 Stability data of a crystal of 2-[2-(acetoxy)benzoyloxy]-N,N-diethylacetamide Test Items Month 0 Month 3 Month 6 Month 9 Month 12 Impurities 2-(diethylamino)-2-   0.35%   0.42%   0.39%   0.45%   0.46% oxoethyl-2-salicylate hydrochloride acetylsalicylic acid  0.0063%  0.0059%  0.0062%  0.0061%  0.0066% salicylic acid 0.00134% 0.00148% 0.00139% 0.00112% 0.00124% Unspecified impurities not detected not detected not detected not detected not detected Assay  99.63%  99.58%  99.64%  99.66%  99.58%

[0124] Although the present disclosure has described specific examples, it is obvious to those skilled in the art that various changes and modifications can be made to the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, the appended claims cover all these changes within the scope of the present disclosure.