TW200811094A - Process and novel intermediates for the preparation of 3,3'-dihydroxyisorenieratine - Google Patents

Abstract

The present invention relates to an improved process for the preparation of 3,3'-dihydroxyisorenieratine of formula I and to novel intermediates of this process.

Description

200811094 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a preparation of the formula k3,3,_ bisphthyl ruthenium ruthenium PJ'-chhydroxyisorenieratin, hereinafter referred to as φ, φ carotenoid diol) The improved method is a novel intermediate with respect to the method.

[Prior Art] 3, 3, 2, 2, 2, 2, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 Vet. 1974, 15 31^44; egg yolk pigmentation: Z. Allg· Mikrobiol· (1970), 10(4), 237_244). Different arrangements for the preparation of φ, φ_carotene _3, 3l diol by fermentation are described in the literature. These methods typically have very low space/time yields. In addition, the separation of pure pigments of formula I requires extremely expensive purification operations and is therefore difficult to tolerate industrially economical implementation (J. Ind. Msicrobiol. Biotechnol. 24, 1, 64-70 (2000); Riv. Zootec Vet. 1974, 1, 31-44; Phytochemistry 22, 11, 207-210, 1983). Therefore, the overall chemical combination is a preferred route for the preparation of pure Φ, Φ-carotene-3,3,-diol of formula I. DE 1593440 describes the synthesis of φ5φ-carotenoid-3,3,_diol of formula I.

In the final stage of the synthesis, as shown in the following reaction scheme, crocetin dialdehyde 1 and two equivalents of scale salt 2 are subjected to double Wittig olefination according to the C10+C2G+C1() synthesis strategy. The reaction is carried out to produce Φ, Φ «carotene 3,3 '-diol of formula I 121668.doc 200811094.

According to DE 1593440, Example 2, only 2. 5 g of Φ, Φ-carotene of formula I is obtained after elimination of the protecting group from 2·5 8 g (8.72 mmol) of diacid.

Alcohol (2.68 mm 〇 1 = 30.7 〇 / 理论 of theory). For industrial processes, the yield is too low. The scale salt of formula 2 required for this synthesis is prepared from the 2,3,6-trimethyl-4-perbenzylbenzene of formula II in a four-stage sequence. According to DE-1593440, Example i, only 14.4 g (11.13 mmol) of the phosphonium salt of the formula 2 is obtained from 14·6 g (89.02 mmol) of the aldehyde of the formula II. This yield is also unsatisfactory.

EP 882 709 describes the synthesis of zeaxanthin according to the following synthetic strategy:

R = tetrahydropyranyl protecting group

Ci〇+ C3 + C2==:Ci5 > C 1 5 + C 1 〇+ C 】5 = C 4 〇〇 This strategy is known in carotenoid synthesis (see, in particular, nCar〇ten〇ldS) , Volume 2: Synthesis", page 192, Birkhauser Verlag 1996, ibid. 92, etc.). SUMMARY OF THE INVENTION 121668.doc 200811094 The object of the present invention is to develop an industrially and economically applicable novel method for preparing φ, φ_, radix-3,3,-diol of formula I from known sniCi〇 structural units. . Another object is to provide a novel intermediate for the novel process for the preparation of the formula φ, φ-carotene diol. This target is achieved by the method of preparing 3,3,-dihydroxyisoranin rutin of formula I:

The method comprises at least one of the following steps: a) making (1:)-aldehyde of formula 11:

Reaction with a compound representing the equivalent of the structural unit of formula Ilia:

It replaces C1 of formula II (the carbonyl oxygen atom of the aldehyde to produce formula IViCi3__:

b) reacting Cn-S of formula IV with a vinyl compound of formula Va:

Va, 121668.doc 200811094 or reacting the iViCu-a with an acetylene compound of the formula vb: =~M1 Vb, followed by partial hydrogenation of the bond to give the Ci5-alcohol of formula VI:

I OH

Wherein M1 is Li, Na, K, MgCl, MgBr, Mgl or Mg1/2, c) reacting an alcohol of the formula 与1 with a strong organic or inorganic hydrazine (an anion of the acid HX) to produce a C15 structure of the formula VII unit:

The C15 of formula VII is then reacted to yield a VIII2C15-scale salt: 15 structural unit is reacted with a triarylphosphine P(aryl)3 to

Or an arylphosphine/HX adduct thioglycine-2,4,6-tri-diuret to react with a formula V(aryl) 3. hydrazine to produce a Ci5-square salt of formula VIII, d) Cw scale salt of formula VIII and formula 2,7_121668.doc 200811094 Diacid (2,7-(!]11161:113^1〇(^-2,4,6-1:1^1^(1131 Reaction: ιχ to produce a compound of formula I. Preferably, in the process of the invention for the preparation of Φ, Φ-carotene-3,3,-diol, at least steps c) and d) are carried out, and in particular Performing steps a), b), c) and d) 步骤 in step a) of the process of the invention, reacting (31()-aldehyde of formula 11 with a compound representing the equivalent of the structural unit of formula Ilia To produce a Ci3_ ketone of the formula Iv, it is possible to use, for example, the following compound as an equivalent of the equivalent of the formula IIIai structure: acetone, 2-oxopropylpropylphosphonic acid bis(31-(::1( ) alkyl ester (such as diethyl 2-oxopropylpropylphosphonate) or i-(triarylsulfinyl)-2-propane (such as triphenylphosphinyl) > 2-propane /\^° Ilia 结构 The structural unit of formula IIIa replaces the carbonyl oxygen atom in the aldehyde of the formula 11 (1). Preferably, in the method In the tick, the formula 醛-aldehyde can be converted to the Cl3 ketone of the formula IV without introducing a protecting group of the phenolic hydrazine H group. Therefore, the step a) representing the extension of A can be known in principle. This is carried out, for example, by means of a base-catalyzed condensation reaction with acetone as an equivalent of the structural unit of the formula IIIa, and the condensation reaction is advantageously carried out using an excess of acetone as a solvent. Examples of suitable base catalysts are alkali metal hydroxides and alkaline earths. Gold 121668.doc •10- 200811094 is a hydroxide 'especially an alkali metal hydroxide, such as sodium hydroxide or hydroxide. Therefore, 'by the age of about 1 〇 2 〇 莫 量Adding to the acid wipe and transferring the solution back after adding about twice the molar amount of the egg powder, the (:1()-aldehyde of the formula 11 can be converted into the formula ketone. Another possibility A method known per se for converting a Cio-aldehyde of the formula II to a ketone of the formula IViCl3_ consists in reacting an aldehyde of the formula with diethyl 2-oxopropylpropylphosphonate as an equivalent of the structural unit of the formula ma.

cA〇~c2hso, a suitable base for this purpose is an alkali metal Cl oxime, an alkali metal thereof (^<4_alcoholate, such as sodium methoxide or ethyl sulphate. Preferably, in the method step In a), the compound representing the effect of the structural unit of the leg is triphenylphosphinylalkyl)_2-propane. Therefore, the more preferred embodiment of converting Cl0_ of the formula π to the formula ^Ci3_嗣 is to make C(10) and the equivalent of the structural unit of the formula IIIa (trisyl-Wiki)-2-propane (C3_) Subunit) reaction, and in particular, heating and heating in an inert solvent of 1_(triphenylarylene)_2-propanone I as follows: 丨3 PPh The preferred solvent is toluene and the excess of k subunit is 5_5() _〇/ ΜΗ) After the separation of the tris-phosphine oxide by, for example, the transition of the dream gum, the oxime can be isolated in good yield and high purity. I21668.doc 200811094 In the step of the method of the present invention, a ketone is converted into an alcohol of the formula: 1 by reacting the ketone with a vinyl compound of the formula Va:

Va, or reacting with an acetylene compound of the formula Vb···2'~ί\4 Vb 9 and subsequently hydrogenating the part of the bond to the alcohol of the formula VI2 Ci5, ..., Na, K, MgCl, MgBr, Mgl or Mg, /2, especially for Li, Na, MgCl or oxime, by reacting a Cn-ketone of the formula IV with an acetylene compound of the formula Vb to convert a Cn-ketone of the formula 1 which has not been described in the literature into a formula which is also not described The alcohol of 卩 can be carried out according to the instructions known in principle. For example, it is possible to convert a 3-keto of the formula to a C15-alcohol of the formula VIa by a 1,2-addition of lithium acetylide or sodium acetylide, a so-called propargyl alcohol:

OH

9 and then the alcohol is partially hydrogenated to the hydrazine alcohol of the formula by the Lindlar process.

Details of the acetylation of ketones and partial hydrogenation of the formed propargyl alcohols can be found, for example, in J. Am. Chem. S〇c. 1952, 74 and 295, and Helv. Chim· Acta 35 (1952), 35 and 445. Preferably, the IVtCu-ketone of the formula IV is converted to the c15-alcohol of the formula 121668.doc -12- 200811094 VI by a vinyllithium or vinyline reagent (vinyl Grignard reagenoiii addition) in a single step. Preferred solvents are liquid ammonia or open-chain or ring-shaped scales, and preferred solvents for the alkylation are open-chain or cyclic ethers. More preferably, in the method step b, the formula IViCu-ketone is ethylene. Reaction of magnesium chloride based, particularly preferably, the vinylation of Cu-ketone of formula IV with vinyl magnesium chloride is carried out in hydrogenfon, based on the ketone of formula IV, the Grignard reagent is 2-5

Moer is more than 3*4 molar equivalent of bauxite. Details of the ketene ethylation are described, for example, in Bull·s〇c Chem. Japan 37, (1964), 2〇7. In the step of the method of the invention, the alcohol of formula VI2Ci5_ is reacted with a strong organic or inorganic acid HX (X is an acid only anion) to produce a ν15 structural unit of the formula νπ: 11 I Λ HO 〆 VII And then reacting the C _ 5 structural unit of formula VII with the triaryl phosphine P(aryl) 3 to yield the formula Villi c15- sulfonium salt:

Or the formula VI2 Cm-alcohol can be used in the form of a separable form or a mixture of a strong organic or inorganic acid HX and a dinuclear P (square group) 3 of the formula p (aryl) 3 · η χ 3 121668.doc 200811094 fang The phosphine/HX adduct is converted directly to the Cl5_square salt of formula VIII. It is known that the conversion of Cls-alcohol according to the above formula is as follows. It should be understood that a strong organic or inorganic acid means an acid having a pKa value of less than 3, preferably a small square. Examples of strong organic or inorganic acids are chlorohalic acids such as hydrochloric acid, hydrobromic acid or j iodic acid such as methanesulfonic acid, p-toluenesulfonic acid or trifluoromethane with acid acid, or such as trifluoroacetic acid or trichloro Acetic acid trisodium acetate. ’

For example, a strong acid such as chlorine, money or triacetic acid converts a C15 alcohol of formula VI to a Ci5 structural unit of formula VII, and X is an ionic, sulfonate or trifluoroacetate, and then the formula The compound of VII can be converted to the SVIII2Ci5_square salt by reaction with a triarylphosphine, especially triphenylphosphine. The strong acid 11 of the Cu structural unit of the formula vn used in the process step c) is preferably hydrobromic acid or hydrochloric acid. In the triarylphosphine P (aryl h, the aryl group is a substituted or unsubstituted C6-C1S-aryl group, preferably a C0_Ci "aryl group and especially a phenyl group. The substituent on the aryl group may be ( For example, halogen and htCi_Ci2_alkyl, especially <4_alkyl. The triarylphosphine p(aryl) 3 used in process step C) is preferably triphenylphosphine. Particularly preferably, in a first variant of process step c), the alcohol of SVI is reacted with hydrobromic acid to produce a Cis-bromide of the formula wherein χ is Br and subsequently the formula VII is The compound is reacted with triphenylphosphine to produce a quaternary salt of the formula vniiCw wherein the aryl group is phenyl and X is Br. In a second variant of method step c), according to a description known in principle (see, for example, j. 〇rg. Chem. 47 (1982), 47 and 2130), 121668.doc -14- 200811094 The alcohol is directly reacted with an appropriate triarylphosphine/ruthenium adduct of the formula p(aryl)rHx. The solvent used in the reaction at a temperature of - to + is preferably a polar protic solvent such as dichloromethane or dimethylformamide. The triarylphosphine/ruthenium adduct of the aryl VHX may preferably be triphenylphosphine hydrochloride or triphenylphosphine hydrogensulfate, especially triphenylphosphine hydrobromide or hydrochloric acid. The reaction is carried out via the core 5_halide of the formula 11 (wherein Χ=Βτ or C1) as an intermediate. To isolate the VIIIiCi5_scale salt, distill off the solvent and prepare the product from another such as acetonitrile. Crystallization in a solvent. Process step C) is preferably carried out according to a second variant, in particular with triphenylphosphine hydrobromide or triphenylphosphine hydrochloride (aryl is phenyl and hydrazine is hydrazine or €1) The VltCn-alcohol is directly converted to the VIIIiCl5•scale salt. In step d) of the process according to the invention, a compound of the formula VI „icl5_ sulphate is reacted with 2,' dimethyloctyl-2,4,6-trienedialdehyde to produce a compound which has not been previously described in the literature. The two-dimensional Tichtion condensation reaction of Ca scaly salt of viii with 2,7-dimercapto- 2,4,6-triene-1, dialdehyde of SIX can be carried out by a method known in principle in the literature of the method (see , "Car〇ten〇ids, Volume 2 · Synthesis", Birkhauser Verlag, 1996). The preferred base for the generation of the dipole is an alkali metal or alkaline earth metal Ci_C6_ alkoxide, preferably in the corresponding Ci a solution in the form of a C6-alcohol; the solvent which can be used is a chlorinated hydrocarbon such as dichlorohydrazine, 1,2-chloroethane and 1,2-dichloropropane, or an open chain or cyclic ether. Examples of the ether solvent to be used are tetrahydrofuran, dioxane or glycol ether. Hydroxy ether-containing groups such as decyloxypropanol or 2-methoxypropane-alcohol may also be used. The Ci_c^ alcohol corresponding to the alkoxide is also suitable for use in the reaction alone or in combination with one of the solvents mentioned above. Another preferred embodiment resides in the use of oxygen as a "latent base"

Ber. 107, 2050, et al. (1974)), for example, by using the formula VIIHC15-salt salt in the presence of a formula, in the presence of v-, in the presence of v-oxygen, as a solvent, in the case of arsenic, AJl lactidine Heating for several hours produces a dipole. The reaction can be carried out in pure oxygen or in a mixture of oxonium and one of the solvents mentioned above. The final product of Formula 1 can be separated in this case by filtering the reaction mixture without additional processing steps.

The method of the present invention opens an easy method for obtaining a dihydroxyisorane ruthine (Φ, Φ-carotene-3,3,-diol). In particular, the following aspects are surprising and are not known to those skilled in the art: The acidity of the phenolic O group in the compounds of Formulas II and IV does not interfere with the C3 and Q extensions occurring in the alkaline medium. Reaction (method step a) & b)), S-electron and thus oxidation-sensitive phenol does not initiate the oxidation process, and in the alkaline conditions required for this purpose, in the method step d) The elimination reaction of triphenylphosphine does not occur in the olefination reaction, and it is well known to those skilled in the art that in the production of ethylene-based dipoles, the scale salt tends to/di-diphenylphosphine (Caroten〇ids, 2 volumes, p. 94). Test

Thus, the method of the present invention achieves the objectives stated at the outset by means of the following synthetic strategy:

Ci〇+C3+C2=Ci5 121668.doc -16- 200811094

Ci5+c10+Cl produces c4〇. It is not possible to carry out the formula II of the phenolic hydroxyl group, even if the above is in the context of the present invention, the following aspects are known to the skilled artisan: the invention with the unprotected c1 (r acid starting) The synthesis can be described in the high yield state of the art. It is suggested that the phenolic hydroxyl group should be protected. The present invention also provides the formula IV2C131 with the same:

IV The invention also provides a C15-alcohol of formula VI:

The invention also provides a structural unit of formula VII:

X is an anion of a strong organic or inorganic acid HX. X is preferably C1戍Br σ. The invention also provides a formula VIII2C15-scale salt:

121668.doc -17- 200811094 wherein is a aryl group, preferably a phenyl group, and X is an anion of a strong organic or inorganic acid hydrazine, preferably C1 or Br. The more general definition of aryl and X corresponds to the definition given in the details of method step c). [Embodiment] The present invention is illustrated by the following examples, but does not mean any limitation.

General Information: Organometallic compounds are prepared and treated under inert gas in the absence of air and moisture. 4-Hydroxy-2,3,6-trimethylbenzoic acid was prepared according to J. Indian Chem. Soc. 40, 6, 472 (1963). Example 1 - Synthesis of C13-keto of Formula IV:

IV 82.1 g (〇.5〇 m〇l) 4-hydroxy-2,3,6-trimethylbenzaldehyde was suspended in 1 ^ toluene. 175 g (〇.55 mol) of 1-(triphenylphosphinoalkyl)propane were added and after that, the mixture was refluxed for 48 hours. Subsequently, the reaction mixture was concentrated on a rotary evaporator at 6 liters down to 2 Torr. The triphenylphosphine oxide was isolated by means of silica gel flash chromatography (solvent: cyclohexane / methyl tert-butyl ether = 2 / 1). The fractions containing the value product are combined and concentrated on a rotary evaporator at +5 (rc as low as 2 Torr). For ultra-purification, the evaporation residue is dissolved in hot acetonitrile; the hot solution is filtered through a groove type The vessel was clarified and cooled to 〇 ° C. The resulting suspension was stirred well (rc) for 1 hour and filtered. The filter 121668.doc -18- 200811094 cake was washed with a small amount of cold acetonitrile and at +5 (TC/20 mbar) Dry final weight: 73.4 g (72.0% of theory)

Μ.ρ. : 106-1〇7〇C HPLC purity: 97.9% Example 2 - Synthesis of C15-alcohol of formula VI

51·〇 g (0.25 mol) of the IViCi3-one from Example 1 was dissolved in tetrahydrofuran. At 0, 833 (L2 molar solution of vinylmagnesium chloride in tetrahydrofuran @1〇 m〇i Grignard reagent) was added dropwise over 1 hour and the mixture was then stirred for a few hours under the arm. For the treatment, the mixture was added dropwise to a 21% aqueous solution of half-saturated ammonium chloride over 3 minutes at 〇 to +5t:. Subsequently, 2 1 methyl tertiary butyl ether was injected with sufficient stirring. The lower aqueous phase was separated and extracted twice with 5 〇〇. The combined organic phases were washed once with a solution of a half-saturated cesium chloride solution and washed with water, dried over sodium sulfate and concentrated on a rotary evaporator at <RTIgt; The evaporation residue was then dried at +50 C as low as 5 mbar to give 671 g of HpLC. It corresponds to a yield of 98% of the theoretical value. The crude product can be processed without further purification. Example 3 - Synthetic 乂111-&(^15-scale salt: 121668.doc -19- 200811094

67·〇 g The crude Ci5· from the formula VI of Example 2, (84·7%; =〇·245 mol) was suspended in 5 μl of dichloromethane. Under 〇〇c, a solution of 84·0 g (〇.245 m〇l) of triphenylphosphine hydrobromide in 48 mL of dichloromethane was injected over 1 hour. The mixture was then stirred under hydrazine for 3 Torr; then, the solvent was distilled off while introducing: 1250 ml of acetonitrile at a transfer temperature of up to +8 cc. The resulting suspension was cooled to 0, stirred well under hydrazine and filtered. The filter cake was washed with a small amount of cold acetonitrile and at +5 Torr. [: 2 〇 mbar dry.

Final weight · 73.9g of Vlll-a C!” scale salt (54.2% of theory) Mp : 235.5-236〇C HPLC purity: 96.8% The filtrate was concentrated on a rotary evaporator and dissolved in 12〇 In dichloromethane, the solvent was distilled off under normal pressure' while introducing 23 〇ml of acetonitrile, and the transfer temperature was as high as +8 ° C. After exchanging the solvent, the mixture was refluxed for 20 hours, cooled to CTC and fully submerged (4) The hourly product was filtered off, washed with a small amount of cold acetonitrile and dried at +5{rc/20 mbar. The final weight of the crystallization product of the younger one·························· 6 g (12.9〇/0 of theory) Μ·ρ· : 234-235〇C HPLC purity: 95.5% 91.5 g (67.1% of theory) Nieling: Formula Vlll-aiC!5- town Overall yield of salt·· Example 4 - Synthesis of formula I 3,3'-dihydroxyisosole 121668.doc -20 - 200811094

133.7 g (0.24 mol) of C15-salt salt of formula Vlll-a prepared according to Example 3, 16.4 g (〇"〇m〇l) of 2,7-dimethyloctyl 2,4 of formula IX, A mixture of 6-trienedioic acid, 500 ml of ethanol and 150 ml of 1,2-butylene oxide was refluxed for 20 hours. The suspension was subsequently cooled to 0 ° C and stirred well for 1 hour at 〇 ° c. The crystalline product was filtered off and dried at +50 ° C /2 0 mbar. • Final weight: 3·4 g of formula 1 of 3, 3 匕 dihydroxyiso-niramidine (68.6% of theory, based on aldehyde of formula IX) Mp : 218-221〇C HPLC purity: 97· 60/〇 was ultra-purified' and the product was suspended in 700 ml of tetrahydrofuran. The suspension was refluxed for 30 minutes and clarified by filtration while hot. Under normal pressure, 600 ml of solvent was distilled from the filtrate through a distillation bridge; 350 (4) acetonitrile was added dropwise to the hot bottom product over 15 minutes. The resulting crystal suspension was refluxed for 5 minutes, cooled to 〇 ° C and stirred well for 1 hour under 〇 °. The crystalline product was filtered off with suction and dried at up to +50 ° C / 20 mbar. , final weight: 35·1 g of product of formula 1 (91.4% of theory, based on the first crystalline product) Mp: 228-230〇C HPLC purity: 98·6% E^CHCU): at 465 nm 2166 121668.doc -21 -

Claims (1)

200811094 X. Patent application scope: 1. A method for preparing 3,3'-dihydroxyisoreneieratin of formula I: The method comprises at least one of the following steps: a) making the formula 1 of the formula 1 aldehyde: Η I Reaction with a compound representing the equivalent of the structural unit of formula Ilia: Ilia Η , which replaces the carbonyl oxygen atom of the formula 11 with 0:1 ()-aldehyde to give the formula IViC13-ketone: b) reacting a Ci3-ketone of the formula IV with a vinyl compound of the formula Va: Va, 121668.doc 200811094 or reacting a ketone of the formula IV2C13-ketone with an acetylene compound of the formula Vb: =--M1 Vb, followed by a key moiety Hydrogenation to produce c15-alcohol of formula VI: Wherein M1 is Li, Na, K, MgCl, MgBr, Mgl or Mg1/2, c) reacting a C15-alcohol of formula VI with a strong organic or inorganic acid HX, wherein X is an anion of the acid HX to yield formula VII C15-structural unit: The C15 structural unit of formula VII is then reacted with a triarylphosphine P(aryl)3 to yield a VIIIiC15-square salt: p+(aryl)3χ· HO VIII or reacting an alcohol of formula VI2C15- with a triarylphosphine/HX adduct of formula P(aryl)3·ΗΧ to yield a C15-square salt of formula VIII, 121668.doc 200811094 To produce a compound of formula I. 2. As requested by the method, where steps _, b), ^d) are performed. In the method of claim 1 or 2, wherein in the method step a), the 〇-acid of the formula C is converted to the formula IV <c13 without introducing a thiol group of the phenolic 〇liA garden H group The method of any one of claims 1 to 3, wherein in the method step a), the compound of the structural unit of the representative core is a compound of a phosphorous alkyl group > 2-propane. The method of any one of claims 1 to 4, wherein in the method step b), the Cl3·ketone of the formula iV is reacted with the vinylmagnesium chloride. 6. According to any one of the claims! The method of the method wherein the method for the conversion of the formula M C15-alcohol to the structure of the Ch structural unit of the formula VII is followed by hydrobromic acid or hydrochloric acid. 7. The method according to any one of the items (1), wherein In step C), the VkCl5-alcohol is converted directly as triphenylphosphine hydrochloride or triphenylphosphine hydrochloride to the c-fibrate salt of formula vm wherein the aryl group is phenyl and or CM. · 8· A ketone having the formula IV ·· 121668.doc 200811094 Wherein X is an anion of a strong organic or inorganic acid HX. 11. A C15-onium salt having the formula VIII: Wherein the aryl group is an aryl group, preferably a phenyl group, and X is an anion of a strong organic or inorganic acid HX, preferably C1 or Br. 121668.doc 200811094 VII. Designated representative map: (1) The representative representative of the case is: (none) (2) The symbol of the symbol of the representative figure is simple: _ VIII. If there is a chemical formula in this case, please reveal the characteristics that can best show the invention. Chemical formula: 121668.doc