JPH03500538A - 2-Method for producing acetonaphtones - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 2-Main method for producing acetonaphtones” L■f view [Technical field of invention] This invention relates to the cyclization of ketal or acyl-substituted benzalacetones. This invention relates to a new method for producing 2-acetonaphtones.

[Description of prior art]

2-acetonaphtones are very useful as pharmaceutical intermediates. Conventionally, 2-aceto Naphtones are described in the above references, U.S. Pat. No. 4,593,125, and LLh Upper Taku (Hori)

J, Org, Chem, 49.384 (1984) and West German patent According to the method described in No. 3, 519.009 and No. 3,518.668. Therefore, it has been manufactured. This invention provides a more sophisticated and Provides an economical route alternative.

Substituted 2-acetonaphtones are used in the chemical industry, especially substituted 2-acetonaphtones. Production of 2-naphthanoic acid and its esters It is also useful as a polymer intermediate for manufacturing. However, 2-naphthanic acid Methodologies for producing esters and their esters are very sparse. these compounds The main challenge posed by the synthesis of - In naphthanic acid, a second functional group must be present in addition to the carboxyl group. That's a good thing.

Furthermore, such functional groups must be present at specific positions on the molecule. subordinate Therefore, a single special isomer 2-naphthalate is selected from a large number of distinguishable isomer naphthanic acids. acid or its ester must be produced. Therefore, the development of such methods production is of great importance to the industry.

For example, U.S. Pat. Nos. 4,594,445, 4,506,092 and 4.486.605, however, none of these methods The common 2-naphthanic acid or It cannot be used for those esters.

Therefore, 2-nafuconic acids and their esters with predictable substitution patterns There remains a need for a simple and general method for synthesizing classes. this The invention can be oxidized to 2-naphthanic acids or their esters by conventional methods. Such synthesis is possible through the production of substituted and unsubstituted 2-acetonaphtones. Ru.

Emperor U”L! This invention is based on the following formula [In the above formula, R1 is H1 halo or (C+ to Cl2) alkoxy, acyloxy represents cy, carboxy, carbalkoxy, acyl, alkyl or thiolkyl ] Regarding the method for producing 2-acetonaphtones represented by the following formula [in the above formula] , R1 are as described above, and each R2 is (C+ to C+z) alkyl. or two R2 together represent (CZ~C+Z) alkylene ] and the following formula [In the above formula, R1 is as defined above, and each R2 is (Cr~C1□) cyclizes the enol ether represented by [representing alkyl or acyl] heating at a temperature effective to obtain said 2-acetonaphtones. The present invention relates to the method.

This invention also relates to the following general formula (In the above formula, R1 is as defined above) can be alkyl glycols and trialls and acetals react with a ketalizing agent; the benzalacetone and the ketalizing agent are reacted with a certain Forming a ketal of the above defined formula or an enol ether of the above defined two in proportion the compound thus obtained under conditions effective for its formation; heating at a temperature effective for cyclization and forming the 2-acetonaphtones; It also relates to a method for the production of 2-acetonaphtones comprising.

Furthermore, this invention provides a method for combining diketones such as acetylacetone with H1 halo or (01-C1□) alkyl, carboxy, carbalkoxy, acyloxy, Reacting benzaldehydes substituted with acyl, alkoxy or alkylthio Separately, the diketone and the benzaldehyde are added in a certain ratio to the acyl of the formula defined above. the acyl-substituted benzalacetone; Substituted benzalacetones and alkyl glycols and trialkyl orthoesters as well as preformed dialkyl acetals or ketals. reaction with a ketalizing agent as defined above in a certain proportion. Useful for producing benzalacetone ketal or enol ether of the formula react under effective conditions; convert the compound thus obtained into a ring. by heating at a temperature effective to form the 2-acetonaphtones. The present invention also relates to a method for producing 2-acetonaphtones.

The fuller merits of this invention and many of its attendant advantages lie in its preferred By referring to the following detailed description of the aspects, you will be able to understand the details further. It will be easier to understand.

Mashishi) Noh's I-Ki-ki The process of the present invention for producing 2-acetonaphtones or based on subsequent thermal ring closure of the enol ether. This cyclization occurs in the liquid phase or It can be carried out either in the gas phase or in the gas phase; The latter is generally preferred as it may provide higher yields of product.

When the cyclization is carried out in the gas phase, the temperature is preferably 350° to 800″C5. °~600°C, O,OO1ma+Hg~3 atm, preferably 0.1 mmH g to atmospheric pressure. However, temperatures exceeding soo'c Above all, high temperatures can also be used without difficulty. These temperatures are can be easily achieved in a typical environment.

More commonly, gas phase cyclization reactions are used to facilitate transport of material through a pyrolysis tank. Performed under ambient pressure using an inert gas purge. However, lower atmospheric pressure All practicable pressures are used to control the starting acid or ester gas. It is actually useful in promoting the development of According to a specific example, a pressure of 10 mm Hg is This can be achieved in a typical environment. Pressures higher than those mentioned above may also be used, especially starting acids. Alternatively, if the ester is volatile, it may be possible to use it. However, departure Since the raw material must be vaporized, the pressure is actually limited to a few atmospheres.

In gas phase reactions, the pyrolysis temperature is high enough that the reaction proceeds at a reasonable rate, and It must be possible to achieve good conversion rates. This temperature also Completely vaporize the ketal or enol ether of syl-substituted benzalacetone It must also be sufficient. In most cases this is a temperature between 470° and 530°C. This is achieved by using the corresponding bath temperature.

Unless operating under high vacuum, these temperatures may or complete consumption of all of the enol ether to yield the reaction product. best article This condition is conducive to rapid vaporization. Therefore, the lowest possible pressure is used. Must be. Industrially, this pressure is 10 mmHg to 60 mmHg. Can be mentioned. This is because -i assumes that these are the lowest economically achievable pressures. Because it will be done. However, in the case of more expensive products, even more Lower pressures may be used to some advantage. Pressures even higher than those mentioned above are , especially when the starting ketal or enol ether is volatile. can be done. The ketal of benzalacetone or The associated enol ether is consumed by 60% to 70%. Therefore, the starting material Even fairly low temperatures are suitable if it is to be reused to increase the quantity.

Such low temperatures can also be reduced if the time of contact with the heated zone of the reactor is extended. It becomes appropriate. This reaction is generally performed using an inert gas to facilitate movement through the tube. This is easily achieved since it is done using a computer. carrier gas flow Simply reducing the speed will increase the contact time.

When thermal ring closure is carried out in the liquid phase, an inert solvent is utilized.

Solvents within the scope of this invention can be used without obvious decomposition and Withstands the high reaction temperatures associated with the cyclization process without reacting with any of the products Defined as a solvent that

Any of the standard high-boiling solvents that fall into this category can be used as an inert solvent at atmospheric pressure. could be used. If the reaction is carried out under pressure, i.e. in an autocoup, In some cases, standard low-boiling solvents can be used to achieve the desired temperature while preserving the solvent in the liquid phase. can be used. 1756-300°C when processing is carried out in liquid phase 1 It is typical to carry out it preferably at a temperature of 200'' to 250°C. The active solvent has a normal boiling point above the reaction temperature for reactions proceeding under atmospheric pressure. or when the reaction has to be carried out under superpressure. If its normal boiling point is low, it must have a normal boiling point as already indicated. No Examples of active solvents include heteroaromatic and polyaromatic solvents, alkylated aromatics Aromatic solvents, including solvents and halogenated aromatic solvents, saturated cyclic and acyclic submersions organic esters, including hydrogen, alkyl, phenyl and benzyl esters, and Examples include organic ethers including diphenyl ether. More concrete examples and These include methyl and L-butyl esters, decalin, 1-methylnaphthalene, Mention may be made of naphthalene and biphenyl. Among the many solvents, ketones, Other suitable additives including halogenated aliphatic hydrocarbon aliphatic esters and alcohols. Active solvents can also be used. Within the above definition of inert solvent are olefins, primary and secondary amines, and solvents containing carboxylic acids, so they are Use must be avoided.

Typically, when the cyclization reaction is carried out in the liquid phase, the eno- The ether or ketal concentration can vary over a wide range. Typically, The ketals and enol ethers range from 0.01 mol to 1.0 mol per 12 of the solvent. exists in the amount of

Examples of suitable R2 groups in the above structure include methyl, ethyl, propyl, butylene. Examples include hexyl, pentyl, hexyl, and decyl; Examples of suitable R2 groups when tar (I) include ethylene, trimethylene and and tetramethylene.

Specific examples of R3 groups include hydrogen; halo such as chloro, bromo and fluoro; Carboxy; alkyl as described for RI and Bt; methoxy, eth Alkoxy such as oxy, propoxy, butoxy and pentoxy; ethano Acyls such as yl, propanoyl, butanoyl and pentanoyl; Noyloxy, propanoyloxy, butanoyloxy and pentanoyloxy Acyloxy such as methoxycarbonyl, ethoxycarbonyl, pro- Carbalkoxy such as poxycarbonyl and butoxycarbonyl; Such as methylthio, ethylthio, propylthio, butylthio and pentylthio. Examples include alkylthio.

In addition, the aromatic ring of benzalacetone may be substituted at any position, but it is preferable to The lower positions are the ortho and para positions of the ring relative to the carboxy-containing group. More details Specifically, the ketal or enol ether of benzalacetone is ring-closed to form 6 -Substituted 2-acetonaphtones, ortho-substituted α-acetylbenzalacetones, to provide 8-substituted 3,4-dihydro-2-acetonaphtones. On the other hand, Ben Meta-substitution of the aromatic ring of zalacetone results in isomeric 5- and 7-methoxy substituted 2-aryl Setonaphtones (e.g., methyl-m-methoxyacetylbenzalacetone) mixtures of alcohols or enol ethers (with a slight preponderance of the latter in the case of enol ethers) bring about.

Enol ethers of acyl-substituted benzalacetones are heated preferably at 25° to 300°C. preferably 75° to 250°C, more preferably over 125°C can be obtained by heating the ketals or by distilling the ketals. Wear.

In certain embodiments of this invention, cyclization of the ketal of an acyl-substituted benzalacetone occurs. In the heating step, the benzalacetone is heated to the temperature mentioned above to of the acyl-substituted benzalacetone thus obtained. The enol ether is heated at a temperature effective to cyclize the enol ether. to produce substituted 2-acetonaphtones. Acyl-substituted benzalacetone If the enol ether cyclization is carried out in the gas phase, it is 1 more preferably a temperature of 350° to 600°C and 0,001 mm Hg It is preferable to carry out under a pressure of ~3 atm, more preferably 0.1 mmHg ~ atmospheric pressure. Delicious. However, very high temperatures, such as temperatures exceeding 800°C, also pose difficulties. It can be used without any problems. More commonly, benzalacetone eno The conditions under which the cyclization of the ethers is carried out are as described above for the cyclization of the corresponding ketals. Condition is similar to M. Conversion of ketal to cyclic product is via enol structure You have to be careful as you proceed.

When the thermal ring closure of the enol ether of benzalacetone is carried out in the liquid phase, the Active solvents are utilized. Typically, for similar reactions of related 5 digits Solvents such as those mentioned above can also be used in this case. This process takes place in the liquid phase If the temperature is between 175" and 300°C It is preferable to carry out at Regarding the cyclization of enol-ful of benzalacetone Similar conditions apply. From the prior art to the present, -i-specific or specific examples Also, the ketals of acyl-substituted benzalacetones yielding 2-acetonaphtones. No ring closure was proposed. Additionally, used to produce naphthalene Even the simpler benzalasetone ketals are not known.

In another embodiment of this invention, the acyl-substituted benzalacetone of the formula defined above 2-acetonaphtones have been produced from and ketalizing agent, where: The resulting ketal is cyclized by heating as described above.

Many methods are known for converting ketones into ketals (Gas arri ni F, Giovannoli, M, and former 5itin, ITetrah edron 40: 14901984) and the literature cited therein].

However, the known application of these methods to acyl-substituted benzalacetones is Not known at all.

As the ketal of acyl-substituted benzalacetone, acyl-substituted benzalacetone can be obtained by using a ketalizing agent. Suitable ketalizing agents are alkyl Glycols and trialkyl orthoesters and preformed dia aceta such as lukyl ketals and glycols of (Ct = Clt) alcohols, such as 1,2- or 1,3-glycols, (C+ to C+z) (C, -C, 2) dialkyl ketals are mentioned. Appropriate glycols and Examples of lusoformates include neopentyl glycol, propanediol, 1,2- and 1,3-ethylene glycol, trimethyl orthoformate, etc. can be mentioned.

Alkyl glycols and alkyl orthoforms having 1 to 5 carbon atoms Groups 3 and 7 are preferred. Alkyl glycols and di- and trialkyl ortho Formates are either commercially available or need not be described herein. can be manufactured by methods known in the art.

The reaction between benzalacetone and the ketalizing agent is preferably carried out at 25@-250"C. It is more preferably carried out at a temperature of 40°C to 200°C in the presence of an acid catalyst. Noriyoshi Typically, this reaction is carried out under atmospheric pressure. However, other pressures are also suitable .

Preferred acid catalysts are strong acid catalysts such as sulfuric acid, trifluoroacetic acid, hydrochloric acid or sulfonic acids. An acid or acidic resin such as an acid exchange resin. Are acidic resins available commercially? or manufactured by methods known in the art so that there is no need to describe them herein. It can be done. A preferred acidic resin is Amberlyst-15 (trade name).

A wide range of variations are possible in the reaction of benzalacetone with ketalizing agents. is usually in the range of 1:1 to 1:5 molar equivalents, preferably 1:1 to 1:3 molar equivalents. It's within. The reaction temperature used is sufficient to carry out the ketalization reaction. However, it is usually within the range of -25° to 250°C, preferably O'' to 200°C. . The reaction proceeds easily under atmospheric pressure, but if necessary, the reaction may be carried out under pressure. stomach.

The ketalization reaction is generally carried out in the liquid phase and an inert solvent can be added. this Within the scope of the invention, inert solvents do not cause significant decomposition of the product or product formation. Defined as a solvent that can withstand the reaction temperatures that produce the ketalization reaction without damage. Ru. A high standard boiling point solvent can be used as an inert solvent under atmospheric pressure. When carried out under pressure, i.e. in an autoclave, the solvent is kept in the liquid phase. Since the desired temperature can be achieved directly, low standard boiling point solvents can be used. inert solvent must have a standard boiling point higher than the reaction temperature for reactions proceeding under atmospheric pressure. and, as already shown, if its boiling point is lower, it can be reacted under overpressure. response must be taken. Examples of inert solvents include acyclic, cyclic and aromatic carbons. hydrogen hydrides, their halides or their azeotropes formed by water , alkylene and alkyl residues of the R2 substituents of the ketals are introduced. Includes coals and glycols. A preferred group of solvents are methanol, ethanol, Alcohols or glycols such as tanol and ethylene glycol Ru.

Acetyl-substituted benzalacetones are benzaldehydes substituted with R1 (R' is as defined above) to acetylacetone (2,4-pentanedione) ) can be obtained by reacting with Aromatic aldehydes and acetylats The Knebenagel condensation of setones is well known, and α-acetylbenzalacetones are It is an effective method for generating [hμ inhibition].

Org, Reactions 15: 204 (1967), this content is quoted. This is the content of this specification].

-a-wise, the reaction between benzaldehyde and diketone is from -25° to 250'C1. Preferably at a temperature of 25″ to 150°C, 0.1 kg to 5 atm, preferably 1 It is carried out under atmospheric pressure. In this reaction, the diketone and benzaldehyde are mixed in a ratio of 10: Preferably, they are present in a ratio of 1 to 1:10, more preferably 1:1 to 2:1. exist.

Cyclic ketals such as those produced by ketalizing vicinal glycols The classes can also be used in this method. These ketals can be is generally carried out in the presence of an acid catalyst while continuously removing the water produced by the reaction. It is produced by treating ketones with glycols.

The ketal or enol ether of this invention is used to obtain 2-acetonaphtones. The cyclization of the product proceeds with a minimum crude yield of 70% to 85% by weight. is obtained with a purity of more than 80% and up to 90% by weight.

These substituted 2-acetonaphtones can be processed by chromatography, distillation, or can be purified by any of a variety of standard methods including crystallization. Ru. After purification, the yield of substituted 2-naphtone based on the starting amount of benzalacetone is: greater than 40 mol % up to 65 mol %, and the starting acyl-substituted benzalacetone depends on the nature of the substituents on the aromatic ring.

Having now provided a general description of the invention, reference may now be made to specific examples. It will be better understood by this. These examples are are included herein for illustrative purposes only, and are intended to be incorporated herein by way of illustration only. is not intended to be limited to any of its aspects.

Sue” L-One layer The intermediate ketals listed below in all examples have their protons NM Mass spectra including accurate masses for R, infrared (IR) and molecular ions Identification based on trimethyl orthoformate/methanol [1/1 (volume/ p-Methyl α-acetylbenzalacetone (IUPAC name: 3 -(4-methylbenzylidene)-2,4-pentanedione) 10.1 g (0,050 mol) and add 2 to 2.2 g of Amberlyst- 15 was added. The reaction mixture was stirred for 2.5 h at room temperature, the solution was filtered and Ao +berlyst-15 resin was removed. Add this solution to Amberlyst-21 (trade name) resin and filtered again. Intermediate monoketal is prepared under reduced pressure It was isolated by distilling off the solvent under pressure (weight of product: 11.9 g).

The compound was characterized spectroscopically and used in the next pyrolysis without further purification. . 1709 Ω-1 and 1655 cm, strong evidence for the E isomer of the ketal. -', whereas the infrared spectrum of the product has a single absorption band at 1697 cm-'. It had a carbonyl absorption rate of . Proton NMR is consistent with product assignment. However, GC-MS revealed the presence of an enol ether as an addition product. did.

A simple dryer consisting of a quartz tube placed in a 12-inch electric furnace. Thermal decomposition was carried out using a type pyrolysis apparatus. Monitor the temperature using a thermocouple and was used at a sustained temperature of 475° to 495°C. Mass transfer through the tube is facilitated by an inert gas purge (50 d/h), and the crude liquid ketal is removed at a rate of 2 Added at d/h. Yield of 6-methyl 2-acetonaphthone after chromatographic purification The amount was 4.67 g (p-methyl α-acetylbenzalacetone to 6-methyl Total conversion to chill 2-acetonaphthone, 66%).

Example 2: 2-acetonaphthone According to the method described in Example 1, α-acetylbenzalacetone was converted into 2-acetonate It was converted to futon with a yield of 64%.

Example 3: Following the method described in Example 1 for 6-chloro 2-acetophtone, P-chloro α-Acetylbenzalacetone is 61% 6-chloro2-acetonaphthone. Converted in yield.

Example 4: p- Methylthio α-acetylbenzalacetone is 6-methylthio-sec-acetonaphtho It was converted to ion with a yield of 56%.

Example 5: Following the method described in Example 1 for 6-methoxy 2-acetophtone, p-methoxy Toxy α-acetylbenzalacetone is converted into 6-methoxy 2-acetonaphthone by 4 A yield of 6% was converted.

Example 6: Preparation of 2-methoxy 2-acetonaphthone according to '.

Similarly to Example 5, dimethyl ketal of p-methoxy α-acetylbenzalacetone was added. 1-Methylnaphthalene (b, p, 240” ~241°C) by dissolving 2.50g of the crude ketal in 50m ketal was cyclized.

This solution was kept under reflux for 10 hours. The product is extracted by distillation under reduced pressure. After removing most of the solvent, first add hexane (remove remaining solvent) and then add By chromatographing the residue using 5% ethyl acetate in xane. I refined it. This method produces 0.76 g of the desired 6-methoxy 2-acetonaphtone. (yield 40%).

By the way, since the present invention has been sufficiently disclosed, those skilled in the art will be able to understand the above-mentioned Many changes and modifications may be made thereto without departing from the spirit or scope of the invention. Clearly, improvements can be made.

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Claims (20)

[Claims] 1. The following formula ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is H, halo, or (C1 to C12) alkoxy, acyloxy represents cy, carboxy, carbalkoxy, acyl, alkyl or thioalkyl. A method for producing 2-acetonaphthone shown in The following formula ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is as described above, and each R2 is an alkyl of (C1 to C12) or the two R2 together represent (C2-C12) alkylene ] or the following formula ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is as defined above, and R2 is an atom of (C1 to C12) represents an acyl or a C2-C12 acyl. Collecting the 2-acetonaphtones by heating the compound at a temperature effective to cyclize the compound. A way of becoming, including doing. 2. The heating is carried out at a temperature of 150° to 800°C under a pressure of 0.001 mmHg to 3 atm. 2. The method according to claim 1, which is carried out in the gas phase. 3. A claim in which the temperature is 350° to 600°C and the pressure is 0.1 mmHg to atmospheric pressure. The method described in Section 2. 4. Claim 1 wherein said heating is carried out at a temperature of 175° to 300°C in the presence of a solvent. Method described. 5. 5. The solvent has a normal boiling point equal to or higher than the reaction temperature. How to put it on. 6. The solvent has a normal boiling point below the reaction temperature and the reaction is above atmospheric pressure. 5. The method according to claim 4, wherein the method is carried out under low pressure. 7. 2. The method of claim 1, wherein the compound heated is the ketal. 8. Claim 7 further comprising distilling the ketal before the heating step. Method described. 9. The heating step is from 75° to obtain the enol ether of benzalacetone. This is done by heating the ketal at a temperature of 300°C, and then the eno heating the enol ether at a temperature effective to cyclize the enol ether; 8. The method according to claim 7, wherein the 2-acetonaphthone is collected by 10. The enol ether is heated in a gas phase at a temperature of 150° to 800°C. 10. The method according to claim 9, which is carried out in. 11. 11. The method of claim 10, wherein the temperature is between 350<0>C and 600<0>C. 12. Heating the enol ether makes it inert at temperatures between 175° and 300°C. 10. The method according to claim 9, which is carried out under a solvent. 13. Claim 1: The solvent has a normal boiling point equal to or higher than the reaction temperature. The method described in 2. 14. The solvent has a normal boiling point below the reaction temperature, and the reaction is carried out at temperatures below atmospheric pressure. 14. The method of claim 13, wherein the method is carried out under higher pressure. 15. 2. The method of claim 1, wherein the R1 substituent is in the ortho or para position. 16. The following formula ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is H, halo, or (C1 to C12) alkoxy, acyloxy represents cy, carboxy, carbalkoxy, acyl, alkyl or thioalkyl. A method for producing 2-acetonaphtones represented by The following formula ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (In the above formula, R1 is as defined above) alkyl glycols and dialkyl acetals, dialkyl ketals , and a ketalizing agent, which can be a trialkyl orthoester. Se; The above benzalacetone and the above ketalizing agent are mixed in a certain ratio, and the following formula is used: ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is as defined above, and R2 is an atom of (C1 to C12) or the two R2 together represent (C1-C12) alkyl. ketal of acyl-substituted benzalacetone, or the following formula: ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is as defined above, and R2 is an atom of (C1 to C12) acyl-substituted benzalyl or (C2-C12) acyl] be present under conditions effective to form the enol ether of acetone, and heating the compound at a temperature effective to cyclize the compound, and heating the compound at a temperature effective to cyclize the compound; A method comprising forming setonaftone. 17. The reaction between the acyl-substituted benzalacetone and the ketalizing agent is between -25° and 2°C. 17. A method according to claim 16, carried out at a temperature of 50<0>C. 18. The reaction between the benzalacetone and the ketalizing agent is carried out in the presence of an acid catalyst. 17. The method according to claim 16. 19. 19. The method of claim 18, wherein the acid is an acidic resin. 20. The following formula ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is H, halo, or (C1 to C12) alkoxy, acyloxy cy, carboxy, carbalkoxy, acyl, alkyl or thioalkyl. and R1 is H, (C1-C12) alkyl, (C6-C20) aryl represents (C7-C21) alkaryl or aralkyl] 2-A method for producing acetonaphthone, the method comprising converting acetylacetone into H, halo or (C1 to C12) alkyl, carboxy, carbalkoxy, acyloxy, Reacts with benzaldehydes substituted with acyl, alkoxy or alkylthio. Se; The diketone and the benzaldehyde are mixed in a certain ratio, and the following formula is used: ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (In the above formula, R1 is as defined above) benzalacetone under conditions effective to form the benzalacetone; Luglycols and dialkyl acetals, dialkyl ketals and trials reacting with a ketalizing agent which can be a kylorthoester; Add acetone and the above ketalizing agent in a certain ratio, and use the following formula: ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is as defined above, and R2 is an atom of (C1 to C12) alkylene or two R2 together represent (C1-C12) alkylene] The ketal of benzalacetone represented by or the following formula ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ [In the above formula, R1 is as defined above, and R2 is an atom of (C1 to C12) or (C2-C12) acyl] and the compound is present under conditions effective to form a compound. heating at a temperature effective to cyclize and form the 2-acetonaphthone. A method comprising: