KR840001724B1 - Process for preparing 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran - Google Patents

Abstract

Title compd. was prepd. by cyclization of 3-isobutenyl-1, 2-dihydroxybenzene or the mint. of 10 wt. % 3-isobutenyl-l,2-dihydroxybenzene and 3-metalyl-1, 2-dihydrozybenzene in the presence of 0.001-5 wt. % organic sulfonic acid at 60-200 deg.C. Thus, Claisen rearrangement of 2-H2C:CMeCH2OC6H4OH in octane at 200oC for 1hr 57min gave a mixt. of 45% 3-Me2C:CHC6H3-(OH)2-1, 2 and 55% 3-H2C:CMeCH2C6H3(OH)2-1,2, which was extracted and recrystallized to give title compd(I).

Description

Method for preparing 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran

The present invention relates to 2,3-dihydro-2,2-dimethyl-7-hydroxy benzofuran represented by the following general formula (I) from isobutenyl pyrocatechol and / or metalylpyrocatechol (hereinafter referred to as DDHB). To abbreviate).

This object may also be referred to as 7-hydroxy-2,2-dimethylcoumaran, which is a pesticide named carbofuran (2,3-dihydro-2,2-dimethylbenzofuranyl methylcarbamate). It is a substance especially effective as an intermediate in synthesis.

Isobutenyl pyrocatechol on the present specification is a compound of 3-isobutenyl-1,2-dihydroxybenzene represented by the following general formula (II), and meralyl pyrocatechol is represented by the following general formula (III) 3-meralyl-1,2-dihydroxybenzene.

Metalrylpyrocatechol can be obtained by isomerization by heating ortho-metall-oxyphenol at a temperature of 150 ° to 250 ° C., preferably in a medium diluted with a solvent, and isobutenyl pyrocatechol is bulky. The metalyl pyrocatechol of can be obtained by heating for a long time, preferably in the presence of a metal surface, and then performing the removal operation of the remaining metalylpyrocatecate.

내지 250℃로 가열을 행하여 메탈릴피로카테콜을 DDHB로 전환시키는 화학적 방법에 의해 수행될 수 있다.The removal operation of the metalyl pyrocatechol is 100 in the presence of water.

To 250 [deg.] C., by heating to 250 [deg.] C. to convert metalrylpyrocatechol to DDHB.

It is an object of the present invention to provide a process for the economic production of DDHB from isobutenylpyrocatechol and mixtures of isobutenylpyrocatecate and metallylpyrocatechol.

The conversion reaction of the alkenylphenol to the heterocyclic aryl compound can be considered as a ring isomerization or an isomerization cyclization reaction.

Ring isomerization of alkenylphenols has long been known. For example, Federal Republic of Germany Patent Publication No. 279,864 / 1913 describes a reaction in which allylphenol or allylcresol is converted to metalylcoumarane in the presence of HBr or pyridine hydrochloride.

However, the production of a benzofuran compound from an alkenylphenol compound is more complicated than a simple isomerization reaction of allyl phenol because a product other than the target product may be produced by the isomerization reaction.

According to Cleisen, allylphenols, which are generally simple, areomerized according to the reaction formula (IV) below to form benzofuran or coumaranic compounds, but when a substituent is present on the terminal carbon atom of the double bond, The following reaction process formula (V) was considered to be a Chroma-based compound (Ann. 442, p. 228, 1925). In the latter case, in the reaction process formula (V), even when one of the R groups is a hydrogen atom, a chromamann compound is obtained.

This fact was recently reported by Mr. Prater (Helv. Chim. Acta 50, pages 225-256, 1967) and by Mr. Piccardi (J. Chem. Soc. Perkin I, 1977). (P. 624).

Isomerization of any of the metalyl monophenols occurs by catalysis in an acid medium, and is performed with benzofuran compounds (isopropyl metalylphenols of US Pat. Nos. 3,876,667 and 3,816,473 and acetylmetallphenol of US Pat. No. 3,419,579). However, if the temperature is lower than 150 ° C, the reaction is too slow, so the reaction temperature is preferably at least 175 ° C (US Patent No. 3,419,579) or 200 ° C or higher (US Patent Nos. 3,876,667 and 3,816,473). It is described.

Particularly, in the case of monophenols substituted with nitro or bromo groups, the corresponding metalylphenols and isobutenylphenols are described that ring isomerization may occur in the presence of a catalyst at 100 ° C or higher (British Patent Publication No. 1,139,001). And French Republic Patent Publication No. 1,472,283). However, in contrast to the foregoing patents, it is more preferable that the temperature is 150 ° C. or higher, and these patents also disclose the ring isomerization of not only isobutenyl phenol but also nitro- or bromo-metallphenol in the presence of HBr and acetic acid-based catalyst. It is not described.

Also, as Klaisen has already described, substituents on terminal carbon atoms of double bonds tend to cause ring isomerization of other compounds in addition to the benzofuran compound, making isomerization of metalylphenol easier than isomerization of isobutenylphenol. What happens is obvious.

Isomerization of isobutenylphenol is much more difficult because the double bond in the isobutenyl substituent is at the conjugated position of the aromatic nucleus.

In other words, because the chemical arrangement of isobutenylphenol is similar to styrene, the polymerization reaction occurs much easier than isomerization.

내지 194℃의 온도에서 8.5시간동안 가열해야 한다는 것이 마르티니(Martini)씨들에 의해 J. Org. Chem. 35(9), 2,904 내지 2,906페이지(1970년)에 서술되어 있다.However, in order to obtain a good yield (84%) in isobutenyl ring isomerization, isobutenylphenol (5-methyl-2-isobutenylphenol) was added in the presence of MgCl ₂ .

To 8.5 hours at a temperature of 1 to 194 ° C., according to J. Org. Chem. 35 (9), pages 2,904 to 2,906 (1970).

As mentioned above, isomerization of alkenylphenol substituted on a double bond terminal carbon atom has been thought to be very difficult, but it has been known that isomerization may occur when a nitro group or a bromo group is substituted.

The isomerization of isobutenylphenols is much more difficult than the isomerization of allylphenols, since isobutenylphenols can be isomerized to benzofuran compounds only at very high and specific reaction temperatures and reaction times.

However, all of the above-mentioned patents are described only in alkenyl monophenols, and little is described about the isomerization of alkenylpyrocatechol. Also, French Patent No. 1,430,952 describes only the cyclization of allylpyrocatechol, but does not describe isobutenylpyrocatechol.

In addition, according to U.S. Patent Nos. 3,816,473 and 3,876,667, the use of pyrocatechol (called catechol's name) for the synthesis of carbofuran intermediates is due to the presence of two reactive hydroxyl groups, resulting in large amounts of undesired by-products. It is stated that it is not preferable because a target product which is produced and low purity is produced.

The present inventors can achieve the above-mentioned objects from isobutenylpyrocatechol and a mixture of isobutenylpyrocatechol and metalylpyrocatechol by the catalytic method, and can solve all the drawbacks of the prior art. The manufacturing method of was discovered.

The present invention relates to a mixture with isobutenylpyrocatechol (3-isobutenyl-1,2-dihydroxybenzene) and, in some cases, metalylpyrocatechol (3-metall-1,2-hydroxybenzene) It is to provide a method for producing 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran (DDHB) characterized in that the heating in the presence of a catalyst composed of sulfonic acid.

The mixture of alkenylpyrocatechols used as starting reaction materials in the present invention generally contains from 10 to 100% by weight of isobutenylpyrocatechol and more generally contains more than 30% by weight of isobutenylpyrocatechol. .

내지 200℃ 이며, 80

내지 150℃의 범위가 바람직하다. 200℃이상의 반응 온도도 사용 할수가 있으나, 경제적인 입장에서 바람직하지가못하다.The reaction temperature is usually 60

To 200 ° C., 80

The range of -150 degreeC is preferable. Reaction temperatures above 200 ° C can also be used, but this is undesirable from an economic standpoint.

The catalyst is a general formula R-SO ₃ H (wherein R is an alkyl, alkenyl, aryl, arylalkyl or arylalkenyl group, and the number of carbon atoms in the alkyl or alkenyl chain is generally less than 17, preferably less than 7). As the aryl group, phenyl and naphthyl groups are preferable, and the above-mentioned groups may particularly use compounds represented by the aromatic group may include substituents such as alkyl, hydroxyl, alkoxy, aryloxy, and the like). Examples of sulfonic acid catalysts that can be used include benzenesulfonic acid, 0-, m- and p-toluenesulfonic acid, 0-, m- and p-ethylbenzenesulfonic acid, 0-, m- and p-cumenesulfonic acid, 0-, m- and p-tert-amylbenzenesulfonic acid, 0-, m- and p-hexylbenzenesulfonic acid, 0-xylene-4-sulfonic acid, p-xylene-2-sulfonic acid, m-xylene-4- or -5-sulfonic acid , Mesitylenesulfonic acid, durensulfonic acid, pentamethylbenzenesulfonic acid, 0-dipropylbenzene-4-sulfonic acid, p-diisopropylbenzenesulfonic acid, α- and β-naphthalenesulfonic acids, 0-, m- and p-biphenyl- Sulfonic acid, α-methyl-β-naphthalenesulfonic acid, p-hydroxybenzenesulfonic acid, p-phenoxybenzenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, propane-1-sulfonic acid, butane-1-sulfonic acid, metalylsulfonic acid, isobutylsulfonic acid , Hexane-1-sulfonic acid, decan-1-sulfonic acid and dodecane-1-sulfonic acid.

The catalyst concentration in the reaction medium is generally from 0.001 to 5% by weight, preferably in the range from 0.1 to 1% by weight.

Since the process according to the invention is preferably carried out in a homogeneous phase, the nature and concentration of the sulfonic acid should be frequently checked so that the reaction medium under the reaction conditions is uniform.

In addition, according to the practice of the process according to the invention, it is preferred to carry out the reaction in the presence of an inert liquid solvent (ie, a solvent which is chemically inert under operating conditions). The nature of the solvent is not critical, but non-basic solvents are preferred, and aromatic, aliphatic and cycloaliphatic hydrocarbons: aromatic ethers: aliphatic, aromatic or cycloaliphatic chlorohydrocarbons and nitriles are preferred. Examples of the solvents that can be used include benzene, toluene, ethylbenzene, xylene (0-, m- and p-), cyclohexane, hexane, octane, dodecane, chlorobenzene, 1,2-dichloroethane, 1, 1,2-trichloroethane, anisole and methylcyclohexane can be enumerated.

The concentration of metallyl and isobutenyl-pyrocatechol in the reaction medium is generally 1 to 50% by weight, preferably 3 to 20% by weight.

The method according to the invention is very effective because it can be operated at ordinary reaction temperatures and reaction times.

The present invention will be described in more detail with reference to the following examples.

Example 1

Ring isomerization

0.1138 g of a mixture of 38.6 parts by weight of isobutenylpyrocatechol and 61.4 parts by weight of metalylpyrocatechol at 100 ° C was added to 2 cc of a solution of 43.5 mmol of benzelsulphonic acid in 1 L of toluene, and the mixture was heated and refluxed for 30 minutes. Cooled to.

Next, 5 cc of aqueous sodium bicarbonate solution was added, the mixture was separated by decantation, and the product was filtered to give 0.108 g of DDHB (yield 94.9%).

Example 2

Preparation of Isobutenylpyrocatechol

50 g of ortho-metalloxyoxyphenol and 450 cc of octane were introduced into a 1.5 L stainless steel autoclave under argon gas atmosphere, and the mixture was heated at 200 ° C. for 1 hour and 57 minutes, followed by cooling. Octane was distilled off and the residue was distilled off under absolute pressure which was reduced to 0.14 mmHg at the top. The distillation apparatus used was a glass apparatus equipped with a distillation column (40 cm in diameter and 3 cm in height) packed with a "knit" packing consisting of a knitted stainless steel gauze.

Distillation time was made into 5 hours and 20 minutes. The final distillate fraction was composed of 45% of 0-isobutenylpyrocatechol and 55% of 0-metallpyrocatechol as a white solid and 10.06 g of a mixture having a melting point of 55 to 57 ° C was obtained. The mixture was recrystallized in hexane to give a mixture of 38.6 ratios of 0-isobutenylpyrocatechol 38.6 and 61.4 of 0-metallpyrocatechol having the same melting point.

1.0522 g of this mixture, 10 cc of octane and 5 cc of water were introduced into an autoclave of 50 cc titanium, cooled, and the aqueous layer obtained by separating the mixture by decantation was extracted with ethyl acetate. The residue obtained by combining the organic layers and evaporating was recrystallized with hexane to isolate 0.2 g of white hydrating 3-isobutenyl-1,2-dihydroxybenzene (91% purity).

Nuclear magnetic resonance (NMR) for this isobutenylpyrocatechol was measured below using tetramethylsilane as a control compound on the nucleus of 13C isotope (13C NMR spectrum) in deuterated DMSO.

Claims (1)

3-isobutenyl-1,2-dihydroxybenzene, or a mixture of 3-isobutenyl-1,2-dihydroxybenzene and 3-metalyl-1,2-dihydroxybenzene at least 10% by weight Compound selected from the group consisting of 60 at cyclization / isomerization temperature in the presence of 0.001 to 5% by weight of the euphonic acid

To 2,3-dihydro-2,2-dimethyl-7-hydroxybenzofuran.