DE2003548A1 - Process for stabilizing furan derivatives - Google Patents

Description

"Method of Stabilizing Steander Derivatives."

Priorityί 28 _O January''1969V Japans Hr »6459/69

The invention relates to a method for stabilizing the 5-Benzyl-3-furylethyl ester of cyclopropanecarboxylic acids, which

Ester the General Foriael I

CH ₂ - O ^ C - CH -

(D

CH * CH

have »in the RC means a hydrogen atom or a methyl group, and R ₂ ^{in the} case when R ^ is a hydrogen atom, an isobutenyl group, and when R ^ is a methyl group, is also a methyl group, an absorption method being used, , /:

The compound of general formula I which has What as R ^ a ser st off atom and when the radical R ₂ is an isobutenyl group, vur-

009832/1973

de for the first time by M * Elliott et al. manufactured". This Yerbindiuö ^ has a strong insecticidal effect and is therefore a valuable insecticide that is non-toxic to warm-blooded animals (see M. Elliott, AW Farnham et al., Nature, Volume 215 (1967), page 493) - The connection of the general formula I, which has R and H ₂ methyl groups as radicals, is described in French patent specification 1,541,065a _o This compound is also outstandingly suitable as an insecticide.

The compounds of the general formula I can easily be processed by f4an reaction of 5 ~ benzyl-3-furylmethanol with a, * cyclopropane

carboxylic acid of the general formula II

HOOC - CH -ßf

^R 2

CH ₅ CH-

in which R ₁ and R _{9 have} the aforementioned © ] << - Jsutung, "or their re

Condensation »- active derivative obtained by known methods · Man

can « ₉ Β. the connection of the forms! A.

/ 3

OH, - 0 -O - OH - OH.CH - C. (A)

π if-OH, - 0 -O - OH - OH

JTT 0 V

^c CH ₅ \ lH

CH _{5 3}

prepare by adding 5-Benzy1-3-furylmethanol in the presence a base with chrysanthemic acid chloride to implement.

The compounds of the general formula X are relatively stable in the pure state, form white crystals and their coloration and other properties do not change on storage at room temperature even after several weeks compounds of the general

009832/1973

my formula I are, however, light yellow crystalline _t - solid substances check discolor quickly and dark brown after about one week of storage at room temperature »caused thereby Kachteile are a reduced sales value as an insecticide, and a quality degradation by a particularly by contact with a _o B _o iron, copper or commercially available ₉ ■ by treatment with certain plastics flüssigkeitsizndurchlässig gemachtenjgr & phitischen materials induced transition into a state is caused gumuiiartigen _ö

Until now there is no procedure for. Stabilization of compounds de.r general formula I known one. in the book "Heterocyclic Compounds", Volume 1, (1950), page 199 by Elder Field

"Method for stabilizing furan-2-carboxylic acid, in which Urea is used, does not satisfy when it is on the

Connections of. general formula I is transferred,

The object of the invention is to provide a new method of stabilization of compounds of general formula 1 are available which cause discoloration and deterioration in quality over time these connections is prevented.

The invention thus relates to a process for stabilizing furan derivatives of the general formula I

CH ₉ - * ■ 0 - C - CH -

- CH - ßC 0 V

GH,

which represents R, a hydrogen atom or a methyl group

009832/19: 73

P ^v ■ - 4- 20035A8

■ and Ε «in the case when R ^ is a hydrogen atom, a

is leobutenyl, and when H- is methyl, also is a methyl group, which process is characterized in that the compound of general formula 1 treated with silica gel or a mixture of silica gel and activated alumina as an adsorbent

The method of the invention comprises the following embodiments

1) The reaction mixture is after the above-described reaction of 5-benzyl-3-furylmethanol with the Cyolopropan-

^w carboxylic acid is dehydrated, mixed with the adsorbent and stirred at a temperature which is below the decomposition temperature of the compound of general formula I.

2) The present as a commercial product compound of general formula 1 is in a solvent with relatively low polarity, such as benzene, toluene, η-hexane, n-pentane, carbon tetrachloride or acetone dissolved, the adsorbent is added to the solution and that mixture is at a temperature below the decomposition temperature the compound of the general formula I is stirred. 5) Pie as a commercial compound of the general Formula I is melted and the adsorbent is added and the mixture is at a temperature which is between

* the peeling point and the decomposition temperature of the compound of the general formula I is stirred.

All three of the aforementioned forms of execution of the JSr-

& · ^Λ »'·» ■ ■ ■■ ■

The finding can easily be carried out on a technical scale

". '. ·" · .; 0 09832/1 Ö 7 3

ORIGINAL INSPECTED

and are very practical

For the proportions of silica gel and activated alumina, to be employed in the method of the invention, there are no special limits _o However, it is sufficient to use the necessary for the adsorption of the impurities of play.

In general, silica gel proportions of at least 1 wt "-? Ä, preferably from about 10 Gewo- ^ j, based on the connects" dung of the general formula I, a _a The mixture of activated alumina and silica gel is preferably in a Share of at least 1 & ewo »$ _f based on the compound of the general formula I ₉ used»

Particularly preferred are proportions of the mixture of silica gel and activated aluminum oxide of about 30% by weight, based on the compound of the general formula I _p where the weight ratio of the silica gel to the activated aluminum oxide is about 1 ϊ 2

The process of the invention can also apply to the optical isomers and stereoisomers of the compounds of the general formula I be applied,

The examples illustrate the invention.

-Example 1

191 g of the solution of the compound of the general formula 1 (R ^ ■ hydrogen atom, K ₂ «isobutenyl group), which was obtained by condensation of 26» 4 g of S-benzyl-S-fury! Methanol and 28.0 g of OhryeanthejaBäureoh] .orid , in foluene are dehydrated and

ΐ 009832/1973

Afterwards with 5.3 g of silica gel and 10.5 g of activated aluminum

The solution obtained is stirred at 20 ° C. for 30 minutes, then filtered under reduced pressure to remove the silica gel and activated aluminum oxide and then freed from the solvent to isolate the desired, purified compound of the general formula I (47.0 g).

at

• In a corresponding comparative experiment, treatment with silica gel and activated aluminum oxide was dispensed with. 4? _f 5 g of the aforementioned compound of the general formula I obtained o

The table below shows the results of an experiment in which the time-related change in color of the compounds of general formula I treated according to the invention or ο the untreated compounds were determined. For this experiment, both compounds were stored in the air at 25 to 30 C in an iron vessel «

!Tabel

with silica gel and activated aluminum oxide treated connection

untreated connection

Trial start

way

light yellow

after 10 days

White

Brown

after 50 days

White

black-brown rubbery

Example 2

98 g of the crude compound from Example 1 are dissolved in 280 ml of toluene dissolved, the solution is mixed with U g of silica gel and stirred thoroughly, and then the silica gel is reduced under reduced pressure

009832/1973

filtered off-ο after the removal of the solvent, 97 g of the purified compound (general formula- I; H ₁ «V / oxygen atom, Ep *» isobutenyl group) «are obtained

The purified compound © seigt even after a 30-day storage at ieraperaturen from 25 to 3O ° C according to Example 1, no discoloration and deterioration ₀

Example 3

98 g of the crude compound iron Example 1 are ^{brought to melt by heating to Go 0} C, 22 g of activated aluminum oxide and 11 g of silica gel are added and the mixture is stirred for 3 hours at 60 G. The silica gel and the activated aluminum oxide are then filtered off under reduced pressure " This gives 97 g of the purified compound _e the purified compound ze.% t at a of example 1 carried out storage test no time-related. Discoloration or deterioration in quality.

The compounds der'allgemeinen formula I "the radicals E and Ε" methyl groups aufweisenj show in a study carried out in accordance with the above examples according to the invention treatment the same properties as the compounds used therein ¹ (Bj ₁ * hydrogen atom, Rg * Isobuteny! Group). They therefore also show no discoloration or impairment of integrity when the temperature is in excess of temperature *

00993 2/197

Claims (1)

P ₁ a ten ta η s ρ r U che Process for stabilizing furan derivatives of the general formula I. CH ₂ - O - C - CH - ^ (I) 0 in which R- ^ denotes a hydrogen atom or a methyl group and Rp in that S ¹ SiIe, when R- is an hydrogen atom, is an isobutenyl group, and when Ily is a methyl group, is also a methyl group, are identified by this I hn et that the compound of the general formula I is treated with silica gel or a mixture of silica gel and activated aluminum oxide as adsorbent. 2, method according to claim 1, characterized in, that the compound of general formula I is treated with the adsorbent at a temperature which between the melting point and the decomposition temperature of the compound lies. 3. The method according to claim 1, characterized in that that one is in the form of a solution in benzene, toluene, η-hexane, n-pentane, carbon tetrachloride or acetone present compound of general formula I at a temperature the! within the decomposition temperature of the compound is treated with the adsorbent SAD 009832/1973 ^BA 4 »The method of claim 'I ₉ characterized ge --- characterizing ζ η calibration, et ,, reacting a reaction mixture obtained by condensation! on of 5-benzyl ~ 3-fury! methanol- with a cy elopr opancar- * acid of the general formula II flöOC - OH - G ^ in which R and Hg have the meaning given in claim 1, or their reactive derivative was obtained and that ^{1 contains} a compound of the general formula I, dehydrated and then at a temperature below the decomposition temperature of the compound of the general formula I is treated with the adsorbent ₀ 5ο method according to claim 1 to 4? characterized g β k eη η ζ η et verifiable, that a silica content of at least 1 Gewc- ^, preferably from about 10 percent, o "$ _e based on the compound of the general formula I, einsetzfo 6 «Method according to claim 1 Ms 4 _S dadmrchge - = ke η η ze ic h η et ₉ that a proportion of the mixture of egg gel and activated aluminum oxide of at least 1 wt, - ^ preferably of about 30 ßev / o- = · ' / ^ based on the compound of the general formula I _{0 ß} and that there is a weight ratio of the liquid gel to the. activated aluminum oxide about '1 s .2 applied "-' y gj ö α Ä / I S) ί «3 7. The method according to claim 1 to 6, characterized in that » that the connection of general Formula I is Chrysa3HhemsHure ~ 5-bensiyl ~ 3 - furylinetnyl ester, 8. The method according to claims 1 to 6, characterized in that that the compound of the general formula 1 2,2,5 »5-ietraiie thylcyclopropaucarbonsäure ~ 5 - benayl-3-furylmetnylester is- 9. Uses of the according to your method according to claim 1 to 8 stabilized compounds of the all ^ emeir ι formula I ale Insecticides odex in insectic »ies» C '■■■ ■ -; 3 2/7 3