FR2511672A1 - FLUORO-4-TRIHYDROXY-2 ', 3', 4 'BENZOPHENONE DERIVATIVES, PROCESS FOR PREPARING THEM AND THEIR APPLICATION - Google Patents

Abstract

THE PRESENT INVENTION CONCERNS 4-FLUOROBENZOPHENONES RESPONDING TO THE FORMULA: (CF DRAWING IN BOPI) IN WHICH R REPRESENTS A HYDROGEN ATOM OR A RADICAL ALKYL CONTAINING FROM 3 TO 12 ATOMS OF CARBON. THE INVENTION ALSO CONCERNS METHODS OF PREPARING THE COMPOUNDS OF FORMULA AND THEIR APPLICATION AS ULTRA-VIOLET RAY ABSORBERS.

Description

The present invention relates to 4-fluoro benzopheno-

  methods for their preparation and their application

  ultraviolet ray absorbers or intermediate bodies. It is known that the benzophenone derivatives corresponding to the formula ## STR2 ## in which R represents a methoxy or hydroxyl radical and X represents a fluorine atom, a fluoralkyl radical or a phenyl fluoro radical each containing from 1 to 9 carbon atoms. These benzophenone derivatives are prepared by reaction of dimethyl ether of resorcinol with a fluorinated-substituted benzoyl chloride in the presence of a catalyst (see US Pat. No. 3,387,035). acylation, especially aluminum chloride, and a diluent, such as n-hexane or carbon disulfide. As the 4-fluoro-benzophenone carrying a hydroxy group, the cited document mentions 4-fluoro-hydroxyethyl 2'-methoxy-4'-benzophenone

melting at 88-89 C.

  The invention provides a means for preparing other 4-fluoro-benzophenones having at least one hydroxy group which can be synthetically prepared in a simple manner and which can be used as ultraviolet ray absorbers.

  as well as an intermediate body for the synthesis of

  active classes of different types.

  The subject of the invention is 4-fluoro benzophenones corresponding to formula (1)

FQ CO OOR,

  HO O in which R represents a hydrogen atom or a radical

  alkyl containing from 3 to 12 carbon atoms.

  It also relates to 4-fluoro benzophenones corresponding to the formula (2>

P-Q <<-COA 2)

  in which R 'represents an alkyl radical containing

1 to 6 carbon atoms.

  The invention furthermore relates to a method for preparing

  4-fluorobenzophenones, characterized in that resorcinol is acylated so as to convert it to a compound of formula (3)

CO C OH

id

  and the reaction product is optionally alkylated to obtain

  a compound of formula (1)

C OR,

  HO in which R represents an alkyl radical containing from 3

at 12 carbon atoms.

  The invention also relates to a process for the preparation of 4-fluoro-benzophenones, a process according to which the resorcinol is acylated so as to convert it to a compound of formula (3)

F CO OH

HO

  then the reaction product is alkylated to obtain a

in the formula (4)

F OR CO OR C,

  <4) HO in which R 'represents an alkyl radical containing from 1 to 6 carbon atoms, and the ether obtained is sulfonated in order to obtain a compound corresponding to formula (2)

XSO 3 H

CO Q O R '(2)

  HO in which R 'represents an alkyl radical containing from 1 to

carbon atoms.

  The invention furthermore relates to non-4-fluoro-benzophenes corresponding to formula (5)

F_ CO OR (5)

1 HO 011

  in which R represents a hydrogen atom or an alkyl radical containing from 3 to 12 carbon atoms These 4-fluoro-benzophenones of formula (5) are prepared by acylating pyrogallol, that is to say trihydroxy-1, 2,3 benzene, to convert it to a compound of formula (6)

P.CO _WOH (6)

  Q co -Q (6) 3 D and optionally alkylating the reaction product to obtain a compound of formula (5) (5)

F CO Q R,

HO OH

  in which R represents an alkyl radical containing from 3 to

12 carbon atoms.

  The compounds according to the invention are in particular

link:

  among the compounds of formula (1), fluoro-4-dihydroxy-

  2 ', 4' benzophenone and the following monoethers thereof:

  4-fluoro-2-hydroxy-4-propoxybenzophenone, 4-fluoro-hydroxy

  2 'butoxy-4' benzophenone, fluoro-4-hydroxy-2 'hexyloxy-4'

  benzophenone and fluoro-4-hydroxy-2'-octyloxy-4'-benzophenone.

/

  among the compounds of formula (2), fluoro-4-hydroxy-

  4-methoxy-4-benzophenone-sulfonic acid, 4-fluoro-2-hydroxy-4-ethoxy-4-benzophenone-sulfonic acid, 4-fluoro-2-hydroxy-4-propoxybenzophenone sulfonic acid. And homologous alkoxy benzophenones, and

  among the compounds of formula (5), 4-fluoro trihydroxy-

  2 ', 3', 4 'benzophenone and homologous 4-alkoxybenzophenones.

  The acylation of resorcinol or pyrogallol is preferably carried out in the presence of a Friedel-Crafts catalyst in an inert organic solvent at a temperature of 40 to 80 ° C.

preferably from 50 to 70 C.

  As catalyst for the acvlation will be used more particularly aluminum chloride as well as zinc chloride, ferric chloride and boron trifluoride The catalyst is involved in an amount of 0.8 to

  1.2 mole per mole of resorcinol or pyrogallol The acylating agent

  lation may be a 4-fluoro benzoyl halide, such as

  4-fluoro-benzoyl bromide or, better still, fluorochemical chloride

  Benzoyl, or more particularly 1-trichloromethyl-4-fluoro benzene can be reacted in a known manner in

  a lower alkanol, more particularly methanol or

  thanol, adding or not adding water, in the absence of a catalyst.

  As the inert organic solvent, nitro-

  benzene or a haloalkane containing from 1 to 3 carbon atoms

  preferably, a chloralkane, for example 1,2-dichloroethane or 1,1,1-trichloroethane. The reaction may also be effected in hydrofluoric acid, which also serves

catalyst and solvent time.

  Fluoro-4-dihydroxy-2 ', 4' benzophenone or fluoro-4

  trihydroxy-2 ', 3', 4 'benzophenone which has been obtained by acylation

  Friedel and Crafts is optionally mono-etherified, by alkylation with a halo-1 alkane containing either from 3 to 12 carbon atoms, preferably from 3 to 8, in which case a mono-ether of formula (1) is obtained or of formula (5), ie from 1 to 6 carbon atoms, preferably from 1 to 4, in which case a mono-ether of formula (4) is obtained. This alkylation is effected at a temperature of 20 to 1600 ° C. preferably from 60 to C, in the presence of a base, in an inert organic solvent As a base there will be used more particularly an alkali metal carbonate or an alkali metal hydrogencarbonate, for example sodium carbonate or sodium hydrogencarbonate The base is used in an amount of 20 to 35% by weight (based on 4-fluoro-2,4-dihydroxybenzophenone or

  4-fluoro-trihydroxy-2 ', 3', 4 'benzophenone) as an organic solvent.

  Inert material will be used here a ketone, such as the cyclone

  hexanone, or an aromatic hydrocarbon preferably containing from 6 to 8 carbon atoms, for example toluene or xylene. The etherification is optionally also carried out with a dialkyl sulphate, for example with dimethyl sulphate.

or diethyl sulfate.

  The mono-ether of formula (4) provided by the alkylation is optionally converted by sulphonation into a compound of formula (2), by reaction with a halosulphonic acid E at a temperature of 20 to 80 ° C., preferably from 40 to 80 ° C. 60 C, in an inert organic solvent The halosulfonic acid is preferably chlorosulfonic acid The inert organic solvent is one of those that can be used for acylatior

from Friedel and Crafts.

  The 4-fluoro-benzophenones according to the invention are obtained with a yield of at least 70%. They are indicated by a high purity, which is at least 99% (high performance liquid phase chromatograph). They are suitable as ultraviolet ray absorbers, more particularly in plastics or in cosmetic compositions,

  as well as as a starting point for the preparation of

  plant protection products or plastics.

  The following examples illustrate the present invention.

  In these examples the percentages relating to quantities of

matter are by weight.

Example 1

  a) 110 g (1 mole) of resorcinol are dissolved in 650 ml of dichloromethane

  To the solution obtained, 133 g are added little by little.

  (1 mole) of aluminum chloride, while maintaining the temperature

  The mixture is stirred at 500.degree. C. and the suspension is added dropwise over 1 hour, while stirring and maintaining the temperature of 500.degree. C., 159 g (1 mole) of chloride.

  4-fluorobenzoyl, and the mixture is then maintained for

  30 minutes at 50 ° C. After that, the reaction mixture is poured

  a mixture of ice and water and extract the

  solid product obtained by hot 1,2-dichloroethane After

  after eliminating the extraction agent, 208 g (90%

  the theoretical amount) of 4-fluoro-2'-dihydroxybenzophenol

  none by recrystallization from aqueous methanol to

  % a product having a melting point of 171-

  1720 C and a purity higher than 99%.

  b) 700 g of a 10% solution of potassium hydroxide are added

  (1.25 moles of KOH) to 232 g (1 mole) of the 4-fluoro dihydroxy-

  2 ', 4' purified benzophenone obtained according to (a), and 62 g (1 mole) of dimethyl sulfate are added dropwise to the mixture at 350 ° C. while stirring.

  reflux for another 30 minutes after cooling.

  at room temperature the organic phase is separated

  and extracted with toluene From the extract

  after removal of the extractant, 194 g (79% of the theoretical amount) of 4-fluoro-2-hydroxy-4-methoxybenzophenone, mp 86-88 o C.

Example 2

  1,2-Fluoro-2-hydroxy-4-methoxybenzophenone obtained in Example 1b) is dissolved in 300 ml of 1,2-dichloroethane and the solution thus obtained is dissolved in 300 ml of 1,2-dichloroethane. C., 11.8 g (0.21 mol) of chlorosulphonic acid are added in the course of 10 minutes at 70 ° C. while stirring. The precipitate which is formed after cooling the mixture at 10 ° C. is filtered off with suction. the

  washed with cold 1,2-dichloroethane and dried.

  holds 55 g (84% of the theoretical amount) of 4-fluoro-2-hydroxy-4'-methoxybenzophenone-5-sulfonic acid which has an acid content of greater than 98% and which decomposes from 180 C

Example 3

  92.8 g (0.4 mole) of the 4-fluoro-2,4-dihydroxybenzophenone obtained according to Example 1a) are heated at 150 ° C. for 5 hours with 77.2 g (0.4 mole). The solids are then filtered off and the filtrate is evaporated to dryness. The waxy residue obtained from this filtra is recrystallized from methanol gives 100 g (72% of the

  theoretical amount) of 4-fluoro-2-hydroxy-4-octyloxy benzophenol

  none melting at 48-49 C and having a purity of 99%.

Example 4

  63 g (0.5 mol) of pyrogallol are dissolved in 300 ml of ethanol. The solution obtained is heated to 65 ° C. and 214 g (2 mol) are added dropwise over 30 minutes while stirring. The reaction mixture is then poured into 1.5 liters of water and the solid product obtained is separated by filtration. After drying for 8 hours at 100 g, 100 g (80.6 g) are obtained. % of the theoretical amount) of crude 4-fluoro-trihydroxy-2 ', 3', 4 'benzophenone By recrystallization from 80% aqueous ethanol, a product is obtained.

  at 149-150 ° C. and having a purity greater than 99%.

Claims (5)

  1. Fluoro-4 benzophenones corresponding to formula (5) F CO R, (5)   In which R represents a hydrogen atom or a radical   alkyl containing from 3 to 12 carbon atoms.   2. Fluoro-4 benzophenones according to the claim   dication 1, chosen from 1-fluoro-4-trihydroxy-2 ', 3', 4 '   benzophenone and homologous 4-alkoxybenzophenones.   3 Process for preparing a fluoro-4   benzophenone, characterized in that the acylated pyro-   gallol to convert it to a compound of formula (6) r Q -CO OQ (6) IHO   and the reaction product is optionally alkylated to give a compound of the formula (5) wherein R represents an alkyl radical containing from 3 to 12 carbon atoms.   4. Application of a compound according to the   1 or 2, as ultraviolet absorbers.   5. Application of a compound according to the   1 or 2, as starting material for the preparation of a medicament, a phytosanitary product or a plastic material.