Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C315/00—Preparation of sulfones; Preparation of sulfoxides
  • C07C315/04—Preparation of sulfones; Preparation of sulfoxides by reactions not involving the formation of sulfone or sulfoxide groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B39/00—Halogenation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
  • C07C201/06—Preparation of nitro compounds
  • C07C201/12—Preparation of nitro compounds by reactions not involving the formation of nitro groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C231/00—Preparation of carboxylic acid amides
  • C07C231/12—Preparation of carboxylic acid amides by reactions not involving the formation of carboxamide groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C253/00—Preparation of carboxylic acid nitriles
  • C07C253/30—Preparation of carboxylic acid nitriles by reactions not involving the formation of cyano groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
  • C07C67/307—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by introduction of halogen; by substitution of halogen atoms by other halogen atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic Table
  • C07F9/02—Phosphorus compounds
  • C07F9/28—Phosphorus compounds with one or more P—C bonds
  • C07F9/38—Phosphonic acids [RP(=O)(OH)2]; Thiophosphonic acids ; [RP(=X1)(X2H)2(X1, X2 are each independently O, S or Se)]
  • C07F9/40—Esters thereof
  • C07F9/4003—Esters thereof the acid moiety containing a substituent or a structure which is considered as characteristic
  • C07F9/4006—Esters of acyclic acids which can have further substituents on alkyl

Definitions

• This invention relates to the fiuorination of organic compounds, in particular, to the fluorination of carbonyl compounds especially those having a carbonyl, nitro, nitrile sulphonyl or phosphoryl group in the 3 -position to the carbonyl group, notably 1,3- dicarbonyl compounds (also known as ⁇ -dicarbonyl compounds).
• Fluorinated carbonyl compounds for example fiuorinated 1,3-dicarbonyl compounds, are very valuable intermediates in the synthesis of other fluorine- containing compounds.
• International Patent Application No PCT/GB94/02547 describes how treating solutions of 1,3-dicarbonyl compounds in various solvents with elemental fluorine gives the corresponding 2-fluoro-1.3-dicarbonyl compounds.
• the fluorination of certain 1,3-dicarbonyl compounds proceeds at an undesirably low rate.
• we have now found that the fluorination not only of 1,3-dicarbonyl compounds but also of other carbonyl compounds is catalysed by compounds of transition metals.
• the present invention provides a method of substituting a carbonyl compound with fluorine at the ⁇ -position, comprising reacting the carbonyl compound with a fluorinating agent in the presence of a metal-containing catalyst.
• the reaction results in replacement of a hydrogen atom by fluorine.
• the catalyst which is used in a catalytically effective amount, is preferably a transition metal.
• the catalyst is a transition metal compound.
• the catalyst is an elemental metal, in which case the carbonyl compound has an activating group attached to the carbon atom which is substituted by fluorine.
• the invention also provides a method of fluorinating a 1 ,3-dicarbonyl compound comprising reacting the 1,3-dicarbonyl compound with a fluorinating agent in the presence of a compound of a transition metal.
• the reaction results in replacement of a hydrogen atom by fluorine.
• a further aspect resides in a process for the fluorination of a ⁇ -dicarbonyl compound by means of a fluorinating agent, the process being carried out in the presence of a metal-containing catalyst, the metal preferably being a transition metal.
• the transition metal compound is preferably a salt.
• the transition metal is usually a first row transition metal.
• Exemplary transition metals are those of Groups Vila, VIII, lb and lib. More specific examples of compounds which may be used as catalysts in a method of the present invention are salts and other compounds of copper, iron, cobalt, nickel, manganese or zinc.
• the identity of the anion of the salt is not critical; suitably it is nitrate, sulphate or acetate, of which nitrate is particularly convenient. A mixture of compounds of two or more metals may be used.
• any amount of catalyst may be added to the fluorination reaction but the amount is suitably up to 25 gram atoms of transition metal ion, and preferably 0.2 to 2.5 gram atoms, to 100 moles of substrate. More preferably, the amount of catalyst added is in the range 0.5 to 10 gram atoms of transition metal ion to 100 moles of substrate.
• a preferred fluorinating agent is elemental fluorine.
• the carbonyl group serves to activate the ⁇ -hydrogen which is replaced.
• the method works well with, inter alia, compounds in which the carbonyl group is ketonic but this feature is far from critical (for example, esteric carbonyl groups are also very suitable).
• the compounds which are fluorinated preferably have another activating group attached to the carbon atom which is substituted by fluorine, for example another CO group or (R ⁇ )2PO, SO2 or CN; R.I is in principle any organic group compatible with the reaction, e.g. alkyl, cycloalkyl or aryl. 1,3-Dicarbonyl compounds are a very preferred class of carbonyl compounds. More particularly, the starting compounds are preferably of the formula (A): RCO.CHR ⁇ R 2 , where:
• R is selected from the group consisting of alkyl, oxyalkyl (i.e. -O-alkyl), cycloalkyl, oxycycloalkyl, aryl and oxyaryl;
• R 1 is selected from the group consisting of CO.R 3 , CO.OR 3 , NO2, CN,
• R 2 is selected from the group consisting of H. F, Cl, NO 2 , CN, alkyl, oxyalkyl, cycloalkyl, oxycycloalkyl, aryl and oxyaryl;
• R and R 1 are joined together to form a cycloalkyl structure, or R 1 and R 2 are joined together to form a cycloalkyl or aryl structure, or R and R 1 as well as R 1 and R 2 are so joined, the two ring structures being fused,
• the fluorination reaction is the fluorination of compounds having the general formula (B): RCO.CHR'CO.R” into compounds having the general formula RCO.CFR'CO.R".
• the group R may be alkyl, substituted alkyl, cycloalkyl, aryl, or substituted aryl
• R' may be hydrogen, chlorine, nitro, cyano, alkyl, substituted alkyl, cycloalkyl, aryl, or substituted aryl
• R" may be alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, OR, NR 2 .
• the groups R and R' may be joined together to form a cyclic structure. Where in the starting material for the fluorination reaction R' is H, the product of the reaction may have the formula RCO.CF 2 CO.R".
• suitable substituents include R and R 2 groups or, as the case may be, R and R' groups; for example, alkyl may be substituted chlorine or fluorine), alkoxy and aryloxy. as well as other groups which are relatively inert to fluorine. Any of the aforegoing substituents may be substituted in turn by one or more other suitable substituents, to form groups such as. for example, haloalkoxy or alkoxyaryl.
• any of the groups R, R 1 and R 2 of formula (A), R, R and R" of formula (B) and R ! is not critical, since they play no part in the reaction.
• the organic moieties may contain up to 10 carbon atoms, e.g. 1 to 4 carbon atoms.
• Cyclohexyl and cyclopentyl may be mentioned as a suitable cycloalkyl groups, and phenyl and naphthyl as suitable aryl groups, amongst others.
• the catalyst is in the form of an elemental metal.
• a particular example of such a catalyst is metallic copper which may be used in the form of, for instance, a powder.
• the carbonyl compound has an activating group in the ⁇ -position to the carbonyl group, like the preferred carbonyl reactants used with the transition metal compound catalysts. Indeed, the preferred compounds described with reference to the transition metal compounds are preferred also for the metal catalysts.
• the compound is a ⁇ -dicarbonyl compound.
• the ⁇ -dicarbonyl compound is a haloacetoacetate. more preferably a chloroacetoacetate.
• the catalyst is used in a small amount. Particularly in the case of metallic copper, a preferred amount is up to 50 mg (8 x 10 grams atom) per 100ml of reactant solution, more preferably 10 to 30 mg (1.6 x 10 to 4.7 x 10 grams atom) 100ml solution and most preferably about 20 mg (3.15 grams atom) per 100ml.
• the metal is used in an amount of up to 0.04 gram atoms, and desirably up to 0.02 gram atoms, per mole of ⁇ -dicarbonyl compound, more preferably 0.004 to 0.012, especially about 0.008 gram atoms per mole of compound. It is possible that the catalyst operates to speed up the enolisation of the compound carbonyl.
• the reactions of the invention are conducted in the presence of a solvent.
• a solvent include formic acid, acetic acid and acetonitrile, the latter being preferably used with a little water to give solubility to the salts.
• fluorine is used as the fluorinating agent, it is preferably diluted with an inert gas such as nitrogen.
• an inert gas such as nitrogen.
• the fluorine is diluted to 1-50% v/v and. preferably in the range 5-20% v/v.
• the temperature of the reaction is preferably 0-10 °C.
• the substrate may be used in a wide concentration range, preferably up to 400 grams/ litre of solvent.
• a reaction without any added salts was carried out.
• a glass reaction vessel fitted with a PTFE coated mechanical stirrer, a FEP (fluorinated ethylene-propylene) thermocouple well and FEP gas delivery tube was charged with ethyl-2-chloroacetoacetate (3.29 gm., 20 mmol.) and formic acid (50 ml) before being cooled to 5-8 °C.
• the vessel was purged with nitrogen and then fluorine (32mmol) diluted to 10% v/v with nitrogen was passed through the stirred solution over a period of two hours. At the end of this treatment, the fluorine supply was turned off and the reaction vessel was purged with nitrogen.
• reaction mixture was then poured into water and extracted with dichloromethane.
• the extracts were dried, evaporated and the colourless residue was analysed by glc which showed that 16% of the ethyl chloroacetoacetate had been converted into ethyl-2- chloro-2-fluoroacetoacetate.
• a glass reaction vessel fitted with a PTFE coated mechanical stirrer, an FEP thermocouple well and FEP gas delivery tube was charged with diethyl malonate (3.2 gm., 20 mmol.), cupric nitrate 3H 2 O (0.48gm., 2.0 mmol.) and acetonitrile (50 ml.) before being cooled to 5-8 °C.
• the vessel was purged with nitrogen and then fluorine diluted to 10% v/v with nitrogen was passed through the stirred solution at a rate of 16 mmol / hour for 4 hours.
• the fluorine supply was turned off and the reaction vessel was purged with nitrogen.
• the reaction mixture was then poured into water and extracted with dichloromethane.
• Example 2 was repeated using less copper nitrate and a shorter exposure to fluorine.
• 3.2 gm. (20mmol.) diethylmalonate and 0.096gm. (0.4mmol.) copper (II) nitrate 3H 2 0 in 50 ml acetonitrile were treated with 32 mmol. fluorine, diluted to 10% v/v with nitrogen, over 2 hours to give diethylfluoromalonate in high yield. Conversion. 88%.
• Example 6 was repeated using O.l l ⁇ gm. (0.4mmol.) nickel nitrate 6H 2 0 instead of copper nitrate. Conversion 70%.
• Example 6 was repeated using ethyl acetoacetate instead of diethyl malonate. 45% of the ethyl acetoacetate reacted to give ethyl-2-fluoroacetoacetate in high yield (80%).
• Example 8 When Example 8 was repeated in the absence of a compound of a transition metal, the conversion was 23%.
• Example 10 Example 6 was repeated using N,N-diethylamino acetoacetamide instead of diethyl malonate. After this treatment, 59% of the N,N-diethylamino acetoacetamide reacted to give N,N-diethylamino-2-fluoroacetoacetamide ⁇ (Found: C, 54.3; H, 8.1 ; N, 7.8.
• Example 10 When Example 10 was repeated in the absence of a compound of a transition metal, the conversion was 46%.
• Example 2 was repeated using ethyl cyanoacetate instead of diethyl malonate. After this treatment, 46% of the starting material was converted and the yield of ethyl cyanofluoroacetate ⁇ (HRMS (NH3/CI*), Found: 149.0730; C 5 H ⁇ 0 FN 2 O 2
• Example 13 When Example 12 was repeated in the absence of a compound of a transition metal, the conversion was ca. 12%.
• Example 2 was repeated using ethyl nitroacetate instead of diethyl malonate. After this treatment, 54% of the starting material was converted and the yield of ethyl nitrofluoroacetate ⁇ (HRMS (CH 4 /CI), Found: 152.0312; C 4 H 7 FNO 4 (M+l)+ requires 152.0391); ⁇ H 1.38 (t, J H ,H 7.1.
• Example 14 When Example 14 was repeated in the absence of a salt of a transition metal, the conversion was ca. 12%.
• Example 2 was repeated using 4,4-dimethyl-3-oxo-2-pentane nitrile instead of diethyl malonate. After this treatment, 70% of the starting material had reacted and the yield of 4,4-dimethyl-3-oxo-2-fluoropentane nitrile ⁇ (HRMS (NH3/CI), Found:
• Example 16 When Example 16 was repeated in the absence of a salt of a transition metal, the conversion was ca. 15%.
• Example 2 was repeated using dimethyl-2-oxypropyl phosphonate instead of diethyl malonate. After this treatment, 95% of the starting material was converted and the yield of dimethyl- 1 -fluoro-2-oxypropyl phosphonate (purified by column chromatography; SiO 2 /ethyl acetate) ⁇ (HRMS, Found: (M+NH 4 ) + 202.0644 C 5 H ⁇ 4 FNO 4 P requires 202.06445); ⁇ H 2.39 (3H, d, 4 J H ,F 4.5, CO.CH 3 ), 3.9 (6 ⁇ , d, d, J H ,p 10.8, J 2.9, CH 3 OP), 5.25 (1 ⁇ , d,d, 2 J ⁇ ,F 47.7, 2 J ⁇ ,p 14.4, CHF); ⁇ F -208 (d,d,q, 2 J F ,P 71.3, 2 J ⁇ , F 47.8, 4 J ⁇ ,F 4.5); ⁇ P 12.7 (d
• Example 18 When Example 18 was repeated in the absence of a salt of a transition metal, the conversion was ca. 5%.
• Example 20 Example 2 was repeated using methanesulphonylpropan-2-one instead of diethyl malonate. After this treatment. 95% of the starting material was converted and the yield of l-fluoro-l-methanesuphonylpropan-2-one (purified by column chromatography; SiO 2 /dichloromethane) ⁇ (Found: C, 31.0; H, 4.4.
• Example 20 When Example 20 was repeated in the absence of a salt of a transition metal, the conversion was ca. 14%.
• Example 22 To a solution of 5.0g ethyl chloroacetoacetate in 100ml formic acid was added 20mg of copper powder. This was stirred at 3 ° C while a gaseous mixture of nitrogen (60ml/min) and fluorine (6.7ml/min) was passed through for 6 hours. The reaction mixture was periodically analysed by GC by taking out an aliquot, drowning into water and extracting with dichloromethane. The results are shown in Table 1 and in Figure 1 of the accompanying drawings.
• Example 22 The same procedure was used as in Example 22, except that 20mg of copper powder were added to the reaction solution after it had proceeded for 4.5 hours.
• the results in this case are given in Table 2 and in Figure 2 of the accompanying drawings.
• Example 22 The same procedure was used as in Example 22, except that lg of copper powder was added at the beginning of the reaction and a further lg after 5.25 hours.
• the results are given in Table 3 and in Figure 3 of the accompanying drawings.
• Example 22 The same procedure was used as in Example 22, except that 30mg of potassium fluoride were added at the beginning of the reaction and 20mg of copper powder were added after 5.5 hours.
• the results are given in Table 5 and in Figure 5 of the accompanying drawings.
• Example 26 investigates the possibility that the reaction is being catalysed by base, for instance fluoride ion from copper fluoride. Traces (30mg) of potassium fluoride were added at the beginning of the reaction. There was no reaction rate increase but rather a slowing down. Addition of 20mg of copper powder after 5.5 hours resulted in an increase in the reaction rate.
• base for instance fluoride ion from copper fluoride.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Molecular Biology (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Catalysts (AREA)

Priority Applications (6)

Applications Claiming Priority (6)

Publications (1)

Family

ID=27268933

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (1)

Citations (4)

• 1998
  • 1998-07-16 WO PCT/GB1998/001905 patent/WO1999003802A1/en not_active Ceased
  • 1998-07-16 EP EP98933760A patent/EP0996606B1/en not_active Expired - Lifetime
  • 1998-07-16 AT AT98933760T patent/ATE212008T1/de not_active IP Right Cessation
  • 1998-07-16 AU AU83466/98A patent/AU8346698A/en not_active Abandoned
  • 1998-07-16 JP JP2000503036A patent/JP2001510173A/ja not_active Withdrawn
  • 1998-07-16 DE DE69803186T patent/DE69803186T2/de not_active Expired - Fee Related
  • 1998-07-16 US US09/463,030 patent/US6300511B1/en not_active Expired - Fee Related

Patent Citations (4)

Also Published As

Similar Documents

Legal Events