IL44599A

IL44599A - Tetrasubstituted alpha-halocyclobutanone derivatives and their preparation

Info

Publication number: IL44599A
Application number: IL44599A
Authority: IL
Original assignee: Shell Bv
Priority date: 1973-04-16
Filing date: 1974-04-10
Publication date: 1977-02-28
Also published as: BR7402924D0; SU554809A3; IL44599A0; FR2225407A1; NL7404949A; BE813520A; DD113347A5; FR2225407B1; HU168443B; GB1437832A; NL189756C; IT1005785B; CH589584A5; JPS5030846A; DE2417615A1; JPS5810371B2

Description

derivatives and their preparation SHELL RESEARCH 42689 This invention relates to novel halocyclobutanones which are of interest as chemical intermediates for the preparation of cyclopropane carboxylic Accordingly the present invention provides halocyclobutanones of general formula wherein and each represents an alkyl group of carbon for example represents an alkyl group of carbon for example methyl and represents an alkyl group of carbon for example methyl or an alkenyl group of up to 6 carbon for example a phenyl or and together form a polymethylene group of up to 6 carbon for example trimethylene or and represents a hydrogen atom or an alkyl of for example and Hal represents a chlorine or bromine The halocyclobutanones of the invention may be prepared by a prooess which oomprises treating the corresponding cyolobutanone of a souroe of chlorine or preferably in a suitable organic solvent such as The chlorine or bromine source may be either the free element a procedure preferred bromine to be or a oompound capable of generating chlorine or bromine in a chemically active form under the reaction When it is desired to introduoe a chlorine atom the use of a generator such as sulphuryl is As mentioned above the halocyclobutanones of the invention are of interest as intermediates for the preparation of oyolopropane carboxylic acids of When the halocyclobutanones of formula I are heated in the presence of a suitably an inorganio base such as aqueous sodium they undergo a ring contraction to give a salt of the acid of formula The free aoid may be liberated by treatment of the salt with a suitable for example an aqueous mineral acid such as aqueous hydrochloric Certain esters of the cyclopropane acids of formula III are of interest as especially certain esters of cyclopropane oarboxylic The invention is illustrated further in the following Example 1 Preparation of was dissolved in ohloroform and to this solution was added dropwise a solution of bromine in chloroform After the addition the solvent was removed under reduoed pressure and the residue was distilled to give the required product as a colourless liquid at n Example 2 Preparation of was dissolved in chloroform and to this solution was added dropwise a solution of bromine in ohloroform was oomplete after the addition of each After the addition the solvent was removed under reduoed pressure to yield the desired product as a pale yellow liquid 20 Example 3 Preparation of was dissolved in ohloroform and sulphury chloride After allowing the mixture to stand for Z hours at the solvent was removed under reduoed pressure to yield the desired product as a pale orange liquid 1 Example Following a similar procedure to that described in Examples 1 to the following oompounds were also yellow 1 2 3 yellow yellow yellow 5 1 lobutanone 1 Example 5 Preparation of oarboxyllo prepared as in Example was added to a saturated solution of sodium carbonate and the mixture was heated under reflux for The cooled solution was then extracted with hexane and the aqueous phase was acidified with oonoentrated hydrochloric The white precipitate formed was filtered off and recrystallised from a methanol mixture to give the required produot pt Analysis Calculated for 02 C H Pound C H Example 6 Preparation of acid prepared as in Example was dissolved in methanol and the solution added to aqueous sodium carbonate solution The mixture was then heated under reflux with vigorous stirring for After the solution was extraoted with hexane and the aqueous phase acidified with concentrated hydroohloric The resulting pale yellow precipitate was filtered off and from mixture to the desired product Analysis Calculated for H Pound C H Example 7 Following a similar procedure to that described in Examples 5 and 6 the following oompounds were also acid Analysis Calculated for C H Found C H oarboxylic acid point Analysis Calculated 02 C H Pound C c acid ll Analysis Calculated for 02 C Pound C H acid Analysis Calculated for Cg C H Pound C H sarboxylic acid Analysis Calculated for C H Pound C H acid insufficientOCRQuality

Claims

44599/2 C L A I M S

1. Halocyclobutanones of general formulax- wherein R^ and R≥ each represents an alkyl group of 1 to 6 carbon atoms; represents an alkyl group of 1 to 6 carbon atoms and R^ represents-an-alkyl group o -lH;o-6-earbon -atom8,—an-alkenyl^ - group of up to 6 carbon atoms, or a phenyl group, or R^ and ^ together form a polymethylene group of up to 6 carbon atoms; and ^ represents a hydrogen atom or an alkyl group of 1 to 6 carbon atoms; and Hal represents a chlorine or bromine atom.

2. Compounds as claimed in claim 1 'wherein R1 and Rg each represents a methyl group; R^ represents a methyl group and R^ represents a methyl, propyl, butenyl or phenyl group, or R^ and ^ together represent an ethylene, trimethylene or pentamethylene group; and R^ represents a hydrogen atom or a methyl group.

3. Compounds as claimed in claim 1 wherein R^ represents an alkyl group of 1 to 6 carbon atoms or a phenyl group.

4. A process for the preparation of halocyclobutanones as defined in claim 1 which comprises treating the corre onding cyclobutanone of formula I - 44599/2 8 - wherein R1 , Rg» ^, R^ and R^ have the meanings defined in claim 1, with a source of chlorine or "bromine.

5. Process as claimed in claim 4 wherein the cyclobutanone of formula II is reacted with a compound capable of generating chlorine or bromine in a chemically active form under the reaction conditions.

6. Process as claimed in claim 5 wherein the chlorine generating compound is sulphury! chloride.

7. Process as claimed in claim 4, 5 or 6 wherein the reaction is carried out in the presence of an organic solvent.

8. Halocyclobutanones when prepared by a process as claimed in any one of claims 5 to 7.

9. « Procese for the preparation of cyclopropane_carboxylic acids of the formula:- wherein R„ , R_, R,f R. and Rc are as defined in claim 1, which comprises heating a halocyclobutanone as claimed in any of claims 1 to 3 or 8 in the presence of a base, and liberating the resultant acid salt by reaction with a suitable acid. 44599/2 - 9

10. Process as claimed in claim 9 wherein the base is an in-organic base and the acid is an aqueous mineral acid.

11. Process as claimed in claim 10 wherein the base is aqueous sodium carbonate and the acid is aqueous hydrochloric acid.

12. Cyclopropane carboxylic acids of formula III as defined in claim 9 when prepared by a process as claimed in any one of claims 9 to 11. HE:dn