FR2501672A1 - PROCESS FOR THE PREPARATION OF 1,1-DICHLORO-4-METHYL-1,3-PENTADIENE AND INTERMEDIATE PRODUCTS OF THIS PREPARATION - Google Patents

Abstract

PROCESS FOR PREPARING DICHLOROPENTADIENE OF FORMULA VI: (CF DRAWING IN BOPI) FROM 1,1,1-TRICHLORO-2-HYDROXY-4-METHYL-PENTENE-3 OF FORMULA I: (CF DRAWING IN BOPI) AND 1 , 1,1-TRICHLORO-2-HYDROXY-4-METHYL-PENTENE-4 OF FORMULA II: (CF DRAWING IN BOPI) THEY OBTAINED BY REACTION BETWEEN CHLORAL AND ISOBUTYLENE. , POSSIBLY AFTER ACYLATION, WITH A METAL POWDER, THE REACTION GIVING 1,1,4-TRICHLORO-4-METHYL-PENTENE OF FORMULA V: (CF DRAWING IN BOPI) WHICH IS REACTED WITH A BASE.

Description

The present invention relates to a process for preparing 1,1-

  dichloro-4-methyl-1,3-pentadiene having the formula VI Cl

C = CH - CH - C - CH3 (VI)

  Cl CH3 and to new intermediate products obtained

  in the course of this preparation.

  According to the invention, the di-

  chloro-pentadiene of formula VI above from 1,1,1-trichloro-2-hydroxy-4-methyl-pentene-3 corresponding to the formula I Cl OH Cl1 C-CH-CH2 = C-CH2 (I) Cl / CH3

  and 1,1,1-trichloro-2-hydroxy-4-methyl-pentene-4

  with formula II Cl OH Cl C - CH - CH - C = CH3 (II) CH3

  themselves obtained by reacting chloral and isobutane

  tylene, by a process which is characterized in that

  reacts the mixture of isomers obtained by reaction

  chloral and isobutylene and which contains trichlo-

  isomeric ropentenes of formulas I and II in proportions

  with hydrochloric acid, this reaction

  giving 1,1,1,4-tetrachloro-2-hydroxy-4-methyl

pentane of formula III Cl OH Cl

I I

  A novel compound which is reacted, if desired, with a sulfonic acid or with a carboxylic acid of the formula VII ## STR2 ##

R1 - COOH (VII)

  wherein R 'represents a C 2 -C 8 alkyl group, or a derivative of such an acid suitable for acid acylation; the tetrachloropentane is then reacted

  formula III or, depending on the option, 1,1,1,4-tetra-

  2-chloro-2-acyloxy-methlyl-pentane of the formula wherein R 2 is C 2 -C 8 acyl or sulfonyl,

  compound, obtained by acylation, with a metal powder

  metallics, preferably in the presence of a protonic organic solvent, which causes the removal of chlorine; 1,1,4-trichloro-4-methyl-pentene-1 of formula V Cl Cl ci is reacted with

C = CH-CH 2 C-CH 3 (V)

C C H3

  -hb, 'i C e_. Depending on the option, you can add water or a sulphonia acid using a baser.

  by deshyidrochlorination it is specified that the order in the-

  i2.1.aC reacts with hydrochloric acid and

  0 cde to the acylation reaction can be reversed.

  1,1-Dichloro-4-methyl-1,3-pentadiene is a

  intermediate product of the synthesis of cyclopro-

  breaded. According to one of the known methods for preparing this

  posed, one starts from 1,1,1-trichloro-4-methyl-4-hydroxy-penta

  it itself obtained by adding 2-methyl-3-butene-2-ol and chloroform, and treated by removal of water and hydrochloric acid or dehydrohalogenation and

  reverse dehydration (R.F.A.

  published under Nos. 2,536,503, 2,536,504 and 2,616,528). Linen-

  The disadvantage of these methods is that the compound obtained

  by chloroformic telomerization contains in impurity an amount of about 15 to 20% of the isomer in which

  the trichloromethyl group is not at the end of chal-

  born. This substance can not be separated by

  physical products and products formed from this

  substance can be found in all phases of operation.

  subsequent losses, causing significant losses

  when it is desired to purify the cyclopropane ester prepared

  térieurement. There are also known processes in which

  reacts isobutylene in the presence of peroxidic catalysts

  diques with trichlorethylene or 1,1-dichloroethylene at a temperature of 400-500 C in a continuously operating tubular reactor (British Patent Nos. 1,532,676 and 1,531,733). The disadvantage of this method is that

  you get a product mix that does not contain the

  only in quantities of 5 to 10%.

  Among the methods of the prior art for

  to achieve the desired product, and in the opinion of the

  the process of Farkas (J. Farkas, P. Kohrim, F. Sorm: Czech Coll., Chem., Commun .: 24 2230 (1959);

  Patent Application No. 2,616,681) is sim-

  from the technical point of view and the least expensive in terms of raw materials. In this process,

  of isobutylene and chloral which are subjected to the reaction

  Prins and the desired product is obtained by iso-

  meriting, acylation and reduction. In the course of the Prins reaction, two trichloropentenols are formed

  isomers: 1,1,1-trichloro-2-hydroxy-4-methyl-pentene-

  4 and 1,1,1-trichloro-2-hydroxy-4-methyl-pentene-3. Only the second of these two compounds can be considered as the starting product of the desired product and the fact that its proportion in the reaction mixture is 20 to 30%.

  maximum, it becomes necessary to carry out isomerisation

  tion. This is the most difficult operating stage in the four-stage reaction sequence because

  is responsible for the purity of the final product. If the isomer

  is not complete, the final product will contain

  in impurity the undesirable isomer, 1,1-dichloro-4-methyl-

  1,4-ethylpentadiene, which can not be completely removed by distillation. This impurity is as active as

  the desired diene isomer in the cyclopro-

  diaozoester and gives a by-product that is not

  can only eliminate by chemical techniques.

  In the process according to the invention, the isomerization and its troublesome consequences are remarkably simple in that the mixture of the liquid isomers obtained in the Prins reaction between chloral and isobutylene is reacted with a solution. aqueous hydrochloric acid with formation of tetrachloropentane

  of formula III, solid, which is separated. In this reaction

  addition of hydrogen chloride to the double bond, leading to the same product, with a yield of

  almost quantitative, for both isomers.

  In the process according to the invention, tetrachloro-

  ropentanes of formulas III and IV are subject to reduction

2501672 '

  This operation gives 1,1,4-trichloro-4-methyl

  thyl-pentene-1 with a good yield.

  Selective reduction of compounds of formula

  General IV takes place in a particularly

  when R represents a C 2 -C 4 acyl group,

  thane-sulfonyl, 4-toluenesulfonyl or benzoyl.

  We know that we can easily reduce a

  carbon-halogen bond with metals - mainly

  Zinc - or by catalytic hydrogenation. In the case of halogen atoms of the same kind, the hydrogenolysis of halogen can be expected only in the case of the molecule or order of bone on which it is attached halogen atoms. In it is filled for the tertiary bone atom in position 4 té with surprise that in the metal powder or by separates first a selective deE> of a single atom B its position inside

reaction of the car atom

  differs from other cases present, this condition

chlorine attached to the atom of

but despite this, we found

  The conditions of a catalytic hydrogenation reduction, he chlorine atoms of the group

  trichloromethyl, this separation being followed by the elimination

  quick nation of the acyl group. A 1,1-dichlorovinyl end group is thus obtained which resists further reduction, and under normal reaction conditions,

  the chlorine atom on tertiary carbon is not affected

  you. This unexpected discovery paved the way for the

  preparation of pure 1,3-diene - free of the 1,4- isomer.

  Indeed, theoretically this hypothesis is justified and can easily be explained by the fact that the elimination

  hydrogen chloride in 1,1,4-trichloro-4-methyl-

  pentene-1, carried out in the presence of a base, gives 1,3-

  conjugated diene because the 1,1-dichlorovinyl group already present favors the deprotonization of the methylene group by

position 3.

  In the process according to the invention, the reduction

  compounds of formulas III and IV are preferably

  with zinc, aluminum or iron powder in a protonic solvent - preferably methanol, ethanol or acetic acid - at a temperature of 25 ° C, and the product obtained is separated in a known manner in itself. If necessary, we can use in the

  reduction of ammonium chloride or mercuric chloride.

  Another advantageous procedure for reducing these

  posed consists of the catalytic hydrogenation of the tet;

  chloropentanes in the presence of the mentioned solvents and

  presence of basic substances which bind the acids -

  potassium carbonate, sodium acetate, triethylamine, magnesia or a similar stost.

  a temperature of 25 to 60 C. It is possible to use as

  noble metal supported catalysts and backbone catalysts, preferably palladium on bone charcoal, Raney nickel, or analogous catalyst. The following examples illustrate the invention without, however, limiting its scope; in these examples the indications of parts and percentages are

weight unless otherwise stated.

Example

  It is mixed at a temperature of 25-35 C during

  3 hours 50.9 g (0.25 moles) of 1,1-trichloro-2-hydroxy-

  4-methyl-pentene-3 and 100 ml of concentrated FHCl; we filter

  the white solid which has separated and is

water until neutral.

  Redemption 58.8 g (98%) of tetrachlorobenzene

  2-hydroxy-4-methyl-pentane, melting at 79 ° C = 8 ° C Elutional kialysis formula em: piriu e C6Hi oG__

(239,90)

22.1 5: O 1 6? 9-

2501672 1

  Calculated: C 30.02% H 4.17% Cl 59.16% Found: C 30.20%, H 4.25% Cl 59.21% IR (KBr): 3420, 2940-2860, 1370, 1230, 1200, 1120, 840, 805, 760 cm -1 1H NMR (CDCl3): Me 1.71 s (6H); CH2CH 2.02 dd (1H) JgEg = 15 Hz, J = 8 Hz, 2.56 dd (1H) J = 1.5 Hz, 4.43 dd (1H); OH 3.11 (1H) 13 C NMR -CDCl 3): Me 32.2q, 34.1q; CH2 46.9t; -C, Cl 68.7s; 80.4d CH-OH; CCl3 103.6s

Example 2

  Starting from the mixture of 50.9 g (0.25 mol) of the two 1,1,1-trichloro-2-hydroxy-4-methyl-pentene-4 isomers and

  1,1,1-trichloro-2-hydroxy-4-methyl-pentene-3 in

  relative portions of 80:20 and one operates as described in

Example 1

  Yield: 59.0 g (98.2%) of 1,1,1,4-tetrachloro-

  2-hydroxy-4-methylpentane melting at 79-81 ° C.

Example 3

  To the solution of 48.0 g (0.2 mole) of 1,1,1,4

  trachloro-2-hydroxy-4-methylpentane prepared with 50 ml of pyridine is added dropwise 25.5 g (0.25 mole) of acetic anhydride and stirred at a temperature of 60 C for 4 hours. The reaction mixture is poured onto a mixture of ice and concentrated HCl and extracted with benzene. After distilling off the solvent, the

vacuum residue.

  Yield: 50.5 g (90%) of product boiling at 134 ° -135 ° C. / mm Hg IR (film): 2940-2880, 1760, 1370, 1200, 1125, 1050, 940, 860, 800, 770 cm -1 1H NMR (CDCl3 3): Me, 1.70 (6H); CH2CH 2.10 dd (1H), 2.61dd (1H) 5.05dd (1H), CH3CO 2.15 s (3H) In these examples, the procedure is as in Example 3 but changing the nature of the acylating agent and

  solvent respectively. The results obtained are

  shown in Table I below.

OR CH3Cl OR

C - CH2 - CH-CC13

CH3

  plExem acylating agent solvent / base Yield pi dI '-

  boiling C / mm Hg 4 pyridine chloride 88% 101-103 / 0.3 benzoyl pyridine chloride 92% 83-85 / 0.2

methacrylic acid

  ne-sulphonic 6 pyridine chloride 94% 138-140 / 0.1

the acid p-

toluene sulfonic

  7 acid anhydride ac 89% 118-119 / 12 acetic acid / NaOAc

Example 8

  To 100 ml of the methanolic solution of 28.2 g (0.1 mole) of 1,1,1,4-tetrachloro-2-acetoxy-4-methyl-pentane is added 3.0 g (0.11 gram atom) of aluminum powder and 0.1 g of mercuric chloride and boiled under stirring for 1 hour. After filtration and distillation

  13.5 g (72%) of 1,1,4-trichloro-4-methylpentene are obtained.

1 boiling at 70-72 C / 16 mm Hg

2501672 1

  IR (film): 2940-2900, 1620, 1375, 1240, 1205, 1115, 930, 845, 800 cm -1 NMR 1H (CDCl3) δ: Me 1.60s (6H), CH2 2.62d (2H) J = 7 Hz; CH = 6.08 t (1H) 13 C NMR (CDCl3): Me2 32.2s; CH 2 45.6q; -C, Cl 68.4s; CH = 125,6d; = CCl2 122.5s

Example 9

  To 50 ml of the methanolic solution of 28.2 g

  (0.1 mole) of 1,1,1,4-tetrachloro-2-acetoxy-4-methyl-pen-

  5.0 g of ammonium chloride are added and then

  stirring and at 60-65 C, 7.2 g (0.11 gram atom) of

  dre zinc. After boiling for 2 hours, the reaction mixture is filtered and separated by hydrochloric acid.

  diluted and extracted with dichloroethane.

  Yield: 15.3 g (81%) of 1,1,4-trichloro-4-

  methyl-pentene-1 boiling at 66-68 ° C / 12 mm Hg.

Example 10

  To 20 ml of the 2.8 g ethanolic solution

  (0.01 mole) of 1,1,4,4-tetrachloro-2-acetoxy-4-methyl-

  pentane is added 1.4 g (0.01 mol) of potassium carbonate

  anhydrous solution and the mixture is hydrogenated in the presence of

  10% palladium on bone charcoal catalyst at room temperature

  ambient temperature until absorption of 0.01 mole of hydrogen.

  After filtration and distillation of the solvent,

  1.05 g (55%) of 1,1,4-trichloro-4-methyl-pentene-1.

  Examples 11 to 14 In these examples, the procedure is as in Examples 8 to 10, but the products are subjected to reduction.

  prepared in Examples 4 to 6. The results obtained

  are shown in Table II below

2501672 '

Table 2

CH3 (Cl red C-CH2-CH-CC13 rd CH3

CH3 ,, C

CH3; "

-CH2-CH = CC12

  Exem- method of return% observa-

  boiling point 12 C6H5CO Zn / C2H50H 78 1 h 13 4-CH3C6H4SO2 Zn / CH3COOH 89 2 h at 60 ° C. CH3C0 H2 / Ni Raney 81 (C2H) 3 N, agent fixing the acids CH3CO H2 / Pd-C 83 CH3COOHNaOCOCH3 EXAMPLE 16 18.75 g (0.1 mole) of

  1,1,4-trichloro-4-methyl-pentene-1 with a solution of

  coolate prepared from 2.3 g of metallic sodium and

  ml of ethanol. After distilling off the solvent,

the residue under vacuum.

  Yield: 13.2 g (88%) of 1,1-dichloro-4-methyl

  thyl (1,3-pentadiene boiling at 60-63 ° C / 15 mm Hg)

Example 17

  We operate as in Example 16 but replace

  the alcohol used in this example in 100 ml of a

  methanolic solution of 5.6 g of KOH.

  Yield: 12.6 g (84%) of 1,1-dichloro-4-methyl

  thyl-1,3-pentadiene boiling at 58-61 ° C / 12 mm Hg.

ii

Claims (8)

  1) Process for preparing dichloropentadiene of formula VI Cl C = CH-CH = C-CH3 (VI)   CH 3 from 1,1,1-trichloro-2-hydroxy-4-methyl-pentene-3 of formula I ## STR1 ## 1,1-Trichloro-2-hydroxy-4-methyl-pentene-4 of formula II ## STR1 ##   themselves obtained by reaction between chloral and iso-   butylene, characterized in that the mixture is reacted   isomer formation obtained by reaction of chloral and iso-   butylene, which contains the isomeric trichloropentenes of formulas I and II in any relative proportions,   with hydrochloric acid, which gives the 1,1,1,4-tetra-   chloro-2-hydroxy-4-methylpentane of the formula III which is reacted, if desired, with a sulphonic acid or a carboxylic acid of the formula ## STR2 ## VII R1 - COOH (VII)   in which R1 represents a C2-C8 alkyl group,   or with a derivative of such an acid suitable for acylating   acidification; the tetrachloropentane is reacted   formula III or, depending on the option, 1,1,1,4-tetrachloro-   2-acyloxy-4-methylpentane of formula IV Ci OR2 Cl c1 _-1! Wherein R2 is a C2-C8 acyl group or a sulfonyl group,   obtained by acylation, with a metal powder, of   in the presence of a protic organic solvent, which causes the elimination of chlorine; 1,1,4-trichloro-4-methylpentene-1 of formula V Cl Cl is reacted CH = CH2 - CH3 (V) Cl CH3   obtained by the elimination of water or, depending on the option, of   carboxylic acid or sulfonic acid, with a base, which causes the elimination of the chlorine atom on the   tertiary carbon in the form of hydrochloric acid,   so specified that the order in which one makes react with   hydrochloric acid and acylation can be carried out. be reversed.   2) Method according to claim 1, characterized   in that the mixture containing the isomers is reacted   formulas I and / or II with an aqueous solution of   hydrochloric acid in excess at a temperature of 25 to 40 C. 2501672;   3) Process according to claim 1, characterized in that the tetrachloropentane of formula III is acylated with the aid of a carboxylic acid anhydride or a carboxylic acid chloride or an acid chloride. sulfonic acid, preferably in the presence of a tertiary amine or a mineral acid fixing the acids at a temperature of 25 to 800C. 4) Process according to claim 1, characterized in that a tetrachloropentane of formula III or of formula IV - in which R2 has the meaning indicated above is reacted - with 0.5 to 1.5 equivalents of zinc or aluminum, if desired in the presence of   ammonium chloride or mercuric chloride serving as   tivateur. 5) Process according to Claim 1, characterized in that the trichloropentene of formula   V with an alkali alkoxide or an alkaline hydroxide in presence of an alkanol.   (6) As an intermediate product of the preparatory   ration of the compound of formula VI, the compound of formula   III Cl OH C1 Cl-C - CH-CH2-C-CH3 (III) Cel ', CH3   7) As intermediate compounds of the pre-   parate compounds of formula VI, the compounds of formula   the IV in which R has the meaning indicated in claim 1.   8) As intermediate compounds of the preparation   of the compounds of formula VI, the compound of formula V Cl Cl C = CH - CH2 - C - CH3 (V) Cl IH3 cl CH3