GB2060680A - Catalytic Hydrogenation - Google Patents
Catalytic Hydrogenation Download PDFInfo
- Publication number
- GB2060680A GB2060680A GB8031078A GB8031078A GB2060680A GB 2060680 A GB2060680 A GB 2060680A GB 8031078 A GB8031078 A GB 8031078A GB 8031078 A GB8031078 A GB 8031078A GB 2060680 A GB2060680 A GB 2060680A
- Authority
- GB
- United Kingdom
- Prior art keywords
- formula
- compound
- group
- carbon atoms
- biphenylyl
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D317/00—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms
- C07D317/08—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3
- C07D317/72—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3 spiro-condensed with carbocyclic rings
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C15/00—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts
- C07C15/40—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts substituted by unsaturated carbon radicals
- C07C15/50—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts substituted by unsaturated carbon radicals polycyclic non-condensed
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/45—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by condensation
- C07C45/46—Friedel-Crafts reactions
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/56—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds
- C07C45/57—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with oxygen as the only heteroatom
- C07C45/59—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds from heterocyclic compounds with oxygen as the only heteroatom in five-membered rings
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C49/00—Ketones; Ketenes; Dimeric ketenes; Ketonic chelates
- C07C49/587—Unsaturated compounds containing a keto groups being part of a ring
- C07C49/657—Unsaturated compounds containing a keto groups being part of a ring containing six-membered aromatic rings
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C49/00—Ketones; Ketenes; Dimeric ketenes; Ketonic chelates
- C07C49/76—Ketones containing a keto group bound to a six-membered aromatic ring
- C07C49/782—Ketones containing a keto group bound to a six-membered aromatic ring polycyclic
- C07C49/792—Ketones containing a keto group bound to a six-membered aromatic ring polycyclic containing rings other than six-membered aromatic rings
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
- C07C5/02—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation
- C07C5/03—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation of non-aromatic carbon-to-carbon double bonds
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C63/00—Compounds having carboxyl groups bound to a carbon atoms of six-membered aromatic rings
- C07C63/33—Polycyclic acids
- C07C63/49—Polycyclic acids containing rings other than six-membered aromatic rings
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
- C07C2523/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals
- C07C2523/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals of the platinum group metals
- C07C2523/42—Platinum
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
- C07C2523/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals
- C07C2523/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals of the platinum group metals
- C07C2523/44—Palladium
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2601/00—Systems containing only non-condensed rings
- C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
- C07C2601/14—The ring being saturated
Abstract
A compound of the formula <IMAGE> wherein R<1> represents straight-chain alkyl containing 1-11 carbon atoms and R<2> represents phenyl, 4-biphenylyl or a group convertible into the carboxyl group, is catalytically hydrogenated and, if desired, the resulting compound is converted in a manner known per se into a a compound of the formula <IMAGE> wherein R<1> has the significance given earlier and n stands for 1 or 2, or into a compound of formula <IMAGE> wherein R<1> has the significance given earlier and R<5> represents cyano, alkyl containing 1-10 carbon atoms or alkoxy containing 1-10 carbon atoms. The liquid crystalline compounds of formulae III and V can be manufactured in accordance with the novel process in high yield and without chromatographic separations.
Description
SPECIFICATION
Catalytic Hydrogenation
The present invention is concerned with a novel process for the manufacture of trans-1,4disubstituted cyclohexane derivatives.
The process provided by the present invention comprises catalytically hydrogenating a compound of the general formula
wherein:
R' represents straight-chain alkyl containing 1-11 1 carbon atoms and R2 represents phenyl, 4- biphenylyl or a group convertible into the carboxyl group, and, if desired, in a manner known per se converting a thus-obtained compound of the general formula
wherein:
R3 represents phenyl or 4-biphenylyl and R1 has the significance given earlier, by introducing the cyano group into the p-position of the phenyl group or into the 4t-position of the 4-biphenylyl group, into a compound of the general formula
wherein:
R1 has the significance given earlier and n stands for 1 or 2, or reacting an obtained compound of the general formula
wherein::
R' has the significance given earlier and R4 represents a group convertible into the carboxyl group, optionally after conversion into the corresponding carboxy compound, with a compound of the general formula
wherein:
R5 represents cyano, alkyl containing 1-10 carbon atoms or alkoxy containing 1-10 carbon atoms, or a suitable salt thereof to give a compound of the general formula
wherein:
R1 and R5 have the significance given earlier.
The compounds of formulae Ill and V have liquid crystailine properties. The invention is also concerned with novel intermediates occurring in the process provided by the present invention, namely the compounds of formula II.
In DOS 2 636 684 there is described a process for the manufacture of phenylcyclohexanes, which yields as intermediates mixtures containing approximately equal amounts of the cis and trans isomeric alcohol. These must be separated chromatographically and subsequently hydrogenated individually. The same is also true with respect to the cyclohexanecarboxylic acid esters which are known from DAS 2 429 093; since the configuration of the cyclohexane ring does not alter in the esterification, in order to obtain a pure trans end product it is necessary to use the corresponding trans compound as the starting material. In contrast to this, phenylcyclohexane mixtures containing ca 90% of trans component are obtained directly according to the process provided by the present invention.
Thereby, chromatographic separations can be avoided and, moreover, the total number of steps in the liquid crystal synthesis can be reduced.
The catalytic hydrogenation of methylenecyclohexane compounds is known from the literature (Herbert 0. House, Modern Synthetic
Reactions, 2nd Edition (1972), W. A. Benjamin,
Inc., Menlo Park, California, page 31), this catalytic hydrogenation yielding mostly mixtures containing predominantly the cis component.
Surprisingly, however, the process provided by the invention yields in the case of cyclohexane derivatives having larger alkylidene groups products containing ca 90% trans compound in very good yields.
In the scope of the present invention the term "straight-chain alkyl containing 1-11 carbon atoms" signifies, in particular, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl and undecyl. The term "alkyl containing 110 carbon atoms" signifies not only straight-chain groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl, but also branched-chain groups such as isopropyl, isobutyl, sec.butyl, tert.butyl, isopentyl, 2methylbutyl, 1-methylbutyl, neopentyl, 1,2dimethylpropyl, tert.pentyl, isohexyl, 3methylpentyl and the like. The term "alkoxy containing 1-10 carbon atoms" signifies the group R60-- in which R6 represents alkyl containing 1-10 carbon atoms.The term "a group convertible into the carboxyl group" means in particuiar, an ester group, an amide group which is optionally N-mono-or N,N-disubstituted, the aldehyde group, an acetal group or the cyano group. The ester groups are preferred; these can be not only alkoxycarbonyl groups but also aryloxycarbonyl groups. There are especially preferred the methyl, ethyl and propyl esters as well as the phenyl esters in which the benzene ring is optionally substituted, particularly the esters of the phenols of formula tV.
The catalytic hydrogenation of a compound of formula II can be carried out under the conditions which are usual for catalytic hydrogenations. The catalytic hydrogenation is conveniently carried out in an inert organic solvent (e.g. an alcohol, ether, alkane or chlorinated hydrocarbon). There are preferably used noble metal hydrogenation catalysts, optionally on a carrier material.
Especially preferred catalysts are platinum, palladium and oxides thereof. The catalytic hydrogenation is conveniently carried out with the addition of a base. Organic bases, especially pyridine, 4-(N,N-dimethylamino)-pyridine or triethylamine, are preferably used. It is particularly preferred to carry out the catalytic hydrogenation using a platinum/carbon catalyst and with the addition of an organic base. The temperature and pressure are not critical aspects in this catalytic hydrogenation. The catalytic hydrogenation is conveniently carried out at normal pressure and at a temperature between room temperature and the boiling point of the mixture.
The introduction of the cyano group into a compound of formula la can be carried out in a manner known per se; for example, according to the following Reaction Scheme in which R', R3 and n have the significance given earlier:
The isolation of the trans-disubstituted cyclohexane derivatives in pure form is conveniently carried out by crystallisation of a compound of formula VI or a compound of formula VII.
The compounds of formula lb can be converted in a manner known per se into the corresponding carboxylic acids which can subsequently be esterified with a compound of formula IV. If the compound of formula Ib is an ester, then a transesterification in a manner known per se with a phenol of formula IV or an appropriate alkali metal salt thereof is also possible. If the compound of formula II is an ester of a phenol of formula IV, then the hydrogenation in accordance with the invention leads directly to an ester of formula V.
The compounds of formula II are novel and also form part of the present invention.
Those compounds of formula II in which R2 represents other than the aldehyde group can be prepared by reacting a cyclohexanone derivative of the general formula
wherein:
R7 represents phenyl, 4-biphenylyl, an ester group, an amide group which is optionally Nmono- or N,N-disubstituted, an acetal group or the cyano group, with an alkyltriphenylphosphonium bromide of the general formula (C6Hs)3PCH2R1@Brs IX wherein:
R1 has the significance given earlier.
The reaction can be carried out under the conditions which are usual for Wittig alkylations.
The reaction is conveniently carried out in an inert organic solvent (e.g. an ether or alkane). An ether, especially dimethyl ether, diethyl ether, tetrahydrofuran, dioxan or dimethoxyethane, is the preferred solvent. Preferred bases are alkali metal alcoholates such as potassium tert.butylate and sodium methylate. The reaction is conveniently carried out at a temperature between room temperature and the boiling point of the reaction mixture.
The compound of formula VIII in which R7 represents 4-biphenylyl is novel and also forms part of the present invention. It can be prepared, for example, by reacting 1 ,4-cyclohexanedione with ethyleneglycol in the presence of acid to give the monoketal, reacting this monoketal with 4biphenylylmagnesium bromide, subjecting the alcohol obtained after the Grignard reaction and subsequent hydrolysis with ammonium chloride solution to dehydration with p-toluenesulphonic acid in benzene to give the ketal olefin, catalytically hydrogenating this ketal olefin under pressure and finally hydrolysing the ketal obtained with p-toluenesulphonic acid in glacial acetic acid to give 4-(4-biphenylyl)-cyclohexanone.
The compounds of formula VIII in which R7 represents other than 4-biphenylyl are known compounds or analogues of known compounds.
Those compounds of formula VIII in which R7 represents an ester, amide or acetal group or the cyano group can be prepared, if necessary, in a manner known per se from the methyl ester of the formula
Those compounds of formula II in which R2 represents a group convertible into the carboxyl group, especially the aldehyde group, can be prepared from the compound of formula Villa by a
Wittig alkylation under the conditions described earlier and, if necessary, subsequent reaction in a manner known per se.
The process provided by the present invention is preferably used for the manufacture of the following compounds:
Trans-4-butylcyclohexanecarboxylic acid 4' cyanophenyl ester, trans-4-propyl- 1 -(4-cyanophenyl)cyclohexane,
trans-4-pentyl- 1 -(4-cyanophenyl)cyclohexane, trans-4-heptyl-1 -(4-cyanophenyl)cyclohexane, trans-4-propylcyclohexanecarboxylic acid 4' cyanophenyl ester, trans-4-pentylcyclohexanecarboxylic acid 4' cyanophenyl ester, trans-4-hexylcyclohexanecarboxylic acid 4' cyanophenyl ester, tra ns-4-heptylcyclohexanecarboxyiic acid 4'cyanophenyl ester,
trans-4-butylcyclohexanecarboxylic acid 4' ethoxyphenyl ester, trans-4-butylcyclohexanecarboxylic acid 4'pentyloxyphenyl ester, trans-4-butylcyclohexanecarboxylic acid 4' hexyloxyphenyl ester, trans-4-pentylcyclohexanecarboxylic acid 4'methoxyphenyl ester,
trans-4-pentylcyclohexanecarboxylic acid 4' propyloxyphenyl ester, trans-4-pentylcyclohexanecarboxylic acid 4' pentyloxyphenyl ester, trans-4-propylcyclohexanecarboxylic acid 4'ethoxyphenyl ester,
trans-4-propylcyclohexanecarboxylic acid 4' butyloxyphenyl ester,
4-(trans-4-propylcyclohexyl)-4'-cyanobiphenyl,
4-(tra ns-4-butylcyclohexyl)-4'-cyanobiphenyl, 4-(trans-4-pentylcyclohexyl)-4'-cyanobiphenyl and
4-(trans-4-heptylcyclohexyl)-4'-cyanobiphenyl.
The following Examples illustrate the present invention:
Example 1
200 g of (4-pentylidenecyclohexyl)benzene are dissolved in 5.2 litres of absolute ethanol in a 10 litre round flask equipped with a stirrer and, after the addition of 13.84 g of absolute pyridine and 20 g of 5% platinum/carbon, the mixture is hydrogenated for about 5 hours at room temperature and normal pressure. After the hydrogen uptake has stopped, the mixture is filtered under suction, the catalyst is back-washed well with about 1 litre of absolute ethanol and the filtrate is evaporated in a rotary evaporator at 600 C. The residual oil is diluted with 2 litres of ethyl acetate, washed three times with 400 ml of 3N hydrochloric acid and thereafter four times with 400 ml of water.Subsequently, the organic phase is dried over 200 g of sodium sulphate and evaporated in a rotary evaporator at 600 C. There are thus obtained 199.9 g of light yellow crude product which contains 7.7% cis- and 90.7% trans-(4-pentylcyclohexyl)benzene according to gas chromatographic analysis.
198.0 g of the crude (4pentylcyclohexyl)benzene are dissolved in 1 325 ml of methylene chloride and 79.63 g of acetyl chloride in a 2.5 litre four-necked sulphonation flask equipped with a stirrer, condenser, thermometer, calcium chloride tube, powder dropping funnel and apparatus for inert gasification and 135.3 g of aluminium chloride are added within 35 minutes. Thereby, the solution becomes orange and begins to boil slightly. The solution is stirred at room temperature for a further 15 minutes, 760 ml of water are then cautiously added dropwise while cooling with ice within 30 minutes and thereafter 100 ml of 37% hydrochloric acid are added dropwise at 200--250C. The organic phase is separated and the aqueous phase is extracted twice with 250 ml of methylene chloride.The combined organic phases are washed successively with 300 ml of saturated sodium chloride solution, 400 ml of 3N sodium hydroxide and three times with 400 ml of saturated sodium chloride solution and the aqueous phases obtained are back-extracted twice with 200 ml of methylene chloride. The organic phases are dried over 200 g of sodium sulphate, filtered and evaporated on a rotary evaporator at 600 C. There are obtained 235.5 g of a yellow-orange, solid residue which contains 89.45% trans-4-(4pentylcyclohexyl)acetophenone. Rf values: educt 0.66, product 0.41 (Merck plates F254/benzene).
686 ml of water and 580 ml of 28% sodium hydroxide are placed in a 10 litre four-necked sulphonation flask equipped with a stirrer, thermometer, 250 ml dropping funnel, 1 litre dropping funnel, condenser and apparatus for argon gasification and the solution is cooled to 50C with an ice-alcohol bath. 11 5 ml of bromine are added dropwise at 40--7 OC within 40 minutes and the orange solution is then stirred at this temperature for a further 5 minutes. After removal of the cooling bath, 750 ml of absolute dioxan are dropped into the solution within 1 5 minutes, the temperature rising to about 1 70C, and then within 70 minutes a solution of 182.5 g of the crude product obtained according to the preceding paragraph in 940 ml of absolute dioxan is added dropwise.The temperature thereby rises to about 440C. The resulting suspension is stirred for a further 45 minutes and subsequently the excess hypobromite is reduced with 72.5 ml of sodium bisulphite solution. While cooling with an ice/methanol bath there are added dropwise within 1 5 minutes 230 ml of 37% hydrochloric acid (pH of the reaction solution =1), and thereafter the mixture is treated in a 20 litre stirring vessel with 4 litres of methylene chloride and 7 litres of saturated sodium chloride solution and stirred well. The aqueous phase is extracted twice with 3 litres of methylene chloride, the organic phases are combined, washed twice with 2 litres of saturated sodium chloride solution and dried over 500 g of sodium sulphate. Upon evaporation on a rotary evaporator at 700C there is obtained a beige, solid residue (189.8 g).This is dissolved in 955 ml of warm ethanol, the solution is cooled slowly to 60C and then stirred at this temperature for 1 5 minutes. There thereby separate white crystals which are filtered off under suction, washed three times with 50 ml of ice-cold methanol and twice with 50 ml of nhexane and dried under a water-jet vacuum at 700C. There are obtained 134.4 g of trans-4-(4pentylcyclohexyl)benzoic acid in a purity of 100% (according to gas chromatography). Melting point 1 77.701 80.20C; Rf values: educt 0.55, product 0.37 (Merck plates F254/benzeneacetone 9:1). Yield 72% based on (4pentylidinecyclohexyl)benzene.
The starting material can be prepared as follows:
537.4 g of pentyltriphenyiphosphonium bromide and 168.3 g of potassium tert.butylate, dissolved in 1 750 ml of absolute dimethoxyethane, are placed in a 4.5 litre sulphonation flask equipped with a stirrer, thermometer, drying tube, 1 litre dropping funnel and apparatus for inert gasification and the solution is stirred at room temperature for 45 minutes. There is obtained a red solution to which is added dropwise over a period of 35 minutes at 250-300C (while cooling with ice) a solution of 174.2 g of 4-phenylcyclohexanone (purity 99%) in 600 ml of absolute dimethoxyethane. The mixture is stirred at room temperature for 3.5 hours and subsequently 250 ml of water are added dropwise over a period of 4 minutes.The mixture is then filtered under suction and the filter cake is washed twice with 250 ml of ether. The filtrate is washed twice with 500 ml of saturated sodium chloride solution and the aqeuous phase is back-extracted with 500 ml of ether. After drying the organic phases over 100 g of sodium sulphate, the solvent is removed by evaporation on a rotary evaporator at 500 C, the residue is treated with 2 litres of n-hexane, stirred well, boiled at reflux for 1 5 minutes and left to stand at 50C overnight. The crystallised-out slurry is filtered under suction and the filter cake is washed three times with 500 ml of n-hexane.
After evaporation of the filtrate on a rotary evaporator, there are obtained 245.3 g of a yellow oil which is distilled using a Widmer flask and a 30 cm long column. There are thus obtained 211.5 g (yield 92.6%) of colourless (4pentylidenecyclohexyl)benzene which is pure according to gas chromatography. Boiling point: 81 0--83.50C/0.025 Torr; Rf values: educt 0.21, product 0.69 (Merck plates F254/ether-hexane 1:1).
Example 2
195.6 g of 97.8% (4-heptylidenecyclohexylbenzene are dissolved in 4.5 litres of absolute ethanol in a 10 litre round flask equipped with a stirrer and, after the addition of 11.8 g of absolute pyridine and 20 g of 5% platinum/carbon, the mixture is hydrogenated for about 13 hours at 500C and normal pressure until the hydrogen uptake comes to a standstill. The mixture is then filtered under suction, the catalyst is back-washed well with about 1 litre of absolute ethanol and the filtrate is evaporated in a rotary evaporator at 600C. The residual oil is diluted with 2 litres of ethyl acetate, washed three times with 400 ml of 3N hydrochloric acid and then three times with 400 ml of water.Subsequently, the organic phase is dried over 200 g of sodium sulphate and evaporated in a rotary evaporator at 600 C. There are thus obtained 184.2 g of light yellow crude product which contains 9.4% cis- and 88.2% trans-(4-heptylcyclohexyl)benzene according to gas chromatographic analysis.
180.35 g of the crude (4heptylcyclohexyl)benzene are dissolved in 1290 ml of methylene chloride and 64.58 g of acetyl chloride in a 4.5 litre sulphonation flask equipped with a stirrer, condenser, thermometer, calcium chloride tube, powder dropping funnel and apparatus for inert gasification and 109.7 g of aluminium chloride are added within 35 minutes.
Thereby, the solution becomes orange and begins to boil slightly. The solution is stirred at room temperature for a further 60 minutes, 620 ml of water are then cautiously added dropwise while cooling with ice within 30 minutes and thereafter 80 ml of 37% hydrochloric acid are added dropwise at 200--250C. The organic phase is separated and the aqueous phase is extracted twice with 250 ml of methylene chloride. The combined organic phases are washed successively with 300 ml of saturated sodium chloride solution, 400 ml of 3N sodium hydroxide and three times with 400 ml of saturated sodium chloride solution and the aqueous phases obtained are back-extracted twice with 1 50 ml of methylene chloride.The organic phases are dried over 200 g of sodium sulphate, filtered and evaporated on a rotary evaporator at 600 C. There are obtained 211.3 g of a light yellow residue which contains 86.3% trans-4-(4heptylcyclohexyl)acetophenone. Rf values: educt 0.54, product 0.40 (Merck plates F254/benzene).
717 ml of water and 606 ml of 28% sodium hydroxide are placed in a 10 litre sulphonation flask equipped with a stirrer, thermometer, 250 ml dropping funnel, 2 litre dropping funnel, condenser and apparatus for argon gasification and the solution is cooled to 50C with an ice/alcohol bath. 120 ml of bromine are added dropwise at 40-70C within 35 minutes and the orange solution is then stirred at this temperature for a further 5 minutes. After removal of the cooling bath, 780 ml of absolute dioxan are dropped into the solution within 1 5 minutes, the temperature rising to about 1 50C, and then within 65 minutes a solution of 208.9 g of the crude product obtained according to the preceding paragraph in 980 ml of absolute dioxan is added dropwise. The temperature thereby rises to about 470C.The resulting suspension is stirred for a further 75 minutes and subsequently the excess hypobromite is reduced with 76 ml of sodium bisulphite solution. While cooling with an ice/methanol bath there are added dropwise within 25 minutes 250 ml of 37% hydrochloric acid (pH of the reaction solution=1), and thereafter the mixture is treated in a 20 litre stirring vessel with 4 litres of methylene chloride and 8 litres of saturated sodium chloride solution and stirred well. The aqueous phase is extracted twice with 2 litres of methylene chloride, the organic phases are combined, washed twice with 2 litres of saturated sodium chloride solution and dried over 500 g of sodium sulphate. Upon evaporation on a rotary evaporator at 700C there is obtained a beige, solid residue (215.5 g).This is dissolved in 1050 ml of warm ethanol, the solution is cooled slowly to OOC and then stirred at this temperature for 1 5 minutes. There thereby separate white crystals which are filtered off under suction, washed twice with 90 ml of icecold methanol and dried under a water-jet vacuum at 700C. There are obtained 155.1 g of trans-4-(4-heptylcyclohexyl)benzoic acid in a purity of 99.5% (according to gas chromatography). Melting point: 157.10-- 1 590C; Rf values: educt 0.62, product 0.45 (Merck plates F254/benzene-acetone 9:1). Yield 71 % based on (4-heptylidenecyclohexyl)benzene.
The starting material can be prepared as follows:
573.8 g of heptyltriphenylphosphonium bromide and 168.3 g of potassium tert.butylate, dissolved in 1 750 ml of absolute dimethoxyethane, are placed in a 4.5 litre sulphonation flask equipped with a stirrer, thermometer, drying tube, 1 litre dropping funnel and apparatus for inert gasification and the solution is stirred at room temperature for 1 hour.
There is obtained a red solution to which is added dropwise over a period of 35 minutes at 250-- 300C (while cooling with ice) a solution of 1 74.25 g of 4-phenylcyclohexanone (purity 99%) in 600 ml of absolute dimethoxyethane. The mixture is stirred at room temperature for 2 hours and subsequently 250 ml of water are dropped into the yellow suspension over a period of 5 minutes. The mixture is then filtered under suction and the filter cake is washed twice with 250 ml of ether. The filtrate is then further treated as described in Example 1. After evaporation on a rotary evaporator at 500C, there are finally obtained 312.4 g of a yellow oil which is distilled using a Widmer flask and a 30 cm long column.
There are thus obtained 241 g (91.9%) of colourless (4-heptylidenecyclohexyl)benzene in a purity of 97.8% (according to gas chromatography). Boiling point: 1120-- 118 0C/0.06-0.07 Torr; Rf values: educt 0.21, product 0.74 (Merck plates F254/ether-hexane 1:1).
Example 3 1 60 g of (4-propylidenecyclohexyl)benzene are dissolved in 4.8 litres of absolute ethanol in a 10 litre round flask equipped with a stirrer and, after the addition of 12.64 g of absolute pyridine and 16 g of 5% platinum/carbon, the mixture is hydrogenated for about 5 hours at room temperature and normal pressure until the hydrogen uptake comes to a standstill. The mixture is then filtered under suction, the catalyst is back-washed well with about 1 litre of absolute ethanol and the filtrate is evaporated in a rotary evaporator at 600C. The residual oil is diluted with 1.5 litres of ethyl acetate, washed three times with 400 ml of 3N hydrochloric acid and then four times with 400 ml of water.
Subsequently, the organic phase is dried over 200 g of sodium sulphate and evaporated on a rotary evaporator at 600 C. There are thus obtained 156.5 g of light yellow crude product which contains 7.5% cis and 91% trans-(4propylcyclohexyl)benzene according to gas chromatographic analysis.
155.1 g of the crude (4propylcyclohexyl)benzene are dissolved in 1420 ml of methylene chloride and 64.6 ml of acetyl chloride in a 4.5 litre four-necked sulphonation flask equipped with a stirrer, condenser, thermometer, calcium chloride tube, powder dropping funnel and apparatus for inert gasification. 120.7 g of aluminium chloride are added within 33 minutes, the solution becoming orange and beginning to boil slightly. The solution is stirred at room temperature for a further 55 minutes, 500 ml of water are then cautiously added dropwise while cooling with ice within 11 minutes and then 88 ml of 37% hydrochloric acid are added dropwise at 200--2 50C. The organic phase is separated and the aqueous phase is extracted twice with 250 ml of methylene chloride.The combined organic phases are washed successively with 400 ml of saturated sodium chloride solution, 400 ml of 3N sodium hydroxide and twice with 500 ml of saturated sodium chloride solution and the aqueous phases obtained are back-extracted twice with 200 ml of methylene chloride. The organic phases are dried over 200 g of sodium sulphate, filtered and evaporated on a rotary evaporator at 600 C. There are obtained 188.1 g of a brown, solid residue which contains 88.5% trans-4-(4propylcyclohexyl)acetophenone. Rf values: educt 0.70, product 0.43 (Merck plates F254/benzene).
806 ml of water and 682 ml of 28% sodium hydroxide are placed in a 10 litre four-necked sulphonation flask equipped with a stirrer, thermometer, condenser, 200 ml dropping funnel, 1 litre dropping funnel and apparatus for argon gasification and the solution is cooled to 50C with an ice-alcohol bath. 135 ml of bromine are added dropwise at 40--7 OC within 1 5 minutes and the orange solution is then stirred at this temperature for a further 5 minutes. After removal of the cooling bath, 880 ml of absolute dioxan are dropped into the solution within 1 5 minutes, the temperature rising to about 1 70C, and then within 65 minutes a solution of 187.9 g of the crude product obtained according to the preceding paragraph in 1100 ml of absolute dioxan is added dropwise.The temperature thereby rises to about 400C. The resulting suspension is stirred for a further 80 minutes and subsequently the excess hypobromite is reduced with 85 ml of sodium bisulphite solution. While cooling with an ice/methanol bath there are added dropwise within 10 minutes 280 ml of 37% hydrochloric acid (pH of the reaction solution=1), and thereafter the mixture is treated in a 20 litre stirring vessel with 4 litres of methylene chloride and 8 litres of saturated sodium chloride solution and stirred well. The aqueous phase is extracted twice with 3 litres of methylene chloride, the organic phases are combined, washed twice with 2 litres of saturated sodium chloride solution and dried over 500 g of sodium sulphate. Upon evaporation on a rotary evaporator at 700C there are obtained 198.6 g of a beige, solid residue.This is dissolved in 1250 ml of hot ethanol on a waterbath, the solution is cooled slowly to OOC and stirred at this temperature for 1 5 minutes. There thereby separate white crystals which are filtered off under suction, washed twice with 80 ml of icecold methanol and dried under a water-jet vacuum at 700C. There are obtained 134.7 g of trans-4-(4-propylcyclohexyl)benzoic acid with a purity of 100% (according to gas chromatography). Melting point: 2110--2140C; Rf value of the product 0.32 (Merck plates
F254/benzene-acetone 9:1). Yield 70.2% based on (4-propylidenecyclohexyl)benzene.
The starting material can be prepared as follows:
48.6 9 of sodium methylate are suspended in 1050 ml of absolute tetrahydrofuran in a 2.5 litre sulphonation flask equipped with a stirrer, thermometer, drying tube, 1 litre dropping funnel and apparatus for inert gasification and treated with 300.5 g of propyltriphenylphosphonium bromide. To this suspension there is then added dropwise, while cooling with ice, at 250--300C within 25 minutes a solution of 104.6 g of 4phenylcyclohexanone in 260 ml of absolute tetrahydrofuran.The mixture is stirred at room temperature for 23.5 hours and subsequently evaporated on a rotary evaporator at 600 C. The residue is treated with 800 ml of n-hexane, stirred well at room temperaturs for 30 minutes and left to stand for 1.75 hours at --100C in an icemethanol bath. Thereafter, the crystallised-out slurry is filtered under suction and the filter cake is washed twice with 200 ml of n-hexane. After evaporation of the filtrate on a rotary evaporator at 600C, there are obtained 124.6 g of a yellow oil which is distilled using a Widmer flask and a 30 cm long column. There are thus obtained 107.9 g (88.5%) of (4propylidenecyclohexyl)benzene in a purity of 98.6% (according to gas chromatography).
Boiling point: 121 or/0.06 Torr; Rf values: educt 0.39, product 0.73 (Merck plates F254/etherhexane 1:1).
Example 4
1.45 g of 4-(4-butylidenecyclohexyl)biphenyl are dissolved in 60 ml of ethanol in a hydrogenation apparatus equipped with a stirrer, thermometer and gas inlet tube and the solution is treated with 0.3 g of 5% platinum/carbon. The mixture is hydrogenated at room temperature and normal pressure. The hydrogenation comes to a standstill after the uptake of 175 ml of hydrogen.
The catalyst is filtered off under suction and the filtrate is evaporated in a rotary evaporator under a water-jet vacuum at 600 C. There are thus obtained 1.4 g of 4-(4-butylcyclohexyl)biphenyl consisting of 80% trans and 20% cis compound (according to gas chromatography).
The 4-(4-butylidenecyclohexyl)biphenyl used as the starting material is prepared as follows:
a) 50 g of 1 ,4-cyclohexanedione are dissolved in 1.1 litre of benzene in a 2.5 litre sulphonation flask equipped with a stirrer, condenser, waterseparator and apparatus for inert gasification.
After the addition of 27.5 g of ethyleneglycol and 0.5 g of p-toluenesulphonic acid monohydrate, the mixture is boiled at reflux for 49 hours while stirring and gassing with argon. Subsequently, the mixture is placed in a 2 litre separating funnel and washed successively with 200 ml of saturated sodium bicarbonate solution and 200 ml of saturated sodium chloride solution. The organic phase is dried over 200 g of sodium sulphate, the drying agent is filtered off under suction and washed on the suction filter with 200 ml of benzene. The filtrate is evaporated in a rotary evaporator under a water-jet vacuum at a bath temperature of 500C and the residue (60.3 g) is chromatographed over silica gel with ether/hexane. There are obtained 26.3 g of 1,4dioxaspiro-[4.5]decan-8-one which is pure according to thin-layer chromatography. Rf values: educt 0.27, product 0.41 (Merck plates
F254/ether).
b) 9.6 g of magnesium shavings are suspended in 330 mi of ether in a 2.5 litre sulphonation flask equipped with a stirrer, thermometer, dropping funnel, condenser, drying tube and apparatus for inert gasification. 76.6 g of 4-bromobiphenyl in 380 ml of ether are added dropwise within 1 hour while stirring and gassing with argon, a brown suspension resulting. This suspension is stirred under reflux for a further 10 hours. Subsequently, a solution of 34.2 g of 1 ,4-dioxaspiro[4.Sjdecan- 8-one in 330 ml of ether is added dropwise at room temperature and without cooling within 30 minutes. The mixture is boiled at reflux for a further 2 hours and subsequently cooled with an ice-bath. 440 ml of saturated ammonium chloride solution are added dropwise within 10 minutes at 15 50-200C while cooling with an icebath. The mixture is filtered and then the inorganic phase is separated and extracted twice with 500 ml of ether. The organic phases are washed four times with 200 ml of water, combined and dried over 300 g of sodium sulphate. The drying agent is filtered off under suction and washed with 300 ml of ether. The filtrate is evaporated in a rotary evaporator under a water-jet vacuum at 400 C.
The solid, light yellow crude product (81.6 g) obtained is chromatographed over silica gel with ether/hexane. There are thus obtained 60.4 g of light yellow product which is crystallised from 180 ml of toluene at --1 OOC. Yield: 51.45 g of 8 (4-biphenylyl)- 1,4-dioxaspiro[4.5]deca n-8-ol which is pure according to thin-layer chromatography; melting point: 1 32 0--1 33 OC; Rf values: educt 0.36, product 0.26 (Merck plates
F254/ether-hexane 3:1).
c) 15.25 g of 8-(4-biphenylyl)-1 ,4- dioxaspiro[4.5]-decan-8-ol are dissolved in 365 ml of benzene in a sulphonation flask equipped with a stirrer, condenser, thermometer, waterseparator, drying tube and apparatus for inert gasification and the solution is treated with 2.8 9 of p-toluenesulphonic acid monohydrate.
Subsequently, the mixture is boiled at reflux for 2 hours while stirring and gassing with argon, then treated with 25 ml of 3N sodium hydroxide and placed in a separating funnel. Two further separating funnels are each charged with 250 ml of benzene and then three 250 ml portions of water are successively passed through the three separating funnels. The organic phases are combined, dried over sodium sulphate, filtered under suction and back-washed with 200 ml of benzene. Subsequently, the filtrate is evaporated in a rotary evaporator under a water-jet vacuum at 500C. The light yellow, solid crude product (42.5 g) obtained is crystallised from 580 ml of cyclohexane and dried.Melting point: 1440-- 1 450C; yield 37.8 g of 8-(4-biphenylyl)-1 ,4- dioxaspiro[4.5]dec-7-ene; purity 98.4% (according to gas chromatography).
d) 21.5 g of 8-(4-biphenylyl)-1 4- dioxaspiro[4.5]dec-7-ene are dissolved in 220 ml of ethyl acetate in a stirring autoclave, treated with 2.1 g of 5% platinum/carbon and hydrogenated for 5 hours at 700C and 100 atmospheres. The mixture is then filtered and the filter cake is washed twice with 100 ml of ethyl acetate. The filtrate is evaporated in a rotary evaporator under a water-jet vacuum at 500C, the solid residue (17.75 g) is recrystallised from 180 ml of methanol, filtered off under suction and washed twice with 20 ml of cold methanol. The white crystals are dried to give 13.4 g of 8-(4 biphenylyl)-1,*4-dioxaspiro[4.5]decane in 95.3% purity (according to gas chromatography); melting point: 1030-1040C.
e) 18.6 g of 8-(4-biphenylyl)-1 4- dioxaspiro[4.5]-decane are dissolved in 93 ml of glacial acetic acid in a sulphonation flask equipped with a stirrer, condenser, drying tube, thermometer and apparatus for inert gasification and the solution is treated with 2.4 g of ptoluenesulphonic acid monohydrate. The mixture is held at 800C for 3 hours while stirring and gassing with argon, subsequently treated with 930 ml of water and extracted three times with 500 ml of methylene chloride. The methylene chloride phases are each washed with saturated sodium bicarbonate solution and water, then combined and dried over sodium sulphate. The drying agent is filtered off under suction, backwashed twice with 200 ml of methylene chloride and subsequently the filtrate is evaporated in a rotary evaporator under a water-jet vacuum at 500C.The residue (25.05 g) is crystallised from 100 ml of hot isopropanol, filtered off under suction, washed twice with 10 ml of methanol and dried. Yield: 14.45 g of 4-(4biphenylyl)cyclohexanone in 99.2% purity (according to gas chromatography); melting point: 1140--1180C.
f) 9.55 g of potassium tert.butylate are suspended in 100 ml of absolute dimethoxyethane in a sulphonation flask equipped with a stirrer, condenser, thermometer, dropping funnel, drying tube and apparatus for inert gasification. 29.45 g of butyltriphenylphosphonium bromide are added while stirring and gassing with argon and the redorange suspension is stirred at room temperature for a further 40 minutes. Subsequently, 14.2 g of 4-(4-biphenylyl)cyclohexanone in 1 50 ml of absolute dimethoxyethane are added dropwise at 250--300C within 12 minutes, the mixture is stirred at room temperature for a further 3 hours and then treated with 14 ml of water. The separated product is filtered off under suction and the filter cake is washed twice with 100 ml of ether.The filtrate is washed three times with 250 ml of water and each of the aqueous phases is extracted twice with ether. The organic phases are combined and dried over sodium sulphate.
Thereafter, the drying agent is filtered off under suction and washed twice with 200 ml of ether.
The filtrate is evaporated in a rotary evaporator under a water-jet vacuum at 600C. The residue (36.4 g) is treated with 1 80 ml of hexane, stirred at 600C for 20 minutes in a rotary evaporator, subsequently cooled two 400 with an icemethanol bath, filtered and the filter cake is washed twice with 50 ml of hexane. The filtrate is evaporated in a rotary evaporator under a waterjet vacuum at 600C and the colourless residue (15.55 g) is chromatographed on silica gel with hexane. Yield: 12.25 g of 4-(4butylidenecyclohexyl)biphenyl in 99.5% purity (according to gas chromatography); melting point: 440--460C; Rf values: educt 0.31, product 0.69 (Merck plates F254/ether-hexane 2:1).
Claims (10)
1. A process for the manufacture of trans-1 ,4- disubstituted cyclohexane compounds, which process comprises catalytically hydrogenating a compound of the general formula
wherein:
R' represents straight-chain alkyl containing 1-11 1 carbon atoms and R2 represents phenyl, 4- biphenylyl or a group convertible into the carboxyl group, and, if desired, in a manner known per se converting a thus-obtained compound of the general formula
wherein:
R3 represents phenyl or 4-biphenylyl and R1 has the significance given earlier in this claim, by introducing the cyano group into the p-position of the phenyl group or into the 4'-position of the 4-biphenylyl group, into a compound of the general formula
wherein::
R1 has the significance given earlier in this claim and n stands for 1 or 2, or reacting an obtained compound of the general formula
wherein:
R1 has the significance given earlier in this claim and R4 represents a group convertible into the carboxyl group, optionally after conversion into the corresponding carboxy compound, with a compound of the general formula
wherein:
R5 represents cyano, alkyl containing 1-10 carbon atoms or alkoxy containing 1-10 carbon atoms, or a suitable salt thereof to give a compound of the general formula
wherein:
R' and R5 have the significance given earlier in this claim.
2. A process according to claim 1, wherein a noble metal hydrogenation catalyst is used as the catalyst.
3. A process according to claim 2, wherein a platinum or palladium catalyst is used as the catalyst.
4. A process according to any one of claims 1 to 3, wherein a starting material of formula II in which R1 represents alkyl containing 1-8 carbon atoms is used.
5. A process according to claim 4, wherein a starting material of formula 11 in which R1 represents alkyl containing 2-6 carbon atoms is used.
6. A process according to any one of claims 1 to 5, wherein a starting material of formula II in which R2 represents phenyl or 4-biphenylyl is used.
7. A process according to any one of claims 1 to 5, wherein a starting material of formula Ii in which R2 represents a group convertible into the carboxyl group is used.
8. A process according to claim 7, wherein a starting material of formula II in which R2 represents an ester group is used.
9. Compounds of the general formula
wherein: R'-represents straight-chain alkyl containing 1-11 1 carbon atoms and R2 represents phenyl, 4- biphenylyl or a group convertible into the carboxyl group.
10. The compound of the formula
wherein:
R7 represents 4-biphenylyl.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH878879 | 1979-09-28 | ||
| CH529880 | 1980-07-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2060680A true GB2060680A (en) | 1981-05-07 |
Family
ID=25697416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8031078A Withdrawn GB2060680A (en) | 1979-09-28 | 1980-09-26 | Catalytic Hydrogenation |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE3036717A1 (en) |
| GB (1) | GB2060680A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0089207A1 (en) * | 1982-03-12 | 1983-09-21 | BUSH BOAKE ALLEN Limited | Friedel-Craft reactions |
| CN103435437A (en) * | 2013-09-06 | 2013-12-11 | 黑龙江省科学院石油化学研究院 | Method for synthesizing 4-(trans, trans-4-alkylcyclohexyl) fluorobenzene liquid crystal monomer compounds |
| US9580651B2 (en) | 2013-07-30 | 2017-02-28 | Semiconductor Energy Laboratory Co., Ltd. | Organic compound, liquid crystal composition, liquid crystal element, and liquid crystal display device |
| CN111039917A (en) * | 2019-12-24 | 2020-04-21 | 彩客化学(沧州)有限公司 | Preparation method of 1, 4-cyclohexanedione mono-ketal |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2017252B1 (en) * | 2006-05-09 | 2012-12-19 | Mitsubishi Gas Chemical Company, Inc. | Preparation of 4-(4-alkylcyclohexyl)benzaldehyde |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2933544A1 (en) * | 1979-08-18 | 1981-03-26 | Kabushiki Kaisha Suwa Seikosha, Shinjuku, Tokio/Tokyo | Cyclohexane-carboxylic acid ester with phenyl-phenol deriv. - useful as liq. crystal compsn. |
-
1980
- 1980-09-26 GB GB8031078A patent/GB2060680A/en not_active Withdrawn
- 1980-09-29 DE DE19803036717 patent/DE3036717A1/en not_active Withdrawn
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0089207A1 (en) * | 1982-03-12 | 1983-09-21 | BUSH BOAKE ALLEN Limited | Friedel-Craft reactions |
| WO1983003247A1 (en) * | 1982-03-12 | 1983-09-29 | Ferber, Gerald, John | Friedel craft reactions |
| US4515990A (en) * | 1982-03-12 | 1985-05-07 | Bush Boake Allen Limited | Preparation of indanes, tetralins and phenyl alcohol in Friedel Craft reaction |
| US9580651B2 (en) | 2013-07-30 | 2017-02-28 | Semiconductor Energy Laboratory Co., Ltd. | Organic compound, liquid crystal composition, liquid crystal element, and liquid crystal display device |
| CN103435437A (en) * | 2013-09-06 | 2013-12-11 | 黑龙江省科学院石油化学研究院 | Method for synthesizing 4-(trans, trans-4-alkylcyclohexyl) fluorobenzene liquid crystal monomer compounds |
| CN111039917A (en) * | 2019-12-24 | 2020-04-21 | 彩客化学(沧州)有限公司 | Preparation method of 1, 4-cyclohexanedione mono-ketal |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3036717A1 (en) | 1981-04-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Tsuji et al. | Palladium-catalyzed decarboxylation-allylation of allylic esters of. alpha.-substituted. beta.-keto carboxylic, malonic, cyanoacetic, and nitroacetic acids | |
| KR101140523B1 (en) | Process for the preparation of stilbene derivatives | |
| JPH0641446B2 (en) | Cyclohexanecarbonitriles | |
| US4432885A (en) | Decalins | |
| US4707295A (en) | Bicyclooctane derivatives | |
| Olson et al. | A Stereospecific Synthesis of Vitamin A from 2, 2, 6‐Trimethyl‐Cyclohexanone | |
| CA2030107A1 (en) | Process for the production of 1-(aminomethyl)cyclohexane acetic acid | |
| GB2060680A (en) | Catalytic Hydrogenation | |
| US4652089A (en) | Liquid crystalline compounds and mixtures | |
| US4053380A (en) | 1,1,1-trihalogeno-4-methylpentenes, method of preparing the same and use of the same in the preparation of 1,1-dihalogeno-4-methyl-1,3-pentadienes | |
| KR101429426B1 (en) | 4-(4-alkylcyclohexyl)benzaldehyde | |
| US4970345A (en) | Process for preparing oxocyclopentene derivatives | |
| EP3505506A1 (en) | Method for producing 3,7-dimethyl-7-octenol and method for producing 3,7-dimethyl-7-octenyl carboxylate compound | |
| EP1162190A2 (en) | Production process of cyclohexenyl methyl ketones | |
| US3949006A (en) | Synthesis of vitamin A, intermediates and conversion thereof to vitamin A | |
| US4092366A (en) | Synthesis of Vitamin A, intermediates and conversion thereof to Vitamin A | |
| US4009202A (en) | 2(or 3)-methyl-1-acetoxy-4-alkoxy (or phenoxy)-1,3-butadienes | |
| Goering et al. | Preparation and determination of absolute rotations and configurations of 6, 7-dimethoxy-1, 2-dimethyl-exo-2-benzonorbornenyl derivatives | |
| US4064162A (en) | Synthesis of intermediates for vitamin A | |
| US4594456A (en) | Racemic and optically active 3-hydroxy-alpha-cyclocitral, its acetals and optically active 3-oxo-alpha-cyclocitral acetals, and their preparation | |
| US5777170A (en) | Process for the preparation of a naphthylbutanone | |
| US5302745A (en) | Process for the preparation of alkyl 3-oxo-2-pentyl-1-cyclopentene acetates | |
| US5563297A (en) | Intermediates for the preparation of vitamin A and carotenoids and process for their preparation | |
| US4547586A (en) | Preparation of 2-isopropenyl-or 2-isopropylidenyl-3-hexenoates from chrysanthemic acid esters | |
| Dahill et al. | Stereospecific synthesis of trans-3 (exo-5-exo-isocamphyl) cyclohexanol |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |