Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Patent
1990-05-03
1991-11-26
Maples, John S.
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
25229901, 2522996, 25229963, 25229964, 25229965, 25229966, 25229967, 558423, 558414, 558415, 558416, 558425, 558428, 558431, 560 59, 560102, C07C25500, C09K 1952
Patent
active
050683896
DESCRIPTION:
BRIEF SUMMARY
The invention relates to tertiary alcohols of the formula I ##STR2## wherein R.sup.1 is halogen or alkyl which has 1-15 C atoms and in which one or two non-adjacent CH.sub.2 groups can be replaced by 0 atoms and/or --CO-- groups and/or --CO--O-- groups and/or --CH.dbd.CH-- groups, or, in the event that Y is H or CN, R.sup.1 is also H, monosubstituted or polysubstituted by halogen and/or CH.sub.3 groups, single bond, polysubstituted by halogen and/or CH.sub.3 groups, ##STR3## Z.sup.2 is --COOR or --CN, Q.sup.3 is alkylene having 1-15 C atoms, alkylidene having 2-15 C atoms, an aromatic system or a single bond, metal alcoholates thereof and to a process for the preparation of these compounds.
Tertiary alcohols of the formula I are of great interest as intermediate products for the preparation of liquid-crystal compounds.
Readily accessible intermediate products from which the corresponding substances having liquid-crystal properties can be obtained in as few stages of synthesis as possible are required for the preparation of liquid-crystal substances.
It was the object of the present invention to find appropriately readily synthesizable intermediate products for the preparation of liquid crystals and also a process for their preparation.
This object has been achieved by providing the tertiary alcohols of the formula I and a process for their preparation.
All the processes hitherto known for the preparation of similar compounds of the formula I lead to unsatisfactory results. The factors responsible for this are, above all, poor yields and in some cases starting compounds which are difficult of access.
Para-substituted phenylcyclohexanecarboxylic acids and their esters are prepared, for example, by reacting cyclohexene with acetyl chloride/AlCl.sub.3 and with benzene, followed by haloform degradation of the ketone to the carboxylic acid (described in J. Amer. Chem. Soc. 67, 1045 (1945), W.S. Johnson et al. and by Nenitzescu et al., Ann. 519 (260) 1935). The substituent in the p-position, for example OCH.sub.3, must then be introduced by electrophilic aromatic substitution (for example nitration, reduction, diazotization, introduction of the OH group and methylation), which is a very involved route.
A further example describes the process for the preparation of 4-[4-(trans-4-alkylcyclohexyl)-phenyl]-cyclohexanecarboxylic acids (according to EP 90,671) by reducing 4-[trans-4-alkylcyclohexyl]biphenyl-4-carboxylic acid with metallic sodium in isoamyl alcohol. The disadvantages of this process are a very high consumption of reducing agent and relatively low yields. A process is also known for the preparation of compounds of the formula I, described in J. Org. Chem. 39, 2787, in which corresponding Grignard compounds are reacted with cyclohexanones. Undesirable side reactions (such as, for example, aldol reactions between the carbonyl compounds) often take place in this process, however.
Products similar to the compounds of the formula I are also described, for example, in German Patent Specification 2,701,591. In this patent 4-alkylcyclohexanones are reacted with aromatic Grignard compounds.
However, this process is not possible for the preparation of the tertiary alcohols of the formula I, since Grignard compounds would attack both the keto group on the cyclohexanone and also the CN or ester group present in the p-position. In the case of reaction with Grignard compounds, it would be necessary to re-introduce a substituent of this type subsequently.
It was therefore the object of the present invention also to find a process for the preparation of the compounds of the formula I which does not have the disadvantages described in the present processes or has these disadvantages only to a slight extent.
It has been found, surprisingly, that organozirconium or organotitanium compounds are excellently suitable for the preparation of compounds of the formula I.
The invention therefore relates to the compounds of the formula I', ##STR4## wherein R.sup.1, A.sup.1, Z.sup.1, m, A.sup.2, Y, Q.sup.3 and Z.sup.2 have the meani
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Eidenschink Rudolf
Krause Joachim
Kurmeier Hans-Adolf
Wachtler Andreas
Maples John S.
Merck Patent Gesellschaft mit beschrankter Haftung
Treanor Richard
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