Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1999-01-29
2000-03-07
Geist, Gary
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568315, 568317, 568347, 568349, 568395, C07C 4548
Patent
active
06034279&
DESCRIPTION:
BRIEF SUMMARY
1. SUBJECT-MATTER OF THE INVENTION
The present invention relates to improvements in a process for preparing .gamma.,.delta.-unsaturated ketones by a Carroll reaction.
A number of .gamma.,.delta.-unsaturated ketones have proved to be valuable aroma substances and to be intermediates for producing vitamins E and K.sub.1 and carotenoids.
2. Prior art
DE 1 193 490 discloses a process for preparing .gamma.,.delta.-unsaturated ke-tones by reacting a tertiary alcohol with enol ethers in the presence of an acid catalyst at elevated temperature. A particularly suitable acid catalyst mentioned here is phosphoric acid. The reaction times required to achieve complete conversion of the tertiary allyl alcohol are from 13 to 18 hours at from 125 to 140.degree. C., a pressure of approximately 10 bar and a phosphoric acid concentration of from 0.1 to 0.2% by weight. A disadvantage of this method is the long reaction times which, in an industrial process, give rise to large reaction volumes and thus high capital expenditure.
The conventional way of accelerating chemical reactions is to increase the reaction temperatures and/or to increase the amount of catalyst. If this is attempted in the reactions described in DE 1 193 490, the yields of .gamma.,.delta.-unsaturated ketones decrease, so that an industrial process is no longer economical (see comparative examples 1-3).
3. OBJECT OF THE INVENTION
It is an object of the present invention to decrease the reaction times of the reaction of tertiary allyl alcohols with alkenyl ethers without impairing the yield.
4. SUMMARY OF THE INVENTION
We have found that this object is achieved, surprisingly, by special phosphorus derivatives which catalyze the reaction of tertiary allyl alcohols with alkenyl ethers very selectively at comparatively short reaction times.
The present invention therefore relates to a process for preparing .gamma.,.delta.-unsaturated ketones of the formula I ##STR2## where R.sup.1 and R.sup.2 are each a saturated or unsaturated branched or unbranched alkyl, an aryl or an alkylaryl, each of which is unsubstituted or substituted by an oxygen-containing group of which may be substituted by one or more lower alkyls, allyl alcohol of the formula II ##STR3## with an alkenyl alkyl ether of the formula III ##STR4## where R.sup.3 is a C.sub.1 -C.sub.4 -alkyl, preferably a methyl, and R.sup.4 and R.sup.5 have the meaning specified above, catalyst, which comprises carrying out the reaction in the presence of a phosphorus derivative of the formula IV ##STR5## where A and B are each a branched or unbranched alkyl or alkoxy having from 1 to 10 carbons, an aryl, cycloalkyl, aryloxy or cycloalkyloxy, each of which may be substituted by one or more C.sub.1 -C.sub.4 -alkyl or alkoxy groups, OH groups or halogen; be substituted by one or more alkyls having 1 or 2 carbons, or together are a substituted or unsubstituted 1,2-phenyl-diol or a substituted or unsubstituted 1,1'-binaphthyl-2,2'-diol.
The process according to the invention is particularly successful if the tertiary allyl alcohol of the formula II is reacted with the alkenyl alkyl ether of the formula III in the presence of phosphorus-containing aryl or aryloxy derivatives. Examples are, in particular, phenylphosphonic acid, diphenylphosphinic acid, phenyl phosphate and diphenyl phosphate. On an industrial scale, a mixture of phenyl phosphate and diphenyl phosphate is generally used, as obtained simply and cheaply in the reaction of phenol with POCl.sub.3 and subsequent hydrolysis.
The catalysts claimed for the process according to the invention may be readily synthesized on a preparative scale using standard methods (cf. Houben-Weyl, "Methoden der Organischen Chemie" [Methods in organic chemistry], 4th edition, 1964, Volume 12,2, pages 143 to 376 for phosphoric esters; volume 12,1, pages 220 to 266 for the phosphinic acids and volume 12,1, pages 348 to 550 for the phosphonic acids).
They are generally used in a concentration of from 0.0001 mol to 1 mol, preferably from 0.001 mol to 0.05 mol, of catalyst per kg o
REFERENCES:
patent: 3453317 (1969-07-01), Marbet et al.
patent: 4892977 (1990-01-01), Nieh
patent: 5077442 (1991-12-01), Hara et al.
Houben-Weyl, "Methods in Organic Chemistry", 4.sup.th Edition, 1964, vol. 12,2 (pp. 143-376 for phosphoric esters).
Houben-Weyl, "Methods in Organic Chemistry", 4.sup.th Edition, 1964, vol. 12,1 (pp. 220-266 for the phosphinic acids).
Houben-Weyl, "Methods in Organic Chemistry", 4.sup.th Edition, 1964, vol. 12,1 (pp. 348-550 for the phosphonic acids).
Kashammer Stefan
Ruff Detlef
BASF - Aktiengesellschaft
Geist Gary
Padmanabhan Sreeni
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