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US 5,396,014 AGranted
Process for the preparation of 4,4-dimethyl-2-pentene
AssigneeFirmenich SA
InventorsJean-Paul Leresche, Yves Mentha
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AssigneeFirmenich SA
InventorsJean-Paul Leresche, Yves Mentha
Estimating the term…
1,1,2,3,4,4,6-Heptamethyl-1,2,3,4-tetrahydronaphthalene, a novel naphthalenic compound, is useful as an intermediate for the preparation of 5,6,7,8-tetrahydro-3,5,5,6,7,8,8-heptamethyl-2-naphthalenecarbaldehyde. It is prepared by a process consisting in the addition of an olefin of formula ##STR1## wherein R.sup.1 and R.sup.2 represent different substituents and each defines a hydrogen atom or a methyl radical, with p-cymene. 4,4-Dimethyl-2-pentene [compound (III): R.sup.1 =CH.sub.3 ; R.sup.2 =H] is obtained by the co-metathesis reaction of an olefin of formula ##STR2## wherein R.sup.1 and R.sup.2 represent identical substituents designating each a hydrogen atom or a methyl radical, with an olefin of formula ##STR3## wherein R.sup.3 and R.sup.4, identical or different, designate each a hydrogen atom or a methyl radical in the presence of an appropriate catalyst consisting of Re.sub.2 O.sub.7 on an inert solid carrier, or of WCl.sub.6 /(C.sub.2 H.sub.5).sub.2 O/Bu.sub.4 Sn.
Process for the preparation of 4,4-dimethyl-2-pentene, comprising contacting an olefin of formula ##STR14## wherein R.sup.1 and R.sup.2 represent identical substituents designating each a hydrogen atom or a methyl radical, and an olefin of formula ##STR15## wherein R.sup.3 and R.sup.4, identical or different, designate each a hydrogen atom or a methyl radical, at a temperature comprised between around 30.degree. and 100.degree. C., with a catalytic system consisting of Re.sub.2 O.sub.7 on an inert solid carrier, or of WCl.sub.6 /(C.sub.2 H.sub.5).sub.2 O/Bu.sub.4 Sn.
Dependencies are inferred from the claim text.
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With a bicyclo ring system containing ten carbon atoms: completely or partially hydrogenated naphthalenes
Metathesis reactions at an unsaturated carbon-to-carbon bond: at a carbon-to-carbon double bond
Manganese, technetium or rhenium: rhenium
Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon…
Term ended 29 Mar 2013 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to the field of organic synthesis. More particularly, it concerns a novel naphthalenic compound and its use as an intermediate product for the preparation of a prized perfuming ingredient.
Published European patent application No. 405 427-A2 describes a series of naphthalenic compounds of formula ##STR4## wherein a) indexes m and n are identical and each defines an integer number equal to 0, symbols R.sup.1 and R.sup.2 are identical and represent each a hydrogen atom, or are different and represent each a hydrogen atom or a methyl radical, symbols R.sup.5 and R.sup.8 represent each a methyl radical, symbols R.sup.6 and R.sup.7, identical or different, represent each a hydrogen atom or a methyl radical, and either symbol R.sup.4 represents a methyl radical and symbol R.sup.3 a hydrogen atom or a methyl radical, or symbols R.sup.3 and R.sup.4 represent each a methylene radical belonging to a cycle as indicated by the dotted line, with the proviso that the following combinations are excluded:
1. R.sup.1 =R.sup.2 =R.sup.3 =R.sup.6 =R.sup.7 =H, or
The present invention is provided in this context. It brings in fact a novel solution of which there was no suggestion in the cited reference. It hinges on a critical element consisting of a useful intermediate of the synthesis of 5,6,7,8-tetrahydro-3,5,5,6,7,8,8-heptamethyl-2-naphthalenecarbaldehyde. Said intermediate is a hydrocarbon of formula ##STR5## or 1,1,2,3,4,4,6-heptamethyl-1,2,3,4-tetrahydronaphthalene (hereafter designated as "HpMT"), which can be converted into the desired aldehyde via a formylation reaction according to the following reaction scheme: ##STR6##
HpMT is a novel chemical entity which can be obtained, thanks to a process which is also the object of the invention, by reacting p-cymene and an olefin of formula ##STR7## wherein R.sup.1 and R.sup.2 represent distinct substituents and each defines a hydrogen atom or a methyl radical. This is a reaction which can be carried out by analogy with known methods [see, to this effect: patent application JP 82 40420 -cf. C.A. 97, 38653 f]. It is based on the principle illustrated by way of the following reaction scheme: ##STR8##
The reaction takes place in the presence of catalytic amounts of aluminium chloride, to which there is optionally added iodine [cf. U.S. Pat. No. 4,551,573].