Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-07-03
2003-08-19
Keys, Rosalynd (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S630000, C568S633000, C568S648000
Reexamination Certificate
active
06608232
ABSTRACT:
The present invention relates to a process for preparing a benzyl type ether from an aromatic compound.
The term “benzyl type ether” means a compound comprising at least one aromatic carbocycle or heterocycle wherein one hydrogen directly bonded to the aromatic ring is replaced by an ether finction.
Benzyl type ethers are not easy to produce on an industrial scale.
Not only are the reactants generally expensive, but also secondary reactions are possible since the starting alcohols and the ethers obtained readily form peroxides, which carry a large risk of explosion.
The aim of the present invention is to provide a process for producing a benzyl type ether from an aromatic compound that can avoid the disadvantages mentioned above.
More precisely, the invention provides a process for preparing a benzyl type ether from an aromatic compound, characterized in that it consists of;
in a first step, acylating an aromatic compound by reacting said compound with an acylation agent in the presence of an effective quantity of a zeolite or a Friedel-Crafts catalyst to produce a ketone compound;
in a second step, reducing the carbonyl group to a carbinol group to produce a benzyl type alcohol;
in a third step, etherifying the hydroxyl group by reacting the benzyl type alcohol with a further alcohol in the presence of an effective quantity of a zeolite.
In accordance with the process of the invention, in the first step, an aromatic compound is acylated by reacting it with an acylation agent.
The term “aromatic compound” as used in the present invention defines the conventional notion of aromaticity as defined in the literature, in particular by Jerry MARCH, “Advanced Organic Chemistry”, 4
th
edition, John Wiley & Sons, 1992, pp. 40 ff.
The term “acylation agent” is used in a generic manner and designates any agent that can enable a carbonyl group to be attached to an aromatic nucleus, in particular benzoylation agents.
More precisely, the present invention provides a process for acylating an aromatic compound with general formula (I):
in which:
A represents the residue of a cycle forming all or a portion of an aromatic, monocyclic or polycyclic, carbocyclic or heterocyclic system: said cyclic residue may carry a group R representing a hydrogen atom or one or more identical or different substituents;
n represents the number of substituents on the cycle.
The invention is of particular application to aromatic compounds with formula (I) in which A is a residue of a cyclic compound preferably containing at least 4 atoms in the cycle, preferably 5 or 6, which may be substituted, and representing at least one of the following cycles:
an aromatic, monocyclic or polycyclic carbocycle;
an aromatic, monocyclic or polycyclic heterocycle containing at least one of the heteroatoms O, N or S.
Without in any way limiting the scope of the invention, residue A, which may be substituted, represents the following residue:
1. of a monocyclic or polycyclic, aromatic carbocyclic compound. The term “polycyclic carbocyclic compound” means:
a compound constituted by at least two aromatic carbocycles forming ortho- or ortho- and peri-condensed systems between them;
a compound constituted by at least two carbocycles only one of which is aromatic and forming-ortho- or ortho- and peri-condensed systems between them.
2. of an aromatic, monocyclic or polycyclic heterocyclic compound. The term “polycyclic heterocyclic compound” means:
a compound constituted by at least 2 heterocycles containing at least one heteroatom in each cycle wherein at least one of the two cycles is aromatic and between them they form ortho- or ortho- and peri-condensed systems;
a compound constituted by at least one hydrocarbon cycle and at least one heterocycle wherein at least one of the cycles is aromatic and between them they form ortho- or ortho- and peri-condensed systems.
3. of a compound constituted by a concatenation of cycles, as defined in paragraphs 1 and/or 2 bonded together:
by a covalent bond;
by an alkylene or alkylidene group containing 1 to 4 carbon atoms, preferably a methylene or isopropylidene group;
by one of the following groups:
in which formulae, R
0
represents a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms, a cyclohexyl group or a phenyl group.
More particularly, residue A, which may be substituted, represents the residue:
of an aromatic monocyclic carbocyclic compound such as benzene, toluene, isobutylbenzene, anisole, thioanisole, phenetole or veratrole, guaiacol, guetol;
of an aromatic condensed polycyclic compound such as naphthalene or 2-methoxynaphthalene;
of an aromatic, carbocyclic, non condensed polycyclic compound such as phenoxybenzene;
of a partially aromatic, carbocyclic condensed polycyclic compound such as tetrahydronaphthalene or 1,2-methylenedioxybenzene;
of a partially aromatic, carbocyclic non condensed polycyclic compound such as cyclohexylbenzene;
of an aromatic, heterocyclic, monocyclic compound such as pyridine, furan or thiophene;
of an aromatic, partially heterocyclic, condensed polycyclic compound such as quinoline, indole or benzofuran;
of an aromatic, partially heterocyclic, non condensed polycyclic compound such as phenylpyridines or naphthylpyridines;
of a partially aromatic, partially heterocyclic condensed polycyclic compound such as tetrahydroquinoline;
of a partially aromatic, partially heterocyclic non condensed polycyclic compound such as cyclohexylpyridine.
In the process of the invention, an aromatic compound with formula (I) is preferably used in which A represents an aromatic nucleus, preferably a benzene or naphthalene nucleus.
The aromatic compound with formula (I) may carry one or more substituents.
The number of substituents present on the cycle depends on the carbon condensation of the cycle and the presence or otherwise of unsaturated bonds on the cycle.
The maximum number of substituents that can be carried by a cycle can readily be determined by the skilled person.
In the present text, the term “plurality” generally means less than five substituents on an aromatic nucleus.
Examples of substituents are given below but this list is not limiting in nature. Particular examples that can be cited are:
linear or branched alkyl groups, preferably containing 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms;
linear or branched alkenyl groups, preferably containing 2 to 6 carbon atoms, more preferably 2 to 4 carbon atoms;
linear or branched halogenoalkyl groups, preferably containing 1 to 6 carbon atoms and 1to 13 halogen atoms, more preferably 1 to 4 carbon atoms and 1 to 9 halogen atoms;
cycloalkyl groups containing 3 to 6 carbon atoms, preferably cyclohexyl;
the phenyl group;
the benzyl group;
the hydroxyl group;
the NO
2
group;
R
1
—O— alkoxy groups or R
1
—S— thioether groups in which R
1
represents a linear or branched alkyl group containing 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, or the phenoxy group; and alkenyloxy groups, preferably an allyloxy group;
—N—(R
2
)
2
groups, in which groups R
2
, which may be identical or different, represent a hydrogen atom, a linear or branched alkyl group containing 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, or a phenyl group;
—NH—CO—R
2
groups, where group R
2
has the meaning defined above;
carboxy groups or R
2
—O—CO— derivatives in which group R
2
has the meaning defined above;
acyloxy or aroyloxy R
1
—CO—O— groups in which group R
1
has the meaning defined above;
a halogen atom, preferably a fluorine atom;
a CF
3
group;
two groups R placed on two neighbouring carbon atoms may together with the carbon atoms carrying them form a cycle containing 5 to 7 atoms, optionally comprising a further heteroatom.
When n is 2 or more, two groups R and two successive atoms of the aromatic cycle can be bonded together by an alkylene, alkenylene or alkenylidene group containing 2 to 4 carbon atoms to form a saturated, unsaturated or aromatic heterocycle containing 5 to 7 carbon atoms. One or more carbon atoms can be replaced by a further heteroatom, preferably oxygen or sulphur. Groups R may r
Jacquot Roland
Spagnol Michel
Chimie Rhodia
Keys Rosalynd
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