Title of Invention

PROCESS FOR PRODUCING NOVEL INDENOL ESTERS OR ETHERS

Abstract The present invention relates to a process for making indenol esters or ether from an α-substituted cinnamic aldehyde derivative such as an acetal or an acylal. Said reaction is promoted by the use of strong mineral acids, sulphonic acids, acidic zeolites or Lewis acids.
Full Text Technical field
The present invention relates to the field of organic synthesis, and more
particularly it provides a process for making novel indenol esters or ethers from an α-
substituted cinnamic aldehyde derivative such as an acyclic acetal or an acylal. Said
reaction is promoted by the use of strong mineral acids, sulphonic acids, acidic zeolites or
Lewis acids.
Prior art
The compounds of formula (I), as defined below, can be useful as perfuming
ingredients and/or as starting material for the synthesis of compounds having a more
complex skeleton.
The methods of preparation of said compounds reported in the prior art are in
general quite long and/or expensive and use different reagents. For example, syntheses of
an indenol ester are described by J.A. Pincock et al. (Can.J.Chem. 2003, 1083) by an aryl-
propanoin acid ester cyclisation and then reduction or by reacting an indenol and a
carboxylic acid chloride, or by S.Kapur et al (CanJ.Chem. 1998, 2888) by pyrolisis of a
diazoindene, or by S.Hansson et al. (J.O.C. 1990, 975) by reacting indene and an acetic
acid.
It is therefore highly desirable to access such compounds by means of a simple and
efficient isomerisation process wherein the starting material is an easily accessible
material. To the best of our knowledge, in the prior art there is no report of an
isomerisation process giving a direct access to compounds of formula (I) from the
compound of formula (II).
Description of the invention
In order to solve the problems aforementioned, a first embodiment of the present
invention provides a process for making a compound of formula


wherein R1 represents a formyl group, a -COCOOH group or a group of formula
-(CO)n-R, n being 0 or 1 and R representing an optionally substituted phenyl group or a
C1-6 alkyl or alkenyl group optionally halogenated;
R2 represents a C1-10 alkyl or alkenyl group; and
at least one R3 represents a hydrogen atom and the other R3 represent each a hydrogen
atom or a C1-5 alkyl, alkenyl or alkoxy group;
comprising the cyclisation, at a temperature above 10° C, of the corresponding compound
of formula

wherein each R4, taken separately, represents a fonnyl group or a -(CO)n-R group, or
the R4, taken together, represent a -COCO- group;
the wavy line indicates that the configuration of the carbon-carbon double bond is E or
Z or a mixture thereof; and
n, R, R2, R3 and R4 have the meaning as indicated above;
in the presence of a compound, which promotes the reaction, selected from the group
consisting of strong mineral protic acids, sulphonic acids, acidic zeolites and Lewis acids.
Examples of the substituent of R, when it is a phenyl, are one or two halogen
atoms, C1-5 alkyl or alkoxy or C0-6 amino groups. Examples of halogens for R are chlorine
or fluorine atoms.
For the invention purpose, it is important that R2 is not a hydrogen atom, indeed if
R2 is H then the reaction does not take place.
According to an embodiment of the present invention R1 represents a group of
formula -(CO)n-R, n being 0 or 1 and R representing an optionally substituted phenyl
group or a C1.5 alkyl group.
According to another embodiment of the present invention, R2 represents a C1-6
alkyl group.

According to a further embodiment of the present invention, at least two R3
represent a hydrogen atom and the other R3 may represent each a hydrogen atom or a C1-5
alkyl or alkoxy group.
According to a particular embodiment of the invention the compounds of
formula (I) are of formula

and are obtained by cyclisation of the corresponding compounds of formula

wherein the wavy line R1, R2 and. R4 have the same meaning as indicated above, and one
R3 is a hydrogen atom and the other R3 is a C1-5 alkyl group
The compounds of formula (I') wherein one R3 is a hydrogen atom and the other
R3 is a C1-5 alkyl group are new compounds and can be used as starting compounds for the
synthesis of indenols. Amongst said compounds of formula (F) can be cited the ones
wherein R2 is a methyl group and both R3 are hydrogen atoms or the ones wherein R2 is a
methyl group and one R3 is a hydrogen atom and the other R is a methyl group.
Amongst the compounds of formula (I'), those of formula


• wherein one R5 is a hydrogen atom and the other R5 is a C1-5 alkyl group and R6 or R7
represents a methyl or ethyl group;
are also new and can be used as perfuming ingredient to impart floral and/or indole odor
notes.
For example, one may cite 2,6-dimethyl-1H-inden-l-yl acetate which possesses an
odor of the muguet, acetophenone type with some cedar and indol connotations, or also
2,6-drmethyl-1H-inden-1-yl propanoate which has a floral-estery odor.
The compounds, which can be used in the invention's process to promote it, are a
strong mineral protic acid, a suphonic acid, an acidic zeolite or a Lewis acid. By '"mineral"
we mean here an acid having an anion which does not contain a carbon atom. By "strong"
we mean here a protic acid having a PKAB By "Lewis acid" we mean here an acid which is not essentially a protic acid. For
example one may cite BF3 and its adducts or Fe, Zn, Sn or Cd salts with weakly
coordinating anions such as halides, sulphonates carboxylates or non-coordinating anion.
Said compounds can be in the anhydrous form or also in the hydrate form, except
for those acids which are unstable in the presence of water.
According to another particular embodiment of the invention, the compound
promoting the reaction is selected from the group consisting of H2SO4, p-
toluenesulphonic acid, NaHS04, KHSO4, H3PO4, HCl, HNO3, BF3 and its adducts with
C2-6 ethers or with C2-6 carboxylic acids, poly(styrene sulphonic acid) based resins, K-10
Clay, SnX4, FeX3 and ZnX2, ZnI2, X representing a halogen atom, such as CI or Br, or a
C1-6 carboxylate, such as acetate or trifluoroacetate, or a C1-7 sulphonate, such as a triflate
or tosylate.
Preferably, the catalyst is H3PO4, FeX3 or ZnX2, and in particular FeCl3 or ZnCl2.
Said compounds can be added to the reaction medium in catalytic or
stoichiometric amounts or even in excess. As- non-limiting examples, one can cite
catalytic amounts ranging from 0.001 to 0.50 molar equivalents, relative to the molar
amount of the starting compound (II). Preferably, the catalyst concentrations will be
comprised between 0.005 and 0.30, or even between 0.005 and 0.15, molar.equivalents. It
goes without saying that the optimum concentration of catalyst will depend on the nature
of the catalyst and on the desired reaction time.

Another parameter of the invention's process is the temperature. In order to allow
the cyclisation to occur, it is useful to carry out the invention's process at a temperature of
at least 10°C. Below said temperature the speed of the reaction decreases quite rapidly.
The upper limit of temperature range is fixed by the reflux temperature of the reaction
mixture that, as skilled persons know, depends on the exact nature of the starting and final
product and optionally, as explained below, of the solvent. However, as non-limiting
example, one can cite a preferred temperature ranging between 60°C and 180°C. Of
course, a person skilled in the art is also able to select the preferred temperature as a
function of the melting and boiling point of the starting and final products as well as of
the solvent.
The process of the invention can be carried out in the presence or in the absence of
solvent. As a person skilled in the art can anticipate, the presence of a solvent is
mandatory only in the case in which the starting compound is a solid compound under the
reaction conditions.
However, according to a preferred embodiment of the invention, and
independently of the physical state of the starting compound, the process is
advantageously carried out in the presence of a solvent. Preferably, said solvent is
anhydrous or does not contain more than 5% w/w water.
Non-limiting examples of such a solvent are C4-C8 ethers, C3-C6 esters, C3-C6
amides, C6-C9 aromatic solvents, C5-C7 linear or branched or cyclic hydrocarbons, C1-C2
chlorinated solvents and mixtures thereof.
Furthermore, the reaction can also be carried out in the presence of a solvent'
belonging to the family of orthoesters of formula (RO)3CR or, and preferably, to the
family of carboxylic anhydride of formula RC(O)O(O)CR, R being defined as above,
optionally containing the corresponding carboxylic acid R8COOH.
The compound of formula (II) can be made and isolated according to any prior art
method. Alternatively, compound (II) can be also generated in situ, i.e. in the reaction
medium just before its use, according to any know prior art method.
In particular, preferably the compound of formula (II) is made or generated by a
method using the corresponding enal as starting material. Indeed, the enal can be easily
obtained by an aldol condensation, as a person skilled in the art knows well.

Therefore, another object of the present invention is an invention's process, as
defined above, further comprising the step of generating in situ the compound of
formula (H) starting from the corresponding enal of formula

wherein R2 and R3 have the same meaning indicated above.
A process comprising the in situ generation of the compound of formula (II) is
particularly useful when said compound (II) is an acylal, i.e. a geminal dicarboxylate.
Now, when the compound of formula (II) is an acylal, we have also noticed that
the compounds that are able to promote the cyclisation of the acylal are also useful to
promote the conversion of the enal into the corresponding acylal.
Therefore, another object of the present invention, and in fact a particular
embodiment of the above-mentioned process, is a process for making an ester of
formula (I), as defined above, comprising the step of reacting, in the presence of a catalyst
as defined for the cyclisation step, an enal of formula (IV), as defined above, with an
orthoesters of formula (RO)3CR or, and preferably, a carboxylic anhydride of formula
RC(O)O(O)CR, R being defined as above.
The invention will now be described in further detail by way of the following
examples, wherein the abbreviations have the usual meaning in the art, the temperatures
are indicated in degrees centigrade (°C). The NMR spectral data were recorded in CDCl3
at 400MHz or 100MHz for 1H or 13C, respectively, the chemical displacements δ are
indicated in ppm with respect to TMS as standard, and the coupling constants J are
expressed in Hz. All the abbreviations have the usual meaning in the art.

Example 1
Cyclisation of 2-alkylcinnamic aldehyde via the acylal derivative
a) Preparation of 2-pentyl-1H-inden-1-yl acetate
t
4.13 ml of a G.25 M solution of FeCI3'6H2O in Ac2O (1.03 mmol) where diluted into
Ac2O (30.2 g) and the resulting solution was added dropwise during 1 hour to a stirred
solution of 2-pentylcinnamaldehyde (20 g, 99 mmol) in AcOH (18.5 g) at reflux.
After a further 2 hours at reflux the cooled mixture was poured into a mixture of H2O
and Et2O. Then, solid Na2CO3 (44.7 g) was added portionwise to the stirred mixture.
After one hour stirring the aqueous phase was saturated with NaCl and extracted with
Et2O. The organic layers were dried over anhydrous Na2SO4, and the solvent
evaporated to afford a crude product, which was further purified by distillation under
vacuum to give the desired compound (yield = 87%).
B.p. 86-9370.05 mbar
1H-NMR: 0.90(br.t,J=7,3H); 1.35(4H); 1.58(m,2H); 2.17(s,3H); 2.29(m52H);
. 6.21(s,1H) ; 6.43(s,1H); 7.09(dd,J=7, J=7,1H) ; 7.13(d,J=7,1H); 7.23(m,1H);
7.37(d,J=7,1H)
13C-NMR: 171.4(s); 149.2(s); 143.7(s); 142.0(s); 128.9(d); 128.2(d); 125.1(d);
124.2(d) ; 120.4(d); 77.5(d); 31.6(f) ; 28.2(f) ; 27.7(f); 22.5(f) ; 21.1(q) ; 14.0(q)
b) Preparation of2-hexyl-1H-inden-1-yl acetate
Using the same experimental procedure as under a), 2-hexylcinnamaldehyde (20 g,
92.6 mmol), FeCl3'6H2O (3.85 ml of a 0.25 M solution in Ac2O, 0.96 mmol), Ac2O
(28.3 g, 0.28 mol) in AcOH (17.4 g) were reacted together. After a further 3 hours at
reflux the cooled mixture was treated to the same workup as before to provide the title
compound (yield = 83%)
B.p. 89-101°/ 0.035 mbar
1H-NMR: 0.89(t,J=7,3H); 1.25-1.40(613); 1.58(m£H); 2.17(s,3H); 2.29(m,2H);
6.21(s,1H); 6.43(s,1H); 7.09(dd,J=7,J=7,1H); 7.13(d,J=7,1H); 7,22(m,1H) ;
7.36(d,J=7,1H)

13C-NMR: 171.4(S); 149.3(S); 143.7(S); 142.0(B); 128.9(d); 128.2(d); 125.1(d);
124.2(d); 120.4(d); 77.5(d); 31.7(t); 29.1(t); 28.3(f); 28.0(t); 22.6(f);
21.1(q); 14.1(q)
c) Preparation of2-methyl-1H-inden-1-yl acetate
Using the same experimental procedure as under a), 2-methylcinnamaldehyde (21 g,
0.14 mol) in AcOH (27 g), FeCl3 6H2O (6 ml of a 0.25 M solution in Ac2O, 1.5 mmol)
in Ac2O (53 g) were reacted together. After a further 2 hours at reflux the cooled
mixture was treated to the same workup and purification as before to provide the title
compound (yield = 70%)
B.p. 70-9570.04 mbar.
lH-NMR: 1.98(s,3H); 2.18(s,3H); 6.15(s,1H); 6.41(s,1H) ; 7.09(dd,J=7,7, 1H);
7.12(41=7,111) ; 7.23(m,1H) ; 7.37(d,J=7,1H)
13C-NMR: 171.5(S); 144.4(S); 143.7(s); 142.1(s); 129.3(d); 128.9(d); 125.1(d);
124.2(d) ; 120.3(d); 78.4(d); 21.1 (q) ; 14.0(q)
Example 2
a) Preparation of 1-meihoxy-2-methyl-1H-indene via cyclisation of the acetal
A solution of FeCl3 anhydrous (42 mg, 0.25 mmol) in BuOAc (4 ml) was added
dropwise during 10 minutes to a stirred solution of the 3.3-dimethoxy-2-methyl-1 -
phenyl-1-propene (5 g, 24.7 mmol) in BuOAc (13 ml) at 123° C. After 3 hours the
cooled mixture was diluted with Et2O (50 ml) and washed with saturated aqueous
NaHCO3 and brine. Extraction, drying over anhydrous Na2SO4, concentration and
fractional distillation under vacuum gave a crude product that was further purified by
chromatography (SiO2, cyclohexane/AcOEt 95:5 then AcOEt/Et2O 1:1). There was
thus obtained the title compound with a yield of 33%.
B.p. 32-4370.07 mbar
1H-NMR: 2.03(s,3H) ; 3.03(s,3H) ; 4.85(s,1H); 6.44(s,1H) ; 7.09(dd,J=7,J^7,1H) ;
7.11(d,J=7,1H) ; 7,22(m,1H) ; 7.41(d,J=7,1H)
13C-NMR: 145.9(s); 143.9(S); 141.8(S); 128.7(d); 128.4(d); 124.6(d); 123.7(d);
120.1(d); 84.9(d) ;51.8(q);14.1(q)

b) Preparation of2-methyl-1H-inden-1-yl acetate via cyclisation of the acylal
A solution of FeCl3 anhydrous (21 mg, 0.125mmol) in BuOAc (2 ml) was added
dropwise during 5 minutes to a stirred solution of the 2-methyl-3-phenyl-2-
propenylidene diacetate (3.1 g, 12.5 mmol) in BuOAc (8 ml) at 123°. After 2 h at 123°
the reaction was stopped and worked-up as above. Chromatography (SiO2,
cyclohex/AcOEt 9:1) of the crude product allowed the isolation of the title acetate
(62% yield). Identical spectra as previously described.
Example 3
Synthesis of 2,6-dimethyl-1H-inden-1-yl acetate from the corresponding aldehyde
A solution of (2E)-2-methyl-3-(4-methylphenyl)-2-propenal (100.0 g, 0.62 mol) in
cyclohexane (300.0 g) was added dropwise in 2 hours to a stirred solution of zinc chloride
(3.1 g, 22 mmol) in acetic anhydride (188.4 g, 1.85 mol) at 80°C. The reaction mixture
was stirred farther at 80°C for 18 hours and then cooled to 25 °C. The mixture was washed
twice with water (100.0 g) and a 5% aqueous solution of sodium carbonate (100.0 g) and
concentrated under reduced pressure. The crude product was flash-distilled (B.p.:
75-90°C/ 0.1 mbar) affording 88.5 g of the desired acetate (69%) as a yellow liquid
(purity: 97.1% GC).
1H-NMR: 7.19 (s, 1H); 7.03 (d, J = 7.9, 1H); 6.99 (d, J = 7.9,1H); 6.37 (s, 1H); 6.11 (s,
1H); 2.31 (s, 3 H); 2.17 (s, 3 H); 1.95 (s, 3 H).
I3C-NMR: 171.5 (s); 143.3 (s); 142.3 (s); 141.0 (s); 134.8 (s); 129.2 (d); 125.2 (d); 120.0
(d); 78.4 (d); 21.3 (q); 21.1 (q); 14.0 (q).
Example 4
Synthesis of 2.6-dimethyl-1H-inden-l-yl acetate from the corresponding aldehyde
General procedure
A solution of (2E)-2-methyl-3-(4-methylphenyl)-2-propenal (100.0 g, 0.62 mol) in acetic
anhydride (100.0 g) was added dropwise in 2 hours to a stirred solution of the catalyst in

acetic anhydride (88.4 g, 1.85 mol in total) at 80°C. The reaction mixture was stirred
further at 80°C until the complete conversion of the starting material and then cooled to
25°C. The mixture was diluted with methyl tert-butyl ether (300.0 g), washed
successively with water (twice 100.0 g) and a 5% aqueous solution of sodium carbonate
(100.0 g) and concentrated under reduced pressure. The crude product was flash-distilled
(B.p.: 75-90°C / 0.1 mbar) affording the desired acetate as a yellow liquid.
The results obtained are listed in the following table:

Example 5
Synthesis of l-ethoxy-2-butyl-1H-indene from the corresponding aldehyde
A mixture of 2-butylcinnamic aldehyde (5 g, 26.7 mmol.), triethyl orthoformate (5.9 g,
40 mmol.), absolute ethanol (10 g, 217 mmol.) and Amberlyst® 15 (0.52 g) was heated at
reflux (85°C oil bath). After three days, the mixture was filtered and concentrated under
vacuum. The residue was subjected to silica gel flash chromatography (hexane/efhyl
acetate 98:2), yielding 3.8 g (17.6 mmol., 66% yield) of the indenyl ethyl ether.
1H-NMR: 0.95 (t, J=7.4,3H), 1.15 (t, J=6.9, 3H), 1.46-1.36 (m, 2H), 1.70-1.50 (m, 2H),
2.45-2.30 (m, 2H), 3.27-3.15 (m, 2H), 4.95 (s, 1H), 6.41 (s, 1H), 7.1 (t, J=7.2,
1H), 7.13 (d, J=7.2,1H), 7.21 (t, J=7.2,1H), 7.42 (d, J=7.2,1 K).
13C-NMR: 14.0 (q), 15.7 (q), 22.7 (t), 28.1 (t), 30.5 (t), 60.0 (t), 83.4 (d), 120.2 (d), 123.7
(d), 124.6 (d), 126.9 (d), 128.3 (d), 142.5 (s), 143.6 (s), 151.3 (s).
Example 6
Synthesis of 2-ethyl-1H-inden-1-yl acetate

A mixture of (E)-2-emylcinnamaldehyde (8 g, 50 mmol.) and acetic anhydride (7.7 g,
75 mmol.) was cooled in an ice bath. Anhydrous FeCl3 (0.3 g, 1.8 mmol.) was added and
the mixture stirred for 15 minutes. The reaction mixture was removed from the cold bath
and stirred at room temperature for one day. It then was diluted with 100 ml of diethyl
ether and washed with water (2 x 50 ml). The organic phase was dried (MgSO4), filtered
and concentrated. Kugelrohr distillation (95-105°C, 24 mTorr) yielded 8.0 g (39.6 mmol.,
79% yield) of the title compound.
JR. (film) J'co 1738 cm-1.
1H-NMR: 1.19 (t, J=7.4 Hz, 3H); 2.16 (s, 3H); 2.32 (m, 2H); 6.22 (s, 1H); 6.43 (s, 1H);
7.08 (t, J=7 Hz, 1H); 7.13 (d, J=7 Hz, 1H); 7.22 (t, J=7 Hz, 1 H), 7.36 (d, J=7
Hz, 1 H).
13C-NMR: 12.3 (q); 21.1 (q); 21.5 (t); 77.6 (d); 120.5 (d); 124.2 (d); 125.1 (d); 127.4 (d);
128.9 (d); 142.0 (s); 143.6 (s); 150.7 (s); 171.5 (s).
Example 7
Synthesis of 2-isopropvl-1H-inden-1-yl acetate
A mixture of (E)-2-isopropylcinnamaldehyde (18 g, 103 mmol.) and acetic anhydride
(15.9 g, 155 mmol.) was cooled in an ice bath. Anhydrous FeCl3 (0.75 g, 4.6 mmol.) was
added and the mixture stirred for 15 minutes. The reaction mixture was removed from the
cold bath and stirred at room temperature for one day. It then was diluted with 100 ml of
diethyl ether and washed with water (2 x 100 ml). The organic phase was dried (MgSO4),
filtered and concentrated. Kugelrohr distillation (93-104°C, 30 mTorr) yielded 18.2 g
(84 mmol., 82% yield) of the title compound.
IR (film) vco 1739 cm-1.
1H-NMR: 1.15 (d, J=6.7 Hz, 3H); 1.23 (d, J=6.7 Hz, 3H); 2.17 (s, 3H); 2.59 (sp, J=6.7
Hz, 1H); 6.34 (s, 1H); 6.44 (s, 1H); 7.09 (t, J=7 Hz, 1H); 7.14 (d, J=7 Hz, 1H); '
7.23 ft J=7 Hz, 1H); 7.35 (d, J=7 Hz, 1H).
13C-NMR: 20.9 (q); 21.1 (q); 22.9 (q); 27.3 (d); 76.6 (d); 120.6 (d); 124.2 (d); 125.2 (d);
126.6 (d); 128.9 (d); 142.1 (s); 143.4 (s); 155.0 (s); 171.4 (s).

Example 8
Synthesis of 1-ethoxy-2,6-dimethyl-1H-indene
Anhydrous FeCl3 (2.0 g, 12.3 mmol.) was added to a solution of (2E)-2-methyl-3-(4-
methylphenyl)-2-propenal (5.0 g, 31.3 mmol.) and triethyl orthoformate (5.1 g,
34.5 mmol.) in dichloromethane (35 ml). The dark red solution was stirred at room
temperature for 1 day, then diluted with 100 ml of diethyl ether and washed with water (3
x 75 ml). The organic phase was dried (MgSO4), filtered and concentrated. Kugelrohr
distillation (54°C, 20 mTorr) yielded 1.4 g (7.4 mmol., 24% yield) of the title compound.
1H-NMR: 1.66 (t, J=7,3H); 2.01 (s, 3H); 2.34 (s, 3H); 3.22 (m, 2H); 4.84 (s, 1H); 6.36
(s, 1H); 7.0 (m, 2H); 7.24 (s, 1H).
13C-NMR: 14.1 (q); 15.7 (q); 21.4 (q); 59.9 (t); 84.4 (d); 119.7 (d); 124.7 (d); 128.0 (d);
128.7 (d); 134.2 (s); 141.0 (s); 142.9 (s); 145.3 (s).
Example 9
Synthesis of 1-methoxv-2,6-dimethyl-1H-indene
Anhydrous FeCl3 (2.0 g, 12.3 mmol.) was added to a solution of (2E)-2-methyl-3-(4-
methylphenyl)-2-propenal (5.0 g, 31.3 mmol.) and trimethyl orthoformate (36.4 g,
34.3 mmol.) in dichloromethane (35 ml). The dark red solution was stirred for one hour,
then diluted with 100 ml of diethyl ether and washed with water (3 x 75 ml). The organic
phase was dried (MgSO4), filtered and concentrated. Kugelrohr distillation (65-80°C,
20 mTorr) yielded 3.2 g (18.4 mmol., 59% yield)' of the title compound.
1H-NMR: 2.00 (s, 3H); 2.35 (s, 3H); 3.03 (s, 3H); 4.82 (s, 1H); 6.40 (s, 1H); 7.02 (m,
2H); 7.24 (s, 1H).
13C-NMR: 14.1 (q); 21.4 (q); 51.8 (q); 84.8 (d); 119.8 (d); 124.8 (d); 128.5 (d); 128.8 (d);
1343-(s); 141.2-(s); 142.1 (s); 144.7 (s).

Example 10
Synthesis of 2,6-dimethyl-1H-inden-1-yl propionate from the corresponding aldehyde
Same procedure as for the corresponding acetate (example 3) but using propionic
anhydride instead of acetic, anhydride. The crude product was distilled through a short
Vigreux column (B.p.: 75-90°C/ 0.1 mbar) affording 98.0 g of the desired propionate
(71%) as a yellow liquid (purity: 97.3% GC).
1H-NMR: 7.18 (s, 1H); 7.02 (d, J = 8.2,1H); 6.99 (d, J = 8.2,1H); 6.38 (s, 1H); 6.13 (s,
1H); 2.45 (q, J = 7.7,2 H); 2.31 (s, 3 H); 1.95 (s, 3 H); 1.22 (t, J = 7.7,3 H).
13C-NMR: 175.0 (s); 143.4 (s); 142.5 (s); 141.0 (s); 134.8 (s); 129.2 (d); 129.1 (d); 125.2
00; 120.0 (d); 78.3 (d) 27.8 (0; 21.3 (q); 14.0 (q); 93 (q).

WE CLAIM:
1. A process for making novel indenol esters or ethers of formula (I):

wherein R1 represents a fomryl group, a -COCOOH group or a group of formula
-(CO)n-R, n being 0 or 1 and R representing an optionally substituted phenyl group or a
C1-6 alkyl or alkenyl group optionally halogenated;
R2 represents a C1-10 alkyl or alkenyl group; and
at least one R3 represents a hydrogen atom and the other R3 represent each a hydrogen
atom or a C1-5 alkyl, alkenyl or alkoxy group;
comprising the cyclisation, at a temperature above 10° C, of the corresponding compound
of formula

wherein each R4, taken separately, represents a formyl group or a -(CO)n-R group, or
the R4, taken together, represent a -COCO- group;
the wavy line indicates that the configuration of the carbon-carbon double bond is E or
Z.or a mixture thereof; and .
n, R, R2, R3 and R4 have the meaning as indicated above;
in the presence of a compound, which promote the reaction, selected from the group
consisting of strong mineral protic acids, sulphonic acids, acidic zeolites and Lewis acids.

2. A process as claimed in claim 1, wherein R1 represents a group of formula
-(CO)n-R, n being 0 or 1 and R representing an optionally substituted phenyl group or a
C1-5 alkyl group and R2 represents a C1-6 alkyl group.
3. A process as claimed in claim 1, wherein the compounds of formula (I) are
of formula

and are obtained by cyclisation of the corresponding compounds of formula

wherein the wavy line R1, R2, R3 and R4 have the same meaning as in claim 1.
4. A process as claimed in claim 1, wherein the compound, which promote
the reaction, is selected from the group consisting of H2SO4, p-toluenesulphonic acid,
NaHSO4, KHSO4, H3PO4, HCl, HNO3, BF3 and its adducts with C2-6 ethers or with C2-6
carboxylic acids, poly(styrene sulphonic acid) based resins, K-10 Clay, SnX4, FeX3 and
ZnX2, ZnI2, X representing a halogen atom, or a C1-6 carboxylate, or a C1-7 sulphonate.
5. A process as claimed in claim 4, wherein the compound is H3PO4, FeX3 or
ZnX2, X having the same meaning as in claim 4.

6. A process as claimed in claim 1, which is carried out in the
presence of a carboxylic anhydride of formula RC(O)O(O)CR or of a orthoester of
formula (RO)3CR, R being as defined in claim 1.
7. A process as claimed in claim 1, which involves the step of generating
in situ the compound of formula (II) starting from the corresponding enal of formula

wherein R2 and R3 have the same meaning as indicated in claim 1.
8. A novel compound of formula (I')

wherein one R3 is a hydrogen atom and the other R3 is a C1-5 alkyl group, and R1 and R2
have the same meaning as defined in claim 1.
9. A compound as claimed in claim 8, wherein R2 is a methyl
group and both R3 are hydrogen atoms or R2 is a methyl group and one R3 is a hydrogen
atom and the other R3 is a methyl group.

10. A novel compound of formula (III):

wherein one R5 is a hydrogen atom and the other R5 is a C1-5 alkyl group and R6 or R7
represents a methyl or ethyl group;
11. A compound as claimed in claim 10, which is 2,6-dimethyl-1H-inden-1-yl
acetate or 2,6-dimethyl-1H-inden-1-yl propanoate.
12. A perfuming ingredient comprising a compound as claimed in claim 10.


The present invention relates to a process for making indenol esters or ether from an α-substituted cinnamic aldehyde
derivative such as an acetal or an acylal. Said reaction is promoted by the use of strong mineral acids, sulphonic acids, acidic zeolites
or Lewis acids.

Documents:

02972-kolnp-2006 abstract.pdf

02972-kolnp-2006 assignment.pdf

02972-kolnp-2006 claims.pdf

02972-kolnp-2006 correspondence others.pdf

02972-kolnp-2006 description(complete).pdf

02972-kolnp-2006 form-1.pdf

02972-kolnp-2006 form-3.pdf

02972-kolnp-2006 form-5.pdf

02972-kolnp-2006 international publication.pdf

02972-kolnp-2006 international search authority report.pdf

02972-kolnp-2006 pct others document.pdf

02972-kolnp-2006 priority document.pdf

02972-kolnp-2006-assignment-1.1.pdf

02972-kolnp-2006-correspondence others-1.1.pdf

2972-KOLNP-2006-ABSTRACT.pdf

2972-KOLNP-2006-AMANDED CLAIMS.pdf

2972-KOLNP-2006-AMANDED PAGES OF SPECIFICATION.pdf

2972-KOLNP-2006-ASSIGNMENT.pdf

2972-KOLNP-2006-CORRESPONDENCE.pdf

2972-KOLNP-2006-DESCRIPTION (COMPLETE).pdf

2972-KOLNP-2006-EXAMINATION REPORT REPLY RECIEVED.pdf

2972-KOLNP-2006-EXAMINATION REPORT.pdf

2972-KOLNP-2006-FORM 1.pdf

2972-KOLNP-2006-FORM 18 1.1.pdf

2972-kolnp-2006-form 18.pdf

2972-KOLNP-2006-FORM 2.pdf

2972-KOLNP-2006-FORM 3 1.1.pdf

2972-KOLNP-2006-FORM 3.pdf

2972-KOLNP-2006-FORM 5.pdf

2972-KOLNP-2006-FORM-27.pdf

2972-KOLNP-2006-GPA.pdf

2972-KOLNP-2006-GRANTED-ABSTRACT.pdf

2972-KOLNP-2006-GRANTED-CLAIMS.pdf

2972-KOLNP-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

2972-KOLNP-2006-GRANTED-FORM 1.pdf

2972-KOLNP-2006-GRANTED-FORM 2.pdf

2972-KOLNP-2006-GRANTED-SPECIFICATION.pdf

2972-KOLNP-2006-OTHERS 1.1.pdf

2972-kolnp-2006-others.pdf

2972-KOLNP-2006-PETITION UNDER RULE 137.pdf

2972-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf


Patent Number 249850
Indian Patent Application Number 2972/KOLNP/2006
PG Journal Number 46/2011
Publication Date 18-Nov-2011
Grant Date 16-Nov-2011
Date of Filing 13-Oct-2006
Name of Patentee FIRMENICH SA
Applicant Address 1, ROUTE DES JEUNES, P.O. BOX 239 CH-1211 GENEVA 8
Inventors:
# Inventor's Name Inventor's Address
1 WOMACK GARY BERNARD 23 BRANDON ROAD, HOPEWELL, NJ 08648
2 MOSIMANN HERVE RUE DES CHERMETTES 6, CH-1227 CAROUGE
3 BIRKBECK ANTHONY ALEXANDER QUAI DES ARENIERES, 10, CH-1205 GENEVA
4 SNOWDEN ROGER LESLIE 512, MONTEE DU FORT, LE FORT, F-74580 VIRY
PCT International Classification Number C07C 35/27
PCT International Application Number PCT/IB2005/001474
PCT International Filing date 2005-05-10
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/849,559 2004-05-18 U.S.A.