Alcohols containing 2-methylphenyl or 2-methoxyphenyl groups, and fragrances containing same

The invention discloses compounds of the general formula ##STR1## in which R represents a methyl radical or a methoxy radical when R.sup.1 is a hydrogen atom; or PA0 R represents a methyl radical when R.sup.1 is a methyl radical. The compounds of the invention are useful as fragrances.

The present invention generally relates to alcohol compounds which contain 
2-methylphenyl or 2-methoxyphenyl groups, and their use as fragrances. 
More particularly, the present invention relates to 2-methylphenyl- or 
2-methoxyphenyl-containing alcohols which have the beneficial properties 
of oakmoss perfumes, but without the undesirable or otherwise toxic 
characteristics of such perfumes. 
Oakmoss perfumes are known, but such perfumes are mostly phenol 
derivatives, such as 3-methyl-5-methoxyphenol, having known harmful 
phenolic properties, such as causticity or irritant action and 
discoloration. 
Furthermore, 2-methyl-3-(2-methylphenyl)-propan-1-ol is known from J. 
Indian Chem. Soc., Vol. L, September 1973, but a use for this compound was 
not given in this publication. 
It is therefore an object of the present invention to provide fragrances 
which have an oakmoss character, high stability and none of the harmful 
properties generally associated with oakmoss perfumes, such as causticity, 
irritant action or discoloration. 
The foregoing and related objects are achieved by the present invention 
which relates to compounds of the formula 
##STR2## 
wherein R denotes a methyl or methoxy radical when R.sup.1 is a hydrogen 
radical, and R denotes a methyl radical when R.sup.1 is a methyl radical, 
and 2-methyl-3-(2-methylphenyl)-propan-1-ol is excluded. 
A process for the preparation of 2-methyl-3-(2-methylphenyl)-propan-1-ol 
and 2-methyl-3-(2-methoxyphenyl)-propan-1-ol is also provided and 
comprises the steps of: 
(a) reacting 2-methylbenzaldehyde or 2-methoxybenzaldehyde with 
propionaldehyde in the presence of bases, and 
(b) hydrogenating the reaction product from (a). 
The benzaldehyde and propionaldehyde used as starting compounds are known 
substances. 
The reaction in step (a) preferably takes place using alkali metal 
hydroxides, in particular sodium hydroxide or potassium hydroxide, at 
temperatures of, preferably, -5.degree. to 80.degree. C. in polar 
solvents, such as alcohols, for example, methanol or ethanol. The reaction 
product from step (a) is then hydrogenated using reduction catalysts, such 
as palladium on activated charcoal or Raney nickel, and hydrogen, and 
finally separated into the aldehyde or alcohol by fractional distillation. 
A further process for the preparation of 
2-methyl-3-(2-methylphenyl)-propan-1-ol or 
2-methyl-3-(2-methoxyphenyl)-propan-1-ol comprises the steps of: 
(a1) reacting 2-methylbenzyl chloride or 2-methoxybenzyl chloride with 
diethyl methylmalonate, 
(b1) thermally decarboxylating the reaction product from (a1) after 
hydrolysis, and 
(c1) hydrogenating the reaction product from (b1). 
The benzyl chlorides and diethyl methylmalonate used are known compounds. 
The reaction in step (a1) preferably takes place at temperatures of 
70.degree. to 120.degree. C. in the presence of a base, such as sodium 
hydroxide or potassium hydroxide, and thermal decarboxylation in step (b1) 
is carried out preferably at 120.degree. to 150.degree. C. The acid 
obtained is reacted, optionally, after esterification using alcohols, such 
as methanol or ethanol, with hydrogenating agents, usch as lithium 
aluminum hydride or hydrogen, in the presence of a catalyst. 
A process for the preparation of 3-methyl-4-(2-methylphenyl)-butan-2-ol 
comprises reacting 2-methylbenzyl chloride with methyl ethyl ketone in an 
organic/alkaline two-phase system in the presence of a phase-transfer 
catalyst. 
2-Methylbenzyl chloride and methyl ethyl ketone are known compounds. Methyl 
ethyl ketone is preferably employed in excess. The organic/alkaline 
two-phase system is formed from the reaction components, and also, 
optionally, an organic water-immiscible inert solvent and a 5-50% strength 
aqueous solution of an alkali metal hydroxide or, in solid form, an alkali 
metal hydroxide or alkali metal carbonate. Examples of alkali metal 
hydroxides are sodium hydroxide or potassium hydroxide. Examples of the 
phase-transfer catalysts employed are crown ethers, quaternary ammonium 
salts or quaternary phosphonium salts in amounts of 0.5-5 mole-% relative 
to benzyl chloride. The reaction product from this reaction is then 
reduced to 3-methyl-4-(2-methylphenyl)-butan-2-ol in a manner which is 
known per se using reducing agents, such as sodium borohydride, lithium 
aluminum hydride or hydrogen, and a catalyst. The examples which follow 
hereinafter further detail such synthesis processes. 
The invention further relates to the use of the compounds, according to the 
invention, as fragrances. In this case, 
2-methyl-3-(2-methylphenyl)-propan-1-ol is not excluded. 
The fragrances according to the invention exhibit an oakmoss character and 
high chemical and physical stability. Due to their stability, they have a 
very broad range of applications. Besides use in perfumery, they are also 
suitable for perfuming soaps and detergents, textiles, plastic products 
and the like.

The invention will now be explained in greater detail by reference being 
made to the following examples. It should, however, be understood that the 
following examples are provided for purposes of illustration only and are 
not intended as a definition of the scope or limits of the present 
invention. 
EXAMPLE 1 
2-Methyl-3(2-methoxyphenyl)-propan-1-ol 
While flushing with argon, 6.5 g of KOH were dissolved in 200 ml of ethanol 
(95% strength), and the solution was cooled to 4.degree. C. 98 g of 
2-methoxybenzaldehyde were then added, and 45 g of propionaldehyde were 
added dropwise over the course of 4.5 hours. The reaction temperature was 
kept at 8.degree.-9.degree. C. After a post-reaction time of 15 minutes, 
ice, water and ether were added and the organic phase was separated off. 
It was washed by shaking four times with 200 ml of water in each case and 
distilled through a 19 cm packed column containing glass coils. After 
removal of the solvent and preliminary fraction, a fraction (88 g) 
containing 94% of 2-(2-methoxybenzylidene)-propionaldehyde was obtained 
from 86.degree.-92.degree. C. at 0.07 mbar. 87 g of this substance, 150 ml 
of ethanol and 10 g of Raney nickel were heated at 130.degree. C. for 14 
hours in a shaken autoclave under a hydrogen pressure of 100 bar. After 
removal of the catalyst and solvent, the mixture was distilled through the 
above-mentioned column. 70 g of 2-methyl-3-(2-methoxyphenyl)-propan-1-ol 
were obtained at 98.degree. C./0.13 mbar. 
Odor note: earthy-phenolic, comparable to the characteristics of roots and 
oakmoss. 
EXAMPLE 2 
2-Methyl-3-(2-methylphenyl)-propan-1-ol 
220 g of 2-methylbenzyl chloride, 320 g of diethyl methylmalonate, 320 g of 
potassium carbonate, 13 g of potassium iodide and 10 g of 18-crown-6 were 
stirred at 90.degree. C. for 12 hours in 1 liter of toluene. The cooled 
mixture was stirred with 800 g of ice in water, and the aqueous layer was 
separated off and extracted once with ether. The combined organic layers 
were washed by shaking three times with 400 ml of water in each case. The 
solvent and unreacted diethyl methyl malonate were then removed by 
distillation, partly under reduced pressure. The residue (413 g) was 
hydrolyzed using 540 g of 25% strength NaOH with addition of a spatula tip 
of tetradecyltrimethylammonium bromide (14 hours reflux). During this 
procedure, liberated ethanol was removed by distillation and a little 
water was added. 
The mixture was then acidified using concentrated hydrochloric acid, and 
the organic phase was taken up on xylene and slowly heated to reflux over 
several hours for decarboxylation. The xylene was subsequently removed 
again by distillation, and the 2-methyl-3-(2-methylphenyl)-propionic acid 
remaining was esterified azeotropically using ethanol and cyclohexane. The 
ester was distilled through a 20 cm packed column (220 g, boiling point 
68.degree.-71.degree. C. at 0.1-0.2 mbar). 
1.2 liters of dry tetrahydrofuran were introduced into a 2 l four-necked 
flask, 38 g of lithium aluminum hydride were added under argon, and a 
mixture of 200 g of the above ester with 200 ml of ether was added 
dropwise with ice cooling. After a post-reaction time of 2 hours at room 
temperature, the batch was poured into water and acidified using 
hydrochloric acid, and the layers were separated. The aqueous phase was 
extracted twice with ether, and the combined organic phases were washed by 
stirring with sodium carbonate solution and distilled (20 cm packed column 
containing glass coils). 148 g of 2-methyl-3-(2-methylphenyl)-propan-1-ol 
of boiling point 80.degree. C. at 0.13 mbar were obtained. 
Odor note: oakmoss and vetiver. 
EXAMPLE 3 
3-methyl-4-(2-methylphenyl)-butan-2-ol 
56 g of KOH, 56 ml of water, 10 g of 18-crown-6 and 5 g of KI were warmed 
to 75.degree. C. with 200 ml of toluene with exclusion of air. A mixture 
of 100 g of 2-methylbenzyl chloride and 100 g of methyl ethyl ketone was 
added dropwise over 30 minutes with vigorous stirring, and the mixture was 
stirred at 85.degree. C. for 11 hours. The phases were then separated, and 
the organic layer was washed by shaking with water and distilled through a 
short packed column. After removing the solvent and the preliminary 
fraction, 29 g of 3-(2-methylbenzyl)-butanone were obtained at 
54.degree.-55.degree. C./0.07 mbar. 25 g of this compound was stirred with 
3 g of NaBH.sub.4 in 100 ml of ethanol, initially for 2 hours at 
25.degree. C., then for a further 2 hours at the reflux temperature. After 
the reducing agent and solvent had been removed, the reaction product was 
distilled through a short Vigreux column. 15.5 g of 
3-methyl-4-(2-methylphenyl)-butan-2-ol were obtained from 
64.degree.-67.degree. C./0.07 mbar. 
Odor note: oakmoss, with a sweet-powdery component. 
While only several embodiments and examples of the present invention have 
been shown and described, it will be obvious to those skilled in the art 
that many changes and modifictions may be made thereunto, without 
departing from the spirit and scope of the invention.