A process for imparting, enhancing or modifying the flowery odorous note in perfumes, perfume compositions or artificial essential oils, for use in a perfume composition, a perfumed article, a cologne, a foodstuff, an alcoholic or nonalcoholic beverage, a toothpaste, a medicinal product or a chewing gum, comprising the step of adding an organoleptic property modifying quantity of 1,1-Di(C.sub.1 -C.sub.6 -alkyl)-2-phenylethan derivatives of formula A, wherein R is a formyl-, hydroxymethyl-, formoxymethyl-, acetoxymethyl- or a nitrilo group and the total number of carbon atoms in both alkyl substituents together is at most 8. ##STR1## .

THE INVENTION 
The present invention relates to the field of perfumery and flavoring, in 
particular it relates to the use of 1,1-dialkyl-2-phenyl-ethan-derivative 
Ae-e, wherein R is a formyl-, hydroxy-, methyl-, acetoxymethyl-, nitrilo- 
or formoxymethyl group, as an aroma chemical or as a constituent of 
fragrance compositions in particular for cosmetic and technical perfumes. 
The invention will first be described on the basis of the 
.alpha.,.alpha.-dimethyl-derivatives 1a-1d. 
##STR2## 
BACKGROUND OF THE INVENTION 
Aroma chemicals with floral olfactory characteristics are of great interest 
to the perfume industry. Since the distillates or extracts of plants 
containing the appropriate characteristic fragrance are either very 
expensive--as is the case with attar of roses or jasmine-absolue-, or 
un-obtainable because of their instability- for example lilac or lily of 
the valley-, it has always been the aim of the aroma chemical industry to 
prepare synthetic substitute products. Whereas chemical partial or total 
synthesis already exist for most of the different active perfuming 
ingredients in stable plant distillates or extracts, and these are often 
suitable for manufacture, only technically stable, synthetic substitutes 
are available for the unstable natural fragrances such as lily of the 
valley or lilac, which may have a similar fragrance to the natural product 
but have a different structure. Examples of this kind of widely used 
sythetic aroma chemicals with floral olfactory characteristics include 
dimethyl-benzyl-carbinol (2) or phenylethyldimethyl-carbinol (3). The 
odour of compound 2 is described as warm, herbal-floral, slightly animal 
with a side note of freshly cut wood and nuances of lily and elder flower 
(S. Arctander, Perfume and Flavor Chemicals, 1969, Nr 989) Compound 3 
(Arctander, Nr. 1043) has a floral, green slightly herbal and oily odour 
reminiscant of lily and hyacinth. Both compounds 2, 3 are only obtainable 
by means of Grignard-reactions, which require relatively sophisticated 
technology. 
The secondary alcohols anologous to the tertiary alcohols 2 and 3 are not 
used in perfumes, however the corresponding primary alcohols 4 and 5 are. 
However the odour notes of these compounds are very different from those 
of 2, 3. 
##STR3## 
The odour of phenylethyl-alcohol (4), which is used in large amounts, is 
described as "mild and warm, rose- and honey-like" (Arctander, Nr. 2513). 
Dihydrocinnamic-alcohol (5) has an odour resembling cinnamon, described as 
"warm and mild, balsamic- floral, sweet" (Arctander, Nr. 2589). 
.alpha.-methyl-dihydro-cinnamic alcohol (6) prepared by means of aldol 
condensation of benzaldehyde and propionaldehyde with subsequent 
hydrogenation has a very week, cinnamon like-sweet, slightly woody odour 
and is not used as an aroma chemical. 
PREFERRED EMBODIMENTS OF THE INVENTION 
It is therefore suprising that .alpha.,.alpha.-dimethyl-substituted primary 
alcohol 1b has a strong diffusive and pleasantly floral odour resembling 
lily of the valley and hyacinth, reminiscant of certain olfactory aspects 
of tertiary carbinols, but having a superior natural character in perfume 
compositions. .alpha.,.alpha.-dimethyl-compound 1b has been described in 
chemical literature, but its particular olfactory characteristics were 
neither recognized nor mentioned. [V. G. Purohit and R. Subramanian, Chem. 
and Ind. 1978, 731. P. Warrick and W. H. Saunders, J.Am. Chem. Soc., 84, 
4095 (1962); A. Haller and E. Bauer, Ann. Chim., 9, 15 (1918)]. It was 
discovered that the olfactory characteristics of compound 1b make it very 
suitable for incorporation in fragrances of a floral type, giving these a 
more natural character. 
Aldehyde 1a has a pronounced aldehydic-green odour which is suitable for 
in-corporation in fragrances, especially in low dosages. The preparation 
of .alpha.,.alpha.dimethyl-substituted aldehyde 1a has been described by 
H. K. Dietl and K. C. Brannock (Tetrahedron Letters 1973, 1273), but the 
olfactory characteristics of the compound were not mentioned. 
We prepared various esters from primary alcohol 1b using the usual 
esterification process. Of these the acetate 1c and the formiate 1b have 
particular olfactory effects. The odour notes of 1c may be described as 
"woody, sweet-herbal, floral" and those of 1e, as "woody, herbal, green". 
The nitrile 1d has a herbal-balsamic odour with floral and fruity 
side-notes. Compounds 1a-1d may be prepared from basic chemicals in a 
relatively simple manner and can therefore be produced in large amounts. 
##STR4## 
Substances 1a-d are prepared from benzylchloride (7), which has been 
converted to aldehyde 1a in a known per se manner in a phase-transfer 
reaction with isobutyraldehyde (8). This reaction has been described, 
using 50% aqueous sodium hydroxide and catalytic amounts of 
tetrabutyl-ammonium-iodide as catalyst (H. K. Dietl and K. C. Brannock, 
Tetrahedron Letters 1973, 1273). It was discoverd that the expensive 
tetrabutylammonium-iodide used by Dietl and Brannock could be replaced by 
cheaper tricapryl-methyl-ammonium-chloride (Aliquat 336). The reaction is 
carried out at high temperature, preferably at boiling point, in a 
two-phase system consisting of toluene and a 50% solution of NaOH. 
Approximately 60% yield of aldehyde 1a was obtained by means of the usual 
processing and distillation. The reduction of aldehyde 1a to the primary 
alcohol 1b is preferably carried out by means of catalytic hydrogenation 
using Raney-Nickel or copper-chromite in undiluted condition or using 
polar aprotic solvents such as methanol. The reduction was also carried 
out using hydrides such as sodiumborohydride or lithiumaluminiumhydride, 
observing the usual conditions for the reaction. 
Esterification was carried out in a known per se manner by converting the 
alcohol 1b with acid anhydrides in the presence of acid binding substances 
such as sodium carbonate or potassium carbonate. The acetate 1c was 
prepared by converting 1b with acetanhydride/sodiumcarbonate. 
The nitrile 1d was prepared in a known per se manner by reacting 
hydroxylamine with 1a in a basic medium producing oxime 9 which was 
subsequently dehydrated by the action of acetanhydride at boiling point. 
The reaction steps described for the preparation of compounds 1a-1d are 
transferable to homologous compounds. Thus .alpha.-alkyl-substituted 
aldehyde with a maximum of 10 carbon atoms, such as 2-methyl-butanal, 
2-methyl-pentanal, 2-ethyl-butanal, 2-ethyl-pentanal, 2-ethyl-hexanal, 
2-propylpentanal may be alkylated with benzylchloride using phase transfer 
catalysts, preferably tricaprylammoniumchloride and alkalimetalhydroxides. 
The aldehydes with the general formula Aa produced in this way have fresh 
notes and some have woody-herbal notes. The acetates with the general 
formula Ac prepared in an analogous fashion to 1c have woody and 
sweet-herbal odour notes, whereas the primary alcohols with the general 
formula Ab obtained in an anologous fashion to 1d have mild-floral, 
sometimes fresh olfactory aspects. The nitriles with the general formula. 
Ad obtained in analogous fashion to 1d have sweet-floral and herbal notes, 
and the formiates Ae have fresh-woody notes. 
The olfactory aspects of compounds Aa-d become heavier and less bright as 
their molecular weight increases, sometimes also less intense than the 
dimethyl-substituted compounds 1a-d. On the other hand, the fixative and 
rounding effects in perfume compositions are more dominant at higher 
molecular weights. On the basis of their olfactory characteristics, their 
fixative characteristics and their stability in cosmetic and technical 
media, the compounds with the general formuli Aa-Ae are very suitable for 
perfuming cosmetic and technical products. 
##STR5## 
The aldehyde 11a with 15 carbon atoms corresponding to the general formula 
Aa was prepared from benzylchloride (7) and .alpha.-ethyl-hexanal (10) 
according to the method given for 1a. The odour notes may be described as 
bright, herbal, fruity (Agrumen-aspects). Alcohol 11b with mild-floral 
notes was obtained by means of reduction in an analogous fashion to 1b. 
The following examples describe the preparation of compounds 1a-d and their 
application in fragrances.