JPS5811410B2 - Norbornane and norbornene derivatives - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel norbornane and norbornene derivatives represented by the following formula (I), in which the dotted bond is present or absent.

The compound (■) of the present invention has a sandalwood aroma, and is particularly a norbornene derivative [(■) in which a bond represented by a dotted line is present, i.e., 1-(norhorn-5
'-en-2'-yl)-2-methylbent-1-en-3-ol] has a strong sandalwood-like odor, and norbornane derivatives [(I), in which there is no bond represented by a dotted line, That is, 1-(norhorn-2'
-yl)-2-methylbent-1-en-3-ol]
has a sandalwood-like aroma with green notes, and both are important compounds as fragrances.

Natural sandalwood oil is an oil obtained by steam distilling the heartwood and roots of the white tan tree grown in the Malay region, and is an important flavoring agent for oriental flavor preparations.

However, sandalwood oil is a special plant that produces seeds that are longer than the roots and grows parasitic on the roots of other trees, and it takes up to 30 years to cultivate it from seed and collect sandalwood oil, so it is a special plant that produces seeds that are longer than the roots. Even in India, resources have become scarce and there has been a shortage of supply in recent years, making it expensive.

In addition, the main component of natural sandalwood oil is α, β-santalol, but the industrial production method for this has not yet been successful, and there is a desire to develop synthetic fragrances with aromas similar to this. Although several products are available on the market, these products do not satisfy the general demand in terms of price and fragrance.

Therefore, the present inventor conducted intensive research to satisfy such demand, and as a result, α.

We succeeded in synthesizing a new compound of formula CI) having an odor similar to β-santalol.

The compound (I) of the present invention can be obtained by reacting cyclopentadiene (II) and acrolein (III) by Diels-Alder reaction according to the following reaction formula to form an adduct (IV).
and diethyl ketone (V) in the presence of an alkali.
is condensed to form a ketone compound (VI), which is then reduced with sodium borohydride etc. to form a norbornene derivative (I-a), i.e. 1-(norhorn-5'-
2-methylbent-1-ene-3
-ol, also the adduct (IV)
is catalytically reduced in the presence of a palladium-activated carbon catalyst (■
) was reacted with diethyl ketone in the same manner as above, and then ring-formed to form a norbornane derivative (I-b
), i.e. 1-(norhorn-2'-yl)-2-
It is produced by obtaining methylbent-1-en-3-ol.

Next, an example will be given and explained.

Example 1 (i) 460 g of cyclopentadiene was placed in a reaction flask No. 31, and 433 g of acrolein was added to it under stirring while cooling with water.
A mixture of 500 ml of ether and 500 ml of ether was added dropwise over a period of 2 hours while maintaining the internal temperature at 25 to 30°C, and the mixture was further reacted at the same temperature for 15 hours.

After the reaction was completed, the contents were transferred to a distillation flask, and after distilling off the ether, distillation was carried out under reduced pressure to obtain fraction 728.1.9 with a temperature of 70-72°C/18 mmHg.

This product had an IR (1710 cm-1,715 m-1) and was confirmed to be compound (IV).

(ji): methanol 1.5'7,4 in one reaction flask
0% caustic soda solution 5 (B9, diethyl ketone 456g
and 244 g of compound (IV) at 62°C under heating under reflux.
was added dropwise over 45 minutes, and the mixture was further heated under reflux for 2 hours.

Methanol was distilled off under reduced pressure, and 500% of ether was added to the concentrate.
ml was added and dissolved, and the mixture was washed three times with 300 r/l of saturated saline.

The ether solution was placed in a distillation flask, and after distilling off the ether, it was distilled under reduced pressure to obtain 5 g of 82-b 313.

This one is IR (1660cm-1,710cm-1)
, NMR, (6,0-6.8 (m, 3H), 1.8 (
bs, 3H) and 1.05 (t, 3H)), which confirmed that it was compound (Vl).

(iii) 190 g of compound (■) in 11 reaction flasks,
Add 224ml of methanol, 8g of 15% caustic potassium,
While heating to 0°C and stirring, add sodium borohydride 14 to this.
．． A solution of 2 g, 0.88 g of caustic garri, 112 ml of water and 112 ml of methanol was added dropwise over 1 hour, and
Stirred for 0 minutes.

After the reaction, methanol was distilled off and concentrated under reduced pressure, 300 ml of toluene was added to the concentrated solution to dissolve it, and the toluene solution was washed twice with 300 ml of saturated brine.

The toluene solution was transferred to a distillation flask, the toluene was distilled off under reduced pressure, and the residual liquid was distilled under reduced pressure to 89-95°C/1.
5mmHg fraction 154. , 8.9 was obtained.

This one is IR (3350m-1,710cm-').

NMR (6,15(b,2H):5.37,4.95(
bd, IH): 3.80 (q, IH): 1.
60 (bs, 3H): 0.80 (t, 3H)
), therefore (I-a), that is, 11-(norhorn-5'-en-2fuyl)-2-methylpent-
It was confirmed that it was a 1-en-3-ol compound.

Example 2 (i) 24.4 g of compound (IV) obtained in Example 1,
Put 24g of cyclohexane, 7g of 5% palladium-activated carbon into a 200ml autoclave,
Hydrogen pressure 5-10ky/Cr under water cooling? Hydrogenated with L.

The reaction stopped after absorbing the theoretical amount of hydrogen.

The reaction solution was filtered to remove the catalyst, and cyclohexane was distilled off under reduced pressure to obtain 25.9 g of a residue.

This product gave a single peak in gas chromatography analysis and was confirmed to be compound (■).

(ii) In a 300 ml reaction flask, add 5 g of 40% caustic soda solution, 1'50 ml of methanol, and 4 ml of diethyl ketone.
25.9 g of compound (■) was added under heating and reflux.
The mixture was added dropwise over 5 minutes, and the mixture was further heated under reflux for 2 hours.

Methanol was distilled off under reduced pressure, and 100% of ether was added to the concentrate.
After washing with 100 ml of saturated brine three times, the mixture was transferred to a distillation flask and the ether was distilled off.

The residue was distilled under reduced pressure to obtain fraction 27.5.9 at 87-93°C/1.5mmHg.

IR: 1660CrIl-', NMR: 6.47
(bd.

9.0Hz, IH).

(iii) 13 g of the fraction obtained above was placed in a 200 ml reaction flask, 130 ml of ether was added, and 1.5 g of lithium aluminum hydride was added little by little while stirring under water cooling, and the reaction was further allowed to proceed for 1.5 hours.

Water was added to the reaction solution to decompose it with stirring, and the ether layer was separated, dried over anhydrous sodium sulfate, and then the ether was distilled off.

The residue was distilled under reduced pressure to obtain a fraction 9.92-95'C/1, 5 mmHg. Obtained Og.

This one has IR (3340cm-1), NMR (5,2
8 (bd.

9,0Hz,IH,),3.80(t,6H2,I
H) tO,82(t, 9.5Hz, 3H)), so the compound '(I-b), i.e. 1-(norhorn-2'-yl)-2-methylbent-1-ene-
It was confirmed that it was 3-ol.

[Brief explanation of the drawing]

Figure 1 shows the infrared and absorption spectra of the norbornene derivative (I-b), Figure 2 shows the NMR spectrum of the same compound, Figure 3 shows the infrared absorption spectrum of the norbornene derivative (I-a), and Figure 4 shows the infrared absorption spectrum of the same compound. The NMR spectrum is shown.

Claims (1)

[Scope of Claims] 1. Norbornane and norbornene derivatives represented by the following general formula (I) (wherein the dotted bond is present or absent).