JPS605583B2 - Method for producing novel alicyclic ketoesters and related compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel cyclic ketoesters, particularly the methyl or ethyl esters of 2-alkyl-3-oxo-cyclobentanecarboxylic acids, which have interesting aromatic properties and are therefore useful in the preparation of a wide variety of perfume compositions. It also relates to a novel cyclic nitroketone and a method for converting the cyclic nitroketone to the above-mentioned cyclic ketoester.

The nitroketone according to the present invention has the following general formula 1 (in formula 1, R
' represents a hydrocarbon group having 4 to 8 carbon atoms).

The substituents represented by R in the above formula 1 are n-butyl, n-bentyl, n-hexyl, and n-hef. It may be a straight chain group such as tyl, n-octyl, or it may be a branched alkyl group, i.e. a secondary or tertiary alkyl group,
Alternatively, it may be an alicyclic group. The cyclic nitroketone represented by Formula 1 can be produced by reacting 2-alkyl-2-cyclobentenone and nitromethane.

This synthesis reaction is shown by the following schematic reaction formula. The addition of nitromethane to 2-alkyl-2-cyclobentenones can be carried out in a variety of solvents in the presence of a variety of basic catalysts, of which penzyltrimethylammonium hydroxide has been found to be the most effective. Ta.

The nitroketone represented by formula 1 is a new compound. The cyclic nitroketone is converted to the corresponding ketoester in a modified Victormeyer type reaction.

This conversion reaction is shown by the following reaction formula. In the above formula, R' is methyl or ethyl.

Alcoholysis of nitroketone (1) to ketoester (m) is carried out by heating the nitroketone with the corresponding alcohol in the presence of equivalent amounts of any of various organic or inorganic acids.

The ketoesters according to the invention are novel aromatic substances with very characteristic aromatic properties. The ketoester according to the invention can be prepared using a blotter strip for evaporation.
When left alone after being applied to products such as rips), it unexpectedly emits a distinct floral aroma that becomes extremely uplifting. These new compounds are associated with numerous other aromatic and floral notes,
It exhibits aroma modulating abilities by producing interesting new scent notes when mixed with woody and/or fantasy compositions. Because these compounds have retention properties, they can provide many fragrances with long-lasting, strong, and elegant scent notes.
Because of these properties, the novel compounds according to the invention have the particular advantage that when used in compositions, the proportion of natural flower cosocles and absolutes can be reduced. Depending on the type of composition, the new esters according to the invention exhibit their desired effect within a very wide concentration range of 0.1% to 10%. In floral fragrance bases used as additives for other compositions, the novel compounds according to the invention can be used in proportions of 3% by weight or more. Example 1 2-n-hexyl-3-nitromethylsic.

Preparation of PentanoneIn a flask equipped with a reflux condenser, add 21n-hexyl-2-cyclobentenone,
183 Nitromethane, 40% methanol solution of penzyltrimethylammonium hydroxide (Triton B) 3
Charge 0 and 200' of dry dioxane.

The reaction mixture is refluxed for 2 small hours. The solvent is evaporated under reduced pressure and the residue is dissolved in ether. The ethereal solution is washed successively with dilute hydrochloric acid, water and sodium bicarbonate solution and then dried over anhydrous sodium sulfate. The solvent is removed at normal pressure and the residue is distilled through a short Picro column. After the low-boiling fraction consisting of 2-n-hexy-2-cyclobentenone (35 pm, 65 pm 0/0.2 willow) is extracted, the product is collected on the 135 oo/0.3 side.

Yield: 365 evenings (80%), n customers: 14,733. Cyclic nitrates listed in Table 1.

The ketone analog was prepared according to the method described in Example 1. Table 1 Example 5 Preparation of methyl 2-n-hexyl-3-oxocyclobentanecarboxylate In a stainless steel autoclave for 0.5 hours, 2-n-hexyl-3-nitromethylcyclobentanone was added for 4.8 hours for 11.4 days. of methanesulfonic acid and 1
Pour in 80% methanol solution.

The reaction mixture is held at 100°C for 2 hours. The solvent is removed under reduced pressure and the residue is dissolved in ether. The ethereal solution is washed with sodium bicarbonate solution and water and dried over anhydrous sodium sulfate. The ether is distilled off at normal pressure and the residue is distilled through an efficient column. 10 ○/
Collect methyl 2-n-hexyl-3-oxocyclobentanecarboxylate on the 0.2 side.

Yield 6.2 evenings (55%). Example 6 Production of methyl 2-n-hexyl-3-oxocyclobentanecarboxylate
．． 5. Into the three flasks, add a solution of 22.4 ml of 21n-hexyl-3-nitromethylcyclobentanone and 1.8 ml of water dissolved in 180 ml of anhydrous methanol.

Claims (1)

[Claims] 1 Structural formula III ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the above formula, R is selected from the group consisting of branched chain and straight chain alkyl groups containing 4 to 8 carbon atoms, and R' is 1 to 2
2-alkyl of the general formula II▲ Numerical formulas, chemical formulas, tables, etc.▼ (in the above formula, R represents the above meaning) -2-
By reacting cyclopentenone and nitromethane, the general formula
I▲There are mathematical formulas, chemical formulas, tables, etc.▼ Making a nitroketone (R in the above formula has the meaning above) and converting this nitroketone into a compound of structural formula III by treating it with alcohol in the presence of an acid. A method for producing a compound of the above formula III, characterized by: