This disclosure relates to 7-(prop-l '-enyl)-2H-benzo[b][l,4]dioxepin-3(4H)-one and to its use in fragrance applications.

There is provided 7-(prop-l '-enyl)-2H-benzo[b][l,4]dioxepin-3(4H)-one.

7-(Prop-l '-enyl)-2H-benzo[b][l,4]dioxepin-3(4H)-one has the structural formula I,

I and will hereinafter be referred to as "the compound I".

The benzylic double bond may either be in (E)- or in (Z) -configuration (both configurations, individually and collectively, are comprehended by the use of "the compound I" in this description), but in general the (^-configured compound I is preferred for its olfactory properties and its ease of preparation.

The compound I may conveniently be prepared from 4-allyl-2-(methoxycarbonyl- methoxy)phenoxyacetate by isomerisation of the double bond and Dieckmann condensation with subsequent saponification and decarboxylation as is illustrated in

Example 1 hereinunder. 4-Allyl-2-(methoxycarbonylmethoxy)phenoxyacetate is, for example, accessible from eugenol according to the procedure described by P. Kraft and W.

Eichenberger, Eur. J. Org. Chem. 2003, 3735-3743. Under thermodynamic conditions for the double-bond isomerisation, for instance by employing a reversible base such as potassium fer/-butoxide, the (is)-conflgured isomer is obtained almost isomerically pure, while with other conditions the (E/Z)-ratio could be adjusted. The compound I has unusual and desirable fragrance characteristics, which may be described as very intense marine, mossy, algae-like, green-spicy odour with powdery vanillin- and guaiacol-like aspects. This is unexpected; the unstable aldehyde 3-oxo-3,4- dihydro-2H-benzo[b][l,4]dioxepine-7-carbaldehyde and the related nitro arene 7-nitro-2/-/- benzo[&][l,4]dioxepin-3(4H)-one possess a spicy, vanilla note (Η. M. Ηugel, B.

Drevermann, A. R. Lingham, and P. J. Marriot, 'Marine Fragrance Chemistry' in 'Current Topics in Flavor and Fragrance Research' (Eds.: P. Kraft, K. A. D. Swift), Verlag Helvetica Chimica Acta, Zurich, and Wiley-VCH, Weinheim, 2008, p. 199-209), but no known odorant possesses a marine character with additional powdery vanillic- spicy aspects.

The compound I may be used in fragrance compositions, that is, compositions whose function it is to provide fragrance, either as a fine fragrance or as a functional fragrance in an application whose primary function is not the provision of fragrance. In this, the compound I may be used alone, or in combination with other known fragrance ingredients and ancillary materials, as more fiilly described hereinunder.

There is therefore also provided a floral-fruity, aqueous fragrance composition with a spicy- vanillic signature, comprising the compound I. This distinctive spicy- vanillic signature enhances and enriches the floral- fruity theme, thereby extending its volume and depth.

Non-limiting examples of other fragrance ingredients that may be used in conjunction with the compound I include:

- ethereal oils and extracts, e.g. bergamot oil, grapefruit oil, jasmine absolute, lemon oil, mandarin oil, patchouli oil, vetiver or ylang-ylang oil;

- alcohols, e.g. citronellol, dihydromycrenol, Ebanol™, eugenol, geraniol, Florol ^® , Super Muguet™, linalool, phenylethyl alcohol, Sandalore™, terpineol or Timberol™ ;

- aldehydes and ketones, e.g. Adoxal™, Aldolone ^® , α-amylcinnamaldehyde, Azurone ^® , Cyclohexal™, α-damascone, β-damascenone, Florhydral™, Georgywood™, Hedione ^® , hydroxycitronellal, Iso E Super™, Isoraldeine™, lauryl aldehyde, maltol, methyl cedryl ketone, methyl ionone, 2-methylundecanal, Myraldene™, Transluzone ^® , undecanal, Vertofix™ or vanillin;

~ ether and acetals, e.g. Acetal E™, Amhrox™, geranyl methyl ether, rose oxide or Spirambrene™ ;

- esters and lactones, e.g. allyl amyl glycolate, benzyl acetate, benzyl salicylate, cedryl acetate, Cyclogalbanate™, γ-decalactone, Helvetolide ^® , linalyl acetate, Serenolide ^® , γ- undecalactone, Verdox™ or vetivenyl acetate;

- macro- and polycycles, e.g. ambrettolide, ethylene brassylate, Exaltolide™, Galaxolide ^® or Moxalone™; and

- heterocycles, e.g. isobutylchinoline.

In addition to its admixture with other fragrance ingredients, the compound I may be admixed with one or more ingredients or excipients conventionally used in conjunction with fragrance ingredients in perfume compositions, for example carrier materials, and other auxiliary agents commonly used in the art, e.g., solvents such as dipropylene glycol (DPG), isopropyl myristate (IPM), and triethyl citrate (TEC).

There is additionally provided a fragrance application, comprising a fragrance application base and the compound I. By 'fragrance application' is meant any composition for any use in which the presence of fragrant substances is desired. By "fragrance application base" is meant the totality of fragrance application ingredients other than those present as part of a fragrance composition.

There is therefore also provided a method of providing to, or improving, enhancing or modifying in, a fragrance application marine, a green-spicy odour with vanillic character, comprising the addition thereto of the compound I. The fragrance application may be in any field of fine and functional perfiimery, non- limiting examples of which include fine fragrances, household products, laundry products, body care products and cosmetics. Specific exemplary and non-limiting examples include fine fragrances, such as eaux de perfume and eaux de toilette; household products, such as liquid and powder detergents for laundry use and dishwashers; laundry ancillary products, such as fabric softeners and conditioners; surface cleaners, air fresheners; bleaches; body care products, such as after-shave lotions, shampoos, shower gels, shower and bath salts, hygiene product; and cosmetics, such as deodorants and vanishing creams.

In the formulation of fragrance applications, there may also be used any of the known ingredients commonly used in such applications, non-limiting examples including surfactants, solvents, pigments, dyestuffs, extenders, thickeners, rheology modifiers and the like.

The compound I may be employed in fragrance compositions and applications in widely varying amounts, depending upon the specific application, the nature and quantity of other fragrance ingredients and the desired odour. As a general indication, up to about 3% by weight may be employed in fine fragrances, e.g. from about 0.01% by weight to about 3% by weight, and up to about 5% by weight based on the perfume composition in other fragrance applications, e.g. laundry products. However, these values are given only by way of example, since the experienced perfumer may also achieve effects or may create novel accords with lower or higher concentrations.

The compound I may be employed into the fragrance application simply by directly mixing a fragrance composition (comprising the compound I alone or in combination with other fragrance ingredients) with a fragrance application base. The fragrance composition may be used in liquid form, or it may be used in entrapped form. Any of the known entrapped forms may be used; these include polymers, capsules, microcapsules and nanocapsules, liposomes, film formers, absorbents such as carbon or zeolites, cyclic oligosaccharides and mixtures thereof, or they may be chemically bonded to substrates, which are adapted to release the fragrance molecule upon application of an external stimulus such as light, enzymes, or the like. The combination of the fragrance application ingredients, including the compound I, may be in any desired order using any known method. The disclosure will now be further described with reference to the following non-limiting examples. These examples are for the purpose of illustration only and it is understood that a person skilled in the art can make variations and modifications. The IR signals are given in order of decreasing intensity, the NMR data are given relative to internal SiMe ₄ standard.

Exam ^p le 1: Preparation of (VE)-7-{¥rop-V-enyϊ)-2H~ber\zo[b] [l,4]dioxepin-3(4H> one

At 0 ⁰ C, a solution of methyl 4-allyl-2-(methoxycarbonylmethoxy)phenoxyacetate (2.93 g, 9.96 mmol) in THF (30 mL) was added dropwise in the course of 5 min. to a stirred suspension of potassium fert-butoxide (2.62 g, 23.4 mmol, 2.35 eq.) in THF (30 mL). The reaction mixture was refluxed for 20 h, allowed to cool to ambient temperature, and then poured into ice/water (50 mL). The resulting mixture was acidified to pH 2 with aqueous 2N hydrochloric acid, and extracted with dichloromethane (3 x 200 mL). Without drying (e.g. over MgSO ₄ or Na ₂ SO ₄ ), the combined organic extracts were concentrated under reduced pressure on the rotary evaporator, and the resulting oil was taken up in ethanol (20 mL). Aqueous 2N hydrochloric acid (20 ml) was added, and the mixture was refluxed for another 20 h. The resulting dark brown reaction mixture was poured into ice/water (100 mL), and extracted with dichloromethane (3 x 100 mL). The organic combined extracts were washed with water (100 mL) and dried (MgSO ₄ ), the solvent was removed on the rotary evaporator under reduced pressure, and the resulting residue was purified by flash chromatography (hexane/ethyl acetate, 4:1, i? _f 0.58) to yield the title compound (0.345 g, 17%) as a colourless oil which crystallized in colourless needles upon prolonged standing at room temperature; m.p. 56-59 ⁰ C.

FT-IR (neat): v = 1263 / 1278 (s, v ring), 1043 / 1032 / 1118 (s, vC-O-C), 1501 / 1417 / 1438 / 1576 (s, vC=C ar), 1732 (s, vC=O), 881 / 903 (m, δ=C-H ar o.o.p, 1,2,4-tri), 962 (m, 5C=C aliph) cm ^"1 . - ¹ H NMR (CDCl ₃ ): δ =1.79 (dd ₃ J= 6.5, 1.5 Hz, 3 H, 3'-H ₃ ), 4.62 / 4.63 (2s, 4 H ₅ 2-, 4-H ₂ ), 6.05 (dq, J= 15.5, 6.5 Hz, 1 H, 2'-H), 6.22 (dq, J= 15.5, 1.5 Hz, 1 H, l'-H, (^-configured), 6.83-6.90 (m, 3 H _? 6-, 8-, 9-H). - ¹³ C NMR (CDCl ₃ ): δ = 18.3 (q, C-3'X 75.6 / 75.7 (2t, C-2, -4), 117.9 (d, C-8), 120.9 / 121.3 (2d, C-6, -9), 125.7 (d, C- T), 129.6 (d, C-F) ₅ 134.3 (s, C-7), 147.1 (s, C-9a), 148.2 (s, C-5a), 204.5 (s, C-3). - MS (EI): mlz = 205 (13) [(M + H) ⁺ ], 204 (100) [M ⁺ ], 175 (4) [M ⁺ - CHO] ₅ 161 (7) [M ⁺ - C ₂ H ₃ O] ₅ 120 (24) [C ₇ H ₄ O ₂ ⁺ ], 91 (58) [C ₇ H ₇ ⁺ ], 77 (2) [C ₆ H ₅ ⁺ ].

Odour description: very intense marine, mossy, algae-like, green-spicy odour with 5 powdery vanillin- and guaiacoMike aspects.

Example 2: Floral-Fruity, Spicy- Vanillic Aqueous Feminine Fine Fragrance

Compound / Ingredient parts by weight 1/1000

10

1. Citronellol, extra 30

2. Cyclohexal (4-(4'-hydroxy-4'-methylpentyl)- cyclo hex- 3 - enecarbaldehyd e) 150

3. Damascenone™ [(2E)-l-(2',6' _? 6-trimethylcyclohexa-

15 1 ⁵ ,3'-dienyl)but-2-en-l-one] @ 10% in DPG (dipropylene glycol) 2

4. ^-Decalactone 2

5. /?-Dihydroionone 55

6. DPG (dipropylene glycol) 76

7. Eugenol, pure 35 20 8. Galaxolide™ 50 BB (4,6,6,7,8,8-hexamethyl-

1 ,3,4,6,7,8-hexahydrocyclopenta[g]isochromene) 275

9. Hedione™ (methyl 2-(3'-oxo-2'-pentylcycloρentyl)acetate) 110

10. Iso E Super™ (2,3,8,8-tetramethyl-l,2,3,4,5,6,7,8- octahydro-2-naphthalenyl methyl ketone and isomers) 145

25 11. Jasmolactone™ ((3' _J- i)-6-(pent-3'-enyl) tetrahydro-2H-pyran-2-one) @ 1 % in DPG 25

12. Linalool 30

13. (1 '£)-7-(Prop- 1 '-enyl)-2H-benzo[6][l ,4]- dioxepin-3 (4#>one @ 10% in DPG 65

30

1000 Addition of only 0.65% of (l'£)-7-(prop-r-enyl)-2H-benzo[Zj][l,4]dioxepin-3(4H)-one to the vanillin- free, feminine green- floral bouquet introduces a dominant marine inflection, boosts the spicy character of the eugenol, thereby harmoniously blending into the overall peony- freesia- carnation concept, and adds to the composition a rich powdery vanillic and guaiacol-like dry-down note providing volume and depth. The sweetness of (1 'E)-7-(prop- 1 '-enyl)-2/i-benzo[6][l,4]dioxepin-3(4H)-one is enhancing the soft, musky character of the Galaxolide™, while its guaiacol-type side aspects support the woody-ambery note of the Iso E Super™. Thereby, (l'£)-7-(prop-l'-enyl)-2H-benzo[6][l,4]dioxepin-3(4H)-one renders this simple green- floral bouquet into a complex, rich,, sweet- powdery, spicy- vanillic feminine fine fragrance of very characteristic dewy-aqueous, spicy- vanillic signature.