Process for the production of beta-springene

Abstract

The present invention relates to a process for the production of β-springene of formula (I) wherein a compound of formula (II) is heated in the presence of a catalyst. ##STR00001##

Claims

1. A process to produce a compound of formula (I): ##STR00005## wherein the process comprises heating a compound of formula (II) at a temperature of 30° C.-80° C.: ##STR00006## in the presence of a catalyst and in the presence of dimethyl sulfoxide (DMSO) to thereby form the compound of formula (I), and wherein the catalyst is selected from the group consisting of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU), Tröger base (2,8-Dimethyl-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine), 1,4-Diazabicyclo[2.2.2]octane (DABCO), Pd(PPh.sub.3).sub.4, Ni(PPh.sub.3).sub.4, Pt(PoTol.sub.3).sub.4, Pt(PPh.sub.3).sub.4, Ni(PoTol.sub.3).sub.4, Pd(PoTol.sub.3).sub.4, Pd(Palkyl.sub.3).sub.4, Ni(Palkyl.sub.3).sub.4, Pd(Palkyl.sub.3).sub.4, Ni(OPPh.sub.3).sub.4, Pd(OPPh.sub.3).sub.4, and Pt(OPPh.sub.3).sub.4, wherein alkyl is a linear or branched C.sub.1-C.sub.6-alkyl.

2. The process according to claim 1, wherein the process is carried out under an inert gas atmosphere.

Description

EXAMPLES

Example 1

Elimination of Acetic Acid from Geranyl Linayl Acetate

(1) Under inert gas atmosphere, 1.4 mmol of geranyl linalyl acetate ((6E,10E)-3,7,11,15-tetramethylhexadeca-1,6,10,14-tetraen-3-yl acetate) were dissolved in 2.9 ml of anhydrous DMSO. At room temperature, subsequently 2.9 mmol (2.00 eq.) of DBU and 0.100 mmol (7 mol %) of Pd(PPh.sub.3).sub.4 were added to the stirred solution. Then, the reaction mixture was heated to 60° C. (oil-bath temperature) and stirred for 2 hours. After that, the reaction mixture was cooled to room temperature, and diluted with ethyl acetate (100 ml). The organic solution was subsequently washed with water (2×100 ml) and brine (100 ml). The aqueous phase was re-extracted with ethyl acetate (3×100 ml). The combined organic layers were dried over Na.sub.2SO.sub.4, filtered, and concentrated under reduced pressure. The crude product (8.27 g) was obtained as a mixture of β- and α-springene in a ratio of 4:1. Quantitative analysis of the crude product showed 50.4% purity for β-springene (77% yield) and 13.0% purity for α-springene (20% yield). The crude material was purified by column chromatography (SiO.sub.2, pentane).

Example 2

(2) Under inert gas atmosphere, geranylgeranyl acetate (1.3 mmol) was dissolved in anhydrous DMSO (2.5 ml). With stirring DBU (2 eq.) and Pd(PPh3)4 (7 mol %) were added and the reaction mixture was warmed to 60° C. within 15 min. After 3 hours reaction time, the mixture was cooled to room temperature and transferred into a separation funnel with 20 ml of ethyl acetate. The organic phase was washed with water (2×20 ml) and brine (20 ml). The aqueous layers were extracted with ethyl acetate (3×20 ml). The combined organic layers were dried over MgSO4 and concentrated under reduced pressure. The product was obtained as an isomeric mixture of β- and α-springene (7:3) in 66% yield.

(3) When using geranylgeraniol or geranyl linallol as starting material, no conversion was observed under the same reaction conditions.