Wine lactone

Structural formula
General
Surname	Wine lactone
other names	(3 S , 3a S , 7a R ) -3,6-dimethyl-3a, 4,5,7a-tetrahydro-3 H -1-benzofuran-2-one
Molecular formula	C 10 H 14 O 2
External identifiers / databases
CAS number 182699-77-0 PubChem 6427076 Wikidata Q424963
properties
Molar mass	166.22 g mol −1
Physical state	firmly
Melting point	50-51 ° C (3 S , 3a S , 7a R ) 58-59 ° C (3 R , 3a S , 7a R ) 59-60 ° C (3 S , 3a R , 7a R ) 49-51 ° C (3 R , 3a R , 7a S )
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

The wine lactone is in the wine -occurring chemical compound from the group of bicyclic lactones . It has an intensely sweet and coconut-like odor that can still be perceived even when diluted.

Isomers

Structural formula with numbered positions and stereocenters marked with an asterisk

Due to the structure of the molecule with three stereocenters, there are four pairs of enantiomers or eight diastereomers .

The actual wine lactone is in the (3 S , 3a S , 7a R ) configuration and has the lowest odor threshold of all isomers , it can already be perceived in a concentration of 0.00001 to 0.00004 nanograms per liter of air.

The very different odor thresholds of the eight isomers in air were determined as follows:

Structural formula	Configuration according to the CIP convention	CAS number	Odor threshold [ng / l]
	(3 S , 3a S , 7a S )	182699-81-6	0.007-0.014
	(3 R , 3a R , 7a R )		14-28
	(3 R , 3a R , 7a S )	182699-78-1	> 1000 (odorless)
	(3 R , 3a S , 7a S )	182699-83-8	8-16
	(3 S , 3a R , 7a R )		0.05-0.2
	(3 S , 3a S , 7a R )	182699-77-0	0.00001-0.00004
	(3 S , 3a R , 7a S )	182699-80-5	80-160
	(3 R , 3a S , 7a R )	182699-79-2	> 1000 (odorless)

The racemate has the CAS number 78168-36-2. The isomers can be separated by gas chromatography on a chiral stationary phase .

presentation

(3 S , 3a S , 7a R ) wine lactone and (3 R , 3a S , 7a R ) wine lactone can be prepared from (1 R ) - trans -isolimones.

After a multi-stage reaction, a mixture of (3 S , 3a S , 6 R , 7 R , 7a R ) -7-iodo-3,6-dimethylhexahydrobenzofuran-2 (3 H ) -one and (3 R , 3a S , 6 R , 7 R , 7a R ) -7-iodo-3,6-dimethylhexahydrobenzofuran-2 (3 H ) -one, which can be separated by chromatography. The desired isomer can then be reacted with diazabicycloundecene to give the corresponding wine lactone.

Individual evidence

1. ↑ ^{a b c d} Stefano Serra, Claudio Fuganti: Natural p-Menthene Monoterpenes: Synthesis of the Enantiomeric Forms of Wine Lactone, Epi-wine Lactone, Dill Ether, and Epi-dill Ether Starting from a Common Intermediate . In: Helvetica Chimica Acta . tape 87 , no. 8 , August 2004, ISSN  0018-019X , p. 2100–2109 , doi : 10.1002 / hlca.200490189 .
2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
3. ^ H. Guth: Determination of the configuration of wine lactone. In: Helvetica Chimica Acta. Vol. 79, Issue 6, 1996, pp. 1559-1571; doi: 10.1002 / hlca.19960790606 .
4. ↑ ^{a b} H.-D. Belitz among other things: Textbook of food chemistry. 5th edition. Springer, Berlin et al. 2001, pp. 343-345. ( limited preview in Google Book search).
5. ↑ Subhash P. Chavan, Rajendra K. Kharul, Anil K. Sharma, Sambhaji P. Chavan: An efficient and simple synthesis of ( -) - wine lactone . In: Tetrahedron: Asymmetry . tape 12 , no. 21 , November 2001, ISSN  0957-4166 , p. 2985-2988 , doi : 10.1016 / S0957-4166 (01) 00511-0 .