2.3- Dimethyl trisulfide

An example of a larval parasitoid that responds to the host sex pheromone is seen with Cotesiaplutellae (Braconidae), also a parasitoid of the diamondback moth. These insects were attracted equally to the pheromone blend (31,32,33, see above), the acetate 32, or aldehyde 31 components [80]. This larval parasitoid, however, was also strongly attracted to host frass volatiles, in particular, dipropyl disulfide 34, dimethyl disulfide 35, allyl isothiocyanate 36, and dimethyl trisulfide 37. In contrast, the egg parasitoid Trichogramma chilonis was only weakly attracted to 36. In both, T. chilonis and C. plutellae, plant volatiles, in particular (3Z)-hex-3-en-l-yl acetate 38, significantly enhanced attraction by the pheromone [80]. 

Host frass volatiles [attraction] Dipropyl disulfide 34, dimethyl disulfide 35, allyl isothiocyanate 36 dimethyl trisulfide 37 [80]... 

Examination of 37 basidiomycetous yeasts indicated formation of several sulfur volatiles 3-(methylthio)-l-propanol, methanethiol (MT), S-methyl thio-acetate, dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), allyl methyl sulfide and 4,5-dihydro-3(2//)-thiophenone. The component produced in the largest amounts, 40 100 mg L-1, was 3-(methylthio)-l-propanol29 Cheeseripening yeasts are considered later (Section 11.1.2.4.5). 

A component of the vaginal secretion, dimethyl disulfide, was found to be the major sex attractant of the golden hamster [ 59 ]. Volatile alcohols, fatty acids and, interestingly, dimethyl trisulfide in the secretion do not appear to enhance the attractancy of the secretion [60]. However, proteins in the mass range of 15-16 kDa that are present in the vaginal secretion act as a mounting pheromone [61]. No comprehensive chemical characterization of the semiochemical secretions of golden hamsters has yet been undertaken. 

Wild and cultivated blackberries have been used as food and medicine for hundreds of years [106]. Approximately 150 volatiles have been reported from blackberries [107]. The aroma profile is complex, as no single volatile is described as characteristic for blackberry [108, 109]. Several compounds have been suggested as prominent volatiles in blackberries using AEDA, e.g. ethyl hexanoate, ethyl 2-methylbutanoate, ethyl 2-methylpropanoate, 2-heptanone, 2-undecanone, 2-heptanol, 2-methylbutanal, 3-methylbutanal, hexanal, ( )-2-hexenal, furaneol, thiophene, dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, 2-methylthiophene, methional, a-pinene, limonene, linalool, sabinene. 

Shallots Allium ascalonicum) are an allium wherein the bulb laterals separate into individual bulbs. Apparently, shallots do not develop a lachrymatory factor, such as thiopropanal-S-oxide upon maceration [35]. The major aroma constituents in shallots are similar to those found in A.cepa. In raw shallots, the most important aroma compounds appear to be dipropyl disulfide, propyl ( )-prope-nyl disulfide, methyl propyl trisulfide, dimethyl trisulfide and dipropyl trisulfide (Table 7.5, Fig. 7.6) [35, 152, 153]. 

The buds and the leaves (less often) of the Brussels sprout plant (Brasska olera-cea var. gemmifera) are eaten cooked with the main meal. In Brussels sprouts, breakdown products from glucosinolates are dominant and represent about 80-90% of the volatiles in headspace samples [176]. The residual volatiles are mostly sulfur compounds [176]. Compounds likely to be associated with the aroma of Brussels sprouts are 2-propenyl isothiocyanate, dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide (Table 7.6) [35,176]. 

The sulfur components ethyl S-(+)-2-methylbutanoate and dimethyl trisulfide (with 0.006 and 0.01 pg/L odour thresholds in water, respectively) were reported as impact-flavour compounds in fresh Hawaiian pineapple essence prepared by solvent extraction. The major volatile components were methyl and ethyl esters [59]. 

Bistrifluoromethyl trisulfide (LI) similarly undergoes photolysis on irradiation to yield XLIX and XLVII the latter was isolated as an intermediate and upon further irradiation gave XLIX. On the other hand, photolysis of dimethyl trisulfide (CH3)sS3 gave a small amount of the di- and tetrasulfides.19... 

DimethyJheptane-4-thione 35 Dimethyl trisulfide 12 Dimelhylphenylthioaluminum 20 (lR,5 )-6.6-Dimethyl-3-... 

Dimethyl trisulfide (Methyl trisulfide, (Methyltrithio)methane) CHjSSSCHj... 

Dimethyl disulfide and dimethyl trisulfide were identified in crayfish tail meat with the former also identified in the boiled crayfish hepatopancreas and the pasteurized crabmeat. These two straight chain sulfur-containing compounds exhibit a cooked cabbage and spoilage odor. 

Although not present as major components in crayfish, these compounds generally are considered undesirable. Dimethyl disulfide and dimethyl trisulfide have been found previously in thermally processed seafoods and meat products (6-11). 

Group 3 volatiles, formed by further interactions, can reach even lower threshold values than those mentioned so far, particularly when sulfur is involved, usually derived by the break down of cysteine (bis(2-methyl-3-furyl) disulfide, 0.00002 2-methyl-3-furanthiol, 0.0004 2-furylmethanethiol, 0.005 dimethyl trisulfide, 0.01 dimethyl disulfide, 0.16 dimethyl sulfide, 0.3 hydrogen sulfide, 10). Into some volatile sulfur compounds other atoms as well as the sulfur of cysteine are incorporated (2-acetylthiazoline, 1 5-acetyl-2,3-dihydro-l,4-thiazine, 1.25 2-acetylthiazole, 10). Other volatiles are more likely to be derived from methionine (methanethiol, 0.2). 

The inflorescence of the dead horse arum Helicodiceros muscivorus (Araceae), distributed in the western Mediterranean regions, mimics a dead mammal and emits an oligosulfide odor, which includes dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide.104 The flower odor is crucial for attracting blowflies, which serve as important pollinators for this flower. In addition, the thermogenesis and respiration of the inflorescence reinforce the stimulation for fly pollination.10... 

Maize (cooked) Dimethyl sulfide, dimethyl trisulfide (122), acetaldehyde, 4-vinylguaiacol (123), 2-acetyl-1 -pyrroline 145... 

Yuzu Citrus junos Dimethyl trisulfide, 6-methyl-5-hepten-2-ol(147), (Z)-9-dodecen-12-olide (148), 8-methylnonanal, 8-methyldecanal 167... 

Tomato (fresh) Solanum 2-acetyl-1 -pyrroline, dimethyl trisulfide, 2,3-diethyl-5-methylpyrazine (Z)-3-Hexenal, hexenal, 1 -octen-3-one, methional 131,169... 

Bell pepper (red) var. grossum octanal, dimethyl trisulfide 2-lsobutyl-3-methoxypyrazine, (+)-3-carene (150), 174... 

Garlic Allium sativum dimethyl trisulfide Allicin (151), di(2-propenyl) disulfide (152), dimethyl 131,171... 

The liquid phase photolysis of dimethyl disulfide (2537 A) has been reported to produce dimethyl sulfide and dimethyl trisulfide in equal quantities, and traces of CH4 and methyl tetrasulflde. Ethyl disulfide again gave mono, tri- and tetra-sulfides with a trace of ethyl mercaptan. All irradiations were prolonged, of the order 24-48 hours. It was claimed that C-S fission in the primary photolytic dissociation... 

The thermal decomposition of dimethyl trisulfide at 80 °C also results in the formation of di- and tetrasulfides . It was further established that the decomposition proceeds via a radical mechanism, probably homolytic S-S cleavage, since in a weakly polar medium such as benzoyl peroxide and triethylamine, the rate of decomposition is greatly accelerated. 

DIMETHYL-TRISULFIDE 2JSO-BUTYL THIAZOL 44ylETHYL VINYL THIAZOLE 2-ACETYL THIAZOLE... 

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