Methyl thiosulfines

Methyl metlviiie thiosulfinate Me thy propyl thiosulfinate ITopyl methyl thiosulfinate Dipropyl thiosulfinate Propcnyl methyl thiosulfinate Methyl propenyl thiosulfinate Propcnyl propyl thiosulfinate Thiopropanal S-oxide... 

The most important flavour compound in raw onions is thiopropanal-S-ox-ide, the lachrymatory factor [145,146]. Other important flavour compounds are 3,4-dimethyl-2,5-dioxo-2,5-dihydrothiophene and alkyl alkane thiosulfonates such as propyl methanethiosulfonate and propyl propanethiosulfonate with a distinct odour of freshly cut onions [35, 36, 147]. Various thiosulfinates that have a sharp and pungent odour may also contribute to the flavour of onions. These compounds, however, are rapidly decomposed to a mixture of alkyl and alkenyl monosulfides, disulfides and trisulfides (Scheme 7.3) of which dipropyl disulfide, methyl ( )-propenyl disulfide, propyl ( )-propenyl disulfide, dipropyl trisulfide and methyl propyl trisulfide are the most important contributors to the aroma of raw and cooked onions (Table 7.5, Fig. 7.6) [148-150]. Recently, 3-mercapto-2-methylpentan-l-ol was identified in raw and cooked onions eliciting intense meat broth, sweaty, onion and leek-like odours [142, 151]. 

In the case of the oxidation of methyl alkyl sulfides, enantioselectivity remains in the range of 50-60% ee (Table 6C.2). Disufides R-S-S-R, sulfenamides R-S-NR 2, and sulfenates R-S-O-R were oxidized to the corresponding chiral thiosulfinates, sulfinamides, and sulfinates, respectively (<52% ee, Table 6C.3) [21]. 

Buffer catalysis of the hydrolysis of phenyl (311 R = Ph) and methyl (311 R = Me) benzenesulfinates to give the sulfinic acid (312) and alcohol ROH is strongly accelerated by both carboxylate and amine components of the buffer which give Bronsted /i values of approximately unity on separate lines. The carboxylates are about 44 tunes more effective than amines of similar basicity. A concerted. S n2 mechanism with a hypervalent intermediate (313) is proposed for the nucleophilic reaction of these esters.286 The reaction of the thiosulfinate esters (314) with sulfenyl chlorides RSCI and sulfenate esters (315) to give sulfinyl chlorides and disulfides and sulfinate esters and disulfides, respectively, has been studied.287 Hydrolysis of 2-(3-aminophenyl)sulfonyl-ethanol hydrogensulfate gives under different conditions various products such as the ether (316) and the sulfone (317).288... 

Garlic also contains S-propylcysteine-sulfoxide (PCSO) and S-methylcysteine-sulfoxide (MCSO). PCSO can generate over 50 compounds depending on temperature and water content. The action of allinase on the mixture of alliin, PCSO, and MCSO can produce many other molecules, including allyl methane thiosulfinate, methyl methanethiosulfinate, and other mixed or symmetrical thiosulfinates (R-S-S-R ), where R and R are methyl, propyl, and allyl groups. 

S-alkylcysteinase S-methylcysteine S-methylcysteine sulfoxide Methanethiol Methyl methane-thiosulfinate... 

Bis(trimethylsilyl) sulfide reacts with methyl, phenyl, or other thiosulfinates (disulfane oxides), R S(0)SR, in anhydrous chloroform at 60 °C to give the symmetrical trisulfane and hexamethyldisiloxane the latter is removed together with the solvent by vacuum distillation, leaving almost pure R2S3 (yields 70 90%). In a similar reaction,... 

Methyl allyl thiosulfinate (0.3 mg/g) -Allyl trans-l-propenyl thiosulfinate (0.05-1.0mg/g)... 

The transformation products of allicin and odier thiosulfinates present in crushed garlic is greatly accelerated and expanded upon heating such as during steam distillation or cooking. As many as 20 different sulfides have been identified in the steam distillate and include diallyl mono to hexasulfides, allyl methyl mono to hexasulfides dimethyl mono to hexasulfides, and allyl 1-propenyl di and trisulfides [38]. 

Related Reagents. Benzenesulfenyl Chloride 2-(Methyl-thio)- li/-isoindole-1,3(2/ -dione N- ferf-Butylthiophthalimide 7V-Phenylthiophthaliinide Dimethyl(methylthio)sulfoniumTetra-fluoroborate Ethyl Thiosulfinate Disulfur Dichloride. 

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