2-Butene-l-thiol

The most striking characteristic of thiols is their appalling odor. Skunk scent, for instance, is caused primarily by the simple thiols 3-methyl-1-butanethiol and 2-butene-l-thiol. Volatile thiols such as ethanethiol are also added to natural gas and liquefied propane to serve as an easily detectable warning in case of leaks. 

Butene-l-thiol is one component of skunk spray. How would you synthesize this substance from methyl 2-butenoate From 1,3-butadiene ... 

Because of their inherent penetrating smell, certain organic sulfur compounds are used for odorization. Repellents from the skunk contain compounds such as trans-2-butene-l-thiol and 3-methyl-1-butanethiol. Ethylmercaptan, because of its extremely low odor threshold, is the favorite compound used as an odorant in natural gas and liquid propane for leak detection. Tetrahydro-thiophene is also often used. Common odorization reagents are summarized in Table 15-1 and Figures 15-1 to 15-3. 

Striped skunk defensive secretion contains a number of compounds but two are largely responsible for the odor tra 5 -2-buten-l-thiol and 3-methylbutane-l-thiol ... 

Spotted skunk (E)-2-Butene-l-thiol Anal glands Wood eta/., 1991... 

The secretion of the anal glands of skunks epitomizes mammalian defense secretions. Sulfur compovmds in the scent of striped skunk Mephitis mephitis) include rra 5-2-butene-l-thiol, 3-methyl-l-butanethiol (Andersen and Bernstein, 1975), rra 5-2-butenyl thioacetate, 3-methylbutanyl thioacetate, and 2-quinolinemethane thiol (Wood, 1990 Fig. 10.9). The thiols, once called mercaptans (because they captured mercury atoms), are like alcohols with a sulfur atom in place of the oxygen. In the striped skvmk, the thioacetates break down in water. They yield thiols, which have the more potent, characteristic skunk odor and linger for up to 2 weeks. In the spotted skunk, by contrast, the... 

Skunks are small animals that wage powerful defensive warfare in the form of spray that has a sickening offensive odor. The compounds that are responsible for skunk spray odor are organosulfur compounds. Although seven or more such compounds have been isolated from the spray of the striped skunk, Mephitis mephitis, it is now believed that there are only three major ones trans-2-butene-l-thiol, t ra .v - 2 - b u t e n y I -1 - thioacetate, and 3-methyl-1-butanethiol5 ... 

The product was previously identified in beer by Andrews (1987) and in human sweat by Polak et al. (1988), and characterized as sunstruck or lightstruck off-flavor. The cause has been attributed to the degradation of bitter isohumulones from hops under the influence of ultraviolet light (Bondeel et al., 1987). By photofragmentation trans-isohumulone liberates a prenyl radical which can trap a thiol radical, producing an undesired flavor for beer. Holscher et al. (1992) have also shown that 3-methyl-2-buten-l-thiol and 3-mercapto-3-methylbutanol are principally formed under pyrolytic conditions in roast model reactions of prenyl alcohol and sulfur-containing amino acids. 

Skunk Mephitis). When threatened, skunks spray an evil-smelling secretion from their anal glands at their enemies. This consists mainly of ( )-2-butene-l-thiol, 3-methyl-1-butanethiol, and other thiols as well as their acetates. These acetates are apparently responsible for the persisting effect of the secretion since they are cleaved by water to the thiols. 

Two major components of a skunk s scent fluid are 3-methyl-l-butanethiol and trans-2-butene-l-thiol. Write structural formulas for each of these compounds. 

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