3- Methyl-l-butanethiol

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... 

A physical characteristic is their odor 2-butene-1-thiol, CH,CH=CHCH2SH, and 3-methyl-l-butanethiol, CH3CH(CH,)CH2CH2SH, contribute to skunk smell. 

Methyl-l-butanethiol (Isopentyl mercaptan) ch3ch(ch3)ch2ch2sh... 

As shown in the case of l-octen-3-one in the beginning of this chapter, aroma-active compounds show an interesting indication as media in human-environment interactions the role of this often disliked compound has some similarity to alarm pheromones. Flavor or smell of food can be categorized into food attractant molecules from this point of view. Infants are able to recognize the body odor of their mother and are attracted to it.189 An opposite example is represented by the notorious ability of skunks to spray, in which thiol compounds such as (E)-2-butene-1 -thiol and 3-methyl-l-butanethiol are used as potent repellents190(see Chapter 4.09). 

The most obvious characteristic of thiols is their appalling odor. Skunk scen for example, is caused primarily by the simple thiols, 3-methyl--l butanethiol and 2-butene-I thiol. Volatile thiols are also added to natural gas to serve] as an easily detectable warning in case of leaks. 

Because a substance combines with oxygen, and because we see carbon in that substance going to CO2, hydrogen going to H2O, and sulfur going to SO2, we classify this reaction as a combustion reaction. The compound C5H11SH is 3-methyl-l-butanethiol, a component of the spray produced by skunks. 

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. 

Acetaldehyde can undergo various interactions with butanedione, hydrogen sulfide, methanethiol and ammonia to give various aliphatic sulfur compounds, thiazoles, thiadiazines and dithiazines as shown in Fig. 1. Compounds identified in YEs are indicated by ( ) (29). The involvement of alternative aldehydes, such as formaldehyde in place of acetaldehyde or mixtures of aldehydes, will lead to the corresponding homologues, some of which have also been reported in YEs. Another aldehyde, 3-methylbutanal, reacts with hydrogen sulfide and methanethiol to give the hemidithioacetal, l-methylthio-3-methyl-l-butanethiol which has been reported in YEs (14). Compounds of this class possess characterisitic meaty aromas with an onion note (14). 

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