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Basic Organic
Nomenclature
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Thiols
Suffix: thiol (or as an alkyl mercaptan)
Prefix: mercapto-
Thiols are the sulfur analog of alcohols. They contain a R-SH functional
group. The H atom attached to the S is weakly acidic and is responsible
for hydrogen bonding making these compounds less volatile than the corresponding
hydrocarbon. The H can be replaced by: another R' group to generate a sulfide
(R-S-R'); a -S-R', producing a disulfide (R-S-S-R'); or it can be oxidized
to sulfoxides (R-SO-R'), and sulfones (R-SO2-R').
There are two basic methods for naming simple thiols,
- the first is to name it as an alkanethiol (note the final -e
is retained as the thiol starts with a consonant)
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the second as an alkyl mercaptan.
- Since the thiol functional group is higher in priority than others studied
to this point, its location on the root chain will determine the numbering
scheme used. Pick the one that gives the thiol group the lowest possible number.
Examples naming simple thiols:
Examples naming more complex thiols:
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Compound Name
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Line Drawing
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4,4-dimethyl-2-pentanethiol
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4-pentene-2-thiol
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4-amino-3-isopropylhexanethiol
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5-bromo-2,4-cyclohexadienethiol
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Thiols as Substituents:
In more complex molecules with higher priority functional groups, the thiol
is named as a mercapto- substituent. It is located by numbering
the longest chain of carbons (according to the higher priority functional
group) and locating the SH group by this numbering scheme. Examples of
these structures will be given in the subsequent pages.
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