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Download the zipped version of the first installments of this series, originally published in the Sci-Tech Translation Journal, of the American Translators Association. The file is approximately 87 KB.

Previous installments of this series appeared in the July 1997, October 1997, January 1998, April 1998, and July 1998 issues of the Translation Journal.

VI. Organic Sulfur Compounds (continued)

Thials, Thiones, and Thiocarboxylic Acids

Some examples of the sulfur analogs of aldehydes, ketones, and carboxylic acids are shown below:
 

Oxidized Organic Sulfur Compounds

We have seen that some organic oxygen compounds have sulfur analogs: alcohols ROH » mercaptans RSH; ethers ROR' » sulfides RSR'; peroxides ROOR' » disulfides RSSR', and we have just looked at some sulfur analogs of aldehydes, ketones, and carboxylic acids. However, because sulfur compounds can readily be oxidized, there are further classes of sulfur compounds with no oxygen analogs.

Dimethyl sulfide CH₃SCH₃ can be oxidized in stages to form two new compounds:

		Dimethyl sulfoxide DMSO		Dimethyl sulfone

Sulfolane is a cyclic sulfone that is useful as a solvent:

Oxidation of methyl mercaptan also proceeds stepwise:

		Methanesulfenic acid		Methanesulfinic acid

Methanesulfonic acid

Alkanesulfenic acids are unstable and cannot usually be isolated, but sulfinic acids and sulfonic acids are stable compounds. The simpler sulfur acids are given radicofunctional names as shown above, but substitutive nomenclature may be more convenient for complex compounds:

4-Methyl-2-sulfinopentane, or 4-methyl-2-pentanesulfinic acid	3-Sulfo-4-decene, or 4-decene-3-sulfonic acid

Of course these acids can form salts and esters:
CH3CH2S(O)ONa	Sodium ethanesulfinate (a salt)
CH3S(O2)OC2H5	Ethyl methanesulfonate (an ester)
Halides and anhydrides of sulfinic and sulfonic acids also exist:
CH3CH2CH2S(O)Br	Propanesulfinyl bromide
CH3S(O2)OS(O2)CH2CH3	Methanesulfonic ethanesulfonic anhydride
	3-Sulfopropionic anhydride
When some of the oxygen atoms attached to the sulfur atom in these compounds are replaced by sulfur atoms, the prefix thio- (with appropriate multiplier) is used:
	Methanemonothiosulfonic O-acid
	Methanedithiosulfonic S-acid

Fortunately for translators, such compounds are rarely encountered in the literature.

Before leaving the subject of sulfur compounds, a comparison of the nomenclature of sulfuric acid derivatives and sulfonic acid derivatives would not be out of place. As a dibasic (inorganic) acid, sulfuric acid HOS(O₂)OH can form monoesters, diesters, and salts, all of which are called sulfates. The esters and salts of sulfonic acids are of course called sulfonates. At first glance their formulas may appear similar; they are differentiated by the fact that only sulfonates have a carbon-to-sulfur bond:
 

VII. Alicyclic Compounds

Although other derivatives in the alkane series remain to be discussed, especially nitrogen compounds, the descriptions given so far of the compounds of carbon, hydrogen, halides, oxygen, and sulfur in their infinite variety permit us to expand our considerations to compounds in which the carbon atoms form rings.
The underlying cycloalkane series C_nH_2n, begins with cyclopropane C₃H₆:

	=		Cyclopropane
			Cyclobutane
			Cyclopentane
			Cyclohexane
			Cycloheptane
			Cyclooctane, and so on.
Naturally, there are also cyclalkenes:
			Cyclobutene
			Cyclopentadiene
			Cyclooctatetraene, and so on.
The case of cyclohexatriene (benzene) needs special consideration and will be discussed later in the section on aromatic compounds. The alicyclic family also includes the same derivatives as the acyclic compounds, for example:
			Chlorocyclohexane
			Cyclopentanone
			Cyclobutenol
			Cyclopropanecarbaldehyde
			Cyclopentanecarboxylic acid
			Methyl 1,3-cyclopentadiene-5-carboxylate

Part XIV will continue the discussion of alicyclic compounds.

Readers are urged to e-mail questions, comments, or suggestions for further topics in the field of organic nomenclature to the author at: 74654.1335@compuserve.com.