ACD/Name

Specific Classes of Compounds

R-5.6.4 Acetals, hemiacetals, acylals, and their analogues

R-5.6.4.1 Acetals. Compounds with the general structure , where R and/or R' may be, but need not be, hydrogen, but R" and R'" cannot be hydrigen, are termed generically "acetals". "Ketals" constitute a subclass of acetals wherein neither R nor R' may be hydrogen. Acetals are named substitutively as "alkoxy-", "aryloxy-", etc., derivatives of an appropriate parent hydride or functional parent compound. Alternatively, according to functional class nomenclature, the name of the appropriate aldehyde or ketone is followed by that of the O-substituent(s), which is in turn followed, after a space, by the word "acetal" or "ketal".

Examples to R-5.6.4.1

Sulfur analogues of acetals and ketals with the general structures or , are termed generically "dithioacetals" or "monothioacetals", respectively. They are named substitutively as "alkylsulfanyl-", "arylsulfanyl-", "alkyloxy-" (or "alkoxy-"), or "aryloxy-", derivatives, as appropriate, of a parent hydride. They may also be named by functional class nomenclature in the same way as acetals (see above). Capital italic latter locants are used to provide structural specificity. Selenium and tellurium and mixed analogues are treated in the same way as their sulfur analogues; generically, they are "monoselenoacetals", "ditelluroacetals", "selenothioacetals", etc., and are named substitutively using prefixes such as "alkylselanyl-", "aryltellanyl-", etc.

Examples to R-5.6.4.1

R-5.6.4.2 Hemiacetals. Compounds with the general structure are termed generically "hemiacetals". Hemiacetals are named substitutively as alkoxy-, aryloxy-, etc., derivatives of an appropriate hydroxy parent compound, such as an alcohol (see R-5.5.1.1), and by functional class nomenclature in the same way as acetals (see R-5.6.4.1) using the class name "hemiacetal".

Example to R-5.6.4.2

Sulfur analogues of hemiacetals with general structures and or are generically "dithiohemiacetals" or "monothiohemiacetals", respectively. They are named substitutively as "alkylsulfanyl-", "arylsulfanyl-", "alkyloxy-" (or "alkoxy-"), or "aryloxy-", derivatives, as appropriate, of a hydroxy parent compound, such as an alcohol (see R-5.5.1.1), or of a thiol parent compound (see R-5.5.1.2). They may also be named by functional class nomenclature in the same way as hemiacetals (see above, R-5.6.4.2). Selenium and tellurium and mixed analogues are treated in the same way as their sulfur analogues; generically, they are "monoselenohemiacetals", "ditellurohemiacetals", "selenothiohemiacetals", etc., and are named substitutively as derivatives of a hydroxy parent compound or a chalcogen analogue, such as a "thiol" or "selenol", using prefixes such as "alkylselanyl-" and "aryltellanyl-", etc.

Examples to R-5.6.4.2

R-5.6.4.3 Acylals. Compounds with the general structure , , etc., are generically called "acylas". Specific compounds are named as esters.

Example to R-5.6.4.3

(traditionally Ethylidene dipropionate,

see Note under R-2.5)

Next:
R-5.6.5 Acyloins
R-5.6.6 Nitrogenous derivatives of carbonyl compounds

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This HTML reproduction is as close as possible to the published version [see IUPAC, Commission on Nomenclature of Organic Chemistry. A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993), 1993, Blackwell Scientific publications, Copyright 1993 IUPAC]. If you need to cite these rules please quote this reference as their source.

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