mercaptal

from The Century Dictionary.

• noun The name of a class of compounds containing the group , where R is any hydrocarbon radical and Alk is an alkyl-group such as methyl or ethyl. The compounds are oils with a highly offensive smell, and are also called thioacetals. They are related to mercaptan in the same way that the acetals are to alcohol.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) Any one of a series of compounds of mercaptans with aldehydes.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun obsolete ,(chemistry) a dithioacetal derived from an aldehyde