Thiotimoline is a fictitious chemical compound conceived by science fiction author Isaac Asimov and first described in a spoof scientific paper titled "The Endochronic Properties of Resublimated Thiotimoline" in 1948.
In Asimov's writing, thiotimoline is notable for the fact that when it is mixed with water, the chemical actually begins to break down before it contacts the water. This is explained by the fact that in the thiotimoline molecule, there is at least one carbon atom such that, while two of the carbon's four chemical bonds lie in normal space and time, one of the bonds projects into the future and another into the past. Thiotimoline is derived from the bark of the shrub Rosacea Karlsbadensis rufo, and the thiotimoline molecule includes at least fourteen hydroxy groups, two amino groups, and one sulfonic acid group, and possibly one nitro compound group as well. The nature of the hydrocarbon nucleus is unknown, although it seems in part to be an aromatic hydrocarbon.
The story of the genesis of this spoof was one of Asimov's favorite personal anecdotes, one he retold a number of times in print. In the spring of 1947, Asimov was engaged in doctoral research in biochemistry and, as part of his experimental procedure, he needed to dissolve catechol in water. As he observed the crystals dissolve as soon as they hit the water's surface, it occurred to him that if catechol were any more soluble, then it would dissolve before it encountered the water.
By that time Asimov had been writing professionally for nine years and was shortly to face the challenge of writing up his research as a doctoral dissertation. He feared that the experience of writing readable prose for publication might have impaired his ability to write the prose typical of academic discourse, and decided to practice with a spoof article (including charts, graphs, tables, and citations of fake articles in nonexistent journals) describing experiments on a compound, thiotimoline, that was so soluble that it dissolved in water up to 1.12 seconds before the water was added.
Asimov wrote the article on 8 June 1947, but he was uncertain as to whether the resulting work of fiction was publishable. He finally offered it to John W. Campbell, the editor of Astounding Science Fiction, his preferred publication outlet. Campbell was delighted with the piece, and accepted it for publication, agreeing to Asimov's request that it appear under a pseudonym in deference to Asimov's concern that he might alienate potential doctoral examiners at Columbia University if he were revealed as the author.
Some months later Asimov was shocked to see the piece appear in the March 1948 issue of Astounding under his own name. In later years Campbell insisted that this was an oversight, though Asimov maintained a suspicion that Campbell had acted deliberately out of greater worldliness, for, in Asimov's words, "The Columbia Chemistry Department proved far less stuffy than I had feared" and his examiners effectively delivered their favorable verdict on his dissertation by good-naturedly asking him a final question about thiotimoline. In Opus 100 (1969) Asimov called the thiotimoline article "an utter success", and noted that the New York Public Library "was pestered for days by eager youngsters trying to find the nonexistent journals so they could read more on the subject".