Pharmacologist and blogger David Kroll offers a primer:
Every area of CNS pharmacology has chemists who try to figure out the smallest possible chemical structure that can have a biological effect. In fact, this is a longstanding practice of any area of pharmacology. Huffman was an excellent chemist who in the 1990s was trying to figure out the most important part of the active component of marijuana that might have psychotropic effects. These compounds made by him and his students, surprisingly simple ones, I prefer to call cannabimimetics since they mimic the effect of the more complex cannabinoids in marijuana. … But since they are simple, they are relatively easy to make – some of Huffman’s work at Clemson was actually done by undergraduate chemistry majors.
So, it was no surprise that they would be picked up by clandestine drug marketers, even though cannabis (UK) and marijuana (US) are freely available. The attraction to users was, until recently, that Huffman compounds (prefixed with “JWH-” for his initials) could not be detected in urine by routine drug testing. Hence, incense products containing these compounds have been called “probationer’s weed.”
Huffman supports banning them. But he also favors legalizing and taxing marijuana. "You can't overdose on marijuana, but you might on these compounds," he said. "These things are dangerous, and marijuana isn't, really."