In terms of actual chemical characterization, none have been described (to my knowledge). However, Fraker et al 2009 (Horm Behav) showed a nice neuroendocrine response from a skin-released compound in larval amphibians. Fish have been well described (e.g., ostariophysan alarm pheromone). The Fraker paper has a nice summary of what is known as well. I doubt my answer helps, but I would also love to know if you have any updates on this question.

HI M,   Thank you very much for your answer!  I don't have any more information about the topic and , as you remerbered, there is just some work about alarm cues characterization, one is from Fraker et al and the other is from Ferland-Raymond et al 2010 (Biochemical Systematics and Ecology). It would be cool to improve our knoledge about kairomones, I am pretty sure they are important for inducing plastic responses, even if the chemical signal is not integrated with alarm cues coming from prey, this let me think to predator-prey coevolution. There is a fantastic example for this, maybe you already know about that, in some papers describing this evolutionary relationship in a tadpole-salamander system (Rana pirica-Hinobius retardatus). You should look at those just for the "bulgy morph" showed by tadpoles after experiencing that specific predator.

Andrea, if you haven't, you should check out Relyea and Schoeppner's paper from 2005 in Ecology Letters. They go into great detail about the importance of kairomones in elucidating the full suite of phenotypic and behavioral responses. 

Henry, thank you for your suggestion!  I read the paper some time ago, authors attemp to eleucidate the source of the cues that elicit anuran tadpoles' responses to predators. I think this is an essential for step to eventually discolse the nature of kairomones but further work is required.