title: (+/-)-2-Depentylperhydrohistrionicotoxin: a new probe for a regulatory site on the nicotinic acetylcholine receptor-channel.
abstract: (+/-)-2-Depentylperhydrohistrionicotoxin (4), several of its analogues, and N- and O-substituted derivatives were prepared and tested for their effects on the neuromuscular transmission of the frog sartorius muscle. Compound 4, its N-methyl derivative 5, the O-acetyl derivative 9, and the quaternary methiodides 19 and 20 blocked the indirectly elicited twitch. The oxidation of 4 and 5 to ketones 12 and 14 and their reduction to the epimeric alcohols 17 and 18 afforded materials with substantially reduced activity. N-Acetylation of 4 to 11 changed the course of the activity to a transient potentiation of muscle twitch. Both 4 and 5 were not very toxic to mice after subcutaneous administration. (+/-)-7-n-Butyl-1-azaspiro[5,5]undecan-8-one (12) epimerized readily at room temperature to afford the epimer 13, and preparation of the hydrochloride of its N-methylated derivative 14 was accompanied by a retro-Michael reaction, affording the 2-n-butyl-3-[4-(methylamino)butyl]cyclohexene-2-one (22). The strongly hydrogen-bonded alcohol 4 was analyzed as the hydrobromide by a single-crystal X-ray analysis, confirming its structure.
mesh_terms: D000664:Amphibian Venoms / Q000138:chemical synthesis* / Q000494:pharmacology / Q000633:toxicity; D000700:Analgesics / Q000138:chemical synthesis; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D011894:Rana pipiens; D011950:Receptors, Cholinergic / Q000187:drug effects*; D011978:Receptors, Nicotinic / Q000187:drug effects*; D014961:X-Ray Diffraction
chemical_list: D000664:Amphibian Venoms; D000700:Analgesics; D007473:Ion Channels; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; C035556:2-depentylperhydrohistrionicotoxin