PURPOSE: To obtain a nonnarcotic analgesic containing a specific crabbine alkaloid derivative, having substance P receptor-antagonistic action, and safely usable for patients suffering from chronic rheumatism, neuralgia, osteoporosis, end-stage cancer, etc.
CONSTITUTION: This analgesic contains a compound (a salt thereof) of formula I [R1 and R2 are each H or a (substituted) hydrocarbon group; R3 is a lower alkyl; ring A and ring B each may have substituent(s); ring D has a double bond either at 8, 9 sites or 9, 10 sites, is substituted by OH (H may be substituted), and may be substituted by oxo group] [e.g. (5R,10S) and (5S,10 R)-8,9-didehydro-6,8-dimethyl-7-oxo-10-ergolinol-]. The compound of formula I is obtained by subjecting a compound of formula II (R7 and R8 are each the same as R1; R9 is the same as R3) to intramolecular amidation followed by reducing the formed amide group, and then, as necessary, conducting OH rearrangement reaction or etherification.
DOI TAKAYUKI
TSUBOYA SHIGETOSHI
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