Analgesic narcotic antagonists. 15. Potent narcotic agonist 7 beta-(arylalkyl)-4,5 alpha-epoxymorphinans

Structure-activity correlations in 7 beta-(arylalkyl)-3-methoxy- or hydroxy-4,5 alpha-epoxymorphinans have been investigated. 6 beta-Hydroxy-7 alpha-hydroxymethyl compounds 7 with 7 beta-substituents CH2CH2R [a, R = H; b, R = CH2CH3; c, R = C6H5; d, R = CH2C6H5; f, R = CH2CH2C6H5; g, R = (CH2)3C6H5; h, R = (CH2)4C6H5] were prepared. Wittig condensations with previously reported 4,5 alpha-epoxy-7 beta-formyl-7 alpha-(hydroxymethyl)-6 beta, 7 alpha-O-isopropylidene-3-methoxy-17-methylmorphinan-6 beta-ol (3), followed by dilute acid removal of the blocking group and then hydrogenation, gave saturated compounds 7. Compounds with a 6 alpha, 7 alpha-oxymethylene ring. 18c,d,f,g, were prepared from 7 beta-formyl derivative 16 and the appropriate Wittig reagent, followed by hydrogenation. Both the 6 beta-hydroxy-7 alpha-hydroxymethyl and 6 alpha, 7 alpha-oxymethylene series containing 7 beta-arylalkyl groups with an alkyl chain length of 2 to 4 ar potent narcotic agonists. The most potent 17-methyl compound, 4,5 alpha-epoxy-7 alpha-(hydroxymethyl)-17-methyl-17 beta-(4-phenylbutyl)morphinan-3,6 beta-diol (8f) was 700 times more potent than morphine in the acetic acid induced mouse writhing assay. 17-Methyl compounds in the c, d, f, g series were converted to 17-cyclopropylmethyl (P series) or 17-cyclobutylmethyl (B series) derivatives. Narcotic antagonistic activity could not be demonstrated for these potent agonist 17-cycloalkylmethyl derivatives. These pharmacological results parallel those previously reported for tertiary alcohol derivatives of the endo-ethenotetrahydrooripavines. Structureal considerations confirm the existence of a lipophilic site extending upward and outward from where the C ring of morphine and congeners bind to opiate receptors.