3-[1-(2-Benzoxazolyl)hydrazino]propanenitrile derivatives were evaluated in the dermal and pleural reverse passive Arthus reactions in the rat. In the pleural test these compounds were effective in reducing exudate volume and accumulation of white blood cells. This pattern of activity was similar to that of hydrocortisone and different from that of indomethacin. The structural requirements for inhibiting the Arthus reactions were studied by systematic chemical modification of 1. These structure-activity relationship studies revealed that nitrogen 1' of the hydrazino group is essential for activity and must be electron rich, whereas chemical modifications of other sites of 1 had only a modest effect on activity.

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The reduction of (5S)-2-amino-5-dibenzylamino-4-oxo-1,6-diphenylhex-2-ene was optimized for diastereoselectivity and overall conversion to (2S,3S,5S)-5-amino-2-dibenzylamino-3-hydroxy-1,6-diphenylhexane (2a). A two-step reduction sequence is described wherein the enamine is reduced with a borane-sulfonate derivative followed by reduction of the resulting ketone with sodium borohydride. The desired 2a was obtained with 84% diastereoselectivity and an acyclic 1,4 stereoinduction ratio of 14:1. This methodology has been used to produce multikilogram quantities of the diamino alcohol core of Ritonavir and should be general to the synthesis of related diamino hydroxyethylene isosteres.

GT-2331 is a potent histamine H(3) antagonist which has entered clinical trials. Efficient multigram syntheses of this compound and its enantiomer are described. The literature reports that GT-2331 is the dextrorotatory (+), more potent, enantiomer of 4-[2-(5,5-dimethylhex-1-ynyl)cyclopropyl]-1H-imidazole with the absolute configuration of (1R,2R)-1. However, we found that the dextrorotatory, more potent, enantiomer of 4-[2-(5,5-dimethylhex-1-ynyl)cyclopropyl]-1H-imidazole has the (1S,2S) absolute configuration. We suggest a reconsideration of the absolute configuration of GT-2331.

A series of eicosatetraenes (2-24) were designed, synthesized, and evaluated in vitro for inhibitory activity against 5-lipoxygenase (20000g supernatant from homogenized rat basophilic leukemia cells). All compounds were found to be active with the potencies (IC50's) ranging from 0.19 to 97 microM. Compounds containing the hydroxamic acid functionality (10-12) exhibited the best activity (IC50 = 0.19-2.8 microM). The most potent inhibitor was 5-[(hydroxyamino)carbonyl]methyl]-6,8,11,14-eicosatetraenoic acid (11), which was 10 times more active than the C-1 hydroxamates of arachidonic acid or 5-HETE. Cyclization of the linear eicosanoids 2 and 14 in the C-1 to C-5 region produced compounds (21 and 24, respectively) with several-fold greater potency.