The discovery of quinoline based single-ligand human H and H receptor antagonists.

A novel series of potent quinoline-based human H and H bivalent histamine receptor antagonists, suitable for intranasal administration for the potential treatment of allergic rhinitis associated nasal congestion, were identified. Compound 18b had slightly lower H potency (pA 8.8 vs 9.

4-acyl-1-(4-aminoalkoxyphenyl)-2-ketopiperazines as a novel class of non-brain-penetrant histamine H3 receptor antagonists.

A series of ketopiperazines were prepared and evaluated for their activity as histamine H 3 antagonists. From investigation of the tertiary basic center in the aminopropyloxyphenyl template, the 2( R)-methylpyrrolidine was identified as the most potent amine. In the more rigid piperidineoxyphenyl template the N-cyclobutyl group was the most potent amine.

Synthesis of the ester side chains of some potently antileukemic harringtonia alkaloids from chiral citrates.

The selective reduction of one of the three carboxyl groups of two chiral citric acid derivatives to the corresponding aldehydes, under Rosenmund conditions, are reported together with the application of these aldehydes to the syntheses of the ester side chains of some potently antileukemic Cephalotaxus alkaloids e.g. anhydroharringtonine.