A new series of antiallergic agents. II. Synthesis and activity of new 6,11-dihydrodibenz[b,e]oxepin-carboxylic acid derivatives.

New methods for the preparation of multi-functionalized-6,11-dihydrodibenz[b,e]oxepins were developed. The structural requirements of KW-4994 (1), a promising orally active antiallergic agent, were defined. A carboxyl group at C-2 was critical for enhanced antiallergic activity of 1. The introduction of bromine atom at C-9 of 1 could elongate the duration of the action of the parent. Antiplatelet activity, a new pharmacological property of this series of compounds, was observed in one of the derivatives of 1.