Synthesis and anti-histamine release activity of phenyl tetrazole compounds

Ongoing effort to find novel antiasthmatic drugs led to the design and synthesis of a series of compounds bearing phenyl tetrazole group based on the SAR study.  The important intermediate 3-(1H-tetrazol-5- yl) benzenamine was synthesized from m-nitroaniline via cyclization and hydrogenation. Followed by amidation, eight new target compounds were obtained.  The structures of these compounds were confirmed with ¹H NMR, ESI-MS and elemental analysis.  Their non-specific and specific anti-histamine effects in the mast cell were  determined.  Compound NP03 could inhibit non-specific histamine release induced by compound 48/80 in mast cell of SD rats.