Antimycobacterial and H sub(1-antihistaminic activity of 2-substituted piperidine derivatives)

2-Substituted derivatives of the antihistaminic agents Bamipine, Diphenylpyraline and of their 1-phenyl analogues were tested for their antimycobacterial and H sub(1-antagonistic activities. They are strong H) sub(1)-receptor antagonists and also inhibit the growth of mycobacterials with a maximum MIC of 6.25 mu g/mL against Mycobacterium tuberculosis H sub(37Rv. H) sub(1)-receptor antagonistic potency was slightly decreased by substitution in ring position 2 and distinctly diminished by N-aryl substitution. The antimycobacterial potency of Diphenylpyraline was in general increased by substitution in ring position 2, whereas only a few Bamipine derivatives showed markedly improved activity. A correlation between the two activities was not detected for those compounds.