New antihistaminic agents: Synthesis and evaluation of h 1 -antihistaminic actions of 3-[(n,n-dialkylamino)alkyl)-1,2,3,4-tetrahydro-(1h)-thioquinazolin-4(3h)-ones and their oxo analogues
1 Department of Pharmaceutical Chemistry, V. L. College of Pharmacy, Raichur, India 2 Medicinal Chemistry Division, University College of Pharmaceutical Sciences, Kakatiya University, Warangal, India
A Raghu Ram Rao Medicinal Chemistry Research Division, University College of Pharmaceutical Sciences, Kakatiya University, Warangal - 506 009 India E-mail: [email protected]
The synthesis of eight new 3-[(N,N-dialkylamino)allkyl]-2(1H)-thioquinazolin-4(3H)-ones (3a-d) and their oxo analogues (4a-d) has been described. H 1 -Antihistaminic activities have been evaluated using in vitro and in vivo standard animal models in comparison to chlorpheniramine maleate as reference drug. Among the test compounds, 3d was found to be the most potent with an IC 50 value of 1.23 µM (in vitro) offering 70.24% protection in vivo .