PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 7783126-13 1995 Unfavorable positions for substitution with bulky groups, like the 3- and 4-positions in the benzofuran compound 14, are explained by steric hindrance with the backbone atoms of helix V. Thus, we were able to rationalize the 5-HT1A SAR of existing N1-phenylpiperazines, as well as a series of newly synthesized bicyclic heteroarylpiperazines, in terms of receptor-ligand interactions. benzofuran 93-103 5-hydroxytryptamine receptor 1A Rattus norvegicus 225-231