Synthesis and structural investigation of some pyrimido[5,4-c]quinolin-4(3H)-one derivatives with a long-chain arylpiperazine moiety as potent 5-HT1A/2A and 5-HT7 receptor ligands

► We prepared of LCAP with a terminal fragment of pyrimido[5,4-c]quinolone. ► The majority of compounds demonstrated high in vitro affinity for 5-HT1A receptor. ► We conducted X-ray analysis, two-dimensional NMR, conformational studies. ► We assessed conformational preferences of ligands in different environments.