169299-08-5Relevant academic research and scientific papers
Synthesis of Donor-Substituted 2-Benzopyrans, Isoquinolines, and Cinnolines with Acetal Structure
Wuensch, Bernhard,Nerdinger, Sven,Hoefner, Georg
, p. 1303 - 1312 (2007/10/02)
At -105 deg C the aryllithium intermediate 7, which was generated by treatment of the donor-substituted bromo acetal 6 with n-butyllithium, was trapped with aromatic and aliphatic aldehydes, with paraformaldehyde, with a ketone, an amide, an imine, and an azo compound to yield the hydroxy acetals 9a-c and 18, the homophthalaldehyde derivative 8, the amino acetal 24 and the hydrazino acetal 28.The acid-catalyzed ring closure of the hydroxy acetals 9a-c and 18, the amino acetal 24, and the hydrazino acetal 28 provided the 2-benzopyrans 10a-c, 19 and 20, the isoquinoline 26, and the cinnolines 29 and 30, respectively.Hydrogenolysis (H2, Pd/C) of the benzyl-protective group led to the phenols 15a-c, 21, 31, and 32.The spiropiperidines 21 and 22 showed a very low affinity for the phencyclidine binding site of the NMDA receptor.In mice weakly sedative effects were caused by application of 21 and 22. - Keywords: Central nervous system agents / Bromine-lithium exchange / 2-Benzopyrans / Spiro / Isoquinolines / Cinnolines
