Synthesis, antinociceptive activity and opioid receptor profiles of trans-3-(octahydro-2H-pyrano[2,3-c]pyridin-4a-yl)phenols and trans-3-(octahydro-1H-pyrano[3,4-c]pyridin-4a-yl)phenols

Chemistry of α-Oxoesters: A Powerful Tool for the Synthesis of Heterocycles

“…From treatment of a solution of 5-(3-methoxyphenyl)-8-methyl-2-oxa-8-azabicyclo[3.3.1]­nonane 895 in H 2 SO 4 /Et 3 N (pH = 3) with methyl glyoxalate in the presence of Et 3 N in water at 80 °C for 18 h, under N 2 atmosphere, hexahydro-1 H -pyrano­[3,4- c ]­pyridine-1-carboxylate 896 was obtained in 52% yield, which transformed into 7-(cyclopropylmethyl)-1-methyloctahydro-1 H -pyrano­[3,4- c ]­pyridin-4 a -yl)­phenol 897 , possessing antinociceptive activity (Scheme ) …”