(4) Isoquinoline group. The opium alkaloids: morphine, codeine, thebaine, papaverine, narcotine, narceine, &c.; and the complicated substances hydrastine and berberine.
Thebaine, another alkaloid, was discovered by Thiboumery in 1835; whilst, in 1848, Merck isolated papaverine from commercial narcotine.
The alkaloids fall into two chemical groups: (i) derivatives of isoquinoline, including papaverine, narcotine, gnoscopine (racemic narcotine), narceine, laudanosine, laudanine, cotarnine, hydrocotarnine (the last two do not occur in opium), and (2) derivatives of phenanthrene, including morphine, codeine, thebaine.
Papaverine, C20H21N04, was investigated by G.
OMe CH2 OMe MeO" OMe CH ?o^,/, CH 2 MeO McO I ^ VN/ H2 NMe 02 CN/ MeO CH - CH - ' I.Papaverine II.Narcotine CH 2 CH2 OMe CH?
Of the other alkaloids narceine is hypnotic, like morphine and codeine, whilst thebaine, papaverine and narcotine have an action which resembles that of strychnine, and is, generally speaking, undesirable or dangerous if at all well marked.