Further investigation of the N-demethylation of tertiary amine alkaloids using the non-classical Polonovski reaction

N-Demethylation of Alkaloids

“…This modified Polonovski reaction has been used to prepare N-norcodeine (2b), N-norcodeine methyl ether (29b) and N-northebaine (38b) from the corresponding N-methyl opiates in 62%, 87% and 78% yield, respectively [53,54]. Isolation of the N-oxide as its hydrochloride salt was found to increase the proportion of the desired N-nor opiate [53].…”

Synthesis of a doxycycline‐[13CD3] standard

“…7,8 Formation of the demethylated tetracyclines is an important intermediate for the synthesis of novel tetracyclines as well as labelled standards. Utilizing a modified Polonovski reaction in a two-step process as shown in Scheme 1, the free base of doxycycline 1 was readily converted to the N -oxide 2 using 3-chloroperoxybenzoic acid ( m -CPBA).…”

Metal‐Terpyridine Complexes in Catalytic Application – A Spotlight on the Last Decade

“…This catalyst has already been introduced in the context of the alkene epoxidation (Section 2.4.1, Scheme ). Basically, the Polonovski reaction, i. e ., the demethylation of tertiary N ‐methylamine derivatives, is demanding due to the intrinsic chemical robustness of N ‐methyl groups (in particular, in the presence of other functionalities); this limitation can be overcome by using a metal‐mediated variant in which various types of Ru‐ or Fe‐based catalysts have already been employed . The applicability of SBA‐15‐immobilized Fe(II)‐tpy in combination with oxone in the Solonovski reaction was demonstrated at the example of the room‐temperature demethylation of N , N ‐dimethylaniline which afforded N ‐methylaniline in 48 % yield (similarly, piperidine was obtained from N ‐methylpiperidine in 78 % yield) .…”