01633nas a2200253 4500008004100000022001400041245011000055210006900165260000800234300001500242490000600257520078100263653001501044653002101059653002301080653001801103653001701121100002401138700002301162700002101185700002501206700002401231856012401255 2022 eng d a2365-654900aRevisiting classical pummerer cyclization reaction: a key strategy for the synthesis of (+/-)-quinagolide0 aRevisiting classical pummerer cyclization reaction a key strateg cJUL ae2022016000 v73 a
A formal synthesis of (+/-)-quinagolide using beta-alanine as a starting material has been achieved. Late stage intramolecular classical Pummerer reaction has been used as a key synthetic tool to construct octahydrobenzo[g]quinoline skeleton of quinagolide. Conjugative reduction of olefin, regioselective C-alkylation over O-alkylation of beta-ketoester followed by retro-Dieckmann/ Dieckmann reaction sequence has been used as a key reaction sequence to achieve prerequisite sulfoxide for the Pummerer reaction. While revisiting the classical Pummerer reaction, the one-pot sequential thionium ion induced cyclocarbamation followed by N-carbamate deprotection and Friedel-Crafts type Pummerer cyclization was observed as an important finding of the present work.
10aAlkylation10aCyclocarbamation10aHyperprolactinemia10arearrangement10aThionium ion1 aChavan, Subhash, P.1 aKawale, Sanket, A.1 aTripathi, Anupam1 aKadam, Appasaheb, L.1 aGonnade, Rajesh, G. uhttp://library.ncl.res.in/content/revisiting-classical-pummerer-cyclization-reaction-key-strategy-synthesis-quinagolide