NEIDLEIN R.; JEROMIN G., J. CHEM. RES. SYNOP., 1980, NO 7, 233, (M 3090-3095)
作者:NEIDLEIN R.、 JEROMIN G.
DOI:——
日期:——
Synthesis of pyrrolizin-3-ones by flash vacuum pyrolysis of pyrrol-2-ylmethylidene Meldrum’s acid derivatives and 3-(pyrrol-2-yl)propenoic esters
作者:Shirley E. Campbell、Murray C. Comer、Paul A. Derbyshire、Xavier L. M. Despinoy、Hamish McNab、Roderick Morrison、Craig C. Sommerville、Craig Thornley
DOI:10.1039/a701749i
日期:——
Monosubstituted pyrrolizin-3-ones 1 with substituents at the 1-, 5-,
6- or 7-positions are prepared in excellent yield by flash vacuum
pyrolysis (FVP) of appropriate Meldrumâs acid derivatives 2. The
mechanism involves formation of the pyrrol-2-ylmethylideneketene 29,
which can also be generated thermally from 3-(pyrrol-2-yl)propenoate
esters (e.g. 30). This alternative route has been used to make
a range of 2-substituted pyrrolizin-3-ones, again in excellent yield.
The 3-oxo-3H-pyrrolizine-2-carboxylic acid 42 could not be made
in this way owing to facile decarboxylation to pyrrolizinone 1, and
extension to the formation of the azaazulenone 48 was again
unsuccessful.