85143-47-1Relevant academic research and scientific papers
Chemistry of pyrrolizinones. Part 1. Reactions of pyrrolizin-3-ones with electrophiles: Synthesis of 3,8-didehydroheliotridin-5-one
McNab, Hamish,Thornley, Craig
, p. 3584 - 3591 (2007/10/03)
The reaction of pyrrolizin-3-one 1 with dry hydrogen chloride gives the 1-chloro-1,2-dihydro derivative 8 (93%) by electrophilic addition. The halogen of 8 is readily displaced by O-nucleophiles to give 6, 9 or 10 in 87-100% yield, and this strategy has been employed in a short synthesis of the necine base didehydroheliotridin-5-one 4. Pyrrolizinone 1 can be brominated by N-bromosuccinimide in the presence of nucleophiles to give 20 or 21, or under free radical conditions to give the 2-bromopyrrolizinone 22 (55%). Vilsmeier formylation of 1 gave a variety of products including the 5-formylpyrrolizinone 26 (16%), but azo-coupling could only be observed under basic conditions to give the coupled propenoate 31 (46%) via the anion of the ring-opened species 30. The Royal Society of Chemistry 2000.
Synthesis of pyrrolizin-3-ones by flash vacuum pyrolysis of pyrrol-2-ylmethylidene Meldrum's acid derivatives and 3-(pyrrol-2-yl)propenoic esters
Campbell, Shirley E.,Comer, Murray C.,Derbyshire, Paul A.,Despinoy, Xavier L. M.,McNab, Hamish,Morrison, Roderick,Sommerville, Craig C.,Thornley, Craig
, p. 2195 - 2202 (2007/10/03)
Monosubstituted pyrrolizin-3-ones 1 with substituants at the 1-, 5-, 6- or 7-positions are prepared in excellent yield by flash vacuum pyrolysis (FVP) of appropriate Meldrum's 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.
Pyrrolylpolyenes. Part 7. Synthesis and Spectra of Pyrrolylpolyenes and 3-Chloropyrrolylpolyenes.
Ahmed, Fawzi R.,Toube, Trevor P.
, p. 3601 - 3641 (2007/10/02)
A number of pyrrolylpolyenes have been prepared.Their properties and spectra are reported and comparisons are made with previously described members of this class of compound.
