3-Hydroxypyrroles and 1 H-pyrrol-3 (2 H)-ones. Part 14. 1, 2 Pyrolysis of oxazolidinylmethylene derivatives of Meldrum's acid–synthesis of N-alkenyl-3- …

AEAM Gaber, GA Hunter, H McNab

Index: Gaber, Abd El-Aal M.; Hunter, Gordon A.; McNab, Hamish Journal of the Chemical Society. Perkin Transactions 1, 2002 , # 4 p. 548 - 554

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Abstract

Flash vacuum pyrolysis (FVP) of the title compounds 14 and 17 at 600–625° C (0.005 Torr) gives the N-alkenylpyrrolones 22 and 23 respectively. The mechanism is shown to involve hydrogen transfer and cyclisation of the methyleneketene intermediate (eg 25) to a fused pyrrolone (eg 28). This species fragments to create an azomethine ylide which provides the alkenyl substituent by a further hydrogen transfer. Similar reactions are shown by the ...