Synthesis

Nitrogen-bridgehead compounds; 401. Cyclization in phosphoryl chloride-polyphosphoric acid mixture

…, Á Horváth, L Vasvári-Debreczy, Z Mészáros

Index: Hermecz, Istvan; Horvath, Agnes; Vasvari-Debreczy, Lelle; Meszaros, Zoltan Synthesis, 1984 , # 2 p. 152 - 158

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Citation Number: 28

Abstract

The cyclization of ester lb in Dowtherm A at 250 C has earlier been reported to afford the 1, 8- naphthyridine derivative 37 due to steric hindrance by the 6-methyl group. We have shown “, however, that even the thermal cyclization of lb leads to compound 2b as the primary product which, depending-on the reaction conditions, may transform into the 1, 8- naphthyridine derivative 3. On the other hand it has been claimed5 that the cyclization of ...