The one-pot cyclization of dilithiated oximes with epibromohydrin provided a convenient and regioselective approach to 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines. The reaction of the latter with phosphorus tribromide resulted in a Beckmann rearrangement and formation of 5-bromomethyl-2-iminotetrahydrofurans. The reaction of dilithiated hydrazones with epibromohydrin afforded oxazolo[3,4-b]pyridazin-7-ones, which were formed by a novel domino cyclization.

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Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and Oxazolo[3,4-b]pyridazin-7-ones. -The title compounds undergo Beckmann rearrangement in the presence of PBr3 to give iminotetrahydrofurans of type (XIII). -(DANG, T. T.; ALBRECHT, U.; GERWIEN, K.; SIEBERT, M.; LANGER*, P.; J.

Oxazine derivatives R 0595Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines by One-Pot-Cyclization of Dilithiated Oximes with Epibromohydrin. -Dilithiated oximes react regioselectively with epibromohydrin due to the higher nucleophilicity of the carbanion compared to the alkoxide within the dianion. The title compounds are isolated in moderate yields. -(ALBRECHT, U.; GERWIEN, K.; LANGER*, P.; Tetrahedron Lett. 46 (2005) 6, 1017-1019; Inst. Chem. Biochem., Ernst-Moritz-Arndt-Univ., D-17487 Greifswald, Germany; Eng.) -Mais 22-165