Beckmann rearrangement in the solid state: reaction of oxime hydrochlorides

Several ketoxime hydrochlorides undergo Beckmann rearrangement upon heating below their melting points for 5-48 h, in excellent yields (generally > 70 %). The absence of a reaction solvent and of by-products (except for HCl) m akes for a very simple work-up. Aldoxime hydrochlorides apparently undergo dehydration to the corresponding nitriles under the above conditions. Diben zyl ketoxime hydrochloride unexpectedly furnished a pyrazine derivative (67 %), presumably via further reaction of the intermediate nitrilium ion in th e crystal lattice. (C) 2001 Elsevier Science Ltd. All rights reserved.