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Oxazine derivatives Oxazine derivatives R 0595Mineral-Supported Syntheses of Benzoxazine-2-thiones under Microwave Irradiation. -The microwave-assisted high yielding and expeditious conversion of salicylaldehyde thiosemicarbazones to benzoxazine-2-thiones is reported. 4-Arylthiosemicarbazones (III) yield 4-hydrazinooxazinethiones (IV), which on reductive dehydrazination on alumina-supported copper(II) sulfate, furnish oxazinethiones (V) under solvent--free microwave irradiation. Under the same conditions, salicylaldehyde thiosemicarbazones (I) undergo cyclodehydrazination to yield oxazinethiones (II). -(YADAV*, L. D. S.; YADAV, B. S.; DUBEY, S.; Tetrahedron 60 (2004) 1, 131-136; Dep. Chem., Univ. Allahabad, Allahabad 211 002, India; Eng.) -Bartels 20-161

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Synthesis of Chiral 3-Acyl-4-alkylthiazolidine-2-thiones as Enantioselective Acylating Agents.-Title compounds, e.g. (V) are used for the enantioselective benzoylation of racemic amines and amino acids, such as (VI). Yields are high (78-94%) and enantioselectivities are moderate to good (48-68% e.e.). -(YADAV, L. D. S.; DUBEY, SUMAN; Indian J. Chem., Sect. B: Org.