| abstract |
(57) [Summary]nThe present invention provides a useful human immunodeficiency virus (HIV) reverse transcriptase inhibitor, (S) -6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3. The present invention relates to a novel method for synthesizing cyclopropylacetylene, which is an essential reagent for asymmetric synthesis of 1,1-benzoxazin-2-one. In this method, cyclopropanecarboxaldehyde is condensed with malonic acid to form 3-cyclopropylacrylic acid, and the 3-cyclopropylacrylic acid is halogenated to form (E, Z) -1-halo-2-cyclopropyl. Ethylene is formed and (E, Z) -1-halo-2-cyclopropylethylene is dehydrohalogenated to form cyclopropylacetylene. This improved process converts inexpensive, readily available starting materials to cyclopropylacetylene with high conversion, provides high overall yields, and can be performed on an industrial scale. |