Process for the preparation of cyclopropylacetylene

Details Process for the preparation of cyclopropylacetylene Process for the preparation of cyclopropylacetylene

1998-07-30

2000-04-11

Griffin, Walter D.

Chemistry of hydrocarbon compounds

Unsaturated compound synthesis

Triple-bond product

585534, 585359, 560124, 562506, C07C 202, C07C 200, C07C 1207, C07C 6974, C07C 6104

Patent

active

060490195

ABSTRACT:
The present invention relates generally to novel methods for the synthesis of cyclopropylacetylene which is an essential reagent in the asymmetric synthesis of (S)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-ben zoxazin-2-one; a useful human immunodeficiency virus (HIV) reverse transcriptase inhibitor. In the process, cyclopropane carboxaldehyde is condensed with malonic acid to form 3-cyclopropylacrylic acid; 3-cyclopropylacrylic acid is halogenated to form (E,Z)-1-halo-2-cyclopropylethylene; and (E,Z)-1-halo-2-cyclopropylethylene is dehydrohalogenated to form cyclopropyl acetylene. This improvement provides for high conversion of inexpensive, readily available starting materials into cyclopropylacetylene, high overall yields and can be conducted on an industrial scale.

REFERENCES:
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patent: 5407599 (1995-04-01), de Meijere et al.
patent: 5468882 (1995-11-01), Schohe-Loop et al.
patent: 5955627 (1999-09-01), Nakazawa et al.
Thompson et al., Tetrahedron Letters, 1995, 36, No. 49, p. 8937-8940.
Carl Bernard Ziegler, Jr., Synthesis and Mechanistic Studies of Polyunsaturated Fatty Acid Hydroperoxides Involving a Novel Vinylcyclopropyl Bromide Ring, Ph.D. Dissertation, Duke University (1981) 139 pp.

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