An Environmentally Friendly, Scalable and Highly Efficient Synthesis of (S,S)-Ethambutol, a First Line Drug against Tuberculosis

Two efficient synthetic routes to (S,S)-ethambutol, a first line drug used for tuberculosis treatment, based on the chiral pool approach viewing L-methionine as a starting material are reported. Several advantages over the traditional synthetic routes were observed: simple, safe, inexpensive reagents, and minimum byproduct formation. The key intermediate (S)-(+)-2-amino-1-butanol was obtained in its enantiomerically pure form from the corresponding aminobutyric acid.