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Protecting Groups

  • Chapter
The Practice of Peptide Synthesis

Part of the book series: Reactivity and Structure Concepts in Organic Chemistry ((REACTIVITY,volume 21))

Abstract

L-Isoleucine (13.1 g, 100 mmol) is suspended (and partially dissolved) in distilled water (50 ml) and completely dissolved by the addition of N NaOH (100 ml). p-Toluenesulfonyl chloride (26.7 g, 140 mmol) is added to the vigorously stirred solution followed by N NaOH in small portions to maintain the alkalinity of the mixture at about pH 9. Some heat is evolved during the reaction and external cooling with cold water or ice-water is necessary to keep the temperature of the reaction mixture at about 20 °C. After no more alkali is used up [3] stirring is continued at room temperature one hour longer. Any unreacted acid chloride is removed by filtration and the solution acidified with 5 N HCl (about 20 ml) to Congo. The mixture is stored in the cold overnight; the crystals are collected on a filter, washed with water, dried in air and finally in vacuo over P2O5. The product, 25 g (88%) melts at 135–136 °C; [α] 21D -12° (c 2, 0.5 N KHCO3) [4, 5].

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  1. Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44 106, USA

    Miklos Bodanszky & Agnes Bodanszky

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  1. Miklos Bodanszky
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© 1984 Springer-Verlag Berlin Heidelberg

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Bodanszky, M., Bodanszky, A. (1984). Protecting Groups. In: The Practice of Peptide Synthesis. Reactivity and Structure Concepts in Organic Chemistry, vol 21. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-96835-8_2

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  • DOI: https://doi.org/10.1007/978-3-642-96835-8_2

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