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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

One-Pot Synthesis Of Chiral Disulfides & Diselenides From α-Amino Acids Mediated By Ammonium Tetrathiomolybdate In Water

Navin, V 05 1900 (has links)
We have described herein a convenient one-pot synthesis of lisulfides/diselenides from a-amino acids mediated by ammonium etrathiomolybdate in water. (Figure 1) (Figure) Figure 1 Transformation of α-amino acids into the corresponding tiiocyanates/selenocyanates/disulfides/diselenides Halo-de-amination of a-amino acids using HBr/NaNCte followed by treatment with ammonium tetrathiomolybdate (NH4)2]VloS4 jLb provided a general route for the the one-pot synthesis of chiral a,a' bis (dithio) carboxylic acids (Figure 1, 2b). The yields were moderate, limited mainly the moderate conversion of a-amino acids into the corresponding chiral a-bromides. It was possible to synthesize the 2-thiocyanto carboxylic acids from the corresponding a-amino acids by a similar strategy. Thus diazotization in the presence of KSCN yielded in the chiral 2-thiocyanto carboxylic acids in moderate yields (Figure 1, 3). Thiocyanato-de-amination thus afforded the thiocyanates which when treated with JJD provided the chiral disulfides (Figure 1, 4a). We could thus synthesize both enantiomers of the disulfide from a single enantiomer of the starting a-amino acid. (Figure 1, 4a,4b) Using a similar strategy we have also demonstrated an efficient method for the synthesis of chiral selenocyanates starting from a-amino acids, using selenocyanate anion as the nucleophile (Figure 1, 5). It is possible to demonstrate a one-pot synthesis of chiral diselenides by reductive coupling of selenocyanates using JJb. (Figure 1, 6) (for figure see the pdf file)

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