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

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)

Identiferoai:union.ndltd.org:IISc/oai:etd.ncsi.iisc.ernet.in:2005/268
Date05 1900
CreatorsNavin, V
ContributorsChandrasekaran, Srinivasan
PublisherIndian Institute of Science
Source SetsIndia Institute of Science
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis and Dissertation
Format2066890 bytes, application/pdf
RightsI grant Indian Institute of Science the right to archive and to make available my thesis or dissertation in whole or in part in all forms of media, now hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.

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