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

by Navin, V

Abstract (Summary)
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 1 Transformation of ?-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)

Bibliographical Information:

Advisor:Chandrasekaran, Srinivasan

School:Indian Institute of Science

School Location:India

Source Type:Master's Thesis

Keywords:organic chemistry tetrathiomolybdate sulfur compounds amino acids carboxylic selinide transfer thiocyanate reductive dimerization selenocyante thiocyanato disulfides diselenides


Date of Publication:05/01/2001

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