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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 13, Number 1
BKCSDE 13(1)
January 20, 1992 

Conversion of 1,3-Thiazolidines to Dihydro-1,4-thiazine by Chlorinolysis
Wha Suk Lee*, He Duck Mah, Kee Dal Nam, Soon Bang Kang
The ring expansion of 1,3-thiazolidines 4 derived from β-ketoacid derivatives to the corresponding dihydro-1,4-thiazines 1 by using the action of chlorine on 4 has been achieved. In the chlorinolysis unisolable sulfenyl chlorides 5 may be formed from chlorosulfonium ions 11 by β -elimination involving carbonyl activated methylene hydrogens. Addition of sulfenyl chloride to the internal double bond appears to form probable thiiranium ions 14, which in turn gave 1 with loss of acidic proton. Imminium ions 15 could be hydrolyzed easily to give enol 8. As a side reaction, dihydrothiazine that was formed was further chlorinated to produce dichlorides 16 which were rearranged readily to the chloromethyl compounds 10.
83 - 87
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