Piperazine-2,5-dithiones

Piperazine-2,5-diones can be converted to the corresponding dithiones by treatment with phosphorus pentasulfide in pyridine. A series of such piperazine-2,5-dithiones has been synthesized and their IR and NMR spectral characteristics have been determined (74BAP115, 74BAP253). 

Iminopiperazine when treated with hydrogen sulfide gives piperazine-2-thione (1614), and A -(aminoacyl)aminoacetonitrile with ammonium hydrogen sulfide gave 5-thiopiperazin-2-one (1619). Piperazine-2,5-dithione may be prepared from aminoacetonitrile and hydrogen sulfide in ammoniacal solution (1642). 

Piperazine-2,5-dithiones, thio analogues of cyclic dipeptides, have been shown to have a flattened boat configuration (1643), and infrared spectroscopic studies indicate that in the trans tautomer (120) the C-N bond has a more pronounced double bond character than that of the trans amide tautomer (1644). 

Heimgartner s reagent, 2,4-bis-(p-tolylthio)-l,3,2A,, 4A, -dithiadiphosphetane-2,4-dithione HEPES, A-2-hydroxyethyl-piperazine-jV -2-ethane-snlfonie aeid HIMDA, A-hydroxyethyhminodiacetic acid Histones... 

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