Thionations Using a P₄S₁₀−Pyridine Complex in Solvents Such as Acetonitrile and Dimethyl Sulfone

Abstract

Tetraphosphorus decasulfide (P(4)S(10)) in pyridine has been used as a thionating agent for a long period of time. The moisture-sensitive reagent has now been isolated in crystalline form, and the detailed structure has been determined by X-ray crystallography. The thionating power of this storable reagent has been studied and transferred to solvents such as acetonitrile in which it has proven to be synthetically useful and exceptionally selective. Its properties have been compared with the so-called Lawesson reagent (LR). Particularly interesting are the results from thionations at relatively high temperatures (∼165 °C) in dimethyl sulfone as solvent. Under these conditions, for instance, acridone and 3-acetylindole could quickly be transformed to the corresponding thionated derivatives. Glycylglycine similarly gave piperazinedithione. At these temperatures, LR is inefficient due to rapid decomposition. The thionated products are generally cleaner and more easy to obtain because in the crystalline reagent, impurities which invariably are present in the conventional reagents, P(4)S(10) in pyridine or LR, have been removed.

Thiosquaramides: pH switchable anion transporters

“…26 Initial attempts to form the thiosquaramide derivatives 5–8 using Lawesson's reagent proved unsuccessful, while reaction with tetraphosphorus decasulfide (P 4 S 10 ) gave thiosquaramide products in low yield as part of a complex mixture of products. However we found that the zwitterionic P 4 S 10 ·pyridine complex, formed by reaction of P 4 S 10 in refluxing pyridine, 27 allowed the conversion of oxosquaramides 1–4 into thiosquaramides 5–8 in 66%, 48%, 37% and 60% yields respectively (Scheme 1). This strategy afforded each of the thiosquaramides in reasonable yields and 6–8 were easily purified by flash chromatography, while thiosquaramide 5 needed no further purification.…”

Transfer of Sulfur: From Simple to Diverse

“…The classical method for the thionation of carbonyl compounds is sulfuration by using Lawesson′s reagent, which has been summarized in several comprehensive reviews 74. Other sulfuration agents with similar S‐transfer mechanisms for the thionation of carbonyl compounds, such as Belleau′s reagent, Davy′s reagent, P 4 S 10 , etc.,75 are summarized in Scheme .…”

New Acyclic Neutral Phosphorus Sulfides and Sulfide Oxides

“…The py 2 P 2 S 7 was synthesized by refluxing stoichiometric amounts of P 4 S 10 and elemental sulfur in pyridine. Two years later the swedish group of Prof. Bergman also published the crystal structure of py 2 P 2 S 5 and discussed its use as thionating agent 8…”