- A THIONATION PROCESS AND A THIONATING AGENT
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A process for transforming a group >C=O (I) in a compound into a group >C=S (II) or into a tautomeric form of group (II) in a reaction giving a thionated reaction product, by use of crystalline P2S5·2 C5H5N as a thionating agent. A thionating agent which is crystalline P2S5·2 C5H5N
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Page/Page column 9; 15
(2012/08/27)
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- A thionation process and a thionating agent
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A process for transforming a group >C=O (I) in a compound into a group >C=S (II) or into a tautomeric form of group (II) in a reaction giving a thionated reaction product, by use of crystalline P2S5·2 C5H5N as a thionating agent. A thionating agent which is crystalline P2S5·2 C5H5N.
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Page/Page column 6
(2012/08/14)
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- Thionations using a P4S10-pyridine complex in solvents such as acetonitrile and dimethyl sulfone
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Tetraphosphorus decasulfide (P4S10) 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, P4S 10 in pyridine or LR, have been removed. 2011 American Chemical Society.
- Bergman, Jan,Pettersson, Birgitta,Hasimbegovic, Vedran,Svensson, Per H.
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experimental part
p. 1546 - 1553
(2011/06/11)
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- Dithio and thiono esters, LIV: Attempted synthesis of α-amino dithio esters by the bislactim ether method
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Sulfhydrolysis of 2,5-bis(methylthio)-3,6-dihydropyrazine (5) gives rise to 2,5-piperazinedithione (8) and not to glycine dithiomethylester (6). The iminium salts 9, obtained by alkylation of 5, add H2S to form the 1,4-dialkyl 2,5-piperazinedithiones 10. 5 reacts with methyl chloroformate to give 2,5-bis(methylthio)-pyrazine (11), and with acetic anhydride to give the 1,4-dihydropyrazine 12. Sulfhydrolysis of the 6-membered and 7-membered iminium salts 14 leads to the thiolactames 15.
- Hartke,Brutsche
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