Thionation with the reagent combination of phosphorus pentasulfide and hexamethyldisiloxane

The combination of P4S10 and hexamethyldisiloxane efficiently converts esters, lactones, amides, lactams, and ketones to their corresponding thiono derivatives. In the presence of elemental sulfur, 3-oxoesters are converted to dithiolethiones by this reagent. Yields are comparable to or superior to those obtained with Lawesson's reagent. The method has the advantage that reagent-derived byproducts may be removed by a simple hydrolytic workup or by filtration through silica gel, rather than by chromatography, as required for Lawesson's reagent.     

Reduction of sulfonic acids with phosphorus pentasulfide

Arene, and alkanesulfonic acids are easily reduced to the corresponding polysulfides R-(S)_n-R (n=2.9≈3.3) by treatment with phosphorus pentasulfide. In this reaction, the formation of both POS and PSH linkages is considered to be involved in the key step of the reduction.     

Halogenation of N-substituted p-quinone monoimines and p-quinone monooxime ethers: XIV. Halogenation of N-[arylsulfonylimino(phenyl)methyl]-2,5-dialkyl-1,4-benzoquinone monoimines and their reduction products

Despite steric hindrances created by the bulky substituent on the nitrogen atom, halogenation of 2,5-dialkyl-N-[arylsulfonylimino(phenyl)methyl]-1,4-benzoquinone monoimines fairly readily gives their derivatives having two halogen atoms in the quinoid ring.     

The reaction of phosphorus pentasulfide with halogen-substituted nitrogen heterocycles

The novel nucleophilic displacement of halogen by sulfur, by the use of phosphorus pentasulfide in boiling pyridine has been shown to be a general reaction for activated halogen nitrogen heterocycles.     

Preparation of fluoroolefins by reaction of polyfluorochlorocarbinols with phosphorus pentasulfide

Conclusions The reaction of polyfluorochlorocarbinols with phosphorus pentasulfide leads to the formation of fluoroolefins.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, p. 1159, May, 1973.     

The reaction of 2,5,5-triphenyl-2-oxazolin-4-one with phosphorus pentasulfide

2,5,5-Triphenyl-2-oxazolin-4-one (3), when refluxed with phosphorus pentasulfide in xylene, is transformed into N-(3-phenyl-2-benzo[b]thienyl)-thiobenzamide (7).     

Halogenation of N-substituted p-quinone monoimines and p-quinone monooxime esrers: XI. Synthesis and halogenation of 4-[aryl(alkyl)aminocarbonyl-oxyimino]cyclohexa-2,5-dien-1-ones

4-[Aryl(alkyl)aminocarbonyloxyimino]cyclohexa-2,5-dien-1-ones were synthesized by treatment of various substituted p-quinone monooximes with aryl isocyanates. The selectivity in the halogenation of the obtained p-quinone monooxime esters depended on the substrate structure and was either completely (syn addition) or partly regioselective (syn or anti addition). In all cases, the effect of steric factor was crucial, and the reaction was accompanied by halogenation of the aryl fragment.     

Halogenation of N-substituted p-quinone imines and p-quinone oxime esters: IV. Chlorination and bromination of N-arylsulfonyl-2(3)-methyl(2-chloro)-1,4-benzoquinone monoimines

The addition of halogens to N-arylsulfonyl-1,4-benzoquinone imines, which exist in a solution as Z and E isomers, is controlled by the steric factor. Z-E Isomerization strongly affects the stability of cyclohexene structures formed by halogenation of 1,4-benzoquinone imines. The halogenation of N-arylsulfonyl-1,4-benzoquinone imines was found to be accompanied by prototropic rearrangement.     

Reaction of 4-Amino-1,2,4-triazines with phosphorus pentasulfide. Deamination during aromatization

Synthesis of several derivatives of thieno[2,3-e]-1,2,4-triazines has been achieved via the action of phosphorus pentasulfide on 6-vinyl- or 6-acylmethyl-5-oxo-1,2,4-triazine derivatives. During these investigations interesting synthetically useful functions for phosphorus pentasulfide in pyridine were observed, among which the deamination of certain N-amino heterocycles is unprecedented.     

Phosphorus pentasulfide and Lawesson reagent in synthesis of 1,3-thiazole-4-thiol derivatives

Available S-amidophenacylation products of thiols and sulfanylphenols on treatment with phosphorus pentasulfide or, which is better, Lawesson reagent convert into the corresponding 1,3-thiazole-4-thiol derivatives that are easily oxidized with hydrogen peroxide. The latter reaction was used to introduce a series of alkyl- or arylsulfonyl groups in the 4 position of the thiazole ring. This general approach significantly extends the limited range of synthetic procedures for 1,3-thiazole-4-thiol derivatives.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1529–1533.Original Russian Text Copyright © 2004 by Belyuga, Brovarets, Drach.This revised version was published online in April 2005 with a corrected cover date.     

Action of phosphorus pentasulfide on 5-acetamidothiohydantoins and 4-bromo-5-acetamidopyrazoles

New condensed systems — (5,4-thiazolo)imidazoline-2-thione and pyrazolo[5,4-d]thiazoles -are formed by reaction of phosphorus pentasulfide with 5-acetamidothiohydantoins and 4-bromo-5-acetamido derivatives of pyrazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 932–934, July, 1974.     

Activated sterically strained C=N bond in N-substituted p-quinone mono- and diimines: XIII. Reactions of N-alkyl(aryl, trifluoromethyl)sulfonyl-, N-arylsulfinyl- and N-arylsulfanyl-1,4-benzoquinone monoimines with alcohols

Steric strains arising between the substituent atoms at nitrogen (S, SO, or SO₂) and the methyl group located in positions 3 or 5 of the quinoid ring of 3,5-dimethyl-substituted quinone monoimines lead to the increased angle C=N-S. As a result in these quinone monoimines the reactions of 1,2-addition become thermodynamically possible since the formation of quinolide structures with the sp³-hybridized carbon atom removes the steric strain.     

Reactions of 2-hydroxybenzophenones with Corey-Chaykovsky reagent

A variety of 2-hydroxybenzophenones on reaction with Corey-Chaykovsky reagent underwent unprecedented rearrangements leading to 3-substituted benzofurans 8 and one-carbon homologated compounds 9 and 12. Compounds 9 could further be quantitatively transformed to 2-substituted benzofuran derivatives 10.     

Reactions of 2-hydroxymethylphenols with Lawesson's reagent

On interacting 2-hydroxymethylphenols and the Lawesson's reagent 2-(4-methoxyphenyl)-4H-1,3,2-benzoxathiaphosphinine-2-sulfides were obtained. The formation of highly reactive o-quinone methides as intermediates is proposed.     

Reactions of phosphorus halides with urethane

By the reaction of phosphorus trichloride, thiophosphoryl chloride, phosphorus oxychloride and phosphorus pentachloride with urethane in stoichiometric ratio 1:1 or 1:2 in benzene, compounds of the type

and

(X = S, O or Cl; n = 1 or 2) have been synthesized. A probable mechanism for their formation has also been suggested.     

Activated sterically strained C=N bond in N-substituted p-quinone mono- and diimines: XIV. Reaction of some 3,5-dimethyl-1,4-benzoquinone monoimines with alcohols

Steric strain in the C=N-C fragment in 3,5-disubstituted N-acyl-1,4-benzoquinone monoimines, unlike their N-arylsulfonyl analogs, leads to increase of the C=N-C angle above 130° or twisting of the double C=N bond and loss of planarity of the quinoid ring. This structural transformation enhances the reactivity of the C=N bond so that 1,2-addition of alcohols becomes possible with formation of sterically unstrained cyclohexadienone structure with sp ³-hybridized C⁴ carbon atom.