Phosphorus pentasulfide, reaction with chloride

OKO-l,3,7-triazanaphthalene (450) forms acyloxy derivatives in situ with phosphorus oxychloride and pentasulfide which undergo nucleophilic displacement with chloride ion and with a complex sulfide ion, respectively, to form the 4-chloro and 4-thioxo derivatives. The 4-carboxymethylthio compoimd failed to undergo the ring-opening reaction (see below) characteristic of more activated azino- and diazino-pyrimidines, but it did yield about 10% of the 4-0X0 displacement product. 

Carius (8) replaced the oxygen in phosphoryl chloride by sulfur. This may be somewhat analogous to the replacement of oxygen in a carbonyl group by sulfur using phosphorus pentasulfide. Prinz (8) used thionyl chloride in his reaction with phosphorus sulfide and De Fazi (2) used carbon tetrachloride in a very interesting preparation of this important intermediate. 

Numerous preparative methods have been reported for these acids and their salts and ester derivatives.1 4 Dithiophosphoric acids are accessible from the reaction of phosphorus pentasulfide with alcohols or phenols (Equation 18). Dithiophosphinic acids can be prepared from thiophosphinic chlorides and sodium hydrosulfide (Equation 19), although the phenyl derivative is better prepared using a modified Friedel-Crafts reaction in which phosphorus pentasulfide is reacted with benzene in the presence of anhydrous aluminium trichloride (Equation 20). 

Thiotraamidophosphoric acids (35) are isoelectronic with phosphoric acids and were initially reported from the reaction of phosphorus pentasulfide with primary amines at high temperatures.62 Subsequently, an improved synthesis for 35 with increased yields and milder conditions has been reported involving the room temperature reaction of thiophosphoryl chloride and primary amines (Equation 50).63 The most convenient route to the analogous selenium derivatives SeP(NHPh)3 is from the oxidation of P(NHPh)3 with elemental selenium (Equation 51).63 Also isoelectronic with phosphoric acids are dithio wamido-phosphoric acids (36), which can be prepared from the reaction of phosphorus pentasulfide with an excess of primary amine at 30°C in toluene (Equation 52).62 The selenium derivatives of 36 can be prepared in a similar reaction from phosphorus (V) selenide, although due to their increased acidity... 

The method described for the preparation of N-methyl-2-pyrrolidinethione is very similar to that of Peak and Stansfield 2 for the preparation of 4-thioacetylmorpholine. N-Methyl-2-pyrrolidinethione has also been prepared by the reaction of 2-chloro-N-methyl-A1-pyrrolinium chloride with hydrogen sulfide [yield 83% b.p. 144-145° (15 mm.)]3 and by heating N-methyl-2-pyrrolidinone with 2 equivalents of phosphorus pentasulfide in xylene [yield not reported b.p. 125-132° (10 mm.)].4 General procedures for the preparation of N,N-disubstituted thioamides have been reviewed.5, 6... 

The cyanobromide (371) was condensed with the bc portion (347) to give the thioether (372) sulfide contraction to give (373) was accomplished using tris(/3-cyanoethyl) phosphine, and with phosphorus pentasulfide the thiolactam-thiolactone (374) was produced. After treatment with Meerwein s salt, reaction with dimethylamine opened the lactone with concomitant formation of an exocyclic methylene group, and subsequent treatment with cobalt chloride or iodide gave the chelate (375) which was reacted with diazabicyclononane to give bisnorcobyrinic add [Pg.435]

Pyrazino[2,3-d]pyridazine-5,8-dione (104) can be dithiated with phosphorus pentasulfide to give the unisolated intermediate (105), which yields the bis(benzylthio) product (106) on reaction with benzyl chloride. Acetylation and tosylation of this starting dione (104) produce the monoacetyl and the monotosyl products, respectively (66JHC512). 

Reactions of 5f/-2-methyl-l,2,4-triazepino[2,3- ]benzimidazol-4-one 71, prepared by reaction of 1,2-diaminobenz-imidazole 72 with acetoacetic ester 73, with different reagents was described, in the search of new heterocycles with biological activity <2002CHE598>. When lactam 71 was treated with aromatic aldehydes in boiling 1-BuOH with addition of piperidine 74, 577-3-arylidene-2-methyl-l,2,4-triazepino[2,3- ]benzimidazol-4-ones 75a-c were obtained (Scheme 7). Coupling lactam 71 with phenyldiazonium chloride 76 in dioxane afforded the 3-phenylazo-substituted tricycle 77. When 71 was treated with phosphorus pentasulfide 78 in boiling dioxane or pyridine, its thio analog 79 was obtained. The reaction proceeded most efficiently when lactam 71 was refluxed with twofold excess of 78 in dry dioxane. These thiones 79 react with ammonia and amines by nucleophilic substitution. When 79 was refluxed with ammonia, benzylamine, piperidine, or morpholine, the 4-amino-substituted tricycles 80a-d were obtained. All the described compounds were identified by NMR, mass spectrometry, and IR spectroscopy. 

ZDDPs are formed by the reaction of phosphorus pentasulfide (P2S5) dimer with alcohol (ROH) or phenol (dithiophosphoric acid ester formation), followed by reaction with zinc powder or zinc oxide or with zinc chloride and sodium hydroxide solutions (see below). The various types of ZDDPs differing in R-group structures are shown in Table 2.6 (SAE, 1983 Yamaguchi et al., 1966). Scheme of the formation of zinc dialkyldithiophosphate, ZDDP ... 

The [4+1] cycloadducts formed from 4,4-bis(trifluoromethyl)-l-oxa-buta-1,3-dienes (92JPR219) and tin(II )-chloride are transformed on heating into 4,4-difluoro-3-trifluoromethylbut-3-en-l-ones, which on treatment with sodium hydride yield 2-fluoro-3-trifluoromethylfurans (92CC348). When heated with phosphorus pentasulfide, l-aryl-4,4-difluoro-3-trifluor-omethylbut-3-en-l-ones give 2-fluoro-3-trifluoromethylthiophenes. The fluorine atom at C—2 of the furans and thiophenes can readily be substituted by a wide variety of nucleophiles (92JPR3II). This reaction sequence represents a preparatively useful method for the selective introduction of biologically relevant substituents into the C—2 position of 3-trifluoro-methyl-substituted furans and thiophenes (Scheme 87). 

R = Ph) is also formed in the reaction between diazomethane and thiobenzoyl chloride, probably via a 1,3-dipolar addition of diazomethane to the thiocarbonyl group. Similar additions have been observed by Huisgen et The reaction between thioacyl chlorides and diazo compounds was first studied by Staudinger and Siegwart.i 3 (R = Ph) has been prepared by cyclization of 11 with triethylortho-formate, and also from 2-phenyl-1,3,4-oxadiazole and phosphorus pentasulfide. ... 

Several publications and patents describe the preparation of 2,5-di-aryl-l,3,4-thiadiazoles by treatment of mono- or 1,2-diacylhydrazines with phosphorus pentasulfide or by oxidation of thiobenzhydrazones of aromatic aldehydes with ferric chloride. The 2,5-bis-4-pyridyl derivative was prepared by reaction between thioisonicotinamide and hydrazine. Hydroxydithiobenzoates, useful as thioacylating agents in the method of Jensen, are readily available by a new synthetic... 

In the presence of hydrogen chloride, a-acetylenic ketones react with thioacetic acid to give a monothio-)S-diketone which is converted to a 1,2-dithiolium ion by phosphorus pentasulfide or hydrogen sulfide. These reactions, which involve some sort of oxidation, are discussed in the next paragraph. 

Treatment of 3-phcnylpyridazino[4,5-c]pyridazine-5,8-diol with phosphoryl chloride in pyridine yields 5,8-dichloro-3-phenylpyridazino[4,5-c]pyridazine (64%),10 whereas attempts to synthesize the 3-unsubstituted or 3-methyl compound by analogous methods are unsuccessful.8 Substitution of the chlorine atoms in 5,8-dichloro-3-phenylpyridazino[4,5-r]pyridazine by amines yields the corresponding morpholino or piperidino compounds (yield 74 and 42%, respectively).10 The preparation of 3-methylpyridazino[4,5-c]pyridazine-5,8-dithiol is achieved by the reaction of the corresponding dihydroxy compound with phosphorus pentasulfide in boiling pyridin yield 59% mp > 210°C (dec.).8... 

The reactions of hexafluoroacetone with trimethylsilyl ethers of enols form 4,4-bis(trifluoromethyl)-l-oxabuta-l,3-dienes (92JPC311). When heated in the presence of tin(II) chloride, the latter are transformed into 4,4-difluoro-3-trifluo-romethylbut-3-en-l-one. Subsequent treatment with sodium hydride leads to 2-fluoro-3-trifluoromethylfuran, while with phosphorus pentasulfide the product is 2-fluoro-3-trifluoromethylthiophene (92JCS(CC)348). Partially fluorinated 1-oxopenta-1,4-diene, derived from hexafluoroacetone, is employed as an intermediate in the syntheses of fluorinated furans (92JCS(CC)349) and thiophenes (92JFC(58)380) (Scheme 9). 

The reductive cyclization of 2-nitrophenylselenoacetic acid (168) with iron and acetic acid yields 2/7-l,4-benzoselenazin-3(4//)-one (169) (Equation (38)) <30JPR336>. This product is also available by the annulation of zinc di(2-aminophenyl)selenide (170) through reaction with chloroacetic acid and hydrogen chloride in ethanol. When treated with phosphorus pentasulfide the corresponding thione (171) is formed, and this, with bromoacetone and perchloric acid, affords 1-methyl-thiazolo[2,3-c]-l,4-benzoselenazium perchlorate (172), the basis of some cyanine dyestuffs... 

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