Sulfides pyridine

There is evidence for extensive delocalization of electron density between the Ru centers in [(NH3)5Ru(/i-L)Ru(NH3)5] where L = 4,4 -dithiodipyridine, and an overview of a range of Fe, Ru, and Os-containing complexes containing 4,4 -dithiodipyridine or bis(4-pyridine) sulfide provides a useful summary of the properties of these species. ... 

The desired pyridylamine was obtained in 69 % overall yield by monomethylation of 2-(aminomethyl)pyridine following a literature procedure (Scheme 4.14). First amine 4.48 was converted into formamide 4.49, through reaction with the in situ prepared mixed anhydride of acetic acid and formic acid. Reduction of 4.49 with borane dimethyl sulfide complex produced diamine 4.50. This compound could be used successfully in the Mannich reaction with 4.39, affording crude 4.51 in 92 % yield (Scheme 4.15). Analogous to 4.44, 4.51 also coordinates to copper(II) in water, as indicated by a shift of the UV-absorption maximum from 296 nm to 308 nm. 

Pyridyl)hydrazine (Aldrich), 4-acetylpyridine (Acros), N,N,N -trimethylethylenediamine (Aldrich), methylrhenium trioxide (Aldrich), InQj (Aldrich), Cu(N0j)2-3H20 (Merck), Ni(N03)2-6Il20 (Merck), Yb(OTf)3(Fluka), Sc(OTf)3 (Fluka), 2-(aminomethyl)pyridine (Acros), benzylideneacetone (Aldrich), and chalcone (Aldrich) were of the highest purity available. Borane dimethyl sulfide (2M solution in THE) was obtained from Aldrich. Methyl vinyl ketone was distilled prior to use. Cyclopentadiene was prepared from its dimer immediately before use. (R)-l-acetyl-5-isopropoxy-3-pyrrolin-2-one (4.15) has been kindly provided by Prof H. Hiemstra (University of Amsterdam). 

In contrast to the 4-hydroxy isomers, the thermally stable 5-hydroxy-THISs add to the C=C bond of cyclopropenylidenes (4. 18, 27. 28). The adducts eliminate carbonyl sulfide, and the strained bond breaks resulting in ring-expansion with formation of pyridin-4-ones. -thiones, or -imines. or 4-alkylidenedihydropvridines (20, X = 0. S.NR. or CRR ) (Scheme 19). 

The higher reactivity of 2-halogenothiazoles with respect to halogenopyridines can be related to the different aromaticity of the two systems, less for thiazole than for pyridine, for example, the relatively stronger fixation of the tt bond in the thiazole than in the case of pyridine. As the data reported in Table V-1 (footnote a) indicates, the free thiophenol is more reactive than the thiolate anion toward the 2-halogenothiazoles. This fact should be considered when one prepares the thiazolyl sulfides. 

With pyridine, reaction takes place at the nitrogen rather than at a double bond, and an yUd [27032-01-5] is formed (57,58). Sulfides react similarly to give sulfOidenes and carbonyl cyanide (59). 

Pyridazines with an appropriate side chain attached to the sulfur atom at position 3 can be transformed into bicyclic systems. For example, pyridazinyl /3-ketoalkyl sulfides are cyclodehydrated in sulfuric acid to give thiazolopyridazinium salts, and 3-carboxymethyl-thiopyridazines are transformed by acetic anhydride in pyridine into 3-hydroxythiazolo[3,2-6]pyridazinium anhydro salts (Scheme 52). 

Nitro-filter cloths are composed of cellulose nitrate, which is an ester of cellulose. Any chemical compound that will saponify the ester will destroy the cloth. Caustic soda or potash in strengths of 2% at 70° C or over alkali sulfides, polysulfides and sulfohydrates or mixtures of ethyl alcohol and ether, ethyl, amyl and butyl acetates, pyridine, ferrous sulfates, and other reducing agents are detrimental to the cloth. 

A recently discovered variant of the Wallach technique is the silver ion cata lyzed fluorination of aryl diazo sulfides in hydrogen fluonde-pyridine-toluene solvent [57] (equation 12) Electron withdrawing substituents such as acetyl give higher yields of aryl fluoride (71%) than electron donating groups (butyl 39%, methoxy, 2-14%), reductive dediazoniation competes with fluorination... 

Wlieii thiomethoxymethyl hexachloroaiitimoiiate was treated with pyridine, a methylthio derivative 28 was isolated in low yield in addition to the expected chlorinated sulfides (71T4209). Several A, A -haloalkyl-bis-4,4 -pyridiniumethenes 29 have been reported in a Japanese patent (80JAP75479). Tliese compounds are promising candidates for the construction of electrochromic display devices (Scheme 7). 

A thioamide of isonicotinic acid has also shown tuberculostatic activity in the clinic. The additional substitution on the pyridine ring precludes its preparation from simple starting materials. Reaction of ethyl methyl ketone with ethyl oxalate leads to the ester-diketone, 12 (shown as its enol). Condensation of this with cyanoacetamide gives the substituted pyridone, 13, which contains both the ethyl and carboxyl groups in the desired position. The nitrile group is then excised by means of decarboxylative hydrolysis. Treatment of the pyridone (14) with phosphorus oxychloride converts that compound (after exposure to ethanol to take the acid chloride to the ester) to the chloro-pyridine, 15. The halogen is then removed by catalytic reduction (16). The ester at the 4 position is converted to the desired functionality by successive conversion to the amide (17), dehydration to the nitrile (18), and finally addition of hydrogen sulfide. There is thus obtained ethionamide (19)... 

Recently, Kricheldorf and Jahnke [108] reported pyridine and pyridazine containing poly(ether-sulfide)s by... 

Pyridinium ylide is considered to be the adduct car-bene to the lone pair of nitrogen in pyridine. The validity of this assumption was confirmed by Tozume et al. [12J. They obtained pyridinium bis-(methoxycarbonyl) meth-ylide by the photolysis of dimethyl diazomalonate in pyridine. Matsuyama et al. [13] reported that the pyridinium ylide was produced quantitatively by the transylidalion of sulfonium ylide with pyridine in the presence of some sulfides. However, in their method it was not easy to separate the end products. Kondo and his coworkers [14] noticed that this disadvantage was overcome by the use of carbon disulfide as a catalyst. Therefore, they used this reaction to prepare poly[4-vinylpyridinium bis-(methoxycarbonyl) methylide (Scheme 12) by stirring a solution of poly(4-vinylpyridine), methylphenylsulfo-nium bis-(methoxycarbonyl)methylide, and carbon disulfide in chloroform for 2 days at room temperature. 

Likewise, azepine-2-thiones, e. g. 18, obtained by treating azepin-2-ones with phosphorus penta-sulfide in refluxing pyridine, yield the 2-(ethylsulfanyl) derivatives.77,227... 

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