Iminium carbonic acid derivative salts. XII . electrophilic reactions of 2-methylthio-4,5-dihydrothiazolium iodides, 5-methyl-2-methylthiothiazolium iodides and 2-methylthio-5,6-dihydro-1,3-thiazinium iodides. part III. With Vinylogous and Phenylogous Active Methylene Compounds

3-Benzyl-2-memyltmo-4,5-dmydrothiazolium iodide ( 1 ), 5-metlyl-2-methylthio-3-phenethylthiazolium iodide ( 4 ) and 3-methyl and 3-benzyl-2-methylthio-5,6-dihydro-1,3-thiazinium iodides 7a, b were reacted with the vinylogous doubly activated CH-acidic compounds 2a-d and the phenylogous doubly activated components 8, 11, 16, 19 and 21 to yield new types of S, N-heterocycles 3, 5, 6, 9, 10, 12, 13, 14, 15 with the partial structure of push-pull substituted butadienes and 17, 18, 20, 22, 23 and 24 with the character of push-pull substituted phenyl ketene S, N-acetals.     

Reaction of 2-alkoxy-2-methylthio-5,6-dihydro-4H-1,3-thiazines with phenoxyacetyl chloride

The reaction of 4-alkoxytetrahydro-1, 3-thiazine-2-thiones with methyl iodide and subsequent treatment of the resultant S-alkylation products by suitable sodium alcoholates yielded 4-alkoxy-2-methylthio-S, 6-dihydro-4H-1, 3-thiazines, which upon reaction with phenoxyacetyl chloride in the presence of triethylamine was stereospecifically converted into 4-alkoxy-6-methylthio-7-phenoxvcephams.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 557–560, April, 1996.     

Proton spin-lattice relaxation rate studies. 1-Aryl-4,4-dimethyl-2-methylthio-2-imidazolin-5-ones

Proton spin-lattice relaxation rates (R₁ values) have been measured, at 270 MHz, for a series of 1-aryl-4,4-dimethyl-2-methylthio-2-imidazolin-5-ones, using both null-point and non-linear regression methods; the two procedures give the same rates. A normalization procedure has been used to enable comparisons to be made between the R₁ values of different compounds; this is necessary because the experimental values are affected by changes in motional correlation times associated with changes in molecular structure. A substantial (five-fold) dynamic range of R₁ values has been observed for the protons of individual compounds, and the values have been correlated with the molecular environments of the nuclei. Evidence for anisotropic molecular motion and inter-ring proton relaxation in these compounds has been considered.     

Synthese von 1-Ary1-4-methylthio-2-azetidinonen

TheN-arylthioformimidates4 a-e, which may be obtained byS-alkylation of the thioformanilides3 a-e, react with chloroacetylchloride/triethylamine to yield the (3R,4S/3S,4R)-1-aryl-3-chloro-4-methylthio-2-azetidinones5 a-e and the formanilides6 a-e. Dehalogenation of5 b-e with tri-n-butyltinhydride yield the title compounds7 b-e. Hydrogenolysis of7 b and7 c yields7 f and7 g.

     

Interaction between Non-Conjugated Chromophores: 5,6-Dimethylidene-exo-2-norborneol, 5,6-Dimethylidene-exo,exo-2,3-norbornanediol and 5,6-Dimethylidene-2-norbornanone

Preparation of the title compounds 11 , 12 and 13 is described. Preliminary kinetic results indicate that the hydroxyl substituents in 11 and 12 have a very small retardation effect on the Diels-Alder reactivity of 2,3-dimethylidene-norbornane. The keto group in 13 exerts a larger retardation effect, although it is much smaller than the retardation effect introduced by an exo-5,6-epoxide ring in 2,3-dimethylidene-norbornane.     

Iminium carbonic acid derivative salts. IX. Synthesis of N,S-containing heterobicycles from N-protected 2-methylthio-1,3-thiazinium and 2-methylthiothiazolium salts part 1. Preparation of N-protected 2-methylthio-1,3-thiazinium and 2-methylthiothiazolium salts and their reaction with CH-acidic compounds

N-Boc-protected 1,3-thiazine-2-thiones and thiazolidin-2-thiones were transformed into the corresponding 2-methylthio-1,3-thiazinium and 2-methylthiothiazolium salts by methyl iodide or trimethyloxonium tetrafluoroborate. This activated species were reacted with CH-acidic compounds forming ketene-N,S-acetals. The protection group was removed with trifluoracetic acid to yield the N-unsubstituted ketene-N,S-acetals.     

Synthesis of 5,6-dihydro-2H-thiopyrans

Synthesis of 5,6-dihydro-2H-lhiopyrans by mild dehydromesylation of the corresponding tetrahydro-4H-thiopyran-4-mesylates using commercial grade Woelrn W-200 (activity, Super 1) neutral alumina is described. Cis- and trans-stereoisomers of 2,6-diphenyl-5,6-dihydro-2H-thiopyrans were prepared for the first lime without isomerization.     

Acyl iodides in organic synthesis: XIII. Reaction of acyl iodides with nitrogen-containing heteroaromatic compounds

Reactions of acetyl iodide with pyridine at room temperature and with quinoline both at 20–25°C and on cooling to −50°C involve dehydrohalogenation of acetyl iodide with formation of ketene and pyridinium or quinolinium iodides. The reaction of acetyl iodide with pyridine at −5 to −50°C led to the formation of N-acetylpyridinium iodide. Benzoyl iodide reacted with both pyridine and quinoline at both −50°C and at 20–25°C to form stable N-benzoylpyridinium and N-benzoylquinolinium iodides. The reaction of pyrrole with acetyl iodide under analogous conditions was accompanied by polymerization.     

Synthesis of 2-Acetamido-5,6-dihalophenyl Acetates

Summary.  2-Acetamido-5,6-dihalophenyl acetates were synthesized as intermediates for the preparation of 6, 7-dihalo-8-quinolinols via the Skraup procedure. Received January 24, 2000. Accepted February 12, 2000     

A heterocyclic arene oxide. 5,6-Diphenylbenz[c]acridine 5,6-oxide

The first synthesis of a benz[c]acridine 5,6-oxide is described. Treatment of 5,6-benz[c]-acridinequinone with phenylmagnesium bromide results in the formation of a trans-diol, which gives the title compound upon dehydration with dimethylformamide dimethylacetal. In sulfuric acid, the epoxide rearranges mainly into 6,6-diphenyl-5-benz[c]acridone.     

Thermal Rearrangement of 5,6-Epimino-5,6-dihydro-β-ionone and Derivatives

Thermolysis of 5,6-epimino-5,6-dihydro-β-ionone ( 1 ) and its N-methyl derivative ( 2 ) leads to their monocyclic isomers 6 and 10 , respectively, presumably due to a direct [1,5]-H shift; on prolonged heating, these isomers are converted easily into pyrrole derivatives. In contrast, the thermoisomer 12 resulting from 5,6-(N-methoxycarbonyl)epimino-5,6-dihydro-β-ionone ( 3 ) by the same mechanism, does not undergo further ring transformation, but equilibrates with its more stable tautomer 13 .     

Photochemistry of 2-Cyclohexene-imines and 2,3,4,4a,5,6-Hexahydroquinolines. Preliminary communication

The 2-cyclohexene-imines 2b–2d and the hexahydroquinolines 5a, b are synthesized. n,π*-Excitation of these α,β-unsaturated imines leads to (E/Z) isomerization for compounds 2 while compounds 5 are unreactive. No cyclobutanes are formed from 2 or 5 under these conditions in the presence of olefins, and only 2d adds to 2,3-dimethyl-2-butene via the C?N bond to give an azetidine. On π,π* excitation 2 and 5 rearrange to the corresponding β,γ-unsaturated imines 8 and 9 with low efficiency. It is concluded that the failure of such imines to undergo [2+2]-photocycloadditions with olefins is not mainly due to radiationless decay via (E/Z) isomerization.     

Synthesis and reaction of 6-substituted 3-methoxycarbonyl-4-methylthio-2H-pyran-2-one derivatives

Reaction of aryl and styryl methyl ketones 1a-m with dimethyl bis(methylthio)methylenemalonate ( 2 ) in the presence of potassium hydroxide in dimethyl sulfoxide gave the corresponding methyl 6-aryl- and 6-styryl-4-methylthio-2-oxo-2H-pyran-3-carboxylates 3a-m . 6-Aryl derivatives 3a-d,g were treated with sodium methoxide in methanol to give the corresponding 6-aryl-4-methoxy-2H-pyran-2-ones 8a-d and 9. Phenylcoumalin ( 7a ) and paracotoin ( 7b ) were synthesized by the desulfurization of 6-aryl-4-methylthio-2H-pyran-2-ones 4a,b. Similarly, anibine ( 8e ) was also synthesized from 3g . Treatment of 3 with hydrogen peroxide or 3-chloroperoxybenzoic acid gave the corresponding 4-methylsulfiny-2H-pyran-2-ones 10a-f in good yields. Displacement reactions of 10a-f with nucleophilic reagents are also described.     

Thiosulfonium ions. Methylthiolation of 3-methylthio-1-butene and cis- and trans-1-methylthio-2-butene

Whereas sulfenyl reagents commonly add to carbon double bonds, addition to sulfur of 3-methylthio-1-butene precedes attack at carbon to give allylic thiosulfonium ions that form reversibly and which rearrange rapidly to $\text{trans}$-2-butenyl analogs. Likewise, rearrangement of $\text{cis}$- to $\text{trans}$-1-methylthio-2-butene occurs by way of thiosulfonium ions.     

Heterocyclization of 3-(R-amino)-3-methylthio-1-phenylpropenones and 5-benzoyl-6-methylthio-1,2-dihydropyridin-2-ones with 1,2- and 1,3-dinucleophilic reagents

The interaction of 3-(R-amino)-3-methylthio-1-phenylpropenones and 1-alkyl-5-benzoyl-3-ethoxy-carbonyl-6-methylthio-1,2-dihydropyridin-2-ones with N,N- and N,C-1,2- and 1,3-dinucleophiles proceeded regioselectively by [3 + 2] and [3 + 3] cyclocondensation with the formation of derivatives of pyrazole, benzimidazo[1,2-a]-pyridine, benzimidazo[1,2-a]pyrimidine, imidazo[1,2-a]pyrimidine, [1,2,4]triazolo[4,3-b]pyridazine, and 6,7-dihydro-2H-pyrazolo[3,4-b]pyridine. The regioselectivity of the reactions carried out was analyzed.     

The reaction of phenylglyoxal with 2-aminoalcohols. Rearrangement of 2-acyloxazolidines to 2-hydroxy-5,6-dihydro-1,4-oxazines

The reactions of phenylglyoxal hydrate with (R)-phenylglycinol and with (1S,2R)-norephedrine were investigated. The expected 2-benzoyloxazolidines 3 and 2a , respectively are initially formed, and undergo a fast, spontaneous stereospecific rearrangement to the corresponding 2-hydroxy-3-phenyl-5,6-dihydro-1,4-oxazines 4 and 5 respectively. The mechanism of this new rearrangement is discussed. The structures and stereochemistry of 4 and 5 were established by X-ray diffraction analysis.     

Synthesis of 4-methylthio-2(1H)-pyridone derivatives using ketene dithioacetals

Reaction of various active methylene compounds with ketene dithioacetals, bis(methylthio)methylenemalononitrile (1a) and bis(methylthio)methylenecyanoacetamide (1b) gave the corresponding 3-cyano-4-methylthio-2(1H)-pyridone derivatives. The transformation of 4-methylthio-2-oxo-2H-pyran-3-carbonitrile in-to 4-methylthio-2(1H)-pyridone derivatives was also described.     

Über 4-Alkylamino-bzw. 4-Arylamino-5,6-dihydro-2(1H)-pyridinthione

Heating 1-alkyl- or 1-aryldihydro-6-methyl-2(1H)-pyrimidinethiones5, 6 in an inert medium causes rearrangement to 4-alkylamino-(4-arylamino-)-5,6-dihydro-2(1H)-pyridinethiones11, 12, probably via the methylene form29, by thermal heterolysis of the N₁/C₂ bond and exchange of the alkylamino (arylamino) group 1 through the carbon atom of the methylene group 6. The aminodihydropyridinethiones11, which can be regarded as cyclic derivatives of 3-aminothiocrotonamide, react with bistrichlorophenylmalonate under diacylation, and with formaldehyde and primary amines to yield aminodialkylation products of the enamine system, tetrahydro-4-hydroxy-7,7-dimethyl-5-thioxopyrido[4,3-b]pyridine-2(1H)-ones13, 14 and hexahydro-7,7-dimethylpyrido[4,3-d]pyrimidine-5(6H)-thiones18, 19, 21 respectively. H₂O₂ converts11 to the corresponding 4-aminodihydro-2(1H)-pyridones22, which can be reconverted into11 with P₄S₁₀.11 reacts with alkyl halides to 2-alkylthiodihydropyridines23, 24, 25. The mechanism of the methylpyrimidine-pyridine rearrangement is discussed.     

Säurekatalysierte Umlagerung von trans-5,6-Dihydroxy-5,6-dihydro-β-jonon

On treatment with acid, trans-5,6-dihydroxy-5,6-dihydro-β-ionone 2 undergoes a clean rearrangement to give a mixture of the furylketone 5 and the aliphatic triketone 6 in good yield.     

δ2-perfluoroalkenyl iodides

Conclusions The action of KI on ²-perfluoroalkyl fluorosulfates gives the direct substitution of the SO₃F group by I without allylic rearrangement.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 220–222, January, 1985.