Hydrolysis of 3,4-diphenyl-1,2,5-thiadiazole-1,1-dioxide. Acid and base catalysis

We have performed a product and kinetic study of the hydrolysis of 3,4-diphenyl-1,2,5-thiadiazole-1,1-dioxide in aqueous solution. Benzil and sulfamide are the only products of hydrolysis and are formed in equimolar yields. The kinetic results indicate that a first order law is followed up to 90% conversion. The observed rate constant is independent of substrate concentration. Ionic strength and buffer concentration do not affect the rate constant, but the reaction is acid-base catalyzed. The rate-pH profile has been determined and a mechanism that fits the experimental data satisfactorily is proposed. Corresponding rate constants and equilibrium constants for the protonation of the substrate are reported.     

1,2-Benzothiazines VIII. A novel semmler-wolff type transformation of 2-methyl-2H-1,2-benzothiazin-4-one 1,1-dioxide oxime

Refluxing the oxime ( 1 ) of 2-methyl-2H-1,2-benzothiazin-4(3H)one 1,1-dioxide with tri-fluoroacetic acid or with boron trifluoride in acetic acid gives the corresponding N-acyl derivative ( 2 or 3) of 4-amino-2-methyl-2H-1,2-benzothiazin-3(4H)one 1,1-dioxide. This transformation appears to be related to the acid catalyzed conversion of α-tetralone oxime to α-naphthylamine.     

Reductive transformation of 3-methoxy-2-methyl-3,4-diphenyl-2,3-dihydro-1,2,5-thiadiazole 1,1-dioxide in the reaction with thiourea and HC1

Russian Chemical Bulletin -     

Synthesis of 4-methyl-5-alkyl-2-imidazolinones

Conclusions 4-Methyl-5-alkyl-2-imidazolinones were synthesized by heating 3-halo-2-alkanones with a mixture of piperidine, N,N-diethylacetamide, urea, zinc chloride and magnesium carbonate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1887–1890, August, 1987.     

Reactivity of 2-methyl-4-(1-pyrrolidinyl)-2H-1,2-benzothiazine 1,1-dioxide towards p-toluenesulphonyl azide

The 2-methyl-2H-1,2-benzothiazin-4-(3H)-one 1,1 dioxide ( 2 ), obtained according to a new, one-pot method, is transformed into the pyrrolidino enamine 3 . Reaction of p-toluenesulphonyl azide with 3 gives, via an unstable triazoline adduct which loses nitrogen, the two isomeric tosylamino derivatives 4 and 5 . The structures have been assigned by exhaustive nmr analysis and some aspects on their formation and chemical behaviour are discussed.     

Synthesis of 3,4-Dihydro-2-methyl-3-oxo-N-aryl-2H-[1]benzothieno[3,2-e1,2-thiazine-4-carboxamide 1,1-Dioxides

A novel synthesis of the title compounds, representing a new heterocyclic ring system, is described. Chlorosulphonation of 3-methylbenzo[b]thiophene followed by reaction with methylamine gave sulfonamide, 4 . Lithiation of 4 , followed by quenching with carbon dioxide yielded acetic acid, 5 . Cyclodehydration of 5 to benzothienothiazine 6 followed by reaction with aryl isocyanates afforded the desired benzothieno[3,2-e]-1,2-thiazine-4-carboxamides 1a-f.     

β-Sultams II: Synthesis of tri-, tetra- and pentamethylene- 1,2-thiazetidine 1,1-dioxides

The unsubstituted parent structure of sulfone analogs of penicillin and its higher homologs are obtained by base promoted cyclization of cyclic β-amino-ethanesulfonyl chlorides.     

Spiro[(2,3-dihydro-2-oxo-imidazo[1,2-a]pyridine)-3,3-(3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine 1,1-dioxide)]-A novel product derived from piroxicam

A novel compound, spiro[(2,3-dihydro-2-oxo-imidazo[1,2-a]pyridine)-3,3-(3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine 1,1-dioxide)] (3) , was isolated during an attempt to convert 4-hydroxy-2-methyl-N-(2-pyridinyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide ( 1 ) (Piroxicam) to an O-trifluoromethanesulfonyl ester. A possible mechanism is offered to explain this unusual transformation.     

Synthesis and some properties of amides of 4-carboxymethyl-2-thiolene 1,1-dioxide

Amides of 4-carboxymethyl-2-thiolene 1,1-dioxide were obtained with aliphatic, heterocyclic, and aromatic amines. A study was carried out on the reactions of these amides with various nucleophilic reagents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1622–1625, December, 1984.     

Reactions of 2-benzylidene-3-methyl-4-nitro-2,5-dihydrothiophene 1,1-dioxide with CH acids

2-Benzylidene-3-methyl-4-nitro-2,5-dihydrothiophene 1,1-dioxide reacted with acyclic CH acids (acetylacetone, diethyl malonate, and its derivatives) according to the 1,4-addition pattern, whereas reactions of the title compound with cyclohexane-1,3-dione and 5,5-dimethylcyclohexane-1,3-dione (dimedone) were complicated by subsequent intramolecular heterocyclization leading to thieno[3,2-b]chromene derivatives.     

2-Benzylidene-3-methyl-4-nitro-3-thiolene-1,1-dioxide and Its Analogs in Aza-Michael Reaction

2-Benzylidene-3-methyl-4-nitro-3-thiolene-1,1-dioxide and its analogs have been introduced in the aza-Michael reaction with hydrazine derivatives. Novel polysubstituted nitrosulfolenes have been obtained; their structures have been confirmed using ¹Н NMR and IR spectroscopy as well as X-ray diffraction analysis.     

Structure of 3,4-dinitro-3,4-dimethyl-1,1-diphenyl-1-silacyclopentane

Conclusions 3,4-Dinitro-3,4-dimethyl-1,1-diphenyl-1-silacyclopentane in the liquid phase has a half-chair conformation, and in the solid phase, its conformation is described by a form intermediate between the half-chair and the envelope conformation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2731–2736, December, 1985.     

New synthetic approaches to 3-carhoxamides of 4-hydroxy-2H-1,2-benzothiazine 1,1-dioxide

Two new synthetic approaches to the title compounds are reported. In the first of these, starting with N-carbobenzyloxysarcosine, four synthetic steps are employed to finally assemble the C³? C⁴ bond of the 1,2-benzothiazine ring. In the second approach, an enol ether is employed as a protecting group to allow formation of the 3-carboxamide function, which is followed by cleavage of the ether function to yield the desired 4-hydroxy-1,2-benzothiazine-3-carboxamide 1,1-dioxide.     

Reaction of 2,5-diphenyl-3,4-diazacyclopentadien-1-one 3,4-dioxide with trialkyl phosphites

Conclusions The trimethyl and triethyl phosphite react with 2,5-diphenyl-3,4-diazacyclopentadien-1-one 3,4-dioxide to give 1-alkyl-3,5-diphenyl-4-pyrazolyl dialkyl phosphates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1422–1424, June, 1972.     

Synthesis of 3-alkyl-2, 4, 6-triphenylpyridines and 1,3-diphenyl-4- and-2-azafluorenes

The previously unknown 3-alkyl-2,4,6-triphenylpyridines were obtained from 1-methyl-3-alkyl-2, 6-diphenyl-4-piperidones. It was established that a mixture of 1,3-diphenyl-4-azafluorene and 1,3-diphenyl-2-azafluorene is formed in the dehydrocyclization of 3-methyl-2,4,6-triphenylpyridine.     

Interaction of 2,5-diphenyl-3,4-diazacyclopentadienone 3,4-dioxide with vinylphosphonic acid dimethyl ester

Conclusion The interaction of 2,5-diphenyl-3,4-diazacyclopentadienone 3,4-dioxide and vinylphosphonic acid dimethyl ester, irrespective of the ratio of reagents, occurred at one nitrone system of the dioxide and led to the formation of the 11 addition product.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1627–1628, July, 1982.