Synthesis of 2,3-disubstituted-4-oxothiazolidine 1-oxides

The reaction of chloramine-T with 2,3-disubstituted-4-oxothiazolidines 1a-c give the corresponding sulfoxides 2a-c , whose structures were based on analytical and spectral data.     

Reaction of 2,3-diphenylpyrazine 1-oxides with acetic anhydride

Some 2,3-diphenylpyrazine 1-oxides were heated with acetic anhydride to give the corresponding 2,3-di-acetoxy-2,3-dihydro-5,6-diphenylpyrazines. By X-ray diffraction analysis, the configuration of two acetoxyl groups was determined to be trans.     

An unusual synthesis of substituted 1,3-oxazolidino [2,3-b] benzimidazoles

Conclusions The reactions of 2-alkyl- and 2-vinylthiobenzimidazoles with tertiary cyanoethynylcarbinols are accompanied by heterocyclization with formation of subsituted 1,3-oxazolidino[2, 3-b] benzimidazoles.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 197–199, January, 1987.     

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides in the synthesis of 2,3-dihydronaphtho- and naphtho[1,2-b]thiophenes

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides, obtained by thermolysis of alkyl 1-naphthyl sulfoxides, are reduced by lithium aluminum hydride to 2,3-dihydronaphtho [1,2-b]thiophenes, whereas under the influence of acetic and trifluoroacetic anhydrides they form naphtho[1,2-b]thiophenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1629–1633, December, 1989.     

The synthesis and reactions of certain pyridazine 1-oxides

Nucleophilic displacement reactions under acidic and basic conditions have been studied with 4,6-dinitro-3-methoxypyridazine 1-oxide ( 1 ) and with 6-chloro-3-methoxy-4-nitropyridazine 1-oxide ( 2 ). Depending on the nature of the nucleophilic reagent and the conditions of the reaction we have found that the chloro group, the nitro group, as well as the methoxy group of 1 and 2 may be displaced by the nucleophile. This type of compound possesses significant in vitro antifungal activity.     

Photochemical route to the synthesis of thiolane 1-oxides

The preparation of thiolane 1-oxide 10 by photochemically mediated rearrangement of sulfoxide 9 in high yield is described. The efficient construction of quaternary carbon centers underscores the utility of this methodology in organic synthesis. Further manipulation of photoadduct 10 leads to the formation of diverse heterocyclic structures.     

New method for the synthesis of 1,2,3-triazole 1-oxides

A general method is proposed for the synthesis of 1,2,3-triazole 1-oxides using 3,4-dinitro- or 4-amino-3-nitrofuroxanes.Deceased.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913, Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 675–679, May, 1996. Original article submitted February 22, 1996. Resubmitted after revision April 5, 1996.     

Convenient synthesis of 1-alkoxy-1,2-dihydrophosphinine 1-oxides by ring enlargement

The addition of dichlorocarbene to the double bond of 1-alkoxy-dihydrophosphole oxides and subsequent thermolysis of the adduct so obtained affords mixtures of the two double bond isomers of alkoxy-dihydrophosphinine oxides, if the latter step is carried out in the presence of triethylamine. Experimental data support the involvement of a cationic intermediate during the opening of the cyclopropane ring. A simplified procedure for the preparation of the starting dihydrophospholes is also presented.     

Convenient synthesis of 1-alkoxy-di- and tetrahydrophosphinine 1-oxides by ring enlargement

The double bond of the P-alkoxy 3,4-dimethyl-2,5-dihydro-1H-phosphole 1-oxides reacts easily with dichlorocarbene to give two diastereomers of an unstable adduct useful in the synthesis of ring expanded products, such as 1,2-dihydrophosphinine oxides or 1,2,3,6-tetrahydrophosphinine oxides. The former can be prepared by thermolysis of the adducts, while the latter are obtained by cyclopropane ring opening effected by silver nitrate in an alcoholic solvent. The preparation of the double-bond isomers of 1-alkoxy-tetrahydrophosphinine oxides containing only one methyl substituent in the ring is also described. The reaction of dihydro-1H-phosphole oxides with dichlorocarbene can be modified to give P-alkoxy 1,4-dihydrophosphinine oxides in an unexpected reaction.     

An unusual one step synthesis of acetylenes

Substituted nitrostyrenes on reaction with H₂O₂/NEt₃ give 1,2 diaryl acetylenes in ~ 30 % yield.     

An unusual synthesis of a spirothioxanthene derivative

The reaction of diphenyl sulfone with 2,3-dibromophthalazine-1,4-dione in the presence of n-butyllithium gave a spiro-9H-thioxanthene-10,10-dioxide derivative in 45% yield, the structure of which was proved by X-ray crystallography.     

A new regioselective synthesis and ambient light photochemistry of quinazolin-1-oxides

Quinazolin-1-oxides were prepared by the oxidation of tetrahydroquinazolines with H₂O₂-tungstate and their ambient light photochemistry was investigated. Substituent effects on their photochemical cyclization and the reactions of the products 1aH-[1,2]oxazireno[2,3-a]quinazolines under photochemical and thermal conditions are reported. The cyclization of quinazolin-1-oxides and the reactions of 1aH-[1,2]oxazireno[2,3-a]quinazolines show pronounced solvent isotope and solvent effects.     

One-pot synthesis of 2,3-dihydro-1H-benzimidazoles

A convenient one-pot method for the synthesis of 2,3-dihydro-1H-benzimidazoles has been elaborated. A set of 2,3-dihydro-1H-benzimidazoles was prepared from various ortho-dialkylaminoanilines and aldehydes using Me3SiCl as a condensation agent and pyridine as a basic medium.     

Pyrrolopyridazines. 1. Synthesis and reactivity of pyrrolo[2,3-d]pyridazine 5-oxides

Reaction of ethyl 4-ethoxymethyleneamino-3-methoxy-5-pyridazinylpyruvate 1-oxide ( 8 ) under various conditions constitutes a new approach to substituted pyrrolo[2,3-d]pyridazines. The resulting substituted pyrrolo[2,3-d]pyridazine 5-oxides were allowed to react further to provide a number of new compounds in this ring system.