Synthesis and chemical transformations of silicon-containing derivatives ofN,N-dimethylhydrazine

Reactions of carbofunctional organosilicon compounds withN,N-dimethyl-N′-trimethylsilylhydrazine andN,N-dimethyl-N′,N′-bis(trimethylsilyl)hydrazine were studied. The composition and structure of the reaction products were found to be dependent on the reagent nature and the reaction conditions. 1,4-Dimethylamino-2,2,5,5-tetramethyl-1,4-diaza-2,5-disilacyclohexane, a first representative of a new type of 2,5-disilapiperazines, was synthesized. A scheme of its formation was proposed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 169–173, January, 1999.     

Synthesis of new 2-substituted 2,5-dihydrofuranone derivatives and their chemical transformations

Russian Journal of Organic Chemistry -     

Synthesis and chemical transformations of cyclobuta[a]naphthalene and -anthracene derivatives

Cyclobuta[a]naphthalene derivatives (2a–c) and an anthracene analog (2d) were prepared by a double annulation procedure from mono- or bicyclic precursors (1a–d). Compound 2a was further converted to 3-hydroxynaphto[a]cyclobutene (10), to the novel quinone 11 and to naphthofuran derivatives (14, 17).     

Synthesis and transformations of furan derivatives

Condensation of thiosemicarbazones of furfural, 3-(2-furyl)acrolein, as well as their 5-nitro derivatives with chloroacetone by boiling in alcohol or acetic acid gives the corresponding 4-methylthiazolyl-(2)hydrazones. 4-Methylthiazolyl-(2)-hydrazones of 5-nitro-2-acetylfuran and 5-nitro-2-furfurilydeneacetone can be prepared by condensing the corresponding thiosemicarbazones with chloroacetone by heating with glacial acetic acid containing fused sodium acetate.For Part IV see [1].     

Synthesis and transformations of pyrimidine derivatives

A methoxyl group in the 4 and 6 positions has a passivating effect on the ability of the methyl group in monomethoxymethylpyrimidine derivatives to enter into azo coupling; at the same time, a methoxyl group in the 2 position does not have an appreciable effect on the activity of the methyl group because the conjugation effect of the methoxyl group in this position is less than in the 4 and 6 positions.See [1] for Communication XVIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1573–1574, November, 1970.     

Synthesis of functionalised azecine and azonine derivatives via an enolate assisted aza Claisen rearrangement

This paper describes the synthesis of functionalised azecine and azonine derivatives incorporating the adrenaline motif. In a key step, an enolate assisted aza Claisen rearrangement was employed to interconvert from 6- and 5-membered heterocycles to their corresponding 10- and 9-membered lactams.     

Synthesis and chemical transformations of perfluoroalkylimidoyl iodides

The addition of perfluoroalkyliodes CF₃(CF₂)_nl (n= 3, 5, 7) to isocyanides 2 produces perfluoroalkylimidoyl iodides 3 under thermal conditions when the isocyanide nitrogen substituent is n-butyl or cyclohexyl, but fails when it is t-butyl or 2,6-dimethylphenyl. The same reaction can be induced at room temperature by the addition of decimolar quantity of copper powder. This type of metal-catalyzed condensation is general for all perfluoroalkyliodides and isocyanides studied. The perfluoroalkylimidoyl-iodides 3 have been transformed into a variety of perfluorocarboxylic acid derivatives (amides, amidines. imidates, imidoylfluorides) and perfluoroalkylamines.     

Synthesis of new heterocyclic derivatives of 2-imino-2,5-dihydro-furans and some of their chemical transformations

New heterocyclic derivatives of 2-imino-2,5-dihydrofurans were synthesized by the reaction of tertiary α-keto alcohols with the substituted amides of cyanoacetic acid. Some of their chemical transformations were realized.     

Synthesis and chemical transformations of mono- and disubstituted cyanamides

The review briefly discusses the known methods for the preparation of substituted cyanamides, their typical transformations, and some aspects of practical applications of these compounds in medicine, various branches of industry, and agriculture.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1439–1454.Original Russian Text Copyright © 2004 by Nekrasov.Dedicated to the memory of Prof. Yu.S. Andreichikov     

Synthesis and transformations of enantiomeric 1,2-disubstituted monoterpene derivatives

Regio- and stereospecific addition of chlorosulfonyl isocyanate to (+)- and (−)-α-pinene 1 resulted in enantiomerically pure β-lactams 2, which were converted to enantiomeric β-amino esters 3 and 1,3-amino alcohols 4 and 6 with ee >99%. The resulting 1,3-difunctional compounds 3, 4 and 6 were transformed to fused saturated 1,3-heterocycles such as tetrahydro-1,3-oxazines 7 and 9, 2,4-pyrimidinedione 11 and 2-thioxopyrimidin-4-one 13 enantiomers.     

Synthesis and transformations of new dihydro-β-campholenolactone derivatives

The reaction of xenon difluoride with enamino lactone 3 furnished the new α-fluoro aldehyde 7, whereas reaction of 3 with anhydrous HF led to racemic dihydro-β-campholenolactone 6. Acid-catalysed rearrangement of α-ethylidenelactone 4 proceeded with retention of configuration to give β-campholenolactone 8. Nitrosation of the novel bicyclic enamino lactone 6 afforded the corresponding oxime 9, while acid-catalysed treatment with primary amines, 2-methyl-1H-indole, potassium cyanide and hydrazine hydrochloride, furnished the dimethylamine substitution products 11–13 and the ‘ring switched’ product 14. The structures were determined by 2D NMR techniques, NOESY spectroscopy and X-ray diffraction.     

Synthesis, structure and chemical transformations of 4-aminobenzaldehyde

A possibility of nucleophilic substitution of the fluorine atom in 4-fluorobenzaldehyde with amines (morpholine, piperidine or cytisine) under convection heating and microwave irradiation was shown. Reactions of 4-morpholinyl- and 4-piperidinylbenzaldehyde with hydrazides of isonicotinic and salicylic acids afford the corresponding hydrazones. The structure of the synthesized compounds was confirmed by IR, ¹H NMR spectroscopy, mass spectrometry, and X-ray analysis data.     

Synthesis and chemical transformations of 2-cyclopropyl-2-diazoacetates

Methyl 2-cyclopropyl-2-diazoacetate was synthesized from acetylcyclopropane in few chemical steps in ∼55% total yield. Its copper or rhodium-catalyzed dediazoniation exclusively proceeds through the intramolecular isomerization of generated cyclopropyl(methoxycarbonyl)carbene to 1-methoxycarbonylcyclobutene, irrespective of the presence or the absence of unsaturated compounds. However, in the presence of acrylates or strained cycloalkenes, this diazo ester is being slowly involved into the 1,3-dipolar cycloaddition, giving cyclopropyl-substituted pyrazolinecarboxylates, which in case of 1-pyrazolines easily lose nitrogen molecule to selectively afford 1-cyclopropylcyclopropanecarboxylate derivatives. Dedicated to Academician V. A. Tartakovsky in honor of his 75th anniversary. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1459–1465, August, 2007.     

Synthesis and transformations of new 1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-dione derivatives

Reactions of cyclohexane-1,3-diones with amines and aldehydes led to the formation of 1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-diones containing alkylaryl, aryl, and hydroxy substituents in position 10. Transformations of 10-hydroxy-1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-diones under oxidation with nitrous acid, reduction with zinc powder, as well as on heating in aprotic solvents and acetic, phosphoric, and polyphosphoric acids, were studied. NMR spectra of 1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-diones having different substituents in positions 9 and 10 were analyzed.     

Synthesis and transformations of 20-oxo-30-nortaraxasteryl acetate derivatives

20,20-Dimethoxy-, Δ²¹-20-oxo-, and 20-oxo-30-nortaraxasteryl acetates were synthesized by selective ozonolysis of taraxasteryl acetate. Baeyer-Villiger oxidation of 20-oxo-30-nortaraxasteryl acetate with SeO₂-H₂O₂ gave 3β-acetoxytaraxa-(19,20)-?-lactone. Mechanism of the ozonolysis of taraxasteryl acetate is discussed. The enthalpies of formation of possible intermediates were calculated by quantum-chemical methods, and most favorable paths of the ozonolysis and dehydrogenation were determined.     

Synthesis and some chemical transformations of 3-ferrocenyl-3-phenylcyclopropene

Crystalline 3-ferrocenyl-3-phenylcyclopropene was obtained by dehydrobromination of 2-bromo-l-ferrocenyl-l-phenylcyclopropane with potassiumtert-butoxide in dimethyl sulfoxide. The compound synthesized undergoes catalytic hydrogenation to l-ferrocenyl-I-phenylcyclopropane, reacts with 1,3-diphenylisobenzofuran to give the expected product of stereospecific [4+2[-cycloaddition and 3-ferrocenylindene, and also undegoes opening of the small ring on treatment with superacids to give 3-ferrocenylindene as the major product. The data of single crystal X-ray diffraction analysis of 1-ferrocenyl-l-phenylcyclopropane and the diene adduct of 3-ferrocenyl-3-phenylcyclopropene with 1,3-diphenylisobenzofuran are given.