Heteroatomic derivatives of aziridine

The reaction of aziridine with trialkylsilanethiols in dry tetrahydrofuran (THF) at 55–60°C, which leads to the formation of mixtures of substances [according to the data from the IR and PMR spectra, hexalkyldisilyl sulfides, 2-mercaptoethylamine, trialkyl(2-aminoethylthio)silanes, and 1-trialkylsilylamino-2-trialkylsilylthioethanes], was studied. 2-Mercaptoethylamine and 1-trialkylsilylamino-2-trialkyl-silylthioethanes, the structures of which were established on the basis of the IR and PMR spectra, were isolated in pure form.See [1] for communication 10.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1652–1653, December, 1979.Original submitted August 11, 1978.     

Heteroatom derivatives of aziridine

Reaction of ethylenimine with boron trifluoride at –78° C gives N--fluoroethyl-B-difluoroborazene FCH₂CH₂NHBF₂. Acetylation of the latter with acetic anhydride gives N-acetyl-N--fluoroethyl-B-difluoroborazene FCH₂CH₂N(COMe)BF₂. The IR spectra of these two compounds are investigated. N--fluoroethyl-B-difluoroborazene can react further with ethylenimine to give ultimately a polymeric product with the composition [(FCH₂CH₂NH)₂BF]_n which is also obtained by reacting BF₃ with excess ethylenimine. Reaction of N-B-fluoroethyl-B-trifluoroborane with triethylamine gives N-triethyl-B-trifluoroborane Et₃NBF₃.For Part III see [1].     

Heteroatom derivatives of aziridine

N-Trialkylsilyl- and N-trialkoxysilyl-2-aminoethanethiols were obtained by reaction of aziridine with trialkylsilyl- and trialkoxysilylalkanethiols or 1-(2-trialkylsilylethyl)aziridines with aliphatic and aromatic thiols.See [1] for communication VII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1507–1509, November, 1977.     

Heteroatomic derivatives of aziridine

The reaction of ethyleneimine with sulfenyl chlorides RSCl at ?10? C in the presence of a hydrogen chloride acceptor (triethylamine) leads to the formation of N-organylthioaziridines\({\text{RS}}{\text{H}}_{\text{2}}\). Compounds with R=n-C₅H₁₁, C₆H₅, o-O₂NC₆H₄ and C₆H₆CH₂ have been obtained by this method.\({\text{(CH}}_{\text{3}} {\text{)}}_{\text{3}} {\text{SS}}{\text{H}}_{\text{2}}\) and\({\text{(C}}_{\text{2}} {\text{H}}_{\text{5}} {\text{)}}_{\text{2}} {\text{NS}}{\text{H}}_{\text{2}}\). have been synthesized analogously.The properties and IR spectra of these compounds have been studied. The action of methyl iodide on N-phenylthioaziridine leads to disproportionation of the molecule with the formation of diphenyl disulfide, Β-iodoethyltrimethylammonium iodide, and free iodine.     

Heteroatomic derivatives of aziridine

Mixtures of N-(-organyl--acylvinyl)aziridines with preponderance of the cis adducts were obtained by the addition of aziridine to acetylenic ketones, The synthesized products react with mercaptosuccinic and thioglycolic acids with opening of the aziridine ring; depending on the reaction conditions, either aminoethylthio derivatives or, as a result of hydrolytic cleavage of the aziridine ring, 3-oxo-1,4-perhydrothiazine are formed. The IR and PMR spectra of the compounds obtained are discussed.See [1] for communication 8.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 55–57, January, 1979.     

Heteroatom derivatives of aziridine

Reaction of ethyleneimine with boron trichloride and tribromide below −20° C, with reactants in ratios 1∶1 and 2∶1, gives labile N-β-halo-genoethyl-substituted halogenoborazenes of the types XCH₂CH₂NHBX₂ and (XCH₂CH₂NH)₂BX (X = Cl, Br). These compounds decomposed spontaneously on coming to room temperature, with the evolution of HX and formation of substances whose compositions are, respectively C₂H₄NBX₂ and C₄H₉N₂BX₂. With a 3∶1 ratio of reactants the product is the relatively stable tris(β-halogenoethylamino)borane (XCH₂CH₂NH)₃ B (X = Cl, Br), which loses only one molecule of HX when heated under vacuum. For Part V see [1].     

Heteroatomic derivatives of aziridine

The reaction of ethyleneimine with sulfenyl chlorides RSCl at –10 C in the presence of a hydrogen chloride acceptor (triethylamine) leads to the formation of N-organylthioaziridines . Compounds with R=n-C₅H₁₁, C₆H₅, o-O₂NC₆H₄ and C₆H₆CH₂ have been obtained by this method. and . have been synthesized analogously.The properties and IR spectra of these compounds have been studied. The action of methyl iodide on N-phenylthioaziridine leads to disproportionation of the molecule with the formation of diphenyl disulfide, -iodoethyltrimethylammonium iodide, and free iodine.For communication VI, see [I].     

Amino acid derivatives of aziridine

Aziridines that contain dipeptide fragments in their compositions were obtained by the reaction of esters of dipeptides with methyl 1,2-dibromopropionate. Aziridines with dipeptide fragments in the 1 and 2 positions of the ring were synthesized when activated esters of 1, 2-dibromopropionic acid were used.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1627–1630, December, 1982.     

Hetero atom derivatives of aziridine

Labile equimolecular coordination complexes of ethyleneimine with trimethyl and triphenyl borates (N-ethylene-B-trimethoxyborazane and N-ethylene-B-triphenoxyborazane) are prepared for the first time and their properties investigated.For Part II see [1].     

A new method for the synthesis of aziridine derivatives

The photoinduced reaction ofN-trialkylstannyl-N-triorganylsilyl-substituted allylamines with perfluorocarbonyl iodides results in the formation of 1-triorganylsilyl-2-(,a-dihydroperfluoroalkyl)aziridines.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 3, pp 759–760, March, 1996.     

Photochemical desulfurization of l-cysteine derivatives

Thiol groups can be reductively eliminated at room temperature by a photochemical method which makes use of triethylboron, triethylphosphite and visible light. Thus, after treating l-Cys 1a, d-Pen 1b, l-Cys-OMe 1c and glutathione (γ-l-Glu-l-Cys-Gly) 3, the corresponding desulfurized compounds l-Ala 2a, d-Val 2b, l-Ala-OMe 2c and γ-l-Glu-l-Ala-Gly 4, respectively, are prepared in high yields and with retention of configuration.     

Photochemical dynamics of indolylmaleimide derivatives

On-the-fly nonadiabatic ab initio molecular dynamics simulations have been carried out for three anionic species of indolylmaleimides (3-(1H-3-indolyl)-2,5-dihydro-1H-2,5-pyrroledione, IM) to clarify the mechanisms of photochemical reactions. The results are obtained for (i) a monovalent anion with a deprotonated indole NH group (IM(-)'), (ii) a monovalent anion with a deprotonated maleimide NH group (IM(-)') and (iii) a divalent anion with doubly deprotonated indole and the maleimide NH groups (IM(2-)). Quantum chemical calculations are treated at the three state averaged complete-active space self-consistent field level for 6 electrons in 5 orbitals with the cc-pVDZ basis set (CAS (6, 5) SCF/cc-pVDZ). Molecular dynamics simulations are performed with electronically nonadiabatic transitions included using the Zhu-Nakamura version of the trajectory surface hopping (ZN-TSH) method. It is found that the nonadiabatic transitions occur accompanied by the stretching and shrinking motions of the N(7)-C(8) bond in the case of IM(-)' and the C(11)-N(12) bond in IM(2-) rather than the twisting motion of the dihedral angle. We also found that the ultrafast S(2)→ S(1) nonadiabatic transitions occur through the conical intersection (CoIn) right after photoexcitation to S(2) in IM(-)' and IM(2-). Furthermore, the S(1)→ S(0) nonadiabatic transitions are found to take place in IM(-)'. It is concluded that IM(2-) would mainly contribute to the photoemission, because the S(1)← S(0) and S(2)← S(0) transitions of IM(-)' are dipole-forbidden transitions and, moreover, IM(2-) is found to be the only species to stay in the S(1) state without non-radiative decay.     

Photochemical studies: Chromones,bischromones and anthraquinone derivatives

Photochemical reaction is a chemical reaction initiated by the absorption of energy in the form of light resulting in different types of reaction. Chromones, bischromones and anthraquinones are the bichromophoric molecules which contain the carbonyl group and double bond in conjugation. Photochemical reactions of these compounds result in the formation of such molecules which are not obtained via conventional methods. This review article describes the photochemical transformations of chromones, bischromones and anthraquinone derivatives and here main emphasis has been laid upon the intramolecular photochemical H-abstraction reactions that provide many exotic heterocyclics as the final photoproducts.     

Tosylated glycerol carbonate, a versatile bis-electrophile to access new functionalized glycidol derivatives

The reactivity of tosylated glycerol carbonate 2 toward nucleophiles has been exploited to generate glycidol analogues protected with carbonate or carbamate groups. The activated glycerol 2 is a reasonable linking agent with thiol and alcohol nucleophiles and an excellent and selective one with primary amines, allowing efficient bis-functionalizations of glycerol.     

Photochemical electron transfer mediated addition of naphthylamine derivatives to electron-deficient alkenes

Using photochemical electron transfer, N,N-dimethylnaphthylamine derivatives are added to α,β-unsaturated carboxylates. The addition takes place exclusively in the α-position of electron-deficient alkenes and mainly in the 4-position of N,N-dimethylnaphthalen-1-amine. A minor regioisomer results from the addition in the 5-position of this naphthylamine. A physicochemical study reveals that the fluorescence quenching of N,N-dimethylnaphthalen-1-amine is diffusion-controlled and that the back electron transfer is highly efficient. Therefore no transformation is observed at lower concentrations. To overcome this limitation and to induce an efficient transformation, minor amounts of water or another proton donor as well as an excess of the naphthylamine derivative are necessary. A mechanism involving a contact radical ion pair is discussed. Isotopic labeling experiments reveal that no hydrogen is directly transferred between the substrates. The hydrogen transfer to the furanone moiety observed in the overall reaction therefore results from an exchange with the reaction medium. An electrophilic oxoallyl radical generated from the furanone reacts with the naphthylamine used in excess. Concerning some mechanistic details, the reaction is compared with radical and electrophilic aromatic substitutions. The transformation was carried out with a variety of electron-deficient alkenes. Sterically hindered furanone derivatives are less reactive under standard conditions. In a first experiment, such a compound was transformed using heterogeneous electron transfer photocatalysis with TiO(2).     

Photochemical synthesis of pentacene and its derivatives

A novel alpha-diketone precursor of pentacene, 6,13-dihydro-6,13-ethanopentacene-15,16-dione, was prepared and converted successfully to pentacene in 74 % yield by photolysis of the precursor in toluene: Irradiation of the diketone solution in toluene with light of 460 nm under an Ar atmosphere caused the solution to change from yellow to fluorescent orange-pink within a few minutes, after which, purple precipitates appeared. After 35 min, the solution changed to colorless and the purple precipitates were filtered to give pentacene in 74 % yield. By contrast, in the presence of oxygen, the color of the solution changed from yellow to pale yellow, and only 6,13-endoperoxide of pentacene was quantitatively obtained. The rate of the reaction upon photolysis was measured by observing the decay of n-pi* absorption of the precursor at 460 nm, and was found to be similar in both the presence and absence of oxygen. Therefore, the photoreaction of the alpha-diketone precursor seemed to occur via the singlet excited state. Because the T-T absorption of pentacene was observed upon photolysis of the precursor in the nanosecond transient absorption measurement under an Ar atmosphere, the excited triplet state of the pentacene generated singlet oxygen by sensitization, and it reacted with the ground-state pentacene to give the 6,13-endoperoxide. The alpha-diketone deposited on glass was also converted successfully to pentacene film by photoirradiation. In addition, diketone precursors of a mixture of 2,8- and 2,9-dibromopentacene and 2,6-trianthrylene were also prepared and their photoconversion was performed.