An unusual effect of exo-endo configuration on the quantum yield Φ of photochemical rearrangement of 4-R-substituted 8-phenyl-3,5,10-trioxa-9-azabicyclo-[5,3,0]-8-decenes

1986 ◽  
Vol 51 (10) ◽  
pp. 2158-2166 ◽  
Author(s):  
Lubor Fišera ◽  
Vladimír Oremus ◽  
Hans-Joachim Timpe ◽  
Ladislav Štibrányi ◽  
Peter Zálupský
Keyword(s):  
Quantum Yield ◽  
Dipolar Cycloaddition ◽  
Tert Butyl ◽  
Photochemical Rearrangement ◽  
Unusual Effect ◽  
Derivatives Of

The dependence has been found of the quantum yield Φ of photochemical rearrangement of the title compounds (where R means ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, 2-furyl, 2-thienyl) on the exo(I) or endo (II) arrangement of the R substituent. The endo derivatives exhibit higher Φ values (0.020-0.041) than the exo derivatives (0.007-0.019). The photochemical rearrangement gives the derivatives of 2-R-6-phenyl-7-formyl-2,4,5,8-tetrahydro-1,3-dioxa-5-azocine as the single products in good yields. The 2-furyl derivative gives polymeric products. The title compounds have been prepared by 1,3-dipolar cycloaddition of benzenenitriloxide to the respective substituted 1,3-dioxep-5-enes.

Derivatives of tetrahydro-2H-pyridine from photorearranged cycloadducts of nitrile oxides

1990 ◽  
Vol 55 (2) ◽  
pp. 512-523 ◽  
Author(s):  
Lubor Fišera ◽  
Vladimír Ondruš ◽  
Hans-Joachim Timpe
Keyword(s):  
Reaction Mechanism ◽  
Double Bond ◽  
Quantum Yields ◽  
Dipolar Cycloaddition ◽  
Mercury Lamp ◽  
Reaction Sequence ◽  
Nitrile Oxides ◽  
Photochemical Rearrangement ◽  
Benzene Rings ◽  
Derivatives Of

1,3-Dipolar cycloaddition of methoxycarbonylnitrile, furannitrile and substituted benzene nitrile oxides (X = 4-CH3, 4-OCH3, 3-OCH3, 4-Cl, 3-Cl, 2,4-diCl, 4-F) to dimethyl 7-(diphenylmethylene)bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylate (XII) led exclusively to exo cycloadducts IV, on irradiation with a low-pressure mercury lamp afforded the required 4-substituted derivatives of dimethyl 2,2-diphenyl-5-formyl-3-azabicyclo[4.3.0]nona-4,9-diene-7,8-dicarboxylate (XI) as sole products. Selectivity of the photorearrangement of isoxazolines IV to enaminoaldehydes XI is due to a stabilization of the biradical VII by the overlap of the radical-electron with π-electrons of the C=C double bond and by two benzene rings. Quantum yields of the photorearrangement, established from the deficit of the starting IV, were found to be greater than those for the analogous oxabicyclic derivatives XVI. The reaction mechanism is proposed and the dependence on various solvents is pointed out; this reaction sequence, viz. the 1,3-dipolar cycloaddition followed by a photochemical rearrangement provides a new method for obtaining derivatives of tetrahydro-2H-pyridine from the well available cyclopentadiene.

Synthesis of Novel 1,2,3-Triazole Derivatives of Isocoumarins and 3,4-Dihydroisocoumarin with Potential Antiplasmodial Activity In Vitro

2020 ◽  
Vol 16 ◽  
Author(s):  
Lucas da Silva Santos ◽  
Matheus Fillipe Langanke de Carvalho ◽  
Ana Claudia de Souza Pinto ◽  
Amanda Luisa da Fonseca ◽  
Julio César Dias Lopes ◽  
...  
Keyword(s):  
Triazole Ring ◽  
Antiplasmodial Activity ◽  
World Health ◽  
Dipolar Cycloaddition ◽  
Terminal Alkynes ◽  
The World ◽  
Ic50 Values ◽  
Derivatives Of ◽  
Active Substances

Background: Malaria greatly affects the world health, having caused more than 228 million cases only in 2018. The emergence of drug resistance is one of the main problems in its treatment, demonstrating the urge for the development of new antimalarial drugs. Objective: Synthesis and in vitro antiplasmodial evaluation of triazole compounds derived from isocoumarins and a 3,4- dihydroisocoumarin. Method: The compounds were synthesized in 4 to 6-step reactions with the formation of the triazole ring via the Copper(I)-catalyzed 1,3-dipolar cycloaddition between isocoumarin or 3,4-dihydroisocoumarin azides and terminal alkynes. This key reaction provided compounds with an unprecedented connection of isocoumarin or 3,4-dihydroisocoumarin and the 1,2,3-triazole ring. The products were tested for their antiplasmodial activity against a Plasmodium falciparum chloroquine resistant and sensitive strains (W2 and 3D7, respectively). Results: Thirty-one substances were efficiently obtained by the proposed routes with an overall yield of 25-53%. The active substances in the antiplasmodial test displayed IC50 values ranging from 0.68-2.89 μM and 0.85-2.07 μM against W2 and 3D7 strains, respectively.

1,3-dipolar cycloaddition in the synthesis of glycoconjugates of natural chlorins and bacteriochlorins

2009 ◽  
Vol 13 (03) ◽  
pp. 336-345 ◽  
Author(s):  
Mikhail A. Grin ◽  
Ivan S. Lonin ◽  
Anna A. Lakhina ◽  
Elena S. Ol'shanskaya ◽  
Alexey I. Makarov ◽  
...  
Keyword(s):  
Triple Bond ◽  
Tautomeric Form ◽  
Click Reaction ◽  
Copper Cation ◽  
Water Soluble ◽  
Dipolar Cycloaddition ◽  
Nmr Studies ◽  
Metal Free ◽  
Cu Complex ◽  
Derivatives Of

Glucose-, galactose- and lactose-containing photosensitizers based on derivatives of chlorophyll a and bacteriochlorophyll a were synthesized with the use of [3+2] cycloaddition between sugar azides and triple bond derivatives of chlorins and bacteriochlorins. Unlike bacteriochlorin cycloimide, chlorin was detected to form a Cu -complex during the click reaction. An approach to the synthesis of metal-free glycosylated chlorins was developed with the use of "protection" by Zn 2+ cation and subsequent demetalation. It is based on the action of alkynyl chlorin e6 derivative Zn -complex, which is resistant to the substitution by copper cation. Bacteriochlorin p cycloimide conjugate with per-acetylated β-D-lactose was obtained and shown to become water-soluble after unblocking of the lactose hydroxy functions. NMR studies allowed for the elucidation of structure, tautomeric form and conformation of the obtained compounds.

Anion complexation by amido derivatives of p-tert-butyl calix[4]arene

2007 ◽  
Vol 60 (1-2) ◽  
pp. 193-196 ◽  
Author(s):  
Abdelwaheb Hamdi ◽  
Rym Abidi ◽  
Jacques Vicens
Keyword(s):  
Tert Butyl ◽  
Anion Complexation ◽  
Derivatives Of

Synthesis of phosphorus derivatives of 2,6-Di-tert-butyl-4-methylphenol

2006 ◽  
Vol 76 (11) ◽  
pp. 1753-1756 ◽  
Author(s):  
A. A. Prishchenko ◽  
M. V. Livantsov ◽  
O. P. Novikova ◽  
L. I. Livantsova ◽  
D. B. Shpakovskii ◽  
...  
Keyword(s):  
Tert Butyl ◽  
Derivatives Of

Thermochemical properties of tert-butyl and cumyl derivatives of peroxide compounds

2013 ◽  
Vol 87 (8) ◽  
pp. 1253-1258
Author(s):  
Yu. P. Pavlovskii ◽  
N. S. Kachurina ◽  
S. I. Gerasimchuk ◽  
Yu. Ya. Van-Chin-Syan
Keyword(s):  
Thermochemical Properties ◽  
Tert Butyl ◽  
Derivatives Of

Bis(ether) derivatives of tetrakis(2-hydroxyphenyl)ethene — Direct synthesis of (E)- and (Z)-bis(2-hydroxyphenyl)-bis(2-methoxyphenyl)ethene via the McMurry olefination reaction

2006 ◽  
Vol 84 (10) ◽  
pp. 1250-1253 ◽  
Author(s):  
Mee-Kyung Chung ◽  
Paul Fancy ◽  
Jeffrey M Stryker
Keyword(s):  
Supramolecular Chemistry ◽  
Direct Synthesis ◽  
Protecting Groups ◽  
Tert Butyl ◽  
Orthogonal Protection ◽  
Protection Strategies ◽  
Titanium Trichloride ◽  
Sterically Hindered ◽  
Derivatives Of

The direct synthesis of sterically hindered, partially etherified derivatives of tetrakis(2-hydroxyphenyl)ethene is reported by using the McMurry reductive olefination reaction on a range of differentially substituted 2,2′-dialkoxy benzophenone substrates. Three orthogonal protection strategies are demonstrated, incorporating β-silylethyl, 3-butenyl, and tert-butyl protecting groups, respectively, into the starting benzophenones. The latter proved most efficient, with both the McMurry coupling and deprotection steps occurring concomitantly under the McMurry conditions to directly yield the desired bis(2-hydroxyphenyl)-bis(2-methoxyphenyl)ethene as a 1:1 mixture of E- and Z-diastereoisomers.Key words: preorganized polyaryloxide ligands, McMurry olefination, titanium trichloride, supramolecular chemistry, tetrakis(2-hydroxyphenyl)ethene, 2,2′-disubstituted benzophenone.

scholarly journals Synthesis of New Antibiotics Derivatives by the Photocatalytic Method: A Screening Research

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1102
Author(s):  
Wojciech Baran ◽  
Ewa Masternak ◽  
Dominika Sapińska ◽  
Andrzej Sobczak ◽  
Ewa Adamek
Keyword(s):  
Quantum Yield ◽  
Biologically Active ◽  
Quantum Yields ◽  
Photocatalytic Process ◽  
Experimental Conditions ◽  
New Antibiotics ◽  
Photocatalytic Reactions ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Uva Radiation

The aim of our study was to assess the possibility of using the photocatalytic process conducted in the presence of TiO2 to obtain new stable derivatives of antibacterial drugs. The possibility of introducing hydroxyl, chlorine, or bromide groups into antibiotics molecules was investigated. The experiments were conducted in aqueous solutions in the presence of TiO2-P25 as a photocatalyst, Cl− and Br- ions, and antibiotics belonging to eight different chemical classes. All experiments were initiated by UVa radiation. The kinetics of photocatalytic reactions and their quantum yield were determined, and the stable products were identified. All of the antibiotics used in the experiments underwent a photocatalytic transformation, and the quantum yields were in the range from 0.63 to 22.3%. The presence of Br- or FeCl3 significantly increased the efficiency of the photocatalytic process performed in the presence of TiO2, although Br- ion also acted as an inhibitor. Potentially biologically active chlorine derivatives from Trimethoprim, Metronidazole, Chloramphenicol, and bromine derivatives from Trimethoprim, Amoxicillin were obtained under experimental conditions. The potentially inactive halogen derivatives of Sulfamethoxazole and hydroxyl derivatives described in the literature were also identified.

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