نتایج جستجو برای: cycloaddition reaction
تعداد نتایج: 415203 فیلتر نتایج به سال:
1- in a search directed to the reaction of compound)23(the cycloaddition reaction of 1,3- diphenylisobenzofurane)14(with p-benzoquinone)19(,followed by addition of cyclopentadiene was carried out.the specific spacial stracture of its ir,nmr,mass spectra. 2- in another attempt the kinetic stability and behavior of compounds)20(and)23(was studied.the main subject of this study was the highly reve...
Cycloaddition reaction between C30 and hula-I, 3-diene was studied within the Snimework of AM I (RHF)level. The reaction involving the double bond between two hexagons and a hexagon and a pentagon, as wellas the cycloaddition products followed by disrotatory ogs s electrocyclic ring openings were considered.Thermodynamics parameters and stability energy and innsation state are evaluated in thre...
in this paper the synthesis of some new polyaromatic monocyclic β-lactams has been reported. these cycloadducts have been synthesized by the [2+2] ketene-imine cycloaddition reaction known as the staudinger reaction. all of the products have been fully characterized by ir, 1h-nmr, 13c-nmr, mass spectroscopy and elemental analyses. the x-ray crystal structure of a cis β-lactam has been also pres...
microwave-assisted three component cyclocondensation reactions of aldehydes, amides and dienophiles in the presence of acetic anhydride and para-toluenesulfonic acid as a catalyst to afford the highly substituted cyclohexene derivatives, in relatively good yields after several minutes are reported.
The cycloaddition reaction of diphenylketene and cycloheptatriene is studied. The reaction proceeds via a highly asynchronous reaction path to the zwitterionic 6 as intermediate. Subsequent CC- bond formation yields 8, 8 diphenylbicyclo [4. 2. I] nona-2, 4-dien-7-one (1) and 7,7-diphenylbicycol [3.2.2] nona-2, 8-dien-ri-one (2) in a 1:1 ratio as formal [6+2] and [4+2] cycloaddition products
thionyl chloride (or oxalyl chloride) has been used as an efficient and cheap acid activator for one-pot synthesis of β-lactams in good to excellent yields by reaction between imines and acids in the presence of triethylamine at room temperature.
cycloaddition reaction between c30 and hula-i, 3-diene was studied within the snimework of am i (rhf)level. the reaction involving the double bond between two hexagons and a hexagon and a pentagon, as wellas the cycloaddition products followed by disrotatory ogs s electrocyclic ring openings were considered.thermodynamics parameters and stability energy and innsation state are evaluated in thre...
Fifteen novel β-lactams bearing the N-ethyl tert-butyl carbamate group 5a-o and fifteen N-(2-aminoethyl) β-lactams 6a-o were synthesized by the ketene-imine [2+2] cycloaddition reaction (Staudinger ). The cycloaddition reaction was found to be totally diastereoselective leading exclusively to the formation of the cis-β-lactam derivatives. These newly synthesized β-lactams were evaluated for the...
We first found experimentally a cycloaddition reaction of a molecule on a symmetry Si pair, 1,3-butadiene on the Si adatom pair of Si(111)7x7, while up to now only asymmetric Si pairs were reported to be involved in cycloaddition reactions on Si surfaces. As the symmetry of a Si pair is expected to influence significantly a cycloaddition product and a reaction pathway, the [4+2]-like cycloaddit...
The cycloaddition reaction of diphenylnitrilimine on the 1,5-benzodiazepines has been studied. New molecules of triazolobenzodiazepines type have been isolated and characterized.
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