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Intramolecular Reaction (intramolecular + reaction)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

ChemInform Abstract: PtII -Catalyzed Intramolecular Reaction of Furans with Alkynes.

CHEMINFORM, Issue 20 2002
Belen Martin-Matute
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: Rearrangement of Ammonium Ylides Produced by Intramolecular Reaction of Catalytically Generated Metal Carbenoids.

CHEMINFORM, Issue 15 2002
Part 2.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

A Gold(I)-Catalyzed Intramolecular Reaction of Propargylic/Homopropargylic Alcohols with Oxirane

CHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2008
Lun-Zhi Dai
Abstract The gold(I)-catalyzed cycloisomerization of epoxy alkynes in the presence of a nucleophile is an efficient protocol to provide ketal skeletons with high stereoselectivity. An intramolecular reaction of propargylic/homopropargylic alcohols with oxirane to produce ketal/spiroketals in moderate yields under mild conditions has been reported. Moreover, the mechanism of this kind of reaction has been discussed on the basis of a series of control and 18O tracer experiments. [source]

Intramolecular Reactions of Hydroperoxides and Oxetanes: Stereoselective Synthesis of 1,2-Dioxolanes and 1,2-Dioxanes.

CHEMINFORM, Issue 5 2006
Peng Dai
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

ChemInform Abstract: Intramolecular Reactions of Benzylic Azides with Ketones: Competition Between Schmidt and Mannich Pathways.

CHEMINFORM, Issue 27 2001
Aaron Wrobleski
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Intramolecular Reactions in Pseudo-Geminally Substituted [2.2]Paracyclophanes,

CHEMISTRY - A EUROPEAN JOURNAL, Issue 14 2007
Lidija Bondarenko Dr.
Abstract A selection of pseudo-geminally substituted [2.2]paracyclophanes, the alkynes 6, 7, 10, 11,a, and 11,b and the alkenes 8 and 9 were prepared for the study of intraannular reactions between functional groups in direct juxtaposition. Whereas 9 and 10 provide the corresponding cyclobutane and cyclobutene derivatives on irradiation (12 and 13, respectively), the bis-alkynes 7 and 11,b do not lead to a cyclobutadiene intermediate. In the latter case the "half-closed" butadiene derivative 17 was isolated. A Paterno,Büchi reaction took place on irradiation of 8 and 6, although the oxetene intermediate 21 produced in the second example did not survive the reaction conditions (ring-opening to 22). Bromine addition to 9, 10, and 7 occurred with high stereoselectivity (formation of the dibromides 27, 30, and 33, respectively), and is rationalized by postulating the formation of the cationic intermediates 26, 29, and 32, respectively. To study the interaction of a carbocation with a facing triple bond, the alcohol 34 was prepared from 6. On acid treatment ring closure to the triply-bridged phane 38 took place, accompanied by the hydration of the triple bond to the ketoalcohol 37. In an interesting intraannular [2+3]cycloaddition reaction the bis-acetylene 11,a, on treatment with n -butyl lithium, provided the cyclopentadiene derivative 42. That the two triple bonds of a pseudo-geminal diacetylene can engage in a cyclization reaction leading to the cyclopentadienone complex 44 was also shown by treating 11,b with iron pentacarbonyl. [source]

Re-evaluation of intramolecular long-range electron transfer between tyrosine and tryptophan in lysozymes

FEBS JOURNAL, Issue 17 2003
Evidence for the participation of other residues
One-electron oxidation of six different c-type lysozymes from hen egg white, turkey egg white, human milk, horse milk, camel stomach and tortoise was studied by gamma- and pulse-radiolysis. In the first step, one tryptophan side chain is oxidized to indolyl free radical, which is produced quantitatively. As shown already, the indolyl radical subsequently oxidizes a tyrosine side chain to the phenoxy radical in an intramolecular reaction. However this reaction is not total and its stoichiometry depends on the protein. Rate constants also vary between proteins, from 120·s,1 to 1000·s,1 at pH 7.0 and room temperature [extremes are hen and turkey egg white (120·s,1) and human milk (1000·s,1)]. In hen and turkey egg white lysozymes we show that another reactive site is the Asn103,Gly104 peptidic bond, which gets broken radiolytically. Tryptic digestion followed by HPLC separation and identification of the peptides was performed for nonirradiated and irradiated hen lysozyme. Fluorescence spectra of the peptides indicate that Trp108 and/or 111 remain oxidized and that Tyr20 and 53 give bityrosine. Tyr23 appears not to be involved in the process. Thus new features of long-range intramolecular electron transfer in proteins appear: it is only partial and other groups are involved which are silent in pulse radiolysis. [source]

A Gold(I)-Catalyzed Intramolecular Reaction of Propargylic/Homopropargylic Alcohols with Oxirane

CHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2008
Lun-Zhi Dai
Abstract The gold(I)-catalyzed cycloisomerization of epoxy alkynes in the presence of a nucleophile is an efficient protocol to provide ketal skeletons with high stereoselectivity. An intramolecular reaction of propargylic/homopropargylic alcohols with oxirane to produce ketal/spiroketals in moderate yields under mild conditions has been reported. Moreover, the mechanism of this kind of reaction has been discussed on the basis of a series of control and 18O tracer experiments. [source]

Structure elucidation of thermal degradation products of amlodipine

MAGNETIC RESONANCE IN CHEMISTRY, Issue 8 2007
A. Siva Lakshmi Devi
Abstract Thermal degradation of amlodipine base causes intramolecular reactions affording three cyclic products, referred to as AMLDEG-I, AMLDEG-II, and AMLDEG-III, respectively. AMLDEG-I is a cyclized product formed by intramolecular elimination of ammonia from amlodipine. AMLDEG-II is a positional isomer of AMLDEG-I. AMLDEG-III is also intramolecular cyclisation product. The three degradation products were isolated by column chromatography and characterized by FT-IR and 1H and 13C NMR spectroscopy data. The AMLDEG-III was crystallized and its structure was solved by single crystal X-ray diffraction (SXRD). Copyright © 2007 John Wiley & Sons, Ltd. [source]