Formation Of Ring-opening Products Research Articles

Iron-Catalyzed Synthesis of Peroxylpyrrolo[2,1-a]isoquinolines through Oxidative Dearomatization.

A mild late-stage modification of pyrrolo[2,1-a]isoquinolines was established through iron-catalyzed oxidative dearomatization and peroxidation. Peroxylated pyrroloisoquinolines have been prepared readily with hydroperoxide in low to good yields (up to 72%) at room temperature. Interestingly, the treatment of fully aromatized pyrrolo[1,2-a]quinolines under the current reaction system resulted in the formation of ring-opening products.

Nucleophilic ring-opening of iron(III)-hydroxy-isoporphyrin.

The reactions of iron(III) hydroxyisoporphyrin, chloro[5-(hydroxy)-5,10,15,20-tetrakis(4-methyl)-5,21H-porphinato]iron(III) [Fe(4-Me-HTPI)(Cl)](-), 1 and chloro[5-(hydroxy)-5,10,15,20-tetrakis(4-methoxy-5,21H-porphinato]iron(III) [Fe(4-OMe-HTPI)(Cl)](-), 2 with different O(-), N(-) and S(-) nucleophiles have been performed to understand the reactivity of iron isoporphyrins with nucleophiles. The treatment of iron(III) hydroxy isoporphyrin with alcohols is found to form ring opened 19-benzoyl-1-alkoxy-bilin iron complexes. When alkyl amines were used the formation of ring opened 19-benzoyl-1-alkylamine-bilin iron complexes was observed, but heterocyclic N-nucleophiles such as pyridine and imidazole form benzoyl bilinone iron complexes. No role of oxygen was found in these nucleophilic ring opening reactions. The treatment of a S-nucleophile such as PhSH is found to reduce iron(III)-hydroxyisoporphyrin in the parent iron(III) porphyrin compound. The ring opening products were characterized using electronic and ESI-mass spectroscopy. The mechanism for the formation of ring opening products is based on the formation of a tetrahedral intermediate at the carbon atom near the saturated meso carbon atom similar to the hydrolytic pathway of verdoheme conversion to biliverdin.

ChemInform Abstract: Reaction of 5‐Alkoxy‐3,4‐dihalo‐2(5H)‐furanones with Secondary Amines: Expected versus Unanticipated Products and Their Preliminary Bioactivity Investigations.

AbstractThe unusual behavior of 5‐methoxy‐3,4‐dihalo‐2(5H)furanones (I) in the reaction with diisopropylamine is studied and a possible mechanism for the formation of ring opening products (V) is proposed.

High temperature bromination. Part 22: Bromination of 1a,2,7,7a-tetrahydro-1 H-cyclopropa[ b]naphthalene

The high-temperature bromination of 1a,2,7,7a-tetrahydro-1 H-cyclopropa[ b]naphthalene and its carboethoxy derivative was studied. Reaction of the title compound with 1 mol of bromine in refluxing carbon tetrachloride resulted in the formation of ring-opening products. In the case of the carboethoxy derivative, bromination took place both regio- and stereospecifically at the benzylic positions, the cyclopropane ring did not undergo bond cleavage. A mechanism for the formation of the products and their dehydrobromination reactions is discussed.

Reactivity of fluorinated sulfur-containing heterocycles towards nucleophilic and oxidizing reagents

The reaction of 5,5-bis(trifluoromethyl)-6-thia-bicyclo[2.2.1]hept-2-ene, 5,5-bis(trifluoromethyl)-6-thia-bicyclo[2.2.2]oct-2-ene and 2,2-bis(trifluoromethyl)-3,6-dihydro-4,5-dimethyl-2 H-thiopyran with i-C 3H 7MgCl leads to the formation of ring opening products as the result of nucleophilic attack of the Grignard reagent on the sulfur atom. According to DFT calculations the reactivity of the sulphur-containing substrate correlates with the strain energy of the heterocycle. The oxidation of 3-thia-4,4-bis(trifluoromethyl)tricyclo[5.2.1.0 2,5]non-7-ene by hydrogen peroxide in hexafluoro- iso-propanol solvent resulted in formation of the corresponding sulfoxide however, the reaction with m-chloroperoxybenzoic acid produced the product of exhaustive oxidation of sulfur and the double bond. In sharp contrast, the oxidation of 5,5-bis(trifluoromethyl)-6-thia-bicyclo[2.2.1]hept-2-ene and 5,5-bis(trifluoromethyl)-6-thia-bicyclo[2.2.2]oct-2-ene by MCPBA (2d, 25 °C) proceeds with the preservation of the double bond, leading to the selective formation of the corresponding sulfones.

Reactions of Cyclopropenes with Organoaluminum Compounds and Other Organometallic Compounds: Formation of Ring-Opened Products

Reactions of 1-ethylspiro[2.5]oct-1-ene and triethylaluminum furnish a product that results from addition of triethylaluminum to the double bond with opening of the three-membered ring to form an allylic organoaluminum compound and a second product that results from addition of this allylic organoaluminum compound to the cyclopropene double bond. Reactions of spiro[2.5]oct-1-ene with triethylaluminum furnish two products resulting from addition to the cyclopropene double bond, one of triethylaluminum and the other of an allylic organoaluminum compound formed by addition of triethylaluminum to the cyclopropene double bond with opening of the three-membered ring. Reactions of the spiro compounds with triethylboron, triethylgallium, diethylzinc, or diethylcadmium also furnish rearrangement products, but reactions with diethylmagnesium or ethyllithium furnish only addition products.

Theoretical study on three-membered silametallacycles toward MeOH: Mechanisms on formation of ring-opening products

The mechanism on the model reaction of Cp ∗(CO)Fe{κ 2(Si,P)-SiMe 2PH 2}, derived from Cp ∗(CO)Fe{κ 2(Si,P)-SiMe 2PPh 2}, with MeOH has been studied by using density functional theory. Our results of calculations reveal that the reaction is favored both kinetically and thermodynamically. The bonding properties of P and Si atoms in the three-membered ring determine variations of the structural parameters of the species involved in the mechanism.

The role of metal sites during the coupled hydrogenation and ring opening of tetralin on bifunctional Pt(Ir)/USY catalysts

The influence of the metal function in bifunctional Pt/USY catalysts in the combined hydrogenation and ring opening of tetralin has been investigated. The key step in the reaction pathway leading to the formation of the desired ring opening products (ROPs) was the isomerization (ring contraction) of the C6 naphthenic rings of decalins. The presence of Pt in the bifunctional Pt/USY catalyst significantly increased the rate of isomerization and hence the formation of ROP as compared to the monofunctional USY sample. The formation of the high cetane ROP increased with increasing the proximity between the Pt and acid sites and with increasing the Pt loading (i.e. the metal/acid ratio) in the range of 0.25–4wt.%. Ring opening of naphthenes was seen to occur exclusively on the Brönsted acid sites of the zeolite. Incorporation of a hydrogenolysis metal (Ir) to the bifunctional Pt/USY catalyst did not lead to a further increase in the formation of ROP and significantly reduced the sulfur tolerance of Pt. This was ascribed to a higher electron density on the Pt sites induced by Ir in bimetallic Pt–Ir particles, as evidenced by XPS.

ChemInform Abstract: MECHANISM‐BASED INACTIVATION OF CYTOCHROME P‐450 BY HETEROATOM‐SUBSTITUTED CYCLOPROPANES AND FORMATION OF RING‐OPENED PRODUCTS

Chemischer InformationsdienstVolume 16, Issue 6 Preparative Organic Chemistry ChemInform Abstract: MECHANISM-BASED INACTIVATION OF CYTOCHROME P-450 BY HETEROATOM-SUBSTITUTED CYCLOPROPANES AND FORMATION OF RING-OPENED PRODUCTS F. P. GUENGERICH, F. P. GUENGERICHSearch for more papers by this authorR. J. WILLARD, R. J. WILLARDSearch for more papers by this authorJ. P. SHEA, J. P. SHEASearch for more papers by this authorL. E. RICHARDS, L. E. RICHARDSSearch for more papers by this authorT. L. MACDONALD, T. L. MACDONALDSearch for more papers by this author F. P. GUENGERICH, F. P. GUENGERICHSearch for more papers by this authorR. J. WILLARD, R. J. WILLARDSearch for more papers by this authorJ. P. SHEA, J. P. SHEASearch for more papers by this authorL. E. RICHARDS, L. E. RICHARDSSearch for more papers by this authorT. L. MACDONALD, T. L. MACDONALDSearch for more papers by this author First published: February 12, 1985 https://doi.org/10.1002/chin.198506108Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume16, Issue6February 12, 1985 RelatedInformation

Mechanism-based inactivation of cytochrome P-450 by heteroatom-substituted cyclopropanes and formation of ring-opened products

Mechanism-based inactivation of cytochrome P-450 by heteroatom-substituted cyclopropanes and formation of ring-opened products

Conversions of alkylcyclopentenes and alkylcyclopentane on erbium oxide : Kh. M. Minachev and G. A. Loginov, Neftekhimiya 3, No. 2, 181–187, 1963

The reaction of 5,5-bis(trifluoromethyl)-6-thia-bicyclo[2.2.1]hept-2-ene, 5,5-bis(trifluoromethyl)-6-thia-bicyclo[2.2.2]oct-2-ene and 2,2-bis(trifluoromethyl)-3,6-dihydro-4,5-dimethyl-2H-thiopyran with i-C3H7MgCl leads to the formation of ring opening products as the result of nucleophilic attack of the Grignard reagent on the sulfur atom. According to DFT calculations the reactivity of the sulphur-containing substrate correlates with the strain energy of the heterocycle. The oxidation of 3-thia-4,4-bis(trifluoromethyl)tricyclo[5.2.1.02,5]non-7-ene by hydrogen peroxide in hexafluoro-iso-propanol solvent resulted in formation of the corresponding sulfoxide however, the reaction with m-chloroperoxybenzoic acid produced the product of exhaustive oxidation of sulfur and the double bond. In sharp contrast, the oxidation of 5,5-bis(trifluoromethyl)-6-thia-bicyclo[2.2.1]hept-2-ene and 5,5-bis(trifluoromethyl)-6-thia-bicyclo[2.2.2]oct-2-ene by MCPBA (2d, 25 °C) proceeds with the preservation of the double bond, leading to the selective formation of the corresponding sulfones.