Fused Ring Compounds Research Articles

Effects of intermolecular interactions on photoluminescence efficiency of crystalline thienylene-S,S-dioxide molecular semiconductors

The effects of intermolecular interactions on the photoluminescence (PL) quantum efficiency of differently substituted thienylene-S,S-dioxide derivatives in the crystalline phase are investigated. The exciton resonance interactions and the transfer integrals are evaluated using a quantum chemistry approach by considering the supramolecular structures obtained from X-ray data. Two classes of thienylene-S,S-dioxides are investigated: (1) rigid, fused ring compounds, for which the PL quantum efficiency can be well correlated with the rate of formation of non-radiatively decaying charge-transfer pairs upon photoexcitation; (2) flexible oligothiophenes for which the high PL quantum efficiency in the solid-state is assigned to a decrease of intramolecular internal conversion process, as confirmed by time-resolved PL measurements in solvents of different viscosity.

The Synthesis of 2-Cyanomethylbenzaldehyde—Useful Substrate for Construction of Fused Ring Compounds

The title compound 4 has been prepared by four-step synthesis starting from methylaminoacetonitrile hydrochloride (5) and α-cyanobenzyl benzenesulfonate (6), in good yield.

Synthesis of Some New Pyridothienopyrimidines and Related [1,2,4]Triazolopyridothienopyrimidines.

4-Chloro-9-phenyl-7-(2-thienyl)pyrido[3',2':4,5]thieno[3,2-d]pyrimidine (5) and 3-amino-3,4-dihydro-4-imino-9-phenyl-7-(2-thienyl)pyrido[3',2':4,5]thieno[3,2-d]pyrimidine (19) were prepared and employed as precursors for synthesizing the fused-ring compounds of the title.

Alkyne and Ketone Induced Novel Cleavage of a C—C Bond and a C—Si Bond in Zirconacyclobutene—Silacyclobutene Fused Ring Compounds.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Mechanistic insights into oxidosqualene cyclizations through homology modeling.

2,3-Oxidosqualene cyclases (OSC) are key enzymes in sterol biosynthesis. They catalyze the stereoselective cyclization and skeletal rearrangement of (3S)-2,3-oxidosqualene to lanosterol in mammals and fungi and to cycloartenol in algae and higher plants. Sequence information and proposed mechanism of 2,3-oxidosqualene cyclases are closely related to those of squalene-hopene cyclases (SHC), which represent functional analogs of OSCs in bacteria. SHCs catalyze the cationic cyclization cascade converting the linear triterpene squalene to fused ring compounds called hopanoids. High stereoselectivity and precision of the skeletal rearrangements has aroused the interest of researchers for nearly half a century, and valuable data on studying mechanistic details in the complex enzyme-catalyzed cyclization cascade has been collected. Today, interest in cyclases is still unbroken, because OSCs became targets for the development of antifungal and hypocholesterolemic drugs. However, due to the large size and membrane-bound nature of OSCs, three-dimensional structural information is still not available, thus preventing a complete understanding of the atomic details of the catalytic mechanism. In this work, we discuss results gained from homology modeling of human OSC based on structural information of SHC from Alicyclobacillus acidocaldarius and propose a structural model of human OSC. The model is in accordance with previously performed experimental studies with mechanism-based suicide inhibitors and mutagenesis experiments with altered activity and product specificity. Structural insight should strongly stimulate structure-based design of antifungal or cholesterol-lowering drugs.

Alkyne and ketone induced novel cleavage of a CC bond and a CSi bond in zirconacyclobutene–silacyclobutene fused ring compounds

Novel cleavage patterns of CC bonds and CSi bonds were achieved via alkyne- or ketone-induced reactions of zirconacyclobutene–silacyclobutene fused ring compounds; thermodynamically favored six-membered zirconacyclohexadiene derivatives were formed in excellent yields from the four-membered zirconacyclobutenes via this unprecedented alkyne-induced CC bond and CSi bond cleavage process.

Efficient Access to Fused Ring Compounds via Dearomatization/Ring-Closing Metathesis

The complex (p-methoxyphenyl oxazoline)Cr(CO)3 is converted in two steps into a cis-fused [6,8] ring system containing a cycohexadiene ring unit, a cyclooctenone ring and a quaternary carbon at the ring junction. The key steps involve a diastereoselective addition of three C-substituents across an arene double bond, followed by an allylation and ring closing metathesis step. cis-Fused [6,7], [6,6], and [6,5] ring systems are also accessible via this methodology.

Synthesis of Some New Pyridothienopyrimidines and Related [1,2,4]Triazolopyridothienopyrimidines

4-Chloro-9-phenyl-7-(2-thienyl)pyrido[3′,2′:4,5]thieno[3,2- d]pyrimidine (5) and 3-amino-3,4-dihydro-4-imino-9-phenyl-7-(2-thienyl)pyrido[3′,2′:4,5]thieno[3,2- d]pyrimidine (19) were prepared and employed as precursors for synthesizing the fused-ring compounds of the title.

Synthesis of Phthalides and 3,4‐Dihydroisocoumarins Using the Palladium‐Catalyzed Intramolecular Benzannulation Strategy.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of phthalides and 3,4-dihydroisocoumarins using the palladium-catalyzed intramolecular benzannulation strategy.

A novel method for the synthesis of phthalides and 3,4-dihydroisocoumarins via the palladium-catalyzed intramolecular benzannulation of bis-enyne and enyne-diyne systems is described. Various kinds of substituted phthalides 9 and 17 and 3,4-dihydroisocoumarins 19 were synthesized from 8, 16, and 18, respectively, in moderate to excellent yields. The benzannulation reaction proceeded chemoselectively to give the corresponding fused ring compounds A without the formation of the regioisomeric products B (eq 6). Furthermore, this methodology was applied to the synthesis of biologically active 3-n-butylphthalide 23.

Second Supplements to the Second Edition of Rodd's Chemistry of Carbon Compounds. Volume IV: Heterocyclic Compounds. Part G. Six-membered Heterocyclic Compounds with (a) a Single Nitrogen Atom in the Ring (cont'd.); Polycyclic Fused Ring Compounds, (b) an Atom of Phosphorus, Arsenic, Antimony or Bismuth. Alkaloids with a Six-Membered Heterocyclic Ring (Chapters 34−35 in this volume). Part H: Six-membered Fused-Ring Heterocyclic

Second Supplements to the Second Edition of <i>Rodd's Chemistry of Carbon Compounds</i>. Volume IV: Heterocyclic Compounds. Part G. Six-membered Heterocyclic Compounds with (a) a Single Nitrogen Atom in the Ring (cont'd.); Polycyclic Fused Ring Compounds, (b) an Atom of Phosphorus, Arsenic, Antimony or Bismuth. Alkaloids with a Six-Membered Heterocyclic Ring (Chapters 34−35 in this volume). Part H: Six-membered Fused-Ring Heterocyclic

4-Methylbicyclo[6.3.0]undecane-2,6-dione, (I), 7-bromo-4-methylbicyclo[6.3.0]undecane-2,6-dione, (II), 7-acetonyl-4-methylbicyclo[6.3.0]undecane-2,6-dione, (III), and 8-methyltricyclo[9.3.0.02,6]tetradec-5-ene-4,10-dione, (IV)

The crystal structures of the four title compounds, C 12 H 18 O 2 , (I), C 12 H 17 BrO 2 , (II), C 15 H 22 O 3 , (III), and C 15 H 20 O 2 , (IV), which were obtained during studies of the preparation of C 5 -C 8 -C 5 fused-ring compounds, have been determined. The eight-membered rings in all four compounds take the boat-chair form.

Second Supplements to the 2nd Edition of Rodd's Chemistry of Carbon Compounds. Volume IV. Heterocyclic compounds. Part G. Six-Membered Heterocyclic Compounds with (a) Single Nitrogen Atom in the Ring (cont'd): Polycyclic Fused Ring Compounds, (b) an Atom of Phosphorus, Arsenic, Antimony or Bismuth. Alkaloids with a Six-Membered Heterocyclic Ring (Chapters 34 and 35 in this Volume). Part H. Six-Membered Fused-Ring

Second Supplements to the 2nd Edition of Rodd's Chemistry of Carbon Compounds. Volume IV. Heterocyclic compounds. Part G. Six-Membered Heterocyclic Compounds with (a) Single Nitrogen Atom in the Ring (cont'd): Polycyclic Fused Ring Compounds, (b) an Atom of Phosphorus, Arsenic, Antimony or Bismuth. Alkaloids with a Six-Membered Heterocyclic Ring (Chapters 34 and 35 in this Volume). Part H. Six-Membered Fused-Ring

Second Supplements to the 2nd Edition of Rodd's Chemistry of Carbon Compounds. Volume IV. Heterocyclic compounds. Part F. Six-Membered Heterocyclic Compounds with a Single Hetero-Atom in the Ring: Pyridine, Quinoline, Isoquinoline and Their Derivatives. Part G. Six-Membered Heterocyclic Compounds with (a) Single Nitrogen Atom in the Ring (cont'd): Polycyclic Fused Ring Compounds, (b) an Atom of Phosphorous, Arsenic, Antimony or

Second Supplements to the 2nd Edition of Rodd's Chemistry of Carbon Compounds. Volume IV. Heterocyclic compounds. Part F. Six-Membered Heterocyclic Compounds with a Single Hetero-Atom in the Ring: Pyridine, Quinoline, Isoquinoline and Their Derivatives. Part G. Six-Membered Heterocyclic Compounds with (a) Single Nitrogen Atom in the Ring (cont'd): Polycyclic Fused Ring Compounds, (b) an Atom of Phosphorous, Arsenic, Antimony or

High-Temperature Slurry Reactors for Synthesis Gas Reactions. 1. Liquid Thermal Stability

The use of slurry reactors has been limited to reactions that take place at temperatures below about 573 K because many of the liquids that have been used to suspend the solid catalyst are not stable above this temperature. The thermal stability of a number of organic liquids was evaluated at temperatures between 648 and 698 K and at H2 partial pressures of about 7 MPa. Certain saturated and partially-saturated, fused-ring compounds with no alkyl groups or bridges are quite stable at these conditions. Of the compounds tested, tetrahydronaphthalene, tetrahydroquinoline, and decahydronaphthalene were the most stable. Analysis of the liquids at the end of the thermal stability evaluation supports some speculation concerning possible degradation reactions.

3-Acetonylbicyclo[6.3.0]undecane-2,6-dione, (I), 7-Acetonyl-4,4-dimethylbicyclo[6.3.0]undecane-2,6-dione, (II), 7,12-Dihydroxy-12-methyltetracyclo[8.2.1.01,5.07,11]tridecan-13-one Monohydrate, (III), and 8,8-Dimethyltricyclo[9.3.0.02,6]tetradec-5-ene-4,10-dione, (IV)

The crystal structures of the four title compounds, C14H20O3, (I), C16H24O3, (II), C14H20O3.H2O, (III), and C16H22O2, (IV), which were obtained during studies of the preparation of C5–C8–C5 fused-ring compounds, have been determined by X-ray diffraction.

High Mobility and Liquid Phase Processable Organic Semiconductors

AbstractNew thiophene oligomers and fused ring compounds have been designed and synthesized with the aim of maximizing semiconductor mobility in thin film transistors (TFTs) while allowing for liquid phase processability. Thiophene hexamers with alkyl side chains of various lengths, some with an ether oxygen embedded in the chain, were synthesized, as were derivatives of the novel heterocycle anthradithiophene. Mobilities of the vaporphase-deposited films ranged from 0.01 cm2/Vs for the hexamers to 0.15 cm2/Vs for dihexylanthradithiophene. The latter is the highest mobility yet reported for a polycrystalline film. Cast films of some of these compounds from solution gave mobilities within factors of 2–10 of the corresponding values from gas-phase-deposited films.

Diquinane Synthesis Based on Anionic [1, 3] Sigmatropic Rearrangements of an Oxy-Cope System Incorporated in the Bicyclo[3.2.1]oct-6-ene Framework

Abstract Treatment of 2-vinylbicyclo[3.2.1]oct-6-en-2-ols with KH in toluene gave mainly [5-5] fused-ring compounds through a [1,3] sigmatropic shift.

High-performance liquid chromatography with non-aqueous solvents Relative elution strength on a polystyrene—divinylbenzene column

A polymeric resin-based stationary phase was used to study the retention of alkylphenols, alkylbenzenes, substituted benzenes and fused-ring compounds with different eluents. Various 100% organic solvents were used as eluents in order to observe the relative ability to solvents to elute compounds of given chemical structure. Plots of log k′ vs. number of carbons in a chain attached to the aromatic ring showed linear correlations with slopes that are dependent on solvent type and solute functionality. Of the solvents studied, acetonitrile exhibited the highest solvating ability for the benzene ring and for several functional groups. Ethanol was shown to have the strongest eluting power for the methylene group. The relative ability of several solvents to elute polynuclear aromatic hydrocarbons in solid-phase extraction was determined. The functional group contribution (τ) was calculated for selected compounds and acceptable agreement was found in the correlation between experimental and predicted values for solute capacity factor.

2,4-Diaminopyrido[3,2-d]pyrimidine inhibitors of dihydrofolate reductase from Pneumocystis carinii and Toxoplasma gondii.

Six previously unknown 2,4-diamino-6-(anilinomethyl)- and 2,4-diamino-6-[(N-methylanilino)-methyl]pyrido[3,2-d]pyrimidines (5-10) were synthesized from 2,4-diamino-6-(bromomethyl)-pyrido[3,2-d]pyrimidine hydrobromide (11.HBr) by treatment with the appropriate aniline or N-methylaniline in dimethylformamide at room temperature, with or without NaHCO3 present. Compounds 5-10 were tested as inhibitors of dihydrofolate reductase from Pneumocystis carinii, Toxoplasma gondii, and rat liver as a part of a larger effort directed toward the discovery of lipophilic nonclassical antifolates combining high enzyme selectivity and high potency. Of the six analogues tested, the most potent and selective against T. gondii DHFR was 2,4-diamino-6-[(3',4',5'-trimethoxy-N-methylanilono)methyl]pyrido[ 3,2-d d pyrimidine (7), which had an IC50 of 0.0047 microM against this enzyme as compared with 0.026 microM against the rat liver enzyme. The potency of 7 against T. gondii DHFR was similar to that of trimetrexate (TMQ, 1) and piritrexim (PTX, 2) but was > 500-fold greater than that of trimethoprim (TMP, 3). However, while 7 was more selective than either TMQ (19x) or PTX (63x) against this enzyme, its selectivity in comparison with TMP was 8-fold lower. 2,4-Diamino-6-[3',4',5'-trimethoxyanilino)methyl]pyrido[3,2-d]pyri midin e (6) was 17-fold less active than 7 and was also less selective. 2,4-Diamino-6-[(3',4'-dichloro-N-methylanilino)methyl]pyrido[3, 2-d]pyrimidine (10) had an IC50 of 0.022 microM against P. carinii DHFR and was comparable in potency to TMQ and PTX. The species selectivity of 10 for P. carinii versus rat liver DHFR was greater than that of either TMQ (21-fold) or PTX (31-fold). On the other hand, even though 10 was slightly more active than TMQ against the P. carinii enzyme, its selectivity was 7-fold lower than that of TMP. Thus, the goal of combining high enzyme binding activity, which is characteristic of the fused-ring compounds TMQ and PTX, with high selectivity for T. gondii and P. carinii DHFR versus rat liver DHFR, which is characteristic of the monocyclic compound TMP, remained unmet in this limited series.