Search results for "furan"

(−)-(4R,5R)-4,5-Bis[hydroxy(diphenyl)methyl]-2,2-dimethyl-1,3-dioxolane

2008

[93379-48-7] C31H30O4 (MW 466.57) InChI = 1S/C31H30O4/c1-29(2)34-27(30(32,23-15-7-3-8-16-23)24-17-9-4-10-18-24)28(35-29)31(33,25-19-11-5-12-20-25)26-21-13-6-14-22-26/h3-22,27-28,32-33H,1-2H3/t27-,28-/m1/s1 InChIKey = OWVIRVJQDVCGQX-VSGBNLITSA-N (chiral shift reagent; chiral host in inclusion compounds; chiral reagent; chiral ligand for asymmetric catalysis) Alternate Name: TADDOL. Physical Data: mp: 190–192 °C1a; 195–196.5  °C1b; 192–193 °C;1c,e 193.5–195 °C;1d [α]RTd=−68.5 °(c = 1, CH3Cl);1a [α]d = −60.6 °(c = 1, CH3Cl);1b [α]20d = −67 ° (c = 1, CH3Cl);1c [α]20d = −65.1° (c = 1, CH3Cl);1d [α]20d = −64.6°(c = 1, CH3Cl)1e Solubility: soluble in toluene, cyclohexane, dichloromethane and tetra…

Micellar fluorescence enhancement of carbamate pesticides

1990

Abstract Different studies have been carried out on the interaction of carbamate pesticides, such as carbofuran and carbaryl, with nonionic and anionic surfactants. Micellar fluorescence enhancements (MEF) of 15–20 for carbofuran in the presence of fatty alcohol ethylene oxide condensates, and of 3.7–8.6 in the presence of anionic surfactants at neutral pH have been obtained. Carbaryl does not interact with surfactants, but when it is hydrolysed to 1-naphthol, MEF values of the order of 2 are obtained in the presence of nonylphenol ethylene oxide condensates. The experimental parameters have been optimized in order to obtain maximum fluorescence. The mechanisms involved in the fluorescence …

Dehydrotriphenylene zum Aufbau gewinkelter molekularer Bandstrukturen

1998

Dehydrotriphenylenes for the Generation of Bent Molecular Ribbons The synthetic sequences 1 11 and 17 23a lead to highly reactive mono- and bisdienophiles whose cycloaddition processes with in situ generated isobenzofuran 13 were studied: 11 + 13 15 and 23a + 2×13 24a.

ChemInform Abstract: Iodocyclization of o-Alkynylbenzamides Revisited: Formation of Isobenzofuran-1(3H)-imines and 1H-Isochromen-1-imines Instead of …

2013

Remarkably, isobenzofuran and benzopyran derivatives are obtained by the title reaction and not as described in earlier publications five- or six-membered lactams.

ChemInform Abstract: Synthesis of Pyrido[2,1-a]isoquinolin-4-ones and Oxazino[2,3-a]isoquinolin-4-ones: New Inhibitors of Mitochondrial Respiratory C…

2014

Benzo[a]quinolizine is an important heterocyclic framework that can be found in numerous bioactive compounds. The general scheme for the synthesis of these compounds was based on the preparation of the appropriate dihydroisoquinolines by Bischler-Napieralski cyclization with good yields, followed by the Pemberton method to form the oxazinones or pyridones derivatives via acyl-ketene imine cyclocondensation. All the synthesized compounds were assayed in vitro for their ability to inhibit mitochondrial respiratory chain. Most of the tested compounds were able to inhibit the integrated electron transfer chain, measured as NADH oxidation, which includes complexes I, III and IV, in the low micro…

Toward an understanding of the acceleration of Diels-Alder reactions by a pseudo-intramolecular process achieved by molecular recognition. A DFT stud…

2007

The pseudo-intramolecular Diels−Alder (DA) reaction between a 2-substituted furan (1) and a N-maleimide derivative (2) has been analyzed using DFT methods. Formation of two hydrogen bonds between the appendages on furan and maleimide derivatives favors thermodynamically the formation of a molecular complex (MC1) through an efficient molecular recognition process. The large enthalpy stabilization associated with the molecular recognition overcomes the unfavorable activation entropy associated with the bimolecular process. As a consequence, the subsequent DA reaction is clearly accelerated through a pseudo-intramolecular process.

1977

The reaction of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 3,6-dioxaoctane-1,8-diol (triethylene glycol), poly(ethylene oxide)s with Mn = 300,1000 and 3000, or with poly(propylene oxide)s with Mn = 425 and 2000 in excess with AIBN leads to the corresponding bis(hydroxyalkyl) 2,2′-azodiisobutyrates (1a–i). These initiators are suited to synthesize telechelics. With equimolar amounts of AIBN and 3-oxapentane-1,5-diol (diethylene glycol), poly(ethylene oxide)s with Mn = 300, 1000 and 12000, poly(propylene oxide) with Mn = 425, or with poly(tetrahydrofuran) with Mn = 1000 and 2000 polymeric azoinitiators of structure 2 are formed. Blockcopolymers may be synthesized by means of these polym…

Anorganische verbindungen als lösungsmittel für polymere und monomere. Polymerisationen in phosphoroxychlorid und thionylchlorid

1966

Die Loslichkeit verschiedener Monomerer, Polymerer und Polymerisationskatalasatoren in anorganischen Verbindungen wurde untersucht. Chloride und Oxychloride des Phosphors und Schwefels zeigten gute Losungseigenschaften. Thionylchlorid und Phosphoroxychlorid wurden als Losungsmittel bei der kationischen Polymerisation von Styrol, Isobutylvinylather, 3,3-Bis-(chlormethyl)-oxetan, Tetrahydrofuran und Epichlorhydrin eingeaetzt. Als geeignete Katalysatoren erwiesen sich hierbei Aluminiumchlorid und Eisentrichlorid. In Phosphoroxychlorid konnten Acrylnitril und Vinylchlorid radikalisch polymerisiert werden. The solubility of a series of monomers, polymers, and initiators in inorganic compounds wa…

Concerning the reaction mechanism of the anionic polymerization of styrene in tetrahydrofuran

1969

Density Functional Theory Study of the Cycloaddition Reaction of Furan Derivatives with Masked o-Benzoquinones. Does the Furan Act as a Dienophile in…

2002

The molecular mechanism for the cycloaddition reaction between 2-methylfuran and a masked o-benzoquinone has been characterized using quantum mechanical calculations at the B3LYP/6-31G theory level. An analysis of the results on the reaction pathway shows that the reaction takes place along a polar stepwise mechanism. The first and rate-determining step corresponds to the nucleophilic attack of the furan ring on the doubly conjugated position of the 2,4-dienone system present at the masked o-benzoquinone to give a zwitterionic intermediate. Closure of this intermediate affords the formally [2 + 4] cycloadduct. For the second step two reactive channels have been characterized corresponding t…