Search results for "Halogen"

Halogenated derivatives of boldine with high selectivity for alpha1A-adrenoceptors in rat cerebral cortex.

1999

The selectivity of 3-nitrosoboldine and different halogenated derivatives of boldine (3-bromoboldine, 3,8-dibromoboldine and 3-chloroboldine) for alpha1-adrenoceptor subtypes was studied by examining [3H]-prazosin competition binding in rat cerebral cortex. In the competition experiments [3H]-prazosin binding was inhibited completely by all the compounds tested. The inhibition curves displayed shallow slopes which could be subdivided into high and low affinity components. The relative order of affinity and selectivity for alpha1A-adrenoceptors was 3-bromoboldine = 3,8-dibromoboldine = 3-chloroboldineboldine3-nitrosoboldine. The competition curves for 3-bromoboldine remained shallow and biph…

Inclusion complexes of Cethyl-2-methylresorcinarene and pyridine N-oxides: breaking the C–I⋯−O–N+ halogen bond by host–guest complexation

2016

C ethyl-2-Methylresorcinarene forms host–guest complexes with aromatic N-oxides through multiple intra- and intermolecular hydrogen bonds and C–H⋯π interactions. The host shows conformational flexibility to accommodate 3-methylpyridine N-oxide, while retaining a crown conformation for 2-methyl- and 4-methoxypyridine N-oxides highlighting the substituent effect of the guest. N-Methylmorpholine N-oxide, a 6-membered ring aliphatic N-oxide with a methyl at the N-oxide nitrogen, is bound by the equatorial −N–CH3 group located deep in the cavity. 2-Iodopyridine N-oxide is the only guest that manifests intermolecular N–O⋯I–C halogen bond interactions, which are broken down by the host resulting i…

Drying of sliced tomato ( Lycopersicon esculentum L.) by a novel halogen dryer: Effects of drying temperature on physical properties, drying kinetics…

2020

Designed Synthesis of New ortho-Carborane Derivatives: from Mono- to Polysubstituted Frameworks

2008

The use of nucleophilic and electrophilic processes allow the designed synthesis of several B-iodinated derivatives of o-carborane. Because of the straightforward Pd-catalyzed conversion of B-I to B-C bond with Grignard reagents, such as methylMgBr and biPhenylMgBr, both, symmetrical 3,6-R 2-1,2- closo-C 2B 10H 10 and asymmetrical 3-I-6-Me-1,2- closo-C 2B 10H 10 could be obtained. Not only conventional reactions in solution have been studied but also a highly efficient, clean and fast solvent-free procedure has provided successful results to regioselectively produce B-iodinated o-carborane derivatives by a careful control of the reaction conditions. The high number of nonequivalent leaving …

A Halogen-Bonded Dimeric Resorcinarene Capsule.

2015

Iodine (I2) acts as a bifunctional halogen-bond donor connecting two macrocyclic molecules of the bowl-shaped halogen-bond acceptor, N-cyclohexyl ammonium resorcinarene chloride 1, to form the dimeric capsule [(1,4-dioxane)3@1(2)(I2)2]. The dimeric capsule is constructed solely through halogen bonds and has a single cavity (V=511 Å(3)) large enough to encapsulate three 1,4-dioxane guest molecules.

Synthesis, Characterization, and Properties of Some Copper( II ) Complexes of 2‐Pyridineformamide Thiosemicarbazone (HAm4DH)

2006

Reactions between different copper(II) salts and 2-pyridineformamide thiosemicarbazone (HAm4DH) in neutral ethanolic media led to the formation of complexes with the formulae [Cu(HAm4DH)X2] (X = Cl or Br) (1, 2) and [Cu(HAm4DH)2]X2 (X = NO3 or ClO4) (3, 4). The same reactions carried out in the presence of triethylamine gave rise to new complexes with the general formulae [Cu(Am4DH)X] (X = Cl, Br, AcO, or NO3) (5–8), [Cu(H2O)(Am4DH)](ClO4) (9), and [Cu(Am4DH)2] (10), many of which were isolated with different molecules of crystallization and contain a deprotonated thiosemicarbazone (Am4DH). These complexes were characterized by elemental analysis, and different spectroscopic and magnetic te…

5-Alkenyl-1,2,3-thiadiazole

1986

Es wird die Herstellung der Titelverbindungen 5 durch Bromierung-Dehydrobromierung entsprechender 5-Alkyl-1,2,3-thiadiazole 3, ihre spektroskopische Charakterisierung und ihre Umsetzung mit 4-Phenyl-4H-1,2,4-triazol-3,5-dion (6) zu 7, 8 beschrieben. 5-Alkenyl-1,2,3-thiadiazoles A method of preparation for the title compounds 5, by bromination-dehydrobromination of the corresponding 5-alkyl-1,2,3-thiadiazoles 3, their spectroscopical characterization, and the reaction of 5 with 4-phenyl-4H-1,2,4-triazole-3,5-dione (6) with formation of 7, 8 is described.

Antimony-121 Mössbauer and infrared spectral studies on 1,10-phenanthroline adducts of antimony(III) halides

1983

Abstract The syntheses of the mono-adducts of 1,10-phenanthroline with SbX 3 (X = F, Cl, Br) and PhSbI 2 are described. These compounds and the 1:1 adduct between 2,2′-bipyridine and PhSbI 2 have been characterized mainly in the solid state by infrared and Mossbauer spectroscopic techniques. The structures of the antimony trihalide complexes appear to be based on halogen bridged polymers in which the stereochemical activity of the lone pair of electrons varies with the halogen, the highest p-character of the lone pair being observed with the trifluoride adduct. Mossbauer results for the PhSbI 2 complexes suggest a ψ-octahedral stereochemistry with the lone pair and the Ph group in trans pos…

Solution stoichiometry determines crystal stoichiometry in halogen-bonded supramolecular complexes

2007

The behavior of the methylisonicotinate (MINC) building block as halogen bonding-acceptor module has been investigated in the solid state. Both the N and the O atoms of MINC interact with the iodine atoms of 1,4-diiodotetrafluorobenzene (DITFB) giving rise to N⋯I and O⋯I interactions. Hierarchy between these interactions allows the control of the composition and thus the structure of the supramolecular complex, according to the composition of the reaction mixture. A structure based on an infinite chain and a trimeric supermolecule have been obtained starting from a 1 ∶ 1 MINC/DITFB stoichiometry or by using a large excess of MINC, respectively. While the former structure shows simultaneous …

C–H Halogenation of Pyridyl Sulfides Avoiding the Sulfur Oxidation: A Direct Catalytic Access to Sulfanyl Polyhalides and Polyaromatics

2019

Palladium-catalyzed oxidative C–H halogenation and acetoxylation reactions of S-unprotected sulfides, selectively directed by pyridinyl groups, allows the formation of C–X bonds (X = I, Br, Cl, OAc) by using simple halosuccinimide or phenyliodine diacetate (PIDA) oxidants. The undesired formation of sulfoxides and/or sulfones, which are usually observed under oxidative conditions, is fully obviated. Under the solvent-dependent conditions that we proposed, sulfide C–H functionalization is achieved in less than 1 h without any direct electrophilic halogenation at the pyridine moiety. N-Directed ortho-C–H activation of aryl also facilitates dibromination reactions which are hardly accessible w…