Search results for "substitut"

On the Reaction of 3-Bromo-2-nitrobenzo[b]thiophene 13C-Labeled at C-2 with 3-(Trifluoromethyl)aniline:  A Preliminary Insight into a Nucleophilic Su…

1997

The results of the title reaction have furnished proofs against a rearrangement of the carbon-atom skeleton and for a nitro group shift in the relevant nucleophilic substitution.

Triazolopyridines. 14. Substitution reactions of 7-amino[1,2,3]triazolo[1,5-a]pyridines.

1993

Abstract Reaction between 7-aminotriazolopyridines 1 or 2 and sulphuric acid gives hydroxyalkylpyridines 3 and 4 ; bromination gives brominated pyridine 5 or triazolopyridine 6. The anions from amines 1 or 2 are ambident, acylating on N but alkylating on N or on C6; in the latter case triazolylalkenylcyanides 16 – 20 or the 6,6-dialkylated derivative 19 are obtained. An X-ray diffraction study has confirmed structure 19.

Sulfotransferase-mediated mutagenicity of 1-hydroxymethylpyrene and 4H-cyclopenta[def]chrysen-4-ol and its enhancement by chloride anions.

1993

1-Hydroxymethylpyrene (HMP), a primary benzylic alcohol, and 4H-cyclopenta[def]chrysen-4-ol (OH-CPC), a secondary benzylic alcohol, were investigated for mutagenicity in Salmonella typhimurium (reversion of the his- strain TA98) in the presence of various xenobiotic-metabolizing systems. In the direct test, HMP was inactive and OH-CPC was very weakly active. In the presence of NADPH-fortified postmitochondrial fraction from rat liver (S9/NADPH), no activation of OH-CPC was observed, whereas strong mutagenic effects were elicited by HMP. In the presence of cytosol and 3'-phosphoadenosine-5'-phosphosulfate (PAPS), both alcohols were activated to potent mutagens. For equal mutagenic effects, a…

ChemInform Abstract: Synthetic and Mechanistic Aspects of the Course of the Color Reaction of Iminodibenzyl with Aryl- or Hetaryl-aldehydes: An Acces…

2010

Preparation of 2-amino-5-methyl-7H-1,3,4-thiadiazolo[3,2-α]pyrimidin-7-ones

2005

2-Amino substituted 7H-1,3,4-thiadiazolo[3,2-α]pyrimidin-7-ones 11a-e were prepared by the reaction of 2-bromo-5-amino-1,3,4-thiadiazole (1b) and diketene (8), subsequent cyclocondensation (9b 3b) and displacement of the bromo substituents by the reaction with primary or secondary amines (3b 11a-e). The hydrogen atom 6-H in the heterobicycle 3b is replaced by a Cl or Br atom in the transformation of 3b 14a,b. The 2-bromo-6-chloro compound 14a reacts chemoselectively in the 2-position with dimethylamine (14a 15). The structure elucidations are based on one- and two-dimensional NMR techniques including a heteronuclear NOE measurement.

ChemInform Abstract: Preparation of 5-Bromo-6-phenylimidazo[2,1-b][1,3,4]thiadiazol-2-ylamines.

2008

The reaction of primary or secondary amines with 2,5-dibromo-6-phenylimidazo[2,1-b][1,3,4]-thiadiazole (5) leads to a chemoselective replacement of the 2-Br substituent. The process represents a convenient route to the corresponding 2-ylamines 7a-d. Hydrazine reacts in an analogous fashion (5 → 7e). The structure determinations are based on an X-ray crystal structure analysis and on one- and two-dimensional NMR measurements.

Site Preference in Multimetallic Nanoclusters: Incorporation of Alkali Metal Ions or Copper Atoms into the Alkynyl-Protected Body-Centered Cubic Clus…

2016

The synthesis, structure, substitution chemistry, and optical properties of the gold-centered cubic monocationic cluster [Au@Ag8@Au6(C≡CtBu)12]+ are reported. The metal framework of this cluster can be described as a fragment of a body-centered cubic (bcc) lattice with the silver and gold atoms occupying the vertices and the body center of the cube, respectively. The incorporation of alkali metal atoms gave rise to [MnAg8−nAu7(C≡CtBu)12]+ clusters (n=1 for M=Na, K, Rb, Cs and n=2 for M=K, Rb), with the alkali metal ion(s) presumably occupying the vertex site(s), whereas the incorporation of copper atoms produced [CunAg8Au7−n(C≡CtBu)12]+ clusters (n=1–6), with the Cu atom(s) presumably occup…

Synthesis, structure and reaction chemistry of a nucleophilic aluminyl anion.

2018

The reactivity of aluminium compounds is dominated by their electron deficiency and consequent electrophilicity; these compounds are archetypal Lewis acids (electron-pair acceptors). The main industrial roles of aluminium, and classical methods of synthesizing aluminium–element bonds (for example, hydroalumination and metathesis), draw on the electron deficiency of species of the type AlR3 and AlCl31,2. Whereas aluminates, [AlR4]−, are well known, the idea of reversing polarity and using an aluminium reagent as the nucleophilic partner in bond-forming substitution reactions is unprecedented, owing to the fact that low-valent aluminium anions analogous to nitrogen-, carbon- and boron-centred…

Methyl [4-methoxy-3-(methylsulfonyloxy)benzoyl]formate

2005

The crystal structure of the title compound, C11H12O7S, confirms an earlier proposal concerning the regioselectivity of electrophilic substitution reactions of mesyl guaiacol.

Crystal Structure of New Heusler Compounds

2009

Heusler compounds are promising materials in many fields of contemporary research. The spectrum of their possible applications ranges from magnetic and magneto-mechanical materials over semiconductors and thermoelectrics to superconductors. An important feature of the Heusler compounds is the possibility of controlling the valence electron concentration by partial substitution of elements. On the other hand, the properties also depend on the degree of ordering of the the crystal structure. In general, Heusler compounds crystallize in the Cu2MnAl-type structure but in many cases certain types of disorder are observed. In this paper a detailed description of the different types of disordered …