Search results for "Alkyl"

Pyrido[2’,3’:4,5]pyrrolo[2,1-d][1,2,3,5]tetrazine-4(3H)-ones, a new class of temozolomide heteroanalogues

2009

Twelve derivatives of new ring system pyrido[2’,3’:4,5]pyrrolo[2,1-d][1,2,3,5]tetrazine were prepared in good yields by reaction of 2-diazo-3-ethoxycarbonyl-pyrrolo[3,2-b]pyridine with alkyl- or aryl-isocyanates. Nine derivatives, screened by the National Cancer Institute (Bethesda, MD) for the in vitro one dose primary anticancer assay against a panel of about 60 human tumor cell lines, showed no significant activity.

Diastereoselective synthesis of 6-functionalized 4-aryl-1,3-oxazinan-2-ones and their application in the synthesis of 3-aryl-1,3-aminoalcohols and 6-…

2010

Abstract Halocyclocarbamation of benzyl N -(1-phenyl-3-butenyl)carbamates afforded 6-functionalized 4-aryl-1,3-oxazinan-2-ones with moderate to excellent diastereoselectivity depending on the N -substituent. Importantly, in contrast to reported cyclocarbamations of homoallylic carbamates, which are generally trans -diastereoselective, cyclization of N -unsubstituted Cbz-protected homoallylamines led to cis -1,3-oxazinan-2-ones, predominantly. The use of N -benzylated and in situ prepared N -silylated derivatives resulted however in trans -selectivity. Transition states are proposed to explain the stereochemical influence of the N -substituent on the cyclocarbamations. The functionalized 1,3…

Ionic liquid crystals based on viologen dimers: tuning the mesomorphism by varying the conformational freedom of the ionic layer

2016

ABSTRACTWe investigated the liquid crystal behaviour of newly synthesised bistriflimide salts of symmetric viologen dimers. A smectic A phase was observed for intermediate spacer lengths and for relatively long lateral alkyl chains. The systems were characterised by thermal analysis, polarised optical microscopy, X-ray scattering and solid-state NMR. An intermediate ordered smectic phase was also exhibited by the compounds (except for systems with very short lateral chains) consisting of molten layers of alkyl chains and partially ordered ionic layers. These results, relating to the mesomorphic behaviour of viologen salts, are qualitatively compared to those of the more common imidazolium s…

1966

Die spontane Autoxydation N,N-dialkylierter Arylamine verlauft langsam. Sie wird durch Essigsaure, Azoisobuttersauredinitril (AIBN), Kobaltverbindungen, Benzylchlorid und Essigsaureanhydrid beschleunigt. Essigsaureanhydrid uberfuhrt die als Inhibitoren sehr wirksamen, durch oxydative Entalkylierung entstandenen sek. Amine in die als Inhibitoren wirkungslosen N-Acetylderivate (Ausbeute bis 90%). Die bei der Autoxydation als Kettentrager wirksamen Aminohydroperoxyde I konnen (a) durch Kondensation in die Dialkylperoxyde II ubergefuhrt und (b) durch Triphenylphosphin desoxygeniert werden. Die Amindialkylperoxyde II lassen sich in Substanz aus den Autoxydationsansatzen isolieren. AIBN lost unte…

A capillary liquid chromatography method for benzalkonium chloride determination as a component or contaminant in mixtures of biocides

2015

A method for quantifying benzalkonium chloride (BAK), an alkyl dimethyl benzyl ammonium compound, in several biocides formulations is proposed. A tertiary amine like N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine (TA) and a straight-chain alkyl ammonium compound like trimethyl-tetradecyl ammonium chloride (TMTDAC), have been employed as trade surfactants besides BAK. Two capillary analytical columns with different polarities are tested: inertsil CN-3 capillary column (150mm×0.5mm i.d., 3μm particle diameter) and a non endcapped Zorbax C18 capillary column (35mm×0.5mm i.d., 5μm particle diameter). This latter column provided the best separation of the BAK homologues in less than 12min using …

A Series of Ultra-Efficient Blue Borane Fluorophores

2020

13 pags., 14 figs., 5 tabs.

N-SUBSTITUTION AND á1-ADRENERGIC RECEPTOR AFFINITY OF LAUDANOSINE ANALOGUES

2006

Benzyltetrahydroisoquinoline (BTHIQ) molecules are able to adopt widely differing conformations that depend on the presence or absence of N-substituents. To assess the possible role of BTHIQ conformation on the affinity of these compounds for α 1 -adrenergic receptors, of interest for the management of hypertension, the racemic N-unsubstituted BTHIQ norlaudanosine and a series of N-alkylated derivatives were assessed for binding to rat brain cortical sites labelled with the radioligand [3H]prazosin. The α 1 -adrenergic affinity in this series increased with the bulk of the substituent on the nitrogen atom, from the N-ethyl to the N-propyl analogue. Comparison of these results with published…

Fine chemistry by TiO2 heterogeneous photocatalysis

2021

Abstract Heterogeneous TiO2 photocatalysis is a promising technology based on the capability of the semiconducting material to generate charges upon irradiation of suitable energy. The photogenerated electrons and holes, in turn, induce redox reactions involving species adsorbed on the surface of the photocatalyst, giving rise to chemical transformations. The presence of highly oxidizing radicals, thus generated, has long led to consider TiO2 photocatalysis only a nonselective oxidation process. In fact, so far it is possible to find in the literature many examples of its use in the field of environmental remediation aimed at the degradation of harmful molecules, although the studies are al…

Oral metronomic cyclophosphamide with and without methotrexate as palliative treatment for patients with metastatic breast carcinoma

2012

Oral metronomic chemotherapy is a therapeutic option which is particularly attractive due to its ease of administration and low toxic burden. Its mechanism of action probably involves antiangiogenetic effect rather than a classical antiproliferative effect like standard maximally tolerated dose-based regimens.A retrospective analysis of 61 patients with advanced breast carcinoma was carried out with the aim of reporting activity in terms of response rate, control of tumor-related symptoms, outcome, and toxicity. All patients had hormonal therapy-resistant metastatic disease and had previously received two lines of chemotherapy. The first cohort of 22 patients received oral cyclophosphamide …

Dose intensification of mitoxantrone in combination with levofolinic acid, fluorouracil, cyclophosphamide and granulocyte colony stimulating factor s…

1997

Fifty-five consecutive patients with metastatic breast cancer (MBC) (n = 57) were treated with a combination of levofolinic acid (I-FA) 100 mg/m2 plus 5-fluorouracil (5-FU) 340 mg/m2 i.v. on day 1-3, cyclophosphamide (CTX) 600 mg/m2 i.v. on day 1 and mitoxantrone (DHAD) 12 mg/m2 i.v. on day 1. DHAD dose was progressively escalated by 2 mg/m2/cycle up to 18 mg/m2 in the absence of dose-limiting toxicities. Granulocyte colony stimulating factor (G-CSF) was given s.c. in order to prevent neutropenia. DHAD dosage could be increased to 18 mg/m2 in 66 out of 317 cycles of chemotherapy (21%). In most patients the dose-limiting toxicity was represented by myelosuppression. A statistically significa…