نتایج جستجو برای: diamines
تعداد نتایج: 2106 فیلتر نتایج به سال:
C2-symmetric vicinal diamines 3b–f, derived from L-tartaric acid, with increasingly bulky terminal ether functionalities were prepared using two distinct sequences. Diamines 3b,c were obtained from the corresponding vicinal diols 4b,c, while diamines 3d–f were generated from dihydroxydiazide 7 via deprotection–reprotection strategies. © 1999 Elsevier Science Ltd. All rights reserved.
[reaction: see text] Organocatalytic asymmetric Mannich reaction of protected amino ketones with imines in the presence of an L-proline-derived tetrazole catalyst afforded diamines with excellent yields and enantioselectivities of up to 99%. The amino ketone protecting group controlled the regioselectivity of the reaction providing access to chiral 1,2-diamines from azido ketones and 1,4-diamin...
Carrion smell is strongly repugnant to humans and triggers distinct innate behaviors in many other species. This smell is mainly carried by two small aliphatic diamines, putrescine and cadaverine, which are generated by bacterial decarboxylation of the basic amino acids ornithine and lysine. Depending on the species, these diamines may also serve as feeding attractants, oviposition attractants,...
0020-1693/$ see front matter 2011 Elsevier B.V. A doi:10.1016/j.ica.2011.07.031 ⇑ Corresponding author. Tel.: +39 49 8275172; fax: E-mail address: [email protected] (D. Mo The polymeric [PdCl(dithiocarbamate)]n complexes, in which the ligand ion is dimethyldithiocarbamate (DMDT), pyrrolidine dithiocarbamate (PyDT, (CH2)4NCS2 ) and sarcosine ethyl ester dithiocarbamate (ESDT, EtO2CCH2N(CH...
von Braun Cyanogen Bromide Reaction Some extensions of von Braun cyanogen bromide reaction have been undertaken on conessine, isoconessine and two simpler bases, dimethyl a-naphthyl amine and diethyl amine. The monocyanamides of conessine and isoconessine yielded acid amides, aminoderivatives (diamines) and guanido derivatives on careful hydrolysis, reduction and treatment with ammonia, respect...
1. The induction of ornithine decarboxylase activity in mouse 3T3 fibroblasts or an SV-40 transformed 3T3 cell line by serum was prevented by addition of the naturally occurring polyamines putrescine (butane-1,4-diamine) and spermidine. Much higher concentrations of these amines were required to fully suppress ornithine decarboxylase activity in the transformed SV-3T3 cells than in the 3T3 fibr...
1-Iodonaphthalene-2,4-diamines in trifluoroacetic acid/chloroform give stable Wheland-like tetrahedral cationic species observable by NMR, through an initial intramolecular protonation. Dynamic equilibria allow proton-deuterium exchange of aromatic protons and provide a mechanism for deiodination of 1-iodonaphthalene-2,4-diamines.
The synthesis of 1,2-diamines has been achieved through a single-step, tandem sequence involving Rh-catalyzed aziridination followed by NaI-promoted rearrangement to an isomeric cyclic sulfamide. Facile ring opening of these products in hot water and pyridine affords differentially protected vicinal diamines. Demonstration of the utility of this method for the syntheses of (±)-enduracididine an...
A method for the synthesis of long chain diamines and tetramines starting from natural α-amino acids is reported. Diamines and tetramines were prepared through the Wittig olefination reaction of N-protected amino aldehydes obtained from phenylalanine and lysine. A 1,2,17,18-tetramine was synthesized using (2S)-1-azido-2-[bis(tertbutoxycarbonyl)-amino]-5-oxopentane as key-intermediate compound.
Palladium(II) complexes carrying chromophoric tropos ligands show a characteristic UV change and strong Cotton effects upon coordination of amino alcohols or diamines. The distinct (chir)optical responses can be used for instantaneous in situ determination of the concentration and ee of diamines and amino alcohols at low concentrations.
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