Nitrogen compounds copper catalysts

The aziridines are the nitrogen analogs of the epoxides and undergo similar electrophilic reactions. No biological data were obtained for these compounds nor were they used as precursors to any CA-4, 7, analogs. They have been included since the synthesis is noteworthy, and they could be interesting intermediates. Xu et al. stereoselectively aziridinated chalcones using the nitrene precursor (PhINTS) and a copper catalyst to form compound 141 (Scheme 36) [82],... 

Arylations of amines and nitrogen-containing heterocycles require the presence of a copper catalyst, usually 10% copper(ll) acetate. For example, the reaction of 4-MeC6H4Pb(OAc)3 with the benzimidazole 20 affords the arylation product 21 in 98% yield.39 40 Similarly, the arylation of the amino groups of heteroaromatic compounds 22 and 23 gives rise to the corresponding products 24a and 25 in good to excellent yields (Equations (7)-(9)).41 42... 

In addition to being important in industry, transition metal ions play a vital role in living organisms. For example, complexes of iron provide for the transport and storage of oxygen, molybdenum and iron compounds are catalysts in nitrogen fixation, zinc is found in more than 150 biomolecules in humans, copper and iron play a crucial role in the respiratory cycle, and cobalt is found in essential biomolecules such as vitamin Bi2-... 

Loss of nitrogen from a diazo compound can be effected by heat, light, or a copper catalyst. This gives either a carbene (heat or light) or a carbenoid (copper). 

Copper complexes of chiral Pybox (pyridine-2,6-bis(oxazoline))-type ligands have been found to catalyze the enantioselective alkynylation of imines [26]. Moreover, the resultant optically active propargylamines are important intermediates for the synthesis of a variety of nitrogen compounds [27], as well as being a common structural feature of many biologically active compounds and natural products. Portnoy prepared PS-supported chiral Pybox-copper complex 35 via a five-step solid-phase synthetic sequence [28]. Cu(l) complexes of the polymeric Pybox ligands were then used as catalysts for the asymmetric addition of phenylacetylene to imine 36, as shown in Scheme 3.11. tBu-Pybox gave the best enantioselectivity of 83% ee in the synthesis of 37. 

Copper Catalysts Direct oxidative functionalization of tertiary amines is of importance both enzymatically and synthetically. The combination of CuBr—TBHP has proved to be as an efficient system in the oxidative activation of sp3 C—H bonds adjacent to a nitrogen atom [10]. Various types of cross-dehydrogenative coupling (CDC) reactions have been developed, including compounds with activated methylene groups [11], indoles [12], and terminal alkynes (Scheme 11.2) [13]. Because 1,2,3,4-tetrahydroisoquinoline derivatives are important structure motifs of natural... 

Peroxy-linked dimers are also formed from linoleate hydroperoxides in the presence of free radical initiators and copper palmitate, and carbon-carbon linked dimers in the presence of copper catalysts. Decomposition of methyl linoleate hydroperoxides at 210°C under nitrogen produces mainly carbon-carbon linked dimers (82%), monomers with loss of diene conjugation, volatile compounds (4-5%) and water. The resulting dimers contain carbonyl and hydroxyl groups and double bonds scattered between carbon 8 and carbon 10. Linoleate hydroperoxides can dimerize by one of the termination reactions discussed in Chapter 1. The termination reactions involving combination of alkyl, alkoxyl, or peroxyl radical intermediates produce dimers with carbon-carbon, carbon ether, or peroxy links. The carbon-carbon and carbon-oxygen linked dimers are favored at elevated temperatures and the peroxy-linked dimers at ambient temperatures. The peroxy-linked dimers may also decompose to the ether-linked and carbon-carbon linked dimers via the corresponding alkyl and alkoxyl radical intermediates. 

The catalyst formed dien oxygen is added to copper(I) chloride in pyridine has found considerable utility in the oxidation of a large number of nitrogen compounds. The preparation of unsaturated nitriles from unsaturated amines can be accomplished in a catalytic manner using cuprous chloride in pyridine [IS]. The oxidative cleavage of o-phenylenediamine catalyzed by cuprous chloride in pyridine takes place at room temperature to give cu,cis-mucononitrile, equation (113) [152]. 

Reaction of Arylamines Copper-catalyzed C—N coupling affords powerful tool for the synthesis of nitrogenated compounds [33]. In 1987, Paine reported soluble cuprous ion as the active catalytic species in Ullmann coupling [34]. Soluble air-stable copper(I) complex, Cu(PPh3)jBr, has been used for the synthesis of functionalized diaryl and triaryl amines (Scheme 20.17) [35]. Copper(I) complexes 7-8 and CuI-PBu have been employed for the coupling of aryl halides with aiyl amines [36, 37]. The catalyst with PBu could be used for the coupling of less reactive aiyl chlorides in the presence of KOTlu. 

Catalysts and accelerators used in the manufacture of thermosets include peroxides, organic nitrogen compounds and copper and cobalt salts of naphthenic and other organic acids. 

Piperazinothiazoies (2) were obtained by such a replacement reaction, Cu powder being used as catalyst (25. 26). 2-Piperidinothiazoles are obtained in a similar way (Scheme 2) (27). This catalytic reaction has been postulated in the case of benzene derivatives as a nucleophilic substitution on the copper-complexed halide in which the halogen possesses a positive character by coordination (29). For heterocyclic compounds the coordination probably occurs on the ring nitrogen. 

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