Amides manganese

Regioselective enolization. The kinetic ketone enolates are formed with manganese amides. Polyalkylation with such enolater is not observed. 

Kinetic enolization. Ketones form kinetic enolates with this manganese amide, which is prepared from MnCU 2LiCl, Ph(Me)NLi, and PhLi in ether. Manganese dialkylamides are much less efficient. 

Adiponitrile undergoes the typical nitrile reactions, eg, hydrolysis to adipamide and adipic acid and alcoholysis to substituted amides and esters. The most important industrial reaction is the catalytic hydrogenation to hexamethylenediarnine. A variety of catalysts are used for this reduction including cobalt—nickel (46), cobalt manganese (47), cobalt boride (48), copper cobalt (49), and iron oxide (50), and Raney nickel (51). An extensive review on the hydrogenation of nitriles has been recendy pubUshed (10). 

Conversion of the nitrile to the amide has been achieved by both chemical and biological means. Several patents have described the use of modified Raney nickel catalysts ia this appHcation (25,26). Also, alkaH metal perborates have demonstrated their utiHty (27). Typically, the hydrolysis is conducted ia the presence of sodium hydroxide (28—31). Owiag to the fact that the rate of hydrolysis of the nitrile to the amide is fast as compared to the hydrolysis of the amide to the acid, good yields of the amide are obtained. Other catalysts such as magnesium oxide (32), ammonia (28,29,33), and manganese dioxide (34) have also been employed. 

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

The new silazane 5 may be reacted with activated metals, organometallic compounds or simple metal amides, or may first be transformed to its lithium salt and then reacted with metal(II) chlorides [11]. In all these cases, metal derivatives of 5 are obtained with the general formula j [Mc (/BuO)Si 9N(9M, which have no further base coordinated to the metal. So far we have synthesized amides with M = Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Ba, all elements in oxidation state +2. X-ray structure determinations have been performed on the calcium, manganese, iron, zinc, and barium derivatives. 

The shift of the amide I mode (FTIR spectra) from 1657 to 1646 cm-1 was attributed to a change in the a-helix native structure to fl-sheets, secondary structure conformations. Atomic Force Microscopy (AFM) images display the coating of the manganese oxide surface as well as the unfolding in a ellipsoidal chain of the protein molecules after adsorption and immobilization on the surface. 

An asymmetric C-H insertion using a chiral 3,3, 5,5 -tetrabromosubstituted (salen)manganese(m) complex 107 with TsN=IPh afforded insertion products with ee up to 89%.258 Che reported the first amidation of steroids such as cholesteryl acetate with (salen)ruthenium(n) complexes 108.259... 

Chiral manganese complexes have been used to perform the enantioselective amidation of saturated C-H bonds.256-258,262 Cationic Mn(salen) 107 showed good catalytic activity and moderate enantioselectivity. Typical examples are shown in Equations (86)-(88). High enantioselectivity of 89% ee was obtained in the reaction of 1,1-dimethylindan (Equation (88)).258 Chiral manganese(m) porphyrin 106 was used in the enantioselective amidation as well nevertheless, the best enantioselectivity was only 54% (Equation (89)).256,257... 

In company with manganese porphyrin complex, ruthenium porphyrins have already shown great catalytic activity in the intermolecular amidation of saturated G-H bonds. However, examples of amidation of aromatic... 

Partial hydration of nitriles to form amides is accomplished under mildly basic conditions, when catalysed by the addition of manganese pentacarbonyl bromide and benzyltriethylammonium chloride [30]. Yields are considerably reduced in the absence of the ammonium salt. 

Complexes. N- )o/ior Ligands. The reaction of manganese and the respective alkali metal in liquid ammonia yields the amide complexes M2Mn(NH2)4 (M = Na, K, Rb, or Cs). °... 

The stability constant (7=0.1, 25 °C) has been reported for the 1 1 manganese(II) complex of the related amide-containing, 15-membered macrocycle l,4,7-trimethylcarboxy-9,14-dioxo-1,4,7,10,13-pentaazacyclopentadecane as 14.7 (log value). ... 

Asymmetric amidation of sp C—H bonds was reported in good yields and moderate enantioselectivities (Scheme 5.27)." ° When benzylic or allylic C—H bonds were used, similar results were also obtained." In these reactions the prepared nitrenes, PhI=NTs, and/or PhI(OAc)2+NH2Ts were used as nitrogen atom transfer sources. The studies showed that Ru=NTs was formed in situ and acted as a possible active intermediate when a ruthenium catalyst was used (Figure 5.12), whereas a radical intermediate might be involved when a manganese catalyst was used. 

The author next tried to stabilize the PGI2 structure by introducing second fluorine atom to the 7-position. However, it had been unknown to make such a difluorovinyl ether unit in the literature. We studied difluorination and Wittig reaction as key steps in the synthetic route of the target difluoro-PGl2 from the Corey lactone. After searching the difluorination reaction, it was found that fluorination with A/-fluorobenzenesulfonimide in the presence of potassium bis(trimethylsilyl) amide and manganese dibromide effectively provided the desired difluoride (Table 7) [106]. 

Like carbene insertions into carbon-hydrogen bonds, metal nitrene insertions occur in both intermolecular and intramolecular reactions.For intermole-cular reactions, a manganese(III) meio-tetrakis(pentafluorophenyl)porphyrm complex gives high product yields and turnovers up to 2600 amidations could be effected directly with amides using PhI(OAc)2 (Eq. 51). The most exciting development in intramolecular C—H reactions thus far has been the oxidative cychzation of sulfamate esters (e.g., Eq. 52), as well as carbamates (to oxazolidin-2-ones), ° and one can expect further developments that are of synthetic... 

As is true for other classes of aromatic nucleophilic substitution, the halogen displacement can frequently be catalyzed by copper or copper(I) salts. Using sodium hydride as the base and copper(I) iodide as catalyst, a series of o-bromophenylethylamine derivatives, including both amides and carbamates, have been cyclized. Oxidation to the indole can be effected with manganese dioxide (81JCS(P1)290). 

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