Amines amidines

Because of their ease of crystallization, alkylzinc alkoxides are often isolated as decomposition products in reactions involving organozinc compounds. The methylzinc lithium tert- butoxide heterocubes [ (THF)LiOBut 2-(MeZnOBu1 ]182 (Figure 58, 123) and [(LiOBu MeZnOBu1 ]183 124 were isolated as hydrolysis products from reactions involving amines, amidines, /< //-butyllithium, and dimethylzinc. 

We found 192 unique structures, with 252 recorded activities on 46 targets (see also Figure 2.3). A vast majority of them (176 structures) are likely to be charged at pH 7.4, as they are aliphatic amines, amidines or guanidines, and sometimes carboxylic acids. This indicates that low MW compounds are likely to require salt bridge interactions... 

A series of special linkers and cleavage strategies has been developed for the release of amines from insoluble supports (Table 3.23). These include the attachment of amines as triazenes, enamines, aminals, amidines, sulfonamides, sulfinamides, hydrazines, or amides. 

Basic ionizable center (positively charged at physiological pH of about 7) (e.g., aliphatic amines, amidines/guanidines, and 4-amino pyridine)... 

The requirement of two distinct pharmacophore points neglects at least one very important class of drugs biogenic amine-containing CNS drugs. Therefore, a second pharmacophore filter has been designed that requires only one pharmacophore point in small molecules of the type amine, amidine, guanidine, or carboxylic acid (PF2). 

The polymerization of formaldehyde can proceed by a cationic, anionic, or insertion mechanism. The anionic polymerization is started by amines, amidines, amides, ammonium salts, phosphines, etc., and is propagated by alkoxy ions ... 

The stopped-flow method has generally been used it has the advantages that it can be used with any solvent, that the product need not be stable for more than a few seconds, that low temperatures can be used, and measurements can be done very quickly. Aliphatic amines, amidines (HN=CR (NR2)), tetramethylguanidine (HN=C(NMe2)2) substituted derivatives,... 

Epoxy/carboxy/acid anhydride systems are also important in OEM clear coats and powder coatings. Catalysts such as tertiary amines, amidines and imidazoles, 1,4-diazabicyclooctane and some alkaline metal-based catalysts such as zinc-based catalysts are commonly used. 

Nitriles react with ammonia, or primary or secondary amines in the presence of an acid catalyst to give amidines (Scheme 26) (75, 77, 81). The catalysts used are hydrochloric acid and aluminium chloride. The amidines are anthelmintics for animals such as sheep, goats, cattle, horses, and Swine. 

As a class of compounds, nitriles have broad commercial utility that includes their use as solvents, feedstocks, pharmaceuticals, catalysts, and pesticides. The versatile reactivity of organonitnles arises both from the reactivity of the C=N bond, and from the abiHty of the cyano substituent to activate adjacent bonds, especially C—H bonds. Nitriles can be used to prepare amines, amides, amidines, carboxyHc acids and esters, aldehydes, ketones, large-ring cycHc ketones, imines, heterocycles, orthoesters, and other compounds. Some of the more common transformations involve hydrolysis or alcoholysis to produce amides, acids and esters, and hydrogenation to produce amines, which are intermediates for the production of polyurethanes and polyamides. An extensive review on hydrogenation of nitriles has been recendy pubHshed (10). 

Cyanopyridazines add ammonia, primary and secondary amines and hydroxylamine to give amidines or amidoximes. Substituted amides, thioamides and carboximidates can be also prepared. With hydrazine, 3-pyridazinylcarbohydrazide imide is formed and addition of methylmagnesium iodide with subsequent hydrolysis of the imine affords the corresponding pyridazinyl methyl ketone. 

Peifluorinated nitriles are highly electrophihc compounds because of the adjacent electron-accepting substituent Therefore, the addition of amines, alcohols, and mer-captans forming amidines, imidates, and thiobnidates is well-documented [63]. 

This reaction is believed to proceed via an amidine (34) and it has been shown that the reactivity of the nitrile group toward nucleophiles is a more important factor than amine basicity in controlling cyclization. 

The propionitrile (94) also yielded a pyrido[2,3-d]pyTimidine (96) when treated with ammonia or methylamine, the intermediate amidine (95) undergoing hydrolysis during the reaction.Amination was shown to be the rate-determining stage. 

A somewhat different approach is used to prepare the compounds containing the amine at the 4 position. Condensation of the amidine from acetonitrile (138) with the enol ether from formylacetonitrile (137) leads to the requisite pyrimidine (139). 

Complete reduction of the azepine ring to hexahydroazepine has been effected with hydrogen and palladium,40 or platinum,135 239 catalysts. For example, ethyl 1 f/-azepine-l-carboxylate is reduced quantitatively at room temperature to ethyl hexahydroazepine-l-carboxylate (92% bp 118 —120 3C).134 136 TV-Phenyl-S/Z-azepin -amine (1), however, with platinum(IV) oxide and hydrogen in methanol yields the hexahydroazepine 2 in which the amidine unit is preserved in the final product.34 The same result is obtained using 5% palladium/barium carbonate, or 2 % palladium/Raney nickel, as catalyst. 

The amidines 10, prepared by condensation of the corresponding imidates with aminoacetal-dehyde dimethyl acetal, undergo cyclization with a variety of acids to l//-3-benzazcpin-2-amines 11 45 Method A has proved to be successful on an industrial scale. 

Diazocinediones react with some secondary amines, with the aid of the titanium(IV) chlor-ide-anisole complex, to give 1,4-diazocine systems containing two amidine moieties.8... 

Although thiirene dioxides do not react with typical tertiary amines like triethylamine, they do react with the amidine 1,5-diazobicyclo-[4.3.0]-non-5-ene (DBN) to give a 1 1 adduct betaine119158 141, analogously to the reaction of thiirene dioxides with soft nucleophiles (equation 57). 

Carbonsaure-imid-ester Oder deren Salze werden durch Natriumboranat in neutralem Medium zu 0,N-Acetalen (s. S. 436 f.) (bzw. Aldehyden) Oder Aminen reduziert. Amidine und Imid-chloride gehen in Amine iiber, Formazane in Amid-hydrazone. 

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