Amidines applications

Owens, T.D., Souers, A.J. and Ellman, J.A. (2003) The preparation and utility of bis(sulfinyl) imidoamidine ligands for the copper-catalysed Diels-Alder reaction. The Journal of Organic Chemistry, 68, 3-10 Kochi, T. and Ellman, J.A. (2004) Asymmetric a-alkylation of N -tert-butanesulfinyl amidines. Application to the total synthesis of (6R,75)-7-amino-7,8-dihydro-a-bisabolene. Journal of the American Chemical Society, 126, 15652-15653. 

A wide variety of /3-lactams are available by these routes because of the range of substituents possible in either the ketene or its equivalent substituted acetic acid derivative. Considerable diversity in imine structure is also possible. In addition to simple Schiff bases, imino esters and thioethers, amidines, cyclic imines and conjugated imines such as cinnamy-lidineaniline have found wide application in the synthesis of functionalized /3-lactams. A-Acylhydrazones can be used, but phenylhydrazones and O-alkyloximes do not give /3-lactams. These /3-lactam forming reactions give both cis and /raMS-azetidin-2-ones some control over stereochemistry can, however, be exercised by choice of reactants and conditions. 

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

This procedure illustrates a broadly applicable method which is essentially that of Roth, Dubs, Gotschi, and Eschenmoser,2 for the synthesis of enolizable /1-dicarbonyl compounds. Although there are various methods for the preparation of /3-dicarbonyl systems,3 the scheme of sulfide contraction widens the spectrum of available methods. The procedure can also be utilized in the synthesis of aza and diaza analogs of /3-dicarbonyl systems. Eschenmoser2 has utilized the method to produce vinylogous amides and amidines in connection with the total synthesis of corrins and vitamin B12.4... 

Mg(THF), when the stoichiometry was 1 2. Monomeric and dimeric amidinate complexes of magnesium have been studied in detail with respect to potential applications of these compounds in the chemical vapor deposition of magnesium-doped Group 13 compound semiconductor films. The reactions and products are summarized in Scheme 16. ... 

Homoleptic lanthanide(III) tris(amidinates) and guanidinates are among the longest known lanthanide complexes containing these chelating ligands. In this area the carbodiimide insertion route is usually not applicable, as simple, well-defined lanthanide tris(alkyls) and tris(dialkylamides) are not readily available. A notable exception is the formation of homoleptic lanthanide guanidinates from... 

Certain aspects of catalytic applications of transition metal amidinate complexes have already been summarized in review articles. The "Chemistry of... 

Two technical applications of C = N-X substrates have been reported. Noyori s Ru-PP-NN catalyst system was successfully applied in a feasibility study by Dow Chirotech for the hydrogenation of a sulfonyl amidine [77], while Avecia showed the commercial viability of its CATHy catalyst based on a pentamethyl cyclopentadienyl Rh complex for the reduction of phosphinyl imines [78] (Fig. 34.11). 

This route was not applicable for the preparation of 2- and 4-nitrophenyl derivatives of 252 (R = 2-N02, 4-NO,), as the amidines obtained from 2-and 4-nitroanilines were not soluble in diethyl malonate (49JOC277). 

During studies on the use of amidines as azomethine ylide sources, Jones et al. (67-69) reported in a series of papers the application of their general strategy to an asymmetric process. Quatemization of the dihydroimidazole 214 with an a-halo ester followed by DBU-induced ylide formation and subsequent cyclization furnished a range of nitrogen heterocycles in a one pot generation and cyclization protocol (70) (Scheme 3.73). 

Application of this one/pot protocol to the preparation of enantiopure amidine (215) derived from phenylglycine led to the formation of the desired cycloadducts (71). The reaction proceeded with good stereocontrol with an endo/exo ratio in the order of 10 1. In the case of the methyl ester derived product 216 (R = Me), a single isomer was isolated. The minor exo products 217 proved to have an unexpected stereochemistry at C(7), which was consistent with the energetically disfavored anti attack of the dipolarophUe, and it was therefore assumed that the product had... 

Triazines containing two different substituents are formed by a variety of methods. The guidelines described above are applicable to these compounds also (see Section 2.20.4.9.4). The condensation of imidates with amidines provides a valuable route to 6-substituted 2,4-dialkyl-l,3,5-triazines (see Section 2.20.4.6.2). 

Complementary reactive centers are needed in the chain synthones in the a- and co-positions. In particular, derivatives of formic acid are used to prepare monomethine dyes for dyes with longer chromophores, the application of vinylogous aminals or CO-methylpolyenals are preferred. In the most famous reactions, the orthoformate was originally proposed (2), and vinylogous amidines that can be regarded as dianils of conjugated dialdehydes are widely used. A general reaction is shown in equation 7 (3), where X = OR, SR, halide, or NIT and Y = O, S, NR, or N + R2 ... 

The N-silylated amidines are easily handled in air, but are best stored under dry nitrogen in a cool, dry place to prevent hydrolysis (as they are slightly moisture-sensitive). This synthetic procedure is applicable to many organic nitriles, and has been used to generate a variety of IV-silylated amidines.6... 

Patel and coworkers87"89 and others90 have been carrying out detailed investigations on the analytical applications of a number of amidines, e.g. JV-hydroxy-JV-phenyl-iV -benzylbenzamicline,91 JV.AT -diaryl substituted A-hydroxy-p-toluamidines87 and hydroxydiarylbenzamidines.88"90... 

Edwards, P. D., et al., Application of fragment-based lead generation to the discovery of novel, cyclic amidine beta-secretase inhibitors with nanomolar potency, cellular activity and high ligand efficiency. J Med Chem, 2007, 50, 5912-5925. 

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