Imidazolidin-2-ones synthesis

Imidazolidin-2-one, l-(5-nitro-2-thiazolyl)-pharmacological activity, 6, 328 Imidazolidin-4-one, l-aryl-3-phenyl-2-thioxo- C NM S, 355 Imidazolidinones C NMR, 5, 355 Imidazolidin-2-ones nucleophilic displacement, 5, 428 polymers, 1, 279-280 reactivity, 5, 376 synthesis, 5, 466, 471 Imidazolidin-4-ones synthesis, 5, 468 Imidazoline, 2-alkyl-synthesis, 5, 463 Imidazoline, 2-amino-applications, 5, 498 Imidazoline, 2-aryl-synthesis, 5, 463 Imidazoline, 2-methyl-synthesis, 5, 487 Imidazoline, 2-nitroamino-synthesis, 5, 471 2-Imidazoline, 2-arylamino-tautomerism, 5, 368 2-Imidazoline, 1-benzyl-methylation, 5, 425 2-Imidazoline, 1,2-diaryl-synthesis, 5, 463... 

Imidazolidin-2-one, 4,5-dihydroxy-4,4-di(p-bromophenyl)-reactions with urea, 5, 406 Imidazolidin-2-one, 1,3-divinyl-polymerization, 1, 280 I midazolidin-2-one, 1 -ethyl-3-vinyl-polymerization, 1, 279 Imidazolidin-2-one, 4-methylene-synthesis, 5, 140... 

The synthesis of these complexes can easily be accomplished by substitution of one or both PCy3 groups of 3 by NHC ligands. The X-ray structure of 6 shows significantly different bond lengths the Schrock double bond to the CHPh group is 1.821(3) A, while the NHC bond to the l,3-diisopropylimidazolin-2-ylidene is 2.107(3) A. Complexes with imidazolidin-2-ylidenes were also synthesized and screened in an extensive study by Fiirstner [153], who found that the performance of those catalysts depends strongly on the application and that... 

Nitrone cycloaddition reactions with alkynes have been widely used for the synthesis of imidazolidine nitroxides (736) and (737), containing chelating enam-ino ketone groups (821). Different heterocyclic systems were obtained, such as 3-(2-oxygenated alkyl)piperazin-2-ones (738) (822), also compounds containing the isoxazolo[3,2-i]indole ring system (739) (823) and a new class of ene-hydroxylamino ketones- (l )-2-( 1-hydroxy-4,4,5,5-tetraalkylimidazolidin-2-ylidene)ethanones (740) (824) (Fig. 2.46). 

Cyclic amides can be used like the thioamides of the previous section. l-(2-Chloroethyl)imidazolidine-2-one 61 with potassium hydroxide affords the tetrahydroimidazo[2,l-A oxazole 62 (Scheme 38) <1957JA5276>. The bicyclic imidazo[2,l-A]oxazole 64 can be prepared by the cyclization of 63 (Scheme 39) <1999H1081>. A similar methodology was applied to the synthesis of oxazolo[3,2- ]benzimidazole 66 by heating 2-chloro-l-phenacylbenzimidazole 65 with sodium benzoate in DMF (Scheme 40) <2001CHE1179, CHEC-III(11.04.9.1.1)151>. 

The formylation of phenols with the electron-rich olefin to give imidazolidin-2-yl-phenols is very selective and avoids mixtures of o- and p-isomers which are frequently obtained by methods commonly employed for the synthesis of phenolaldehydes. Para substitution of the cyclic aminal group in the phenol is preferred. If the p-position is blocked or sterically hindered, the reaction proceeds via the ortho- aminals to salicylaldehydes. Incorporation of more than one aldehyde group in the benzene nucleus is often achieved with hydroxy- and aminophenols. 

Reductive cleavage of imidazolidines 641 was implicated in the one-pot synthesis of N,N,N -trisubstituted ethylenediamines 643 from V,V -disubstituted ethylene diamines and an aldehyde R CHO. Presumably the intermediate iminium ion 642 is reduced by NaBH4 (Scheme 154) <2003SC3193>. Naphthalene-catalyzed lithiation of l,3-dimethyl-2-phenylimidazoline 644 leads to benzylic C-N bond cleavage. The intermediate dianion can be trapped with electrophiles (HjO, alkyl halides, ketones, and aldehydes) to afford diamines 645 <2005T3177>. 

Synthesis of Formamidines. N-(Benzylideneamino) heterocycles structurally transform into formamidines by inversion of the azomethine linkage. A series of formamidines related to l-(benzylideneamino)-imidazolidin-2-ones has been prepared by reaction of substituted formanilides with imidazolidin-2-one (ethylene urea) in thionyl chloride solution. The one-pot method which involves condensation between ethylene urea and an imidoyl chloride, represents a new method for the synthesis of trisubstituted formamidines (Chart VI). 

Synthesis of l-Phenylazo-Imidazolidin-2-ones. Substituent electronic effects are transmitted by the azo link, -N=N-, about 1.5 times more effectively than by a carbon-carbon double bond (23). This difference between azo and ethylenic links may be due to enhanced electronegativity of the nitrogen containing group. For instance, the standard reaction of N-aminoimidazolidin-2-one with aromatic diazonium salts was unsuccessful under a variety of reaction conditions (Table II) none of the desired l-phenylazo-imidazolidin-2-one could be isolated. 

Synthesis of l-(Benzylamino)imidazolidin-2-ones. Catalytic reduction of l-(benzylideneamino)imidazolidin-2-ones was only partially suc-cussful. For example, catalytic reduction over Pd-C with hydrogen in a Parr shaker gave l-(benzylamino)imidazolidin-2-one in low (32%)... 

Even though the most widely used preparation is still the reaction of alkali isothiocyanates or alkyl and aryl isothiocyanates with a-amino carboxylic acid derivatives, the reaction of dithiocarbamic acid esters (CCX) with a-amino carboxylic acids (CCXI) has certain advantages especially in the synthesis of heterocyclically substituted imidazolidin-4-one-2-thiones (221). 

Journal of Applied Polymer Science 89, No.9, 29th Aug.2003, p.2418-25 DURABLE AND REGENERABLE ANTIMICROBIAL TEXTILES SYNTHESIS AND APPLICATIONS OF 3-METHYLOL-2,2,5,5-TETRAMETHYL-IMIDAZOLIDIN-4-ONE(MTMIO)... 

A one-pot synthesis of imidazolidines (30-67%) reacts aromatic aldehydes with diethyl keto-malonate and a benzylamine with a catalytic quantity of p-toluenesulfonic acid <94H(38)587>. The Ugi four-component eondensation of l,l-diethoxy-2-isocyanoethane, cycloketones, amine hydrochlorides, and potassium thiocyanate gives rise to 2-spiro-2W-imidazoles (10-48%) <93LAI229>. 

Of the two objectives (Section I) of investigations on the models of this cofactor, the one translating its functional capability of carbon transfers in the evolution of chemical synthesis has been amply illustrated. With respect to the second objective of providing support to the molecular mechanism of the enzymatic process in which this cofactor plays an essential role, Pandit chose to mimic in totality the thymidylate synthase (TS) catalyzed conversion of deoxyuridine monophosphate (dUMP, 129) to deoxythymine monophosphate (dTMP, 131) that is reported to proceed by transfer of a methylene group of an imidazolidine component of 1 to C-5 of dUMP 129, the nucleophilicity of which is enhanced by the addition of a thiol of apoenzyme at C-6, generating the methylene intermediate 130. The subsequent delivery of the C-6H of 1 as an hydride equivalent to the methylene carbon is followed by elimination of a thiol and formation of dTMP 131 along with 7,8-dihydrofolate 132. 

The formation of the GFP fluorophore involves self-processing reactions that bear similarity to the mechanism of formation of MIO discussed earlier (see Scheme 2). The proposed mechanism for the biosynthesis of the GFP fluorophore is shown in Scheme 16. It is proposed that after translation the protein (48) is folded in a way to encourage nucleophilic attack by the amide nitrogen of Gly67 on the amide carbon of Ser65 to form a cyclic intermediate (49), which loses water to yield an imidazolidin-5-one intermediate (50). This condensation reaction is followed by autoxidation of the a-/ bond of Tyr66 to yield the GFP fluorophore. It should be noted that the isolated tripeptide will not spontaneously undergo these reactions. For synthesis of the GFP cofactor to occur, the protein must be folded in such a manner to position the residues to facilitate the biosynthetic reactions. 

Microwave irradiation has been employed in several published syntheses of substituted imidazoles. Microwave irradiation of aldehydes 87 and TV-substituted a-amino acid amides 88 under solvent-free conditions led to substituted imidazolidin-4-ones 89 <04H(63)1165>. A simple, high yielding synthesis of 2,4,5-trisubstituted imidazoles 91 have been prepared from diketone 90 with aromatic aldehydes in the presence of excess ammonium acetate in acetic acid under microwave irradiation <04OL1453>. Condensation of benzoin 92, aromatie aldehydes, amines and ammonium acetate in the presence of silica gel under microwave irradiation and solvent-free conditions led to tetrasubstituted imidazoles 93 <04H(63)87>. 

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