Imidazolidin

Some tetrahydro azoles can be aromatized, but this is more difficult than in the corresponding dihydro series. Thus the conversion of pyrazolidines into pyrazoles is accomplished with chloranil. Imidazolidines are aromatized with great difficulty. 

Similar alkylations may be effected on oxygen. l-(2-Chloroethyl)imidazolidin-2-one (312) when treated with potassium hydroxide or sodium hydride underwent ring closure to the tetrahydroimidazo[2,l-6]oxazole (313) (57JA5276). This approach can be used for the preparation of bicyclic hydantoins and the corresponding dihydro derivatives of (313) using the mesylate of (312) and NaH (77JHC5U, 79JMC1030). 

Ethers, esters, amides and imidazolidines containing an epithio group are said to be effective in enhancing the antiwear and extreme pressure peiformance of lubricants. Other uses of thiiranes are as follows fuel gas odorant (2-methylthiirane), improvement of antistatic and wetting properties of fibers and films [poly(ethyleneglycol) ethers of 2-hydroxymethyl thiirane], inhibition of alkene metathesis (2-methylthiirane), stabilizers for poly(thiirane) (halogen adducts of thiiranes), enhancement of respiration of tobacco leaves (thiirane), tobacco additives to reduce nicotine and to reduce phenol levels in smoke [2-(methoxymethyl)thiirane], stabilizers for trichloroethylene and 1,1,1-trichloroethane (2-methylthiirane, 2-hydroxymethylthiirane) and stabilizers for organic compounds (0,0-dialkyldithiophosphate esters of 2-mercaptomethylthiirane). The product of the reaction of aniline with thiirane is reported to be useful in the flotation of zinc sulfide. 

Hydantoin — see also Imidazolidine-2,4-dione Hydantoin, 3-aryl-5-benzyl-structure, 5, 351... 

Imidazole-5-thione, 4,4-diphenyl-tautomerism, 5, 368 3 H-Imidazole-2-thione, 1,3-dimethyl-structure, 5, 367 Imidazole-2-thiones acidity, 5, 367 betaines, 5, 372 synthesis, 5, 481 tautomerism, 5, 367 3H-Imidazole-2-thiones synthesis, 5, 473, 6, 992 Imidazolides deacylation, 5, 453 mass spectra, 5, 360 phosphoric acid reactions, 5, 454 reactions, 5, 451-453 Imidazolidine, l-alkyl-3-phenyl-N-oxidation, 5, 427 Imidazolidine, 1,3-benzyl-2-phenyl-oxidation, S, 427... 

Imidazolidine, 4,5-dichloro-l,3-diacetyl-imidazo[4,5-6]pyrazine synthesis from, 5, 646 Imidazolidine, 1,3-dimethyl-conformation, 5, 355 Imidazolidine, diphenyl-dehydrogenation, 5, 427 Imidazolidine, 2-imino-1-substituted nitration, 5, 427... 

Imidazolidine, 5-methyl-1,2-diphenyl-geometrical isomers, 5, 354 Imidazolidine, triketo-synthesis, 5, 466... 

Imidazolidin-2-one, 4,5-diacetoxy-4,4-di(p-bromophenyl)-reactions with urea, 5, 406... 

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... 

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... 

The imidazolidine was prepared from an aldehyde with A/,N -dimethyl-1,2-eth-ylenediamine (benzene, heat, 78% yield) and cleaved with Mel (Et20 HjO, 92% yield). Derivatization is chemoselective for aldehydes. The imidazolidine is stable to BuLi and LDA. The diphenylimidazolidine has been prepared analogously and can be cleaved with aqueous HCl. ... 

The ring-chain tautomerism of the imidazolidines 279 (80H1313) is of interest (Scheme 99). The isomer ratio is determined by the nature of the substituents and is hardly affected by the polarity of the solvent (CCI4, DMSO). 

To complete this section, we note the cleavage of electron-rich DTDAFs by CH-acidic five-membered heterocycles of the oxazolidine, thiazolidine, and imidazolidine types (64BSF2857). 

Tliere is only one report concerning the reaction of A -(l-chloroalkyl)-pyridinium chlorides with secondary diamines (92BSB233). 2-Substituted 1,3-dimethyl- and 1,3-diphenyl-imidazolidines 79 have been prepared (75-95% yields) starting from either -dimethyl- or A, A -diphenylethane-1,2-diamines, respectively (Scheme 25). Reactions are particularly fast for the preparation of the 1,3-dimethylimidazolidines. Reaction times as short as 5 min have been claimed. 

The chiral bicyclic imidazolidine 74 is deprotonated at the 2 position by s-BuLi and the resulting anion adds to alkyl halides, acid chlorides, chlorofor-mates, phenyl isocyanate, and aldehydes. The use of this compound as a chiral formyl anion equivalent seems to be limited, however, since the diastereoselectiv-ity in the addition to aldehydes is poor and hydrolysis of the products 75 to give aldehydes also produces cyclohexane-1,2-diamine, necessitating isolation of the aldehyde as its 2,4-dinitrophenylhydrazone (96SL1109 98T14255). 

Apparently, cyclization involves the formation of open-chain intermediates 342, 343, further closing up to imidazolidines 344 and oxazolidines 345 which eliminate the secondary amine, thus leading to imidazolines 346 and oxazolines 347. The latter exist in the solution exclusively in the enolic forms 348, 349 which are stabilized by conjugation and intramolecular hydrogen bonds. 

Chemical Nama D-a-(imidazolidin-2-on-1-yl-carbonylamino)benzylpenicillin, sodium salt Common Nama —... 

D(-)-Oi-[ (Imidazolidin-2-on-1-yl)carbonylamino] phenyl Acetic Acid 6-Aminopenicillanlc Acid... 

DL-2-Thio-1 -phenyl-imidazolidine 1,2-Dibromoethane d-10-Camphorsulfonic acid... 

Chemicel Name Sodium D(-)-a-[(3-methvlsulfonvl-imidazolidin-2-on-1-vl)-carbonvl-amino] benzylpenicillin... 

The preparative value of this compound lies in the surprising fact that bis(l,3-diphenylimidazolidinylidenc-2) behaves in many reactions ie.g., with aromatic aldehydes,2,7 and with carbon acids 2 7-fJ) as if it dissociated to form a nucleophilic carbene. The hydrolytic cleavage of these derived imidazolidine derivatives makes possible the preparation of formyl compounds, so that the amino olefin can be considered as a potential carbonyla-tion reagent. In many reactions it is not necessary to isolate... 

The action of phosgene or carbon disulfide on the l-(2-aminophenyl)imidazolidin-2-imines 5 gives benzotriazepinones 6a-d or benzotriazepinethiones 6e j, respectively. Selected examples are given.378... 

Cleavage of the imidazolidine moiety by acidic hydrolysis led to chiral lactols 17, which can be further oxidized to lactones 19 or reduced to diols 1848. 

The conjugate addition of lithium cuprates to cinnamates 1 bearing a chiral oxazolidine or imidazolidine ring at the ortho position produced 2 in good to excellent yield upon hydrolysis14. 

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... 

Oxo-4-propyl-4-phenyl-imidazolidin Zu 11,4 g (0,3 Mol) Lithiumalanatin 600ml abs. Ather gibt man unter Riihren 21,8 g (0,1 Mol) 2,4-Dioxo-5-propyI-5-phenyI-imidazoIidin. Die Mischung wird 30 Stdn. unter RiickfluB erhitzt, danach mit 44 ml Wasser und 11m/ 15%-iger Natriumhydroxid-Losung hydrolysiert und fil-triert. Man kocht den Niederschlag mit Athanol aus, filtriert, dampft die Solventien ab und kristallisiert das Roh-produkt aus verd. Athanol urn Ausbeute 8,9 g (480/0 d.Th.) F 207-209°. 

Oxo-4-diphenyl-imidazottdin 2-Oxo-4-melhyl-4-(2-methyl-propyl)-imidazolidin 2-Oxo-4-methyl-4-nonyl-imidazolidin 2-Oxo-4-bis-[2-methyl-propyl]-imidazolidin 2-Oxo-4-diisopropyl- imidazvlidin... 

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