4.5- dihydroimidazole-2 -thione

The unusual condensation of 2-bromoalkylidene malonitrile (66) with 4,5-dihydroimidazole-2-thione (67) gave a substituted 2,3-dihydro-l/7-pyrrolo[l,2-a]imidazole (68) in moderate yield <84TL390l>. A general synthesis of these systems is shown by the intramolecular cyclization reaction of l,3,4,5-tetrasubstituted-2-aminopyrrole (69) to give the corresponding pyrrolo[l,2-a] imidazole derivative (70) in good yield <86JHC393>. Both of these reactions are shown in Scheme 10. 

The reaction of 2-aminobenzyl alcohol 376 with 2-chloro-4,5-dihydroimidazole afforded [2-(4,5-dihydro-177-imidazol-2-ylideneamino)phenyl]methanol hydrochloride 377, which upon treatment with carbon disulfide gave l-(477-3,l-benzoxazin-2-yl)imidazolidine-2-thione 378 (Scheme 71). The assumed reaction mechanism involved the initial formation of the dithiocarbamate 379, which underwent intramolecular nucleophilic addition to furnish the unstable thiazetidine 380. By nucleophilic attack of the hydroxy group on the carbon atom of the thiazetidine ring, thiocarbamate derivative 381 was formed, which gave the final 3,1-benzoxazine 378 by an intramolecular cyclocondensation with the evolution of H2S <2006H(68)687>. 

Hydroxylamino-4,5-dihydroimidazolium-<9-sulfonate 303 is prepared by reacting 2-chloro-4,5-dihydroimidazole with hydroxylamine-O-sulfonic acid. Reaction of 303 with carbon disulfide in the presence of triethylamine presumably proceeds via intermediate 304 to yield the 6,7-dihydro-5//-imidazo[2,l-c][l,2,4]thiadiazole-3-thione 305 by a tandem nucleophilic addition-electrophilic amination reaction <03JOC4791>. In an interesting photochemical reaction, irradiation of 5-phenyl-1,2,4-thiadiazole 306 results in the formation of benzonitrile 307 <03JOC4855>. 

In the laboratory of E.B. Pedersen, several 2-methylsulfanyl-1H-imidazoles were prepared and tested for their activity against HIV-1 These compounds can be regarded as novel non-nucleoside reverse transcriptase inhibitors. The required a-aminoketone hydrochloride building blocks were prepared using the Dakin-West reaction. L-Cyclohexylalanine was dissolved in excess pyridine and propionic anhydride and was kept at reflux overnight. The resulting a-propionylamino ethyl ketone was hydrolyzed with concentrated hydrochloric acid and the a-aminoketone hydrochloride was heated with one equivalent of potassium thiocyanate in water to afford 4-cyclohexylmethyl-5-ethyl-1,3-dihydroimidazole-2-thione. This material was then advanced to 4-cyclohexylmethyl-1-ethoxymethyl-5-ethyl-2-methylsulfanyl-IH-imidazole. 

AI3-16292 Akrochem etu-22 Aperochem ETU-22 CCRIS 298 4,5-Dihydro-2-mercaptoimidazole 4,5-Dihydroimidazole-2(3H)-thione EINECS 202-606-9 Ethylenethiourea Ethylene thiourea Ethylene thiouree I Ethylene thiouree 1,5Ethylene-2-thiourea 1,3-Ethylenethiourea ETU HSDB 1643 lmidazole-2(3H)-thione, 4,5-dihydro- Imidazolidinethione Imidazoline, 2-mercapto- Imidazoline-2-thiol 2-lmidazoline-2-thiol 2-lmidazolidinethione Imidazoline-2(3H)-thione Mercaptoimidazoline 2-Merkaptoimidazolin 2-... 

Dihydroimidazole-2(3//)-thione (ETU) 5-Nitro-2-furaldehyde semicarbazone (Nitrofurazone) 7 45 4212... 

Alam, M.M. and Ito, O., Energy transfer, electron transfer, and addition reactions of triplet state of l,3-dihydroimidazole-2-thiones investigated by laser flash photol) is. Bull. Chem. Soc. Jpn., 72, 339, 1999. 

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