L- imidazolidin-2-one

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). 

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... 

Other degradation products of the cytosine moiety were isolated and characterized. These include 5-hydroxy-2 -deoxycytidine (5-OHdCyd) (22) and 5-hydroxy-2 -deoxyuridine (5-OHdUrd) (23) that are produced from dehydration reactions of 5,6-dihydroxy-5,6-dihydro-2 -deoxycytidine (20) and 5,6-dihydroxy-5,6-dihydro-2 -deoxyuridine (21), respectively. MQ-photosen-sitized oxidation of dCyd also results in the formation of six minor nucleoside photoproducts, which include the two trans diastereomers of AT-(2-de-oxy-/j-D-eryf/iro-pentofuranosyl)-l-carbamoyl-4 5-dihydroxy-imidazolidin-2-one, h/1-(2-deoxy-J8-D-crythro-pentofuranosyl)-N4-ureidocarboxylic acid and the a and [5 anomers of N-(2-deoxy-D-eryfhro-pentosyl)-biuret [32, 53]. In contrast, formation of the latter compounds predominates in OH radical-mediated oxidation of the pyrimidine ring of dCyd, which involves preferential addition of OH radicals at C-5 followed by intramolecular cyclization of 6-hydroperoxy-5-hydroxy-5,6-dihydro-2 -deoxycytidine and subsequent generation of the 4,6-endoperoxides [53]. 

Other tetrahydroimidazoles have been obtained from the reaction of 2-amino-2-deoxyhexoses with isocyanates and with thiocyanates. Thus, 2-amino-2-deoxy-D-glucopyranose hydrochloride (78) reacts readily with phenyl isocyanate to yield77 the corresponding 4,5-D-glucopyrano-l-phenyl-4-imidazolidin-2-one (79). Alternatively, the tetraacetate 80 was converted into the urea derivative 81, the prod-... 

Cyclic amides can be used similarly to the thioamides of the last section. l-(2-Chloro-ethyl)imidazolidine-2-one (64) with potassium hydroxide gave the tetrahydroimidazo[2,l-fc]oxazole (65) (57JA5276). 

The stereochemistry of the 3-hydrazinoaspartates 75 (R = r-Bu) was established by chemical correlation with dimethyl-/V,AT -bis(benzyloxycarbonyl)-3-aminoaspar-tate and with l,3-bis(benzyloxycarbonyl)-4,5-bis(methoxycarbonyl)imidazolidin-2-one. 

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>. 

R)-2-Ammo-2-phenyl- E21a, 827 (l-Acyl-imidazolidin-2-one-Der.-Hydrolysis), 4233 (Oxo -+ Oxim - NH2) (2S,35)-2-Amino-3-phenyl- E16d, 437 (Alkylierung/ Hydrolyse)... 

Successive treatment of diethylphosphonylalkyl a-aminonitriles (219) with l,l -carbonylimidazole (CDI) or l,l -carbonyl-di-(l,2,4-triazole) (CDT) and O-substituted hydroxylamines has proven useful as a convenient protocol for the preparation of new 5-diethoxyphosphorylalkyl derivatives of 3-aralkoxy-4-imino-imidazolidine-2-ones (220) and 4-alkoxy (aralkoxy) imino-imidazoline-2-ones (221) (Scheme 60). ... 

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