- Nitroimidazoles: Part IV - 1-Sulphonyl(carbamoyl/thiocarbamoyl)-3-(1-methyl-5-nitroimidazol-2-yl)-2-imidazolidinones
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Sulphone (5) is condensed with sodium salts of a variety of 1-suplphonyl (7), 1-thiocarbamoyl (9) and 1-carbonyl (10)-2-imidazolidinones to give 3-(2-imidazolyl)imidazolidinones (12), (13) and (14) respectively, out of which 1-methylsulphonyl-3-(1-methyl-5-nitro-imidazol-2-yl)-2-imidazolidinone (12a) is undergoing clinical trials as an antiamoebic-antitrichomonal agent. 15 and 16 are analougous imidazolidinones, while 17 and 18 are benzimidazolone derivatives.The reaction of 5 with the sodium salt of 2-imidazolidinone gives rise to the mono and bis-condensation products 21 and 22 respectively.Several other minor byproducts, 23-27 have been identified. 23, 26 and 27 arise from 21. 24, a transformation product of 5 leads to the ether 25 by a displacement reaction.A second synthesis of 12a involves the nitration of imidazolylimidazolidinone (30) in the terminal step, with 30 becoming available from 1-methyl-2-aminoimidazole (28) and chloroethyl isocyanate, and subsequent reaction of resultant 29 with methanesulphonyl chloride.The higher ring homologue, 33 of 12a is synthesised in poor yield from 5 and 1-methylsulphonylhexahydropyrimidinone.Treatment of 12a and 13a with KI in DMF leads to the isomeric 4-nitro derivatives 38a, b and desmethyl derivates 37a, b.Treatment of 12a with triethyloxonium fluoroborate affords the quaternary isothiourea (35) which is hydrolysed to 36.Treatment of 12a and 13a with aqeous alkali leads to cleavage of imidazolidinone ring to form the ethylenediamines 31a and b.Position isomers 41 and 43 of 12a are respetcively obtained by the reaction of 1-methyl-4-nitro-5-chloro-(40)-, and 1-methyl-5-nitro-4-chloro-(42)-imidazoles with 1-methylsulphonyl-ethylene urea.Treatment of the last compound with various reactive halides, e.g. 2-chlorobenzothiazole, yields several analogues 44a-i of 12a while niridazole (45) and methylsulphonyl chloride affords nitrothiazole analogue 46.
- Nagarajan, K.,Arya, V. P.,George, T.,Sudarsanam, V.,Shah, R. K.,et al.
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p. 928 - 940
(2007/10/02)
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- Nitroimidazoles: Part XI - Some Halonitro- and Dinitroimidazoles
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Methylation of 2-chloro-4-nitroimidazole (6), obtained from imidazole in four steps, either with dimethyl sulphate or with diazomethane affords a mixture of 2-chloro-1-methyl-5-nitroimidazole (10) and the 4-nitro-isomer (7).The corresponding dinitro compounds 11 and 8 are formed in the methylation of 2,4-dinitroimidazole (5), 8 being converted to 7 by the action of POCl3.Reaction of 10 with the sodium salt of N-methanesulphonyl-2-imidazolidinone provides the potent amoebicide, 1-methylsulphonyl-3-(1-methyl-5-nitroimidazol-2-yl)-2-imidazolidinone (2).The isomer 14 issynthesised from 7 in low yield.Ethylation of 5 leads to preponderant N-alkylation, providing a mixture of 1-ethyl dinitroimidazoles (9) and (12), but a small amount of N,C-diethyl derivative 15 is also obtained.The formation of 15 from 5 is rationalised.The diiodination product of imidazole is shown to be 4,5-diiodoimidazole (19), nitric acid transforming it to 4-iodo-5-nitroimidazole (20).Methylation of 20 affords a mixture of isomeric 1-methyliodonitro derivatives (21) and (22).The structures of 21 and 22 are established by 13C NMR data as well as by conversion into morpholine derivatives 26 and 24 respectively which also arise from 1-methylchloronitroimidazoles (25) and (23).A mechanism is proposed for the reported conversion of 5 into 4-chloro-5-nitroimidazole (32) in boiling 2-chloroethanol.
- Sudarsanam, V.,Nagarajan, K.,George, T.,Shenoy, S. J.,Iyer, V. V.,Kaulgud, A. P.
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p. 1022 - 1026
(2007/10/02)
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