Reaction of 2-mercaptobenzimidazole with ethyl phenylpropiolate

The reaction of 2-mercaptobenzimidazole (I) with phenylpropiolic ester results in the formation of 2-phenyl-thiazino[3, 2-a]benzimidazoI-4-one (II). The structure 4-phenyl-2H-l-thiapyrimido[l,2-a]benzimidazol-2-one (III) assigned by earlier workers

Synthesis & anticonvulsant activity of some condensed imidazoles

2-Mercapto-4,5-dihydroimidazole (la), 2-mercapto-3,4,5,6-tetrahydropyrimidine (lb) and 2-mer-_capto-3,4,5,6-tetrahydro-7H-l,3-diazepine (1c) react with methyl iodide to give the corresponding mercaptomethyl derivatives (2a-2c). Reaction of these mercaptomethyl compounds with aminoacetaldehyde diethyl acetal followed by treatment with hydrochloric acid affords lH-2,3-dihydroimidazo[l,2-a]imidazole (4), 5,6,7,8-tetrahydroimidazo[l,2-a]pyrimidine (19) and 9H-5,6,7, 8-tetrahydroimidazo[l,2-a]-[l,3]-diazepine (22), respectively. These condensed imidazoles have been reacted with aromatic acid chlorides, isocyanates and isothiocyanates. The structure and anticonvulsant activity of these compounds are described

Nitroimidazoles: Part XI. Some Halonitro- & dinitroimidazoles

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-l-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 is synthesised from 7 in low yield. Ethylation of 5 leads to preponderant N-alkylation, providing a mixture of l-ethyldinitroimidazoles (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

EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 20, Revision 3 (FGE.20Rev3): Benzyl alcohols, benzaldehydes, a related acetal, benzoic acids, and related esters from chemical groups 23 and 30

<p>The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate five flavouring substances in the Flavouring Group Evaluation 304, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the substances were considered to have genotoxic potential. The substances were evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that the three substances [FL-no: 16.117, 16.123 and 16.125] do not give rise to safety concerns at their levels of dietary intake, estimated on the basis of the MSDI approach. For the remaining two candidate substances [FL-no: 16.118 and 16.124], no appropriate NOAEL was available and additional data are required. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered. Specifications including complete purity criteria and identity for the materials of commerce have been provided for all five candidate substances.</p&gt