{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2023,11,14]],"date-time":"2023-11-14T20:48:17Z","timestamp":1699994897545},"reference-count":13,"publisher":"Elsevier BV","issue":"17","license":[{"start":{"date-parts":[[1997,4,1]],"date-time":"1997-04-01T00:00:00Z","timestamp":859852800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Tetrahedron Letters"],"published-print":{"date-parts":[[1997,4]]},"DOI":"10.1016\/s0040-4039(97)00559-5","type":"journal-article","created":{"date-parts":[[2002,7,26]],"date-time":"2002-07-26T00:36:43Z","timestamp":1027643803000},"page":"3115-3118","source":"Crossref","is-referenced-by-count":9,"title":["1-Aza-1\u2032,3\u2032-Diaza-3,3\u2032-Sigmatropic Rearrangements \u2014 A Convenient Synthesis of Benzimidazole Derivatives"],"prefix":"10.1016","volume":"38","author":[{"given":"M","family":"Teresa","sequence":"first","affiliation":[]},{"given":"V.L","family":"Carvalho","sequence":"additional","affiliation":[]},{"given":"Ana M","family":"Lobo*","sequence":"additional","affiliation":[]},{"given":"Paula S","family":"Branco","sequence":"additional","affiliation":[]},{"given":"Sundaresan","family":"Prabhakar*","sequence":"additional","affiliation":[]}],"member":"78","reference":[{"key":"10.1016\/S0040-4039(97)00559-5_BIB1","doi-asserted-by":"crossref","unstructured":"For a review on the application of hetero-Cope rearrangements in organic synthesis, see: Blechert, S. Synthesis, 1989, 71\u201382.","DOI":"10.1055\/s-1989-27158"},{"key":"10.1016\/S0040-4039(97)00559-5_BIB2","first-page":"151","volume":"48","author":"Pellizzari","year":"1918","journal-title":"Gazz. Chim. Ital."},{"key":"10.1016\/S0040-4039(97)00559-5_BIB3","doi-asserted-by":"crossref","first-page":"1251","DOI":"10.1016\/S0040-4039(01)82458-8","volume":"14","author":"Bird","year":"1974","journal-title":"Tetrahedron Lett."},{"key":"10.1016\/S0040-4039(97)00559-5_BIB4","unstructured":"Supplied by Aldrich Chem. Co (Spain)."},{"key":"10.1016\/S0040-4039(97)00559-5_BIB5","unstructured":"For the preparation, using ClCN, the instability and reactivity of 1-phenyl-2-cyanohydrazine, see: Pellizzari, G; Tivoli, D. Gazz. Chim. Ital., 1892, 22, 226\u2013236; Pellizzari, G. Gazz. Chim. Ital., 1910, 41, 54\u201359."},{"key":"10.1016\/S0040-4039(97)00559-5_BIB6","unstructured":"The predominance of the N-acylcyanamide 4 is to be attributed to the bulkiness of the acylating species (Et3+NCOR2 Cl\u2212) which makes acylation on the nitrogen atom attached to the aryl ring difficult. The use of R2COCl in conjunction with NaHCO3 led to the formation of urea 5 in greater quantity."},{"key":"10.1016\/S0040-4039(97)00559-5_BIB7","unstructured":"It is likely that the formation of the ureas 5 occurs via the 1-aryl-1-acyl-2-cyanohydrazine generated competitively with 4. For example 1-phenyl-1-acetylhydrazine (A) on cyanation (BrCN) affords exclusively the urea C with exceptional ease, most probably due to the intervention of the intermediate B. A similar neighbouring participation is also manifested in the attempted acetylation of the cyanamide D which gives the urea F, via E (unpublished observation from our laboratory). On the other hand, the successful cyclisation of the diazetidin-4-one G to the corresponding benzimidazole H is to be attributed, inter alia, to the geometric impossibility of the carbonyl and N-CN to interact (see: Bird, C.W. J. Chem. Soc., 1964, 5284\u20135289)."},{"key":"10.1016\/S0040-4039(97)00559-5_BIB8","first-page":"57","volume":"24","author":"Graubaum","year":"1984","journal-title":"Chem."},{"key":"10.1016\/S0040-4039(97)00559-5_BIB9","doi-asserted-by":"crossref","unstructured":"a) For a review describing other synthetic methods for 2-aminobenzimidazoles and their important applications, see: Rastogi, R.; Sharma, S. Synthesis, 1983, 861\u2013882. b) All new compounds gave satisfactory elemental analysis or accurate mass measurements. 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