Unexpected reaction of 2-amino-1,4-naphthoquinone with aldehydes: new synthesis of naphtho[2,1-d]oxazole compounds
摘要:
Treatment of 3-substituted 2-amino-1,4-naphthoquinones 3 with an aldehyde in a solution of hydrobromic acid in acetic acid led to 2,4-disubstituted naphtho[2,1-d]oxazol-5-ols. The outcome of this simple conversion is even more remarkable in view of the very similar reactions reported in literature, which all give rise to completely different products. Furthermore, the acquired naphthoxazoles 5-11 could be oxidatively ring opened by means of PIFA or CAN into a series of N-acylated 2-amino-1,4-naphthoquinones. A synthetic pathway towards 2-substituted naphtho[2,3-d]oxazole-4,9-diones was also disclosed as the outcome of CAN mediated oxidation of a 4-chloronaphtho[2,1-d]oxazol-5-ol. (C) 2010 Elsevier Ltd. All rights reserved.
Unexpected reaction of 2-amino-1,4-naphthoquinone with aldehydes: new synthesis of naphtho[2,1-d]oxazole compounds
作者:Sam Van Aeken、Jurgen Deblander、Johan De Houwer、Timothy Mosselmans、Kourosch Abbaspour Tehrani
DOI:10.1016/j.tet.2010.10.082
日期:2011.1
Treatment of 3-substituted 2-amino-1,4-naphthoquinones 3 with an aldehyde in a solution of hydrobromic acid in acetic acid led to 2,4-disubstituted naphtho[2,1-d]oxazol-5-ols. The outcome of this simple conversion is even more remarkable in view of the very similar reactions reported in literature, which all give rise to completely different products. Furthermore, the acquired naphthoxazoles 5-11 could be oxidatively ring opened by means of PIFA or CAN into a series of N-acylated 2-amino-1,4-naphthoquinones. A synthetic pathway towards 2-substituted naphtho[2,3-d]oxazole-4,9-diones was also disclosed as the outcome of CAN mediated oxidation of a 4-chloronaphtho[2,1-d]oxazol-5-ol. (C) 2010 Elsevier Ltd. All rights reserved.