ChemInform Abstract: Diazines. Part 25. Functionalization by Metalation of the Benzene Moiety of Benzodiazines. Determination of Structures by Long-Range 1H—15N Correlation at Natural Abundance.
✍ Scribed by V. Gautheron Chapoulaud; I. Salliot; N. Ple; A. Turck; G. Queguiner
- Publisher
- John Wiley and Sons
- Year
- 2010
- Weight
- 38 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0931-7597
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✦ Synopsis
Diazines. Part 25. Functionalization by Metalation of the Benzene Moiety of Benzodiazines. Determination of Structures by Long-Range 1 H-15 N Correlation at Natural Abundance.
-Direct lithiation of the benzene moiety of several benzodiazines with LiTMP is achieved in the presence of ortho-directing groups like chlorine atom or methoxy group at the benzene moiety. For quinazoline (I), (IV) or quinoxaline derivatives (VI), (IX) lithiation takes place predominantly at the peri-position to a ring nitrogen. Using phthalazine derivatives (XII), however, it is shown that a peri-nitrogen atom is not necessary for lithiation, but the presence of a directing group. Interestingly, lithiation of quinoxaline derivatives without a directing group is successful when the pyrazine ring is substituted with a phenyl group [cf. compound (IX)]. -(CHAPOULAUD, V.