- 1-(3,4-Dihydro-4-oxoquinazolin-3-yl)aziridines (Q-substituted aziridines): Ring-opening reactions with C-N bond cleavage and preparation of Q-free chirons
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The presence of the Q group in ring-opening reactions of N-(Q)-aziridines 3, 4, 5 and 6 has been found to be advantageous in the following ways, (i) nucleophilic ring-opening by cuprate or by azide with inversion of configuration is assisted by the electron-withdrawing character of the Q group, (ii) ring-opening of aziridines 5 or 6 to the corresponding alcohols 36 and 23 with retention of configuration can be accomplished by participation of the Q group: the Q carbonyl oxygen becomes the hydroxy oxygen in the alcohol product, (iii) the combined effects of the electron-withdrawing Q group and ring strain allow preparation of individual aziridine N-invertomers 3 and 4 whose ring-opening with hydrogen chloride in dichloromethane proceeds with complementary stereochemistry. The Q group is also believed to be involved in ring-opening of aziridines 5 and 6 mediated by samarium(III) nitrate hexahydrate with predominant retention of configuration. Reductive removal of the Q group from these ring-opened products gave chirons 12, 19 and 21. The Royal Society of Chemistry 2000.
- Atkinson, Robert S.,Ayscough, Andrew P.,Gattrell, William T.,Raynham, Tony M.
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p. 3096 - 3106
(2007/10/03)
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- Ring-opening of chiral N-(3,4-dihydro-4-oxoquinazolin-3-yl)-substituted aziridines (Q*-substituted aziridines): Access to Q*-free chirons
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The presence of the quinazolin-4(3H)-one ring (Q*) in N-(Q*)-aziridines facilitates ring-opening by nucleophiles: removal of the Q* group from enantiopure ring-opened products gives useful chirons.
- Atkinson, Robert S.,Ayscough, Andrew P.,Gattrell, William T.,Raynham, Tony M.
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p. 497 - 500
(2007/10/03)
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