- Synthesis of Coumarins and Quinolones by Intramolecular Aldol Condensation Reactions of Titanium Enediolates
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Low-valent titanium prepared by the reduction of TiCl3 with zinc dust oxidatively adds to α-ketoamides or α-ketoesters with the formation of the corresponding titanium enediolates.These 1,2-difunctional nucleophiles, which have hardly been used in organic
- Fuerstner, Alois,Jumbam, Denis N.,Shi, Nongyuan
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p. 326 - 332
(2007/10/02)
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- Synthesis of chrysogine, a metabolite of Penicillium chrysogenum and some related 2-substituted 4-(3H)-quinazolinones
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Syntheses of both enantiomers of chrysogine, 2-(α-hydroxyethyl)-4(3H)-quinazolinone, 1 from 2-ammobenzamide are reported. Thus reaction of 2-aminobenzamide and optically active α-acetoxypropionyl chloride gave 9, which upon saponification and cyclization induced by aqueous sodium carbonate at room temperature gave chrysogine. The enantiomeric purity of 1 was determined by NMR. Inversion of (-)-(S)-1, using the Mitsunobo reaction, gave (+)-(R)-1. Reduction of 2-acetyl-4(3H)-qumazolinone 2 with baker's yeast gave the S-enantiomer of 1. The cyclization method used could be extended and a number of 2-(a-hydroxy)alkyl-4-(3H)-quinazolinones are also reported.
- Bergman, Jan,Brynolf, Anna
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p. 1295 - 1310
(2007/10/02)
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