New efficient synthesis of 4-aminocarbonyl substituted 4H-3,1-benzoxazines by a Passerini 3CC/Staudinger/aza-Wittig sequence

Add time:08/28/2019    Source:sciencedirect.com

α-Acyloxy-carboxamide azides 1, obtained from Passerini reaction of easily accessible o-azidobenzaldehyde with isocyanides and carboxylic acids, reacted with triphenylphosphine to give various 4-aminocarbonyl substituted 4H-1,3-benzoxazines 3 in moderate to high yields via sequential Staudinger and intramolecular aza-Wittig reaction. However, α-hydroxy carboxamide azides 5 were obtained in moderate yields when pyruvic acid was used in the Passerini reaction. Further sequential reaction of azides 5 with triphenylphosphine and isocyanates produced 2-amino-4-aminocarbonyl substituted 4H-1,3-benzoxazines 8 via a tandem Staudinger/aza-Wittig/heterocumulene-mediated annulation.

We also recommend Trading Suppliers and Manufacturers of 4H-3,1-Benzoxazine-2,4(1H)-dione (cas 118-48-9). Pls Click Website Link as below: cas 118-48-9 suppliers

Prev:Original articleSynthesis, biological evaluation and molecular docking of novel series of spiro [(2H,3H) quinazoline-2,1′- cyclohexan]-4(1H)- one derivatives as anti-inflammatory and analgesic agents
Next:Chloramphenicol base chemistry. Part 101: Asymmetric synthesis of α-hydroxy chiral alcohols via intramolecular Michael additions of γ-hydroxy-α, β-unsaturated enones with chloramphenicol base derived bifunctional urea organocatalysts)