502770-23-2

Upstream product

• 87191-97-7 3-<(2-Nitrophenyl)methylene>-2,4(3H,5H)-furandione 
• 80012-14-2 (E)-4-amino-pent-3-en-2-one 
• 552-89-6 2-nitro-benzaldehyde 

Downstream Products

• 502770-38-9 3-Acetyl-2-methyl-4-(2-nitrophenyl)-5,7-dihydrofuro[3,4-b]pyridin-5-on 
• 518313-18-3 3-Acetyl-2-methyl-4-(2-nitrosophenyl)-5,7-dihydrofuro[3,4-b]pyridin-5-on 

Relevant academic research and scientific papers

3-(Nitrobenzylidene)-2,4(3H,5H)-furandiones in the Hantzsch pyridine synthesis, part 1.: A new approach to furo[3,4-b]pyridines

The nitrobenzylidenefurandiones 7 react with acetoacetic ester (8) and ammonium acetate or 3-aminocrotonic esters (9a, b) and 2-aminopent-2-en-4-on (9c), respectively heating in acetic acid to yield the tetrahydrofuro[3,4-b] pyridines 10. The dehydrogenation of 10 using nitric acid or activated manganese dioxide leads to the dihydrofuro[3,4-b]pyridines 12. When the reaction is carried out with the tetronic acid derivatives 7 and the enaminocarbonyl compounds 9 at 30°C in tert-butanol the hexahydro-7a-hydroxyfuro[3,4-b]pyridines 11 are obtained. Treating the N,O-acetales 11 with acetic anhydride in pyridine affords the annulated lactones 10.