494198-34-4

Upstream product

• 105-45-3 acetoacetic acid methyl ester 
• 552-89-6 2-nitro-benzaldehyde 
• 108-24-7 acetic anhydride 
• 494198-41-3 Dimethyl-2,4-diacetyl-3-(2-nitrophenyl)pentandioat 

Relevant academic research and scientific papers

Pyrano[3,4-c]quinolines from 1-desaza-1-oxa-nifedipine

The reaction of the 1,5-diketone 1 with acetic anhydride/acetic acid in the presence of zinc chloride yields the 1-desaza-1-oxa-nifedipine 2 and the annulated lactone 3 as a by-product. The structures of 2 and 3 are confirmed by X-ray structure analysis. The pH-dependent reduction of the nitro group from 2 leads to the pyrano[3,4-c]quinolines 4Aa, b by ring closure. The cyclic hydroxamic acid 4Aa represents a weak, non-selective inhibitor of 5-, 12- and 15-lipoxygenase of human full-blood.

Synthesis, structure and stability of 4-aryl-4H-pyrane-3,5-dicarboxylic acid esters

Eight new 4-aryl-2,6-dimethyl-4H-pyrane-3,5-dicarboxylic acid esters 2 and a new 2-amino-2-nor derivative 7 are synthesized using known methods, whose limitations are shown. In contrast to the isoelectronic 4-aryl-1,4-dihydro-pyridines (DHP) 1 the compounds 2e, g possess a nearly planar heterocycle, as found by X-ray crystal structure analysis. The 4H-pyrane-3,5-dicarboxylic acid ester 2e with m-substitution exhibits s-cis/s-cis-conformation, while compound 2g with o-substitution of the aromatic ring represents s-cis/s-trans-conformation. The half-wave potentials (E1/2) show that 4H-pyranes are more stable than the DHP 1. The substitution of the 4-phenyl ring with an electron donating group decreases the potential considerably, whereas an electron acceptor group slightly increases the potential. Replacement of the 2-methyl group by the amino function causes a dramatic loss of stability.