Synthesis of Cyclopentadiene-Fused Chromanones via One-Pot Multicomponent Reactions

Abstract

We have developed one-pot method for the synthesis of functionalized novel cyclopentadiene-fused chromanone scaffolds. A variety of 4-oxo-2,4-dihydrocyclopenta[c]chromene-1,2-dicarboxylates were obtained in moderate to good yields via condensation of 2-hydroxybenzaldehydes and ethyl acetoacetate with 1:1 acetylenecarboxylate-isocyanides in toluene. These reactions presumably proceed via reaction of the in situ generated 3-acetyl-2H-chromen-2-ones with acetylenecarboxylate-isocyanide zwitterionic intermediates through Michael addition/intramolecular cyclization and double [1,5] acyl shift rearrangement cascade.

The new synthesis of pyrrole-fused dibenzo[b,f][1,4]oxazepine/thiazepines by the pseudo-Joullié–Ugi reactionviaan unexpected route with high chemoselectivity

“…Interestingly, by replacing tert -butyl and ethyl in acetylenedicarboxylates 3 with methyl, owing to increasing steric effects, the yields of the desired products were slightly decreased without affecting chemoselectivity (Scheme 2, 4a–4x ). 20 A similar trend was also observed for isocyanides, while the yields of products obtained for phenyl isocyanide were higher than those for tert -butyl, cyclohexyl, isopropyl and n -butyl isocyanide. The reason can be attributed to spatial effects on products.…”

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

“…Component 33 can be replaced by a 1/1 mixture of diethyl acetylenecarboxylate and an alkyl isocyanide. The established one‐pot, stepwise, four‐component reaction produced a variety of 4‐oxo‐2,4‐dihydrocyclopenta[ c ]chromene‐1,2‐dicarboxylate 35 in a straightforward way (Scheme ) …”

One pot synthesis of acridine analogues from 1,2-diols as key reagents

“…The IR spectra were recorded on a Agilent Cary 630 FT-IR Spectrophotometer. 1 H NMR and 13 C NMR spectra were recorded on a Bruker 400 MHz spectrometer using CDCl 3 as a solvents and TMS as an internal standard. The chemical shis are expressed in d ppm.…”

“…Hence, developing new MCRs and improvement of existing MCRs are still important areas of research in the current synthetic and medicinal organic chemistry. [1][2][3][4] The synthesis of acridine derivatives, which contain 1,4dihydropyridines parent nucleus is an important reaction, as these scaffolds are found to be a very important core in numerous synthetic, pharmaceutical and a wide variety of biologically active compounds. [5][6][7][8][9][10][11][12][13] A large number of compounds bearing 1,4-dihydropyridines have entered preclinical and clinical trials over the last few years.…”