Solid-State Melt Reaction for the Domino Process: Highly Efficient Synthesis of Fused Tetracyclic Chromenopyran Pyrimidinediones Using Baylis−Hillman Derivatives

Abstract

A solid-state melt reaction (SSMR) has been demonstrated via a domino process for the synthesis of tetracyclic chromenopyran pyrimidinedione frameworks using Baylis-Hillman derivatives through in situ formation of an olefin followed by an intramolecular [4 + 2] cycloaddition reaction sequence. The tetracyclic frameworks were obtained without using catalyst and solvent in a highly stereoselective and stereospecific fashion. The isolated yield is excellent and does not require column chromatography purification to obtain the pure product.

Assembly of Highly Functionalized Chromenopyranpyrazoles via Multicomponent Quadruple Domino Reaction (MCQDR)

“…Therefore, based on the results, the precursor which possess a trans geometry (aryl and ester groups present in the v icinal positions of compound ( 3 )) provided the anti‐ product and the precursor which holds a cis geometry (aryl and nitrile moieties present in the v icinal positions of compound ( 5 )) generated a syn product which is a clear indication for high stereospecificity of the reaction. The same kind of observation was found in many cases in the previous reports …”

“…Though there are several methods known for the synthesis of chromenopyan,– the synthesis of chromenopyranpyrazole was limited except few reports –. There are very few literature precedents where Knoevenagel condensation/hetero‐Diels−Alder reactions have been used for the preparation of heterocycles but to the best of our knowledge there is no report on the synthesis of functionalized chromenopyranpyrazoles through a multicomponent quadruple domino reaction involving Michael addition, pyrazole formation, Knoevenagel condensation and intramolecular hetero‐Diels‐Alder reaction using O ‐allylated salicylaldehydes, dialkylacetylenedicarboxylate and phenylhydrazine.…”

(E)-Methyl 2-[(2-formyl-6-methoxyphenoxy)methyl]-3-phenylacrylate

“…For background to the synthesis, see: Bakthadoss et al (2009). For related phenyl acrylate compounds, see: Wang et al (2006); Jones & Jä ger (2003).…”

Multicomponent Cascade Assembly for Quinolinopyranpyrazole Architectures

“…Based on the results detailed in our initial report,10a we were prompted to engage N ‐allylated aldehydes 7 , phenylhydrazine ( 8 ) and ethyl/methyl acetoacetate ( 9 ) for the efficient construction of tetracyclic quinolino pyranpyrazoles 10 through the generation of pyrazolinone in situ and domino Knoevenagel intramolecular hetero‐Diels–Alder (IMHDA). To this end, we treated methyl (2 Z )‐2‐(bromomethyl)‐3‐arylprop‐2‐enoates bromo derivatives9f of the Baylis–Hillman adducts and N ‐tosylated aldehyde with the aid of K 2 CO 3 in acetonitrile to generate the required precursor 7 , which we expected would be useful for the construction of the desired tetracyclic quinolino pyranpyrazoles 10 through a multicomponent domino‐Knoevenagel intramolecular hetero–Diels–Alder reaction.…”