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Organic Superbases in Annulation with Propargylic Alcohols: Straightforward Synthesis of the Functionalized Oxazolopyrrolohexahydropyrimidine and Oxazolohexahydropyrimidoazepine Scaffolds
Author(s) -
Trofimov Boris A.,
Shemyakina Olesya A.,
Mal'kina Anastasiya G.,
Stepanov Anton V.,
Volostnykh Ol'ga G.,
Ushakov Igor' A.,
Vashchenko Alexander V.
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201600977
Subject(s) - annulation , chemistry , pyrimidine , organocatalysis , catalysis , organic chemistry , combinatorial chemistry , medicinal chemistry , stereochemistry , enantioselective synthesis
The popular organic superbases 1,5‐diazabicyclo[4.3.0]non‐5‐ene (DBN) and 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) underwent annulation with electron‐deficient propargylic alcohols [EWG = CN, C(O)Ph, CO 2 Me] to afford functionalized condensed hexahydropyrimidine systems, [1,3]oxazolo[3,2‐ a ]pyrrolo[2,1‐ b ]hexahydropyrimidines and [1,3]oxazolo[3′,2′:3,4] hexahydropyrimido[1,2‐ a ]azepines, in good to high yields. The reactions proceeded regioselectively and, in most cases, stereoselectively under mild conditions (without catalyst, 20–25 °C). The synthesized compounds, owing to their potential rich chemistry, are novel promising precursors for pyrimidine‐based pharmaceuticals.