1176244-83-9Relevant academic research and scientific papers
A convenient access to variously substituted spiro[cyclopropane-1,4′- oxazoline]
Dalai, Suryakanta,Es-Sayed, Mazen,Noetzel, Marcus,De Meijere, Armin
supporting information; experimental part, p. 3709 - 3713 (2009/05/26)
Michael additions of carboxamides 2a-d under basic conditions onto methyl 2-chloro-2-cyclopropylideneacetate (1) with subsequent ring closure furnished the 4-spirocyclopropanated methyl oxazolinecarboxylates 3a-d (51-81%yields), from which the corresponding free carboxylic acids 4a-d were obtained by hydrolysis in excellent yield (89-93%). Coupling reactions of 4a-d with different o-hydroxyaniline derivatives in the presence of HOAt/EDC and 2,4,6-collidine gave the anilides 5 in good to very good yields (55-92%). The latter under Mitsunobu reaction conditions (Ph3P/DEAD) furnished the benzoxazole derivatives 6 (81-88%). The bromine substituent in the N-methylated 4-spirocyclopropanated 2-(bromophenyl)oxazoline-5-carboxanilides 8c,d were aminated with various secondary amines under Buchwald-Hartwig reaction conditions to give the 2-(aminophenyl)-oxazolinecarboxanilides 9 (12-90%). Suzuki cross-couplings of 8c with arene- and hetareneboronic acids provided the oxazolines with 2-biaryl substituents 10-13 (65-90%). Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
