98815-59-9Relevant articles and documents
Thermally Induced Intramolecular Benzannulation of Diazoacetoacetate Enones Tethered with Unactivated Alkynes: Synthesis of Substituted 6 H-Benzo[ c ]chromenes
Chen, Yangfan,Huang, Jing,Wang, Yun,Wu, Di,Xu, Xichen,Zhou, Jiawen
, p. 4165 - 4169 (2019)
A facile and efficient intramolecular benzannulation strategy for the synthesis of substituted 6 H-benzo[ c ]chromenes from diazoaceto? acetate enones tethered with unactivated alkynes has been developed. The reaction proceeds in moderate to good yields under operationally simple conditions with thermally induced [4+2]-Annulation of intermediate vinyl ketenes as the key step.
AN EASY SYNTHESIS OF METHYL 4-(2,3:5,6-DI-O-ISOPROPYLIDENE-Α-AND -Β-D-MANNOFURANOSYL)-3-OXOBUTANOATE: A NEW APPROACH TO PYRAZOFURINS
Herrera, Lopez F. J.,Baelo, Uraga C.
, p. 95 - 104 (2007/10/02)
The reaction of 2,3:5,6-di-O-isopropylidene-α-D-mannofuranose with (3-methoxycarbonyl-2-oxopropylidene)triphenylphosphorane, catalysed by benzoic acid in dry benzene, gives methyl 4-(2,3-5,6-di-O-isopropylidene-α- and -β-D-mannofuranosyl)-3-oxobutanoate in good yield.These compounds are easily transformed into 4-hydroxy-3-(α- and β-D-mannofuranosyl)pyrazole-5-carboxamide, which are the mannofuranosyl analogues of pyrazofurins.The anomeric configurations of the products were assigned on the basis of 1H-n.m.r. data.
