Process for the preparation of 9-deazaguanine derivatives
申请人:BioCryst Pharmaceuticals, Inc.
公开号:US20040254181A1
公开(公告)日:2004-12-16
Derivatives of 9-deazaguanine are prepared by reacting an aldehyde or ketone with a dialkylaminomalonate to form the corresponding enamine. The enamine is then reacted with a base to form a cyclic pyrrole. The cyclic pyrrole is reacted with an urea compound or a derivative of carbamimidoic acid to provide a protected guanidino compound. The guanidino is converted to the desired 9-deazaguanine derivative by reacting with trifluoracetic acid or with an alkoxide or hydroxide followed by neutralization with an acid.
alternative to classical cyanomethylation is possible by using electrogenerated bases (EGBs), obtained by electroreduction of aryl halides in an undivided cell fitted with a cadmium coated cathode and a sacrificial magnesium anode. Acetonitrile is used both as solvent and as hydrogen-active compound. A coupling reaction with various electrophilic compounds was carried out. When the electrophilic compound
A catalytic enantioselective synthetic strategy for the aryl-substituted all-carbon quaternary stereocenters of bioactive hydrodibenzofuran alkaloids was achieved by the Michael addition reaction of α-cyano ketones and acrylates using a chiral tertiary amine–thiourea catalyst. This method can tolerate steric bulkiness and multiple functional groups, and 32 Michael adducts were prepared in good to excellent
A variety of substituted enamine derivatives were first found to be conveniently converted to the corresponding 2H-azirines mediated by phenyliodine (III) diacetate (PIDA). The formed 2-aryl-2H-azirines could be applied in the synthesis of indole-3-carbonitriles or isoxazoles via thermal rearrangements.
2-aryl-3-arylazoacrylonitriles are synthesized while attempting the intramolecular N-arylation of 5-aminopyrazoles, using the hypervalent iodine reagent. The synthesis involves phenyl iodine diacetate-assisted ringopening of 5-aminopyrazoles at room temperature. A plausible mechanism for the formation of azoalkenes is proposed.