149125-61-1Relevant articles and documents
Enantioselective Fluorination of α-Branched β-Ynone Esters Using a Cinchona-Based Phase-Transfer Catalyst
Arimitsu, Satoru,Iwasa, Satsuki,Arakaki, Ryunosuke
supporting information, p. 12804 - 12812 (2020/10/09)
Herein, we report the fluorination of α-branched β-ynone esters to afford their corresponding quaternary fluorinated products with good enantioselectivity (ee = 73-90%) using a cinchona-based phase-transfer catalyst. α-Branched β-ynone esters possess a highly acidic α-proton and form their corresponding enolate as a single isomer, which allows the enantioselective fluorination reaction to occur under standard cinchona-based phase-transfer catalyst conditions. Moreover, the obtained α-fluorinated product can be treated with [(SPhos)AuNTf2] (1 mol %) to afford a fluorinated 3,5-diketo carboxylic acid.
4-Homopyrazofurin and an acyclic analogue
Sauer,Schneller,Gabrielsen
, p. 71 - 79 (2007/10/02)
The synthesis of 4-hydroxymethyl-3(5)-(β-D-ribofuranosyl)pyrazole-5(3)-carboxamide (2, 4-homopyrazofurin) is described via a pathway that commences with the dipolar cycloaddition reaction of 2,5-anhydro-3,4,6-tri-O-benzyl-1-deoxy-1-diazo-D-allitol (4) and methyl 4-benzyloxy-2-butynoate (5). Preparation of 3(5)-[(2-hydrox,-ethoxy)methyl]-4-(hydroxymethyl)pyrazole-5(3)-carboxa mide (3) as a derivative of 2 possessing the truncated acyclic side chain of acyclovir has been accomplished in a similar manner beginning with the reaction of 5 with 1-diazo-2-[(2-benzyloxy)ethoxy]ethane (13). Neither compound 2 nor 3 showed any in vitro antiviral activity against human immunodeficiency virus (HIV-1), sandfly fever, Punta Toro, Japanese encephalitis, yellow fever, Venezuelan equine encephalomyelitis, and vaccinia viruses. Both compounds were also nontoxic. These results suggest that direct bonding of the hydroxyl group to the pyrazole ring is important for pyrazofurin based agents to demonstrate biological activity. The synthesis of 4-hydroxymethyl-3(5)- (β-D-ribofuranosyl)pyrazole-5(3)-carboxamide (2, 4-homo-pyrazofurin) is described via a pathway that commences with the dipolar cycloaddition reaction of 2,5-anhydro- 3,4,6-tri-O-benzyl-1-deoxy-1-diazo-D-allitol (4) and methyl 4-benzyloxy-2-butynoate (5). Preparation of 3(5)-[(2-hydrox,-ethoxy)methyl ]-4-(hydroxymethyl)pyrazole-5(3)-carboxamide (3) as a derivative of 2 possessing the truncated acyclic side chain of acyclovir has been accomplished in a similar manner beginning with the reaction of 5 with 1-diazo-2-[(2-benzyloxy)ethoxy]ethane (13). Neither compound 2 nor 3 showed any in vitro antiviral activity against human immunodeficiency virus (HIV-1), sandfly fever, Punta Toro, Japanese encephalitis, yellow fever, Venezuelan equine encephalomyelitis, and vaccinia viruses. Both compounds were also nontoxic. These results suggest that direct bonding of the hydroxyl group to the pyrazole ring is important for pyrazofurin based agents to demonstrate biological activity.
