678193-44-7Relevant articles and documents
N -Chlorinative Ring Contraction of 1,4-Dimethoxyphthalazines via a Bicyclization/Ring-Opening Mechanism
Im, Jeong Kyun,Jeong, Ilju,Yang, Byeongdo,Moon, Hyeon,Choi, Jun-Ho,Chung, Won-Jin
, p. 1760 - 1770 (2020/12/30)
An unprecedented N -chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n -Bu 4NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O -silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA.
N-Chlorination-induced, oxidative ring contraction of 1,4-dimethoxyphthalazines
Im, Jeong Kyun,Yang, ByeongDo,Jeong, Ilju,Choi, Jun-Ho,Chung, Won-jin
, (2020/06/03)
A rarely explored oxidative ring contraction of electron-rich 1,2-diazine is described. Upon treatment with an electrophilic chlorinating reagent (TCICA), 1,4-dimethoxyphthalazines undergo an N-chlorination-induced ring contraction that is accompanied by the loss of one nitrogen atom. The scope of this unusual reactivity was examined with a range of 1,4-dimethoxyphthalazine derivatives. In addition, a mechanism proceeding via a bicyclic species was proposed on the basis of an isolated reaction intermediate and DFT calculations.
3-Phenyl-6-(2-pyridyl)methyloxy-1,2,4-triazolo[3,4-a]phthalazines and Analogues: High-Affinity γ-Aminobutyric Acid-A Benzodiazepine Receptor Ligands with α2, α3, and α5-Subtype Binding Selectivity over α1
Carling, Robert W.,Moore, Kevin W.,Street, Leslie J.,Wild, Deborah,Isted, Catherine,Leeson, Paul D.,Thomas, Steven,O'Connor, Desmond,McKernan, Ruth M.,Quirk, Katherine,Cook, Susan M.,Atack, John R.,Wafford, Keith A.,Thompson, Sally A.,Dawson, Gerard R.,Ferris, Pushpinder,Castro, José L.
, p. 1807 - 1822 (2007/10/03)
Studies with our screening lead 5 and the literature compound 6 led to the identification of 6-benzyloxy-3-(4-methoxy)phenyl-1,2,4-triazolo[3,4-a]phthalazine 8 as a ligand with binding selectivity for the γ-aminobutyric acid-A (GABA-A) α3- and α5-containing receptor subtypes over the GABA-A α1 subtype (Ki: α2 = 850 nM, α3 = 170 nM, α5 = 72 nM, α1 = 1400 nM). Early optimization studies identified the close analogue 10 (Ki: α2 = 16 nM, α3 = 41 nM, α5 = 38 nM, α1 = 280 nM) as a suitable lead for further study. High-affinity ligands were identified by replacing the 6-benzyloxy group of compound 10 with 2-pyridylmethoxy (compound 29), but binding selectivity was not enhanced (K i: α2 = 1.7 nM, α3 = 0.71 nM, α5 = 0.33 nM, α1 = 2.7 nM). Furthermore, on evaluation in xenopus oocytes, 29 was discovered to be a weak to moderate inverse agonist at all four receptor subtypes α1, -7%; α2, -5%; α3, -16%; α5, -5%). Replacement of the 3-phenyl group of 29 with alternatives led to reduced affinity, and smaller 3-substituents led to reduced efficacy. Methyl substitution of the benzo-fused ring of 29 at the 7-, 8-, and 10-positions resulted in increased efficacy although selectivity was abolished. Increased efficacy and retention of selectivity for α3 over α1 was achieved with the 7,8,9,10-tetrahydro-(7,10-ethano)-phthalazine 62. Compound 62 is currently one of the most binding selective GABA-A α3-benzodiazepine-site partial agonists known, and although its selectivity is limited, its good pharmacokinetic profile in the rat (33% oral bioavailability after a 3 mg/kg dose, reaching a peak plasma concentration of 179 ng/mL; half-life of 1 h) made it a useful pharmacological tool to explore the effect of a GABA-A α2/α3 agonist in vivo.
