135450-43-0Relevant articles and documents
Development of a Scalable and Practical Synthesis of AB928, a Dual A2a/A2bReceptor Antagonist
Debien, Laurent P. P.,Jeffrey, Jenna L.,Leleti, Manmohan R.,Miles, Dillon H.,Powers, Jay P.,Rosen, Brandon R.,Sharif, Ehesan U.
, p. 1254 - 1261 (2020)
AB928 is a potent and selective dual antagonist of the A2a and A2b receptors, which is currently in clinical trials. Here, we report the development of two scalable and practical syntheses of AB928. The first-generation synthesis was used to successfully
Spin State Variations and Spin-Crossover in Diiron(II) Complexes of Bis(pentadentate) Pyrazolate-Based Ligands
Schober, Anne,Demeshko, Serhiy,Meyer, Franc
, p. 719 - 728 (2018)
Compartmental pyrazolato-bridged ligands [LPy]? and [LIm]?, each providing two {N5} binding sites but differing in the terminal N-donors (pyridine vs. imidazole), were used to prepare a set of diferrous complexes; the ligand HLIm is new and its synthesis is reported. Complexes [LPyFe2(MeCN)2](OTf)3, (1OTf), [LPyFe2(MeCN)2](BF4)3 (1BF4), [LImFe{Fe(MeCN)}](OTf)3 (2OTf), and [LImFe{Fe(MeCN)}](BF4)3 (2BF4) were characterized by single-crystal X-ray diffraction, revealing a MeCN coligand at both (1OTf, 1BF4) or at only one (2OTf, 2BF4) of the two accessible Fe coordination sites that are directed into the bimetallic cleft. Magnetic measurements (SQUID) and 57Fe M??bauer spectroscopy indicate low-spin states for the six-coordinate FeII ions in 1OTf and 1BF4 that are based on [LPy]?, but two high-spin FeII ions in 2BF4 that is based on [LIm]?, in agreement with structural data. Complex 2OTf shows abrupt spin-crossover (SCO) from a mixed high-spin/low-spin to an all high-spin state at T? = 264 K, which appears to be correlated with the Fe–N≡C(Me) bonding angle. SCO, though gradual, is observed for 2OTf also in solution (T? = 273 K in MeCN, 248 K in EtCN), which was studied by M?ssbauer spectroscopy of frozen solution samples, variable temperature UV/Vis spectroscopy and SQUID magnetometry; the latter methods consistently gave thermodynamic parameters ΔH = 24.2 kJ·mol–1, ΔS = 89 J·mol–1·K–1 for the SCO of 2OTf in MeCN, and ΔH = 19.1 kJ·mol–1, ΔS = 77 J·mol–1·K–1 in EtCN.
Methodology for in situ protection of aldehydes and ketones using trimethylsilyl trifluoromethanesulfonate and phosphines: Selective alkylation and reduction of ketones, esters, amides, and nitriles
Yahata, Kenzo,Minami, Masaki,Yoshikawa, Yuki,Watanabe, Kei,Fujioka, Hiromichi
, p. 1298 - 1307 (2014/01/06)
A methodology for selective transformations of ketones, esters, Weinreb amides, and nitriles in the presence of aldehydes has been developed. The use of a combination of PPh3-trimethylsilyl trifluoromethanesulfonate (TMSOTf) promotes selective transformation of aldehydes to their corresponding, temporarily protected, O,P-acetal type phosphonium salts. Because, hydrolytic work-up following ensuing reactions of other carbonyl moieties in the substrates liberates the aldehyde moiety, a sequence involving aldehyde protection, transformation of other carbonyl groups, and deprotection can be accomplished in a one-pot manner. Furthermore, the use of PEt3 instead of PPh 3 enables ketones to be converted in situ to their corresponding O,P-ketal type phosphonium salts and, consequently, selective transformations of esters, Weinreb amides, and nitriles in the presence of ketones can be performed. This methodology is applicable to various dicarbonyl compounds, including substrates that possess heteroaromatic skeletons and hydroxyl protecting groups.
