74,931 research outputs found
Electrochemical oxidative Z-selective C(sp2)-H chlorination of acrylamides
No full textAn electrochemical method for the oxidative Z-selective C(sp2)–H chlorination of acrylamides has been developed. This catalyst and organic oxidant free method is applicable across various substituted tertiary acrylamides, and provides access to a broad range of synthetically useful Z-β-chloroacrylamides in good yields (22 examples, 73% average yield). The orthogonal derivatization of the products was demonstrated through chemoselective transformations and the electrochemical process was performed on gram scale in flow
Synthesis and crystallographic analysis ofmeso-2,3-difluoro-1,4-butanediol andmeso-1,4-dibenzyloxy-2,3-difluorobutane
No full textA large-scale synthesis of meso-2,3-difluoro-1,4-butanediol in 5 steps from (Z)-but-2-enediol is described. Crystallographic analysis of the diol and the corresponding benzyl ether reveals an anti conformation of the vicinal difluoride moiety. Monosilylation of the diol is high-yielding but all attempts to achieve chain extension through addition of alkyl Grignard and acetylide nucleophiles failed.<br/
The Benefits of Being Economics Professor A (and not Z)
No full textAlphabetic name ordering on multi-authored academic papers, which is the convention in the economics discipline and various other disciplines, is to the advantage of people whose last name initials are placed early in the alphabet. As it turns out, Professor A, who has been a first author more often than Professor Z, will have published more articles and experienced afaster growth rate over the course of her career as a result of reputation and visibility. Moreover, authors know that name ordering matters and indeed take ordering seriously: Several characteristics of an author group composition determine the decision to deviate from the default alphabetic name order to a significant extent.performance measurement, incentives, economists, name ordering
Final word on Jersey Dutch
No full textIn this article, William Z. Shetter compares and contrasts the dialects that developed between different Dutch colonies in the New World. He explores in-depth the nuances of Jersey Dutch, and provides theories to explain how Dutch and colonial languages blended. The article is reprinted from American Speech, December 1958, Volum XXXIII, No. 4
X-ray crystallographic structure and absolute configuration of the cyclic Di-amino acid peptide: Cyclo(L-HomoCySH-L-HomoCySH)
No full textThe cyclic di-amino acid peptide cyclo(l-homoCySH-l-homoCySH) [(3S, 6S)-3, 6-bis(2-sulfanylethyl) piperazine-2,5-dione, C8H14N2O2S2, crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 6.1509(2) Å, b = 18.0217(9) Å, c = 29.6166(14) Å, V = 3283.0(2) Å3, Z = 12 (3 molecules, A, B and C, per asymmetric unit), D c = 1.422 g cm−3 and a linear absorption coefficient of 0.464 mm−1. The crystal structure determination was carried out with MoKα X-ray data measured at 120(2) K. In the final refinement cycle the data/restraints/parameter ratios were 5595/0/385 and goodness-of-fit on F 2 = 1.084. Final R indices for [I > 2sigma(I)] were R1 = 0.0746, wR2 = 0.1356 and R indices (all data) R1 = 0.1092, wR2 = 0.1529. The largest electron density difference peak and hole were 0.526 and −0.445e Å−3. The DKP rings in all three molecules are essentially, and unusually, planar and the C=O oxygen atoms are co-planar with the ring in each case. Ring atom rms deviations, including the =O groups, are 0.0668, 0.0658 and 0.0656 Å in molecules A, B and C, respectively. Details of the molecular geometry are compared with the compound cyclo(Gly-Gly) (Degeilh R, Marsh RE Acta Cryst 12:1007, 1959) and in addition some cyclic di-amino acid peptides in which the DKP rings have more puckered boat conformation
X-ray crystallographic structure of the cyclic di-amino acid peptide: N,N′-Diacetyl-cyclo(Gly-Gly)
No full textThe cyclic di-amino acid peptide N,N;-diacetylcyclo(Gly-Gly), C(8)H(10)N(2)O(4), crystallizes in the triclinic space group P (1) over bar with unit cell parameters a = 9.4855(4) angstrom, b = 10.0250(3) angstrom, c = 10.0763(4) angstrom, alpha = 73.682(2)degrees, beta = 82.816(2)degrees, gamma = 81.733(2)degrees, V = 906.40(6) angstrom(3), Z = 4 (2 molecules, A and B, per asymmetric unit), D(c) = 1.452 g cm(-3) and linear absorption coefficient 0.118 mm(-1). The crystal structure determination was carried out with MoK alpha X-ray data measured at 120(2) K. In the final refinement cycle the data/restraints/parameter ratios were 4124/0/258 and goodness-of-fit on F(2) = 1.0008. Final R indices for [I > 2 sigma(I)] were R(1) = 0.0501, wR(2) = 0.1007 and R indices (all data) R(1) = 0.0864, wR(2) = 0.11180. The largest electron density difference peak and hole were 0.241 and -0.232 e angstrom(-3), respectively. The DKP rings in both molecules A and B have boat conformations with pseudo mm2 (C(2v)) symmetry if the N atoms and CH(2) groups are considered identical. In each case, the prow and stern of the boat are the alpha-carbons C(3) and C(6). The overall molecular symmetry of molecules A and B is approximately C(2) with the twofold symmetry axis of the DKP boat being maintained through the centre of the DKP ring. Details of the molecular geometry are compared with that of the parent compound cyclo(Gly-Gly) in which the DKP ring is planar with exact symmetry (1) over bar (C(i))
Synthesis and Characterization of Platinum and Palladium Complexes Featuring a Rare Secondary Borane Pincer Motif
No full textThe synthesis and characterization
of a series of platinum and
palladium complexes containing a secondary borane Z-class ligand supported
by 2-mercaptopyridine heterocycles is reported herein. Addition of
2 equiv of Na[H2B(mp)2] to [Pt(μ-Cl)(COEOMe)]2 (where COEOMe = 8-methoxycyclooct-4-en-1-ide)
in the presence of 2 equiv of a tertiary phosphine (PR3 = PPh3, PCy3, PCyp3, P(o-tol)3, PPh2(o-tol),
PPh2(2-(3-methyl)indolyl)) leads to the formation of the
complexes [Pt{κ3-S,B,S-HB(mp)2}(PR3)] (1–6).
Addition of 2 equiv of Na[H2B(mp)2] to [Pd(μ-Cl)(COEOMe)]2 in the presence of 2 equiv of a tertiary
phosphine (PR3 = PPh3, PCy3, PCyp3, PPh2(o-tol)) leads to the formation
of the complexes [Pd{κ3-S,B,S-HB(mp)2}(PR3)] (7–10).
It was also demonstrated that the synthesis of the palladium complex 7 could be achieved from the palladium precursor [PdCl(Me)(COD)]
(where COD = 1,5-cyclooctadiene) as an alternative synthetic strategy.
In the above reactions, either the COEOMe fragment or the
methyl fragment serves to act as a “hydride acceptor”
facilitating the ultimate transformation of the borohydride-based
ligand [H2B(mp)2]− to the
corresponding secondary borane κ3-S,B,S coordinated HB(mp)2 pincer ligand. The complexes [Pd{κ3-S,B,S-HB(mp)2}(PR3)] and [Pt{κ3-S,B,S-HB(mp)2}(PR3)] are rare examples of metal–borane
complexes where one hydrogen substituent remains at the boron center.
These compounds have particularly short palladium– and platinum–boron
distances, the shortest of the structurally characterized compounds
being 2.067(6) Å for [Pd{κ3-S,B,S-HB(mp)2}(PPh2(o-tol))] and
2.076(10) Å for [Pt{κ3-S,B,S-HB(mp)2}(PCy3)], respectively (the shorter
distances of two independent complexes in the unit cells of both structures)
Synthesis of a biphenyl library for studies of hydrogen bonding in the solid state
No full textA biphenyl library incorporating amide and sulfonamide groups has been synthesised via microwave-mediated Suzuki-Miyaura couplings. Many derivatives were crystallised from dichloromethane/methanol and analysed by single crystal X-ray diffraction. An interesting structure was obtained for N-(4'-methylbiphenyl-4-yl)acetamide with Z'=6 and hydrogen-bonding networks of the type N-H ··· O in the unit cell
Synthesis and evaluation of metallocene containing methylidene-1,3-dihydro-2H-indol-2-ones as kinase inhibitors
No full text(E)- and (Z)-3-Ferrocenylmethylidene-1,3-dihydro-2H-indol-2-ones 1 have been structurally modified in order to explore SAR against a range of kinases. Of note is the submicromolar to low micromolar inhibition of DYRK3 and 4 by a number of complexes. Screening using Xenopus embryos showed some of the compounds to have potent antiangiogenisis activity
Data set for: A chiral interlocking auxiliary strategy for the synthesis of mechanically planar chiral rotaxanes
No full textData to support article in Nature Chemistry. A chiral interlocking auxiliary strategy for the synthesis of mechanically planar chiral rotaxanes Full characterisation data for all reported compounds (NMR, MS, CD, SCXRD) https://doi.org/10.1038/s41557-021-00875-z</span
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