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Breeding for preharvest sprouting (PHS) resistance is of great interest in wheat-growing areas where high rainfall occurs during grain ripening and harvest. We have characterized 32 wheat accessions using 33 microsatellite markers flanking PHS quantitative trait loci (QTLs) previously identified on group 3, 4, 5, and 6 chromosomes of hexaploid wheat. A(More)
N-Halosuccinimides (NXS, 1) are efficiently activated in trifluoromethanesulfonic acid and BF(3)-H(2)O, allowing the halogenations of deactivated aromatics. Because BF(3)-H(2)O is more economic, easy to prepare, nonoxidizing, and offers sufficiently high acidity (-H(0) approximately 12, only slightly lower than that of trifluoromethanesulfonic acid), an(More)
By using density functional theory (DFT) method at the B3LYP/6-311+G level, it has been shown that the preference for the singlet-state phenyl cation can be dramatically increased relative to the triplet state by introducing onium cationic substituents in the para position. At this level of theory, the singlet ground state for the parent phenyl cation was(More)
Both pivaloyl cation in the presence of hydride donors and protonated pivalaldehyde in superacid media (both aprotic and protic) rearrange to protonated methyl isopropyl ketone involving gitionic dicationic intermediates. In our earlier studies we have found that the rearrangement of pivaladehyde to methyl isopropyl ketone occurs quantitatively in the(More)
Isomeric 1- and 3-isoquinolinols (11 and 12) when activated in CF(3)SO(3)H-SbF(5) acid system undergo selective ionic hydrogenation with cyclohexane to give 5,6,7,8-tetrahydro-1(2H)- and 5,6,7,8-tetrahydro-3(2H)-isoquinolinones (22 and 27). Under the influence of aluminum chloride similar products were also obtained along with 3,4-dihydro-1(2H)- and(More)
Aromatic carboxylic acids are obtained in good to excellent yield essentially free of diaryl ketones by carboxylation of aromatics with a carbon dioxide-Al(2)Cl(6)/Al system at moderate temperatures (20-80 degrees C). To optimize reaction conditions and study the reaction mechanism, experimental variables including temperature, amount of Al(2)Cl(6)/Al,(More)
Structures of the tert-pentyl cation (C(5)H(11)(+)) and its protonated dication (C(5)H(12)(2+), isopentane dication) were studied using ab initio methods at the MP2/cc-pVTZ level. Both C-C and C-H hyperconjugatively stabilized structures 1 and 2 , respectively, were found to be minima on the potential energy surface (PES) of the tert-pentyl cation.(More)
A series of silylated carboxonium ions, 2a-6a, were prepared as long-lived species by treating triethylsilane and triphenylmethyl tetrakis(pentafluorophenyl)borate (Ph3C(+)B(C6F5)4-) with ketones, enones, carbonates, amides, and urea in CD2Cl2 solution. They were characterized by 13C and 29Si NMR spectroscopy at -78 degrees C. The NMR study indicates that(More)
The mechanism of electrophilic aromatic nitration was revisited. Based on the available experimental data and new high-level quantum chemical calculations, a modification of the previous reaction mechanism is proposed involving three separate intermediates on the potential energy diagram of the reaction. The first, originally considered an unoriented(More)
Contrary to previous theoretical studies at the UHF/6-31G* level, the methonium radical dication CH5(2+) is not a Cs symmetrical structure with a 2e-3c bond but a C2v symmetrical structure 1 with two 2e-3c bonds (at the UHF/6-31G**, UMP2/6-31G**, and UQCISD(T)/6-311G** levels). The Cs symmetrical structure is not even a minimum at the higher level of(More)