Synthesis of new cyano-substituted analogues of Troger's bases from bromo-derivatives. A stereochemical dependence of long-range (nJHH, n=4, 5, and 6) proton-proton and proton-carbon (nJCH, n=1, 2, 3, 4, and 5) coupling constants of these compounds

被引:4
|
作者
Dusso, Diego [1 ,2 ]
Ramirez, Cristina [3 ]
Parise, Alejandro [3 ]
Lanza, P. [3 ]
Mariano Vera, D. [3 ]
Chesta, Carlos [2 ]
Moyano, E. Laura [1 ]
Akhmedov, Novruz G. [4 ]
机构
[1] Univ Nacl Cordoba, Fac Ciencias Quim, INFIQC Dept Quim Organ, Ciudad Univ, Cordoba, Argentina
[2] Univ Nacl Rio Cuarto, Fac Ciencias Exactas Fis Quim & Nat, Cordoba, Argentina
[3] Univ Nacl Mar del Plata, Fac Ciencias Exactas & Nat, QUIAMM INBIOTEC Dept Quim, Mar Del Plata, Buenos Aires, Argentina
[4] West Virginia Univ, Eugene Bennett Dept Chem, Morgantown, WV 26506 USA
关键词
bsHSQCNOESY; CIGARAD; cyanation; EXSIDE; GIAO; microwaves; PSYCHE; Troger's bases; C-13; NMR-SPECTRA; ARYL IODIDES; CATALYZED CYANATION; CHEMICAL-SHIFTS; H-1; LIGAND; COPPER; PALLADIUM; GIAO/DFT; WATER;
D O I
10.1002/mrc.4872
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
A free-catalyst microwave-assisted cyanation of brominated Troger's base derivatives (2a-f) is reported. The procedure is simple, efficient, and clean affording the nitrile compounds (3a-e, I) in very good yields. Complete assignment of H-1 and C-13 chemical shifts of 2a-f, I and 3a-d, I was achieved using gradient selected 1D nuclear magnetic resonance (NMR) techniques (1D zTOCSY, PSYCHE, DPFGSE NOE, and DEPT), homonuclear 2D NMR techniques (gCOSY and zTOCSY), and heteronuclear 2D NMR techniques (gHSQCAD/or pure-shift gHSQCAD, gHMBCAD, bsHSQCNOESY, and gHSQCAD-TOCSY) with adiabatic pulses. Determination of the long-range proton-proton coupling constants (n)J(HH) (n = 4, 5, 6) was accomplished by simultaneous irradiation of two protons at appropriate power levels. In turn, determined coupling constants were tested by an iterative simulation program by calculating the H-1 NMR spectrum and comparing it to the experimental spectrum. The excitation-sculptured indirect-detection experiment (EXSIDE) and H-1-N-15 CIGARAD-HMBC (constant time inverse-detection gradient accordion rescaled heteronuclear multiple bond correlation) were applied for determination of long-range carbon-proton coupling constants (n)J(CH) (n = 2, 3, and 4) and for assignment of N-15 chemical shift at natural abundance, respectively. DFT/B3LYP optimization studies were performed in order to determine the geometry of 2c using 6-31G(d,p), 6-311G(d,p), and 6-311 + G(d,p) basis sets. For calculation of H-1 and C-13 chemical shifts, (n)J(HH) (n = 2, 3, 4, 5, and 6), and (n)J(CH) (n = 1, 2, 3, and 4) coupling constants, the GIAO method was employed at the B3LYP/6-31G(d,p), B3LYP/6-31+G(d,p), B3LYP/6-311+G(d,p), B3LYP/6-311++G(2d,2p), B3LYP/cc-pVTZ), and B3LYP/aug-cc-pVTZ) levels of theory. For the first time, a stereochemical dependence magnitude of the long-range (n)J(HH) (n = 4, 5, and 6) and (n)J(CH) (n = 1, 2, 3, 4, and 5) have been found in bromo-substituted analogues of Troger's bases.
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页码:423 / 454
页数:32
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