Chongqing Kerui Pharmaceutical Co. Ltd.

C19H18N2O, orthorhombic, Pna21 (no. 33), a = 21.838(2) Å, b = 13.9663(11) Å, c = 4.9806(4) Å, V = 1519.1(2) Å3, Z = 4, Rgt(F) = 0.0702, wRref(F2) = 0.1948, T = 293 K.

Herein, we disclose a radical desulfurative C-C coupling protocol for the synthesis of 4-alkylpyridines. A variety of substituents on both benzyl thiols and 4-cyanopyridines are tolerated. The reaction is carried out under mild and photocatalyst- and transition-metal-free conditions. Preliminary mechanistic studies show that an electron donor-acceptor complex is formed between benzyl thiols and 4-cyanopyridines under alkaline conditions. Then, a variety of 1°, 2°, and 3° C(sp³)-centered radicals was formed by cleavage of the C-S bond, and the 4-alkylpyridines were achieved through a radical-radical coupling with the pyridyl radical anion.

A review.Anal. and recommendations for determination of heavy metals in Traditional Chinese medicine were introduced.