Nitrogenation of Alkynes with Nitrones to Prepare Functionalized [1,4]Oxazinones through Csp-Csp Bond Cleavage.

Herein, we report a novel strategy of hypervalent iodine(III) compound-mediated selective C-C bond cleavage of alkynes and C═N/N-O bond cleavage of nitrones and recombination of C-C/C-O/C-N multiple bonds to access various functionalized [1,4]oxazinones bearing a vicinal carbon stereocenter in good yields and high diastereoselectivity. Mechanistic studies revealed that the reaction undergoes a domino [4 + 3] cycloaddition, 1,3-rearrangement of N-O bond, intramolecular cyclization, dearomatization, and rearomatization over four steps in a single flask. The present method features good functional group tolerance, broad substrate scope, and C-C/C═N/N-O multiple bonds cleavage and recombination.

[Influencing of hep-2 cell function by RNAi silencing E-cadherin expression].

Objective: To explore the function of human laryngeal carcinoma Hep-2 cell after down-regulating the expression of E-cadherin gene to provide theoretical rationales for gene therapy of laryngeal cancer.

Methods: According to the GenBank database, 3 pairs of shRNA sequences of E-cadherin gene were designed and synthesized. shRNAs were transfected into the cell line Hep-2 by liposome.

Progesterone production requires activation of caspase-3 in preovulatory granulosa cells in a serum starvation model.

Granulosa cells proliferate, differentiate, and undergo apoptosis throughout follicular development. Previous studies have demonstrated that stimulation of progesterone production is accompanied by caspase-3 activation. Moreover, we previously reported that arsenic enhanced caspase-3 activity coupled with progesterone production.