C(alkyl)-C(vinyl) bond cleavage enabled by Retro-Pallada-Diels-Alder reaction.

Activation and cleavage of carbon-carbon (C-C) bonds is a fundamental transformation in organic chemistry while inert C-C bonds cleavage remains a long-standing challenge. Retro-Diels-Alder (retro-DA) reaction is a well-known and important tool for C-C bonds cleavage but less been explored in methodology by contrast to other strategies. Herein, we report a selective C(alkyl)-C(vinyl) bond cleavage strategy realized through the transient directing group mediated retro-Diels-Alder reaction of a six-membered palladacycle, which is obtained from an in situ generated hydrazone and palladium hydride species. This unprecedented strategy exhibits good tolerances and thus offers new opportunities for late-stage modifications of complex molecules. DFT calculations revealed that an intriguing retro-Pd(IV)-Diels-Alder process is possibly involved in the catalytic cycle, thus bridging both Retro-Diels-Alder reaction and C-C bond cleavage. We anticipate that this strategy should prove instrumental for potential applications to achieve the modification of functional organic skeletons in synthetic chemistry and other fields involving in molecular editing.

The Modified Rectangle Flap Epicanthoplasty: A Novel and Individualized Design.

BACKGROUND: The epicanthal fold is ordinary in the eyelids of Asians, and the aesthetic appearance of eyelid surgery could be reduced and undermined; thus, medial epicanthoplasty is commonly performed to eliminate the effect of the epicanthal fold with less scarring. At present, there are a lot of techniques that have been described for the treatment of epicanthal fold. The potential problems, however, such as visible scar or under correction in the medial canthus area are challenges to surgeons. The purpose of our study was to explore a novel and individualized design using a modified rectangle flap with acceptable functional and aesthetic outcomes. METHODS: From January 2017 to January 2018, epicanthoplasty was performed for 40 patients by using a modified rectangle flap. All patients underwent double-eyelid surgery at the same time when they needed it. The evaluation criteria included the intercanthal distance (ICD), interpupillary distance (IPD), the ratio of ICD to IPD (ICD ratio), scar visibility, and cosmetic results. RESULTS: From January 2017 to January 2018, the modified rectangle flap method was carried out on 40 patients, who were evaluated at follow-up from 7 to 15 months. The average intercanthal length was 36.9 ± 2.2 mm preoperatively and decreased significantly to 31.5 ± 1.8 mm postoperatively, 7 months after the surgery (P < 0.01). The excellent cosmetic results, in terms of an open medial canthus, were observed during follow-up periods, with no definite recurrence, hypertrophic scar, or injury of the lacrimal apparatus. The inner canthus and lacrimal caruncle are fully exposed with an invisible scar. Both the patients and the surgeon judged that the aesthetic outcomes were excellent or good. CONCLUSIONS: This modified rectangular flap is an effective and personalized method of correcting the medial folds that leave no additional scar in the medial canthal area, and the procedure meets the patient's aesthetic expectations. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Copper-Promoted 6- endo-trig Cyclization of ß,γ-Unsaturated Hydrazones for the Synthesis of 1,6-Dihydropyridazines.

A novel and efficient strategy for the synthesis of 1,6-dihydropyridazines via copper-promoted 6- endo-trig cyclization of readily available ß,γ-unsaturated hydrazones have been developed. A series of 1,6-dihydropyridazines have been synthesized by this method with good yields, high functional group tolerance, and remarkable regioselectivity under mild conditions. Importantly, the 1,6-dihydropyridazines can be efficiently converted to biologically important pyridazines in the presence of NaOH.

Transfection of adenovirus-mediated mircoRNA-126 gene into infant hemangioma endothelial cells in vitro.

Objective: To investigate the effects of microRNA-126 (miR-126) overexpression on hemangioma endothelial cells (HemECs). Methods: An adenoviral vector containing the miR-126 gene was constructed. HemECs were passaged and expanded and adenovirus-mediated green fluorescent protein (GFP) gene was transfected in vitro. The infection efficiency of adenovirus vector to HemECs was tested by Ad-GFP infection procedure. GFP expression efficiency was observed using a fluorescence microscope and flow cytometry was used to determine the best virus multiplicity of infection (MOI). The experiment was divided into the blank group, AD-GFP group, and AD-miR-126 group. The miR-126 group was transfected into HemECs in vitro with adenovirus-mediated miR-126 gene under optimal MOI conditions. RT-PCR was applied to detect expression of miR-126 gene in cells. The influence of recombinant adenovirus on cell activity was evaluated by CCK-8 assay. Flow cytometry was utilized to detect cell cycle and apoptosis. Results: HemECs could be effectively infected by adenovirus containing GFP gene in vitro, the transfection efficiency had the dose-effect relationship with multiplicities of infection (MOI). When MOI was 400, the infection efficiency was more than 90%. miR-126 expression in HemECs was significantly enhanced in miR-126 group (P<0.05). Compared to the control group, cell proliferation was significantly enhanced (P<0.05) and induced S-phase arrest significantly (P<0.05) when miR-126 was upregulated. In addition, compared with the control group, the early apoptotic rate was significantly decreased by upregulating miR-126 (P<0.05). Conclusion: miR-126 overexpression can successfully promote proliferation and inhibit apoptosis of HemECs. This work will provide the theoretical and experimental basis for further transplantation study in vivo.

K2CO3-Mediated Cyclization and Rearrangement of γ,δ-Alkynyl Oximes To Form Pyridols.

A novel K2CO3-mediated cyclization and rearrangement of γ,δ-alkynyl oximes for the synthesis of pyridols is described. The process accomplishes an efficient [1,3] rearrangement of the O-vinyl oxime intermediate which is in situ generated from the intramolecular nucleophilic addition of γ,δ-alkynyl oximes. The reaction employs readily accessible starting materials, tolerates a wide range of functional groups, and gives a variety of synthetically challenging pyridols in good yields.

[Quantitative HPLC analysis of main effective constituents and integrated chemical quality index(ICQI)in Dida].

"Dida" is one of the most representative commonly used Tibetan medicines in treatment of hepatobilaiary diseases. To analyze and compare the content of 7 effective constituents in 11 species which are used as Dida. Integrated evaluation of them, which supply a basis for the resources exploitation for them. In this paper, most appropriate absorption wavelengths of different natural iridoid compounds, xanthones and oleanolic acid have been performed by using 3D spectrum technique. According to the results, the wavelength 210, 240 and 265 nm were used for detection of 7 effective constituents. By means of calculation, determination of 7 effective constituents indicated good linearity over the linear range with coefficients (r) of 0.999 9 respectively. The recoveries were found in the average range of 99% to 101% with RSD being less than 3%. Normalize and integrate by three-dimension the data. Get their integrated chemical quality index(ICQI). Results suggested that these plants used as Dida in Tibet medicine mostly contain these 7 effective constituents, but the different is notable. The integrated evaluation by the integrated chemical quality index (ICQI) has reference value for quality control.