Synthesis of multi-substituted allenes from organoalane reagents and propargyl esters by using a nickel catalyst.

A highly efficient and simple route for the synthesis of multi-substituted allenes has been developed by a nickel catalyzed SN2' substitution reaction of propargyl esters with organic aluminium reagents under mild conditions, which gave the corresponding multi-substituted allenes in good to excellent yields (up to 92%) and high selectivities (up to 99%) at 60 °C for 6 h in THF. Aryls bearing electron-donating or electron-withdrawing groups in propargyl esters gave products in good yields. In addition, the multi-substituted allenes bearing a thienyl or a pyridyl group were obtained in 95-97% selectivities with isolated yields of 72-83%. Furthermore, the SN2' substitution reaction worked efficiently with propargyl carbonate compounds as well. On the basis of the experimental results, a possible catalytic cycle has been proposed.

Nickel-catalyzed substitution reactions of propargyl halides with organotitanium reagents.

A simple and mild catalytic coupling reaction of propargyl halides with organotitanium reagents is reported. The reaction of propargyl bromide with organo-titanium reagents mediated by NiCl2 (2 mol%) and PCy3 (4 mol%) in CH2Cl2 afforded coupling product allenes in good to excellent yields (up to 95%) at room temperature. However, NiCl2(PPh3)2 was the best catalyst for substituted propargyl halides to yield allenes or alkynes preferentially. On the basis of the experimental results, a possible catalytic cycle has been proposed.

Laparoscopic liver resection under hemihepatic vascular inflow occlusion using the lowering of hilar plate approach.

BACKGROUND: With advances in technology, laparoscopic liver resection is widely accepted. Laparoscopic liver resection under hemihepatic vascular inflow occlusion has advantages over the conventional total hepatic inflow occlusion using the Pringle's maneuver, especially in patients with cirrhosis. METHOD: From November 2011 to August 2012, eight consecutive patients underwent laparoscopic liver resection under hemihepatic vascular inflow occlusion using the lowering of hilar plate approach with biliary bougie assistance. RESULTS: The types of liver resection included right hepatectomy (n=1), right posterior sectionectomy (n=1), left hepatectomy and common bile duct exploration (n=1), segment 4b resection (n=1), left lateral sectionectomy (n=2), and wedge resection (n=2). Four patients underwent right and 4 left hemihepatic vascular inflow occlusion. Four patients had cirrhosis. The mean operation time was 176.3 minutes. The mean time taken to achieve hemihepatic vascular inflow occlusion was 24.3 minutes. The mean duration of vascular inflow occlusion was 54.5 minutes. The mean intraoperative blood loss was 361 mL. No patient required blood transfusion. Postoperatively, one patient developed bile leak which healed with conservative treatment. No postoperative liver failure and mortality occurred. The mean hospital stay of the patients was 7 days. CONCLUSION: Our technique of hemihepatic vascular inflow vascular occlusion using the lowering of hilar plate approach was safe, and it improved laparoscopic liver resection by minimizing blood loss during liver parenchymal transection.

Electrochemical desulfurative formation of C-N bonds through selective activation of inert C(sp3)-S bonds.

In this study, we introduce an efficient, metal-free electrocatalytic desulfurative protocol for forming C-N bonds by selectively activating inert C(sp3)-S bonds of alkyl thioethers. This method offers a straightforward and environmentally friendly approach for modification of heterocyclic compounds from readily accessible thioethers. Preliminary mechanistic investigations suggest that the reaction proceeds via a carbocation intermediate. Furthermore, successful synthesis on a 10-gram scale was achieved in a continuous flow electrochemical reactor.

Metal-free photoinduced C(sp3)-H/C(sp3)-H cross-coupling to access α­tertiary amino acid derivatives.

The cross-dehydrogenative coupling (CDC) reaction is the most direct and efficient method for constructing α-tertiary amino acids (ATAAs), which avoids the pre-activation of C(sp3)-H substrates. However, the use of transition metals and harsh reaction conditions are still significant challenges for these reactions that urgently require solutions. This paper presents a mild, metal-free CDC reaction for the construction of ATAAs, which is compatible with various benzyl C-H substrates, functionalized C-H substrates, and alkyl substrates, with good regioselectivity. Notably, our method exhibits excellent functional group tolerance and late-stage applicability. According to mechanistic studies, the one-step synthesized and bench-stable N-alkoxyphtalimide generates a highly electrophilic trifluoro ethoxy radical that serves as a key intermediate in the reaction process and acts as a hydrogen atom transfer reagent. Therefore, our metal-free and additive-free method offers a promising strategy for the synthesis of ATAAs under mild conditions.

Highly selective cross-coupling reactions of 1,1-dibromoethylenes with alkynylaluminums for the synthesis of aryl substituted conjugated enediynes and unsymmetrical 1,3-diynes.

A highly efficient method for the synthesis of aryl substituted conjugated enediynes and unsymmetrical 1,3-diynes via selective cross-coupling reactions of 1,1-dibromoethylenes with alkynylaluminums using the Pd(OAc)2-DPPE and Pd2(dba)3-TFP complexes as catalysts, respectively, has been successfully developed. Though the alkyl substituted conjugated enediynes and unsymmetrical 1,3-diynes were not obtained, this case is also remarkable as the same starting materials could selectively produce either aryl substituted conjugated enediynes or unsymmetrical 1,3-diynes in moderate to excellent yields (up to 99%) in the different Pd-phosphine catalytic systems.

Cs2CO3 catalyzed direct aza-Michael addition of azoles to α,ß-unsaturated malonates.

A highly efficient method for the synthesis of azole derivatives via a direct aza-Michael addition of azoles to α,ß-unsaturated malonates using Cs2CO3 as a catalyst, has been successfully developed. A series of azole derivatives have been obtained in up to 94% yield and the reaction could be amplified to gram scale in excellent yield in the presence of 10 mol% of Cs2CO3.

Differences between conventional wound closure and a closed suction irrigation method for the prevention of surgical site infection-a comparative study.

BACKGROUND: Wound infections can lead to high risks of postoperative septic complications. To date, the efficacy of a closed suction irrigation method of wound closure on the rate of postoperative wound infection in patients is poorly understood. Therefore, comparing this new strategy with conventional primary wound closure on the incidence of postoperative wound infection can provide value for clinical treatment. METHODS: Our study focused on retrospective research for patients with open abdominal wounds. All patients were referred by tertiary hospitals and registered in our hospital from January 2009 to July 2019. According to wound types, patients were divided into two groups, namely patients with wounds primarily closed as the control group and patients with wounds sutured by closed suction irrigation after primary closure as the study group. RESULTS: A total of 159 patients were collected in our present research, with 86 as study subjects and 73 as control subjects. The wound infection rate was significantly lower in the study group than the control group (P=0.017). The time interval for diagnosing wound infection from the primary operation was 4.895±0.875 days for the study group and 4.509±0.697 days for the control group. The length of hospital stay and the time taken for the wound to heal completely was shorter in patients in the study group compared to patients in the control group (8.046±2.110 vs. 8.983±2.887 days and 8.092±3.258 vs. 10.328±6.074 days, respectively). CONCLUSIONS: The closed suction irrigation method significantly reduced postoperative wound infection rates in patients with a high risk of postoperative septic complications. The discoveries of our investigation should be further validated in large scope randomized controlled trials.

MicroRNA-424 may function as a tumor suppressor in endometrial carcinoma cells by targeting E2F7.

MicroRNAs (miRNAs) are frequently dysregulated in human cancers and can act as potent oncogenes or tumor suppressor genes. Aberrant expression of miR-424 has been identified in some types of cancer, however, its expression and potential biologic role in endometrial cancer are remains to be determined. In the present study, we demonstrated that miR-424 was downregulated in human endometrial cancer and suppressed growth of the human Ishikawa and HEC-1B endometrial cancer cell lines. Bioinformatics analysis indicated that E2F7 was a putative target of miR-424. In a luciferase reporter system, we confirmed that E2F7 was a direct target gene of miR-424. Furthermore, knockdown of E2F7 inhibited Ishikawa and HEC-1B cell growth. These findings indicate that miR-424 targets the E2F7 transcript and suppresses endometrial cancer cell growth, suggesting that miR-424 has a tumor suppressive role in human endometrial cancer pathogenesis.