One-Step Construction of 1,3,4-Oxadiazoles with Anticancer Activity from Tertiary Amines via a Sequential Copper(I)-Catalyzed Oxidative Ugi/aza-Wittig Reaction.

An unparalleled copper(I)-catalyzed synthesis of 1,3,4-oxadiazoles from tertiary amines in one step has been described. The one-pot reactions involving (N-isocyanimine)triphenylphosphorane, tertiary amines, and carboxylic acids resulted in the formation of 1,3,4-oxadiazoles in moderate to good yields through a consecutive oxidative Ugi/aza-Wittig reaction, enabling the direct functionalization of sp3 C-H bonds adjacent to the nitrogen atom. This method offered several notable advantages, including ligands-free, exceptional productivity and a high functional group tolerance. The preliminary biological evaluation demonstrated that compound 4f inhibited hepatoma cells efficiently, suggesting potentially broad applications of the approach for synthesis and medicinal chemistry.

Transplantation of neural stem cells overexpressing glial cell line-derived neurotrophic factor enhances Akt and Erk1/2 signaling and neurogenesis in rats after stroke.

BACKGROUND: Our previous studies have indicated that the beneficial effects of grafting neural stem cells (NSCs) overexpressing glial cell line-derived neurotrophic factor (GDNF) in rats after stroke. However, the underlying mechanisms are highly debatable. In this study, we investigated whether neurogenesis, Akt, and extracellular signal-regulated kinase 1/2 (Erk1/2) signaling were involved in this process. METHODS: Transient ischemic stroke were induced by occluding middle cerebral artery for 2 hours and reperfusion. At 3 days after reperfusion, GDNF/NSCs, NSCs, and vehicle were administered. Immunohistochemical staining was used to evaluate neurogenesis by nestin antibody; phosphorylation of Akt and Erk1/2 was investigated by Western blotting analysis. RESULTS: Transplantation of GDNF/NSCs and NSCs significantly increased nestin-positive cells compared to control group (vehicle) from 1 to 7 weeks after reperfusion, and GDNF/NSCs showed stronger effect than NSCs at 2 and 3 weeks after reperfusion. Meanwhile, enhanced phosphorylation level of Erk1/2 was observed in the GDNF/NSCs and NSCs groups compared with control group, and phosphorylation level of Erk1/2 in GDNF/NSCs group was remarkably higher than that of NSCs group at any given time. In contrast, expression of mitogen-activated protein kinase phosphatase-1 (MKP-1), known as inhibitor of Erk1/2 signaling, was significantly decreased in the GDNF/NSCs and NSCs groups compared with the control group. Moreover, much enhanced and prolonged phosphorylation level of Akt of GDNF/NSCs group was detected compared with control and NSCs group. CONCLUSION: Grafting GDNF/NSCs enhances neurogenesis and activates Akt and Erk1/2 signaling, that may provide the potential for GDNF/NSCs in stroke treatment.

[Effects of Ginsenoside RB1 on neural cell apoptosis and expressions of Bcl-2 and Bax in rats following subjected to cerebral ischemia-reperfusion].

OBJECTIVE: To observe the effects of Ginsenoside Rb1 (GRb1) on neuronal cell apoptosis and the expressions of Bcl-2 and Bax in rats after cerebral ischemia-reperfusion so as to investigate the neuroprotective mechanism of GRb1. METHDOS: The model of cerebral ischemia-reperfusion was established by occluding rat middle cerebral artery for 2 h. The rats were randomly divided into two groups: ischemia-reperfusion group (I/R group) and GRb1 treat group (GRb1 group). GRb1 (40 mg/kg, i.p.) was administered immediately to rats after the onset of reperfusion. Two groups were further subdivided 7 subgroups according to various reperfusion time (3 h, 12 h, 1 d, 2 d, 3 d, 5 d and 10 d, n=4 per time point). HE staining was used to observe histological features. TUNEL and immunohistochemical method were used to analyze the cell apoptosis and expressions of Bcl-2 and Bax, respectively. RESULTS: Compared with I/R group, GRb1 reduced pathological changes, and decreased the number of apoptotic neural cells (P<0.05 on 12 h, 1 d, 2 d and 3 d) and up-regulated the number of Bcl-2 positive cells (P<0.05 on 12 h, 1 d, 3 d, 5 d and 10 d), and meanwhile down-regulated the number of Bax positive cells (P<0.05 on 3 h, 12 h, 1 d, 2 d, 3 d, 5 d and 10 d) in the ipsilateral hemisphere. CONCLUSION: The neuroprotective effect of GRb1 on cerebral ischemia-reperfusion injury is related to inhibit neuronal apoptosis and to up-regulate the expression of Bcl-2 with down-regulating the expression of Bax.