Electrochemically Enabled Double C-H Activation of Amides: Chemoselective Synthesis of Polycyclic Isoquinolinones.

We developed an electrochemically enabled dehydrogenative annulation reaction of amides and alkynes for the synthesis of antitumor polycyclic isoquinolinones through a double C-H activation route. No external oxidant is required in this reaction, and electricity is used for Ru catalyst circulation. The most remarkable feature of this reaction is the effective improvement of product regioselectivity under mild electrolytic conditions in comparison with previously set strong oxidant conditions.

[Effects of fluoride on Fas signal pathway in rat incisor cells].

OBJECTIVE: To investigate the effects of fluoride on Fas expression, caspase-3 and caspase-8 activity and apoptosis in rat incisor cells. METHODS: Forty male SD rats were divided into 4 groups randomly and provided with distilled water containing NaF at the doses of 0, 10, 50 and 100 mg/L respectively. Each group had 10 animals. Five animals were sacrificed at 60 and 90 days respectively. Fas expression was measured with immunohistochemistry, and colorimetric assay was used to examine caspase-3 and caspase-8 activity with enzyme-labelled meter. The apoptosis was detected by flow cytometry in mandibular incisor cells. RESULTS: NaF at the doses of 10, 50 and 100 mg/L for 60 d and 90 d caused Fas overexpression, promoted activity of caspase-3 and caspase-8, increased apoptosis rate in mandibular incisor cells. At 60 days, the value of Fas expression was 0.1819 ± 0.0025 for control, 0.2120 ± 0.0084 for 10 mg/L NaF group, 0.2283 ± 0.0183 for 50 mg/L NaF group, 0.2818 ± 0.0233 for 100 mg/L NaF group. At 90 days, the value of Fas expression was 0.2077 ± 0.0289 for control, 0.2216 ± 0.0105 for 10 mg/L NaF group, 0.2377 ± 0.0059 for 50 mg/L NaF group, 0.2775 ± 0.0088 for 100 mg/L NaF group. Statistics analysis yielded close relationship between the dose of NaF in water and the Fas expression, and also between the dose of NaF in water and caspase-3 activities, and the relative coefficient was 0.9728 (60 d, P < 0.01) and 0.9889 (90 d, P < 0.01) for Fas expression, 0.9533 (60 d, P < 0.01) and 0.9849 (90 d, P < 0.01) for caspase-3 activity respectively. Apoptosis rate and caspase-8 activity also had close relationship with the NaF doses, and the relative coefficient was 0.9733 (90 d, P < 0.01) for apoptosis, 0.9928 (90 d, P < 0.01) for caspase-8. At the doses of 10, 50 and 100 mg/L NaF for 60 d and 90 d, obvious relationship was found between Fas expression and caspase-3 activity, and the relative coefficient was 0.9619 (60 d, P < 0.01) and 0.9912 (90 d, P < 0.01). Obvious relationship between Fas expression and apoptosis, between Fas expression and caspase-8 activity was found in groups for 90 d, and the relative coefficient was 0.9841 (P < 0.01) for apoptosis, 0.9767 (P < 0.01) for caspase-8. CONCLUSIONS: Fluoride could induce Fas overexpression and mediate caspase activation and apoptosis at the doses of 10, 50 and 100 mg/L for 60 d and 90 d in rat mandibular incisor cells.