Low-Temperature Fabrication of Plate-like α-Al2O3 with Less NH4F Additive.

Fluorinated compounds are effective mineralization agents for the fabrication of plate-like α-Al2O3. However, in the preparation of plate-like α-Al2O3, it is still an extremely challenging task to reduce the content of fluoride while ensuring a low synthesis temperature. Herein, oxalic acid and NH4F are proposed for the first time as additives in the preparation of plate-like α-Al2O3. The results showed that plate-like α-Al2O3 can be synthesized at a low temperature of 850 °C with the synergistic effect of oxalic acid and 1 wt.% NH4F. Additionally, the synergistic effect of oxalic acid and NH4F not only can reduce the conversion temperature of α-Al2O3 but also can change the phase transition sequence.

In Vivo Evaluation of a Gallium-68-Labeled Tumor-Tracking Cyanine Dye for Positron Emission Tomography/Near-Infrared Fluorescence Carcinoma Imaging, Image-Guided Surgery, and Photothermal Therapy.

Positron emission tomography (PET)/near-infrared fluorescence (NIRF) dual-modal imaging presents an enticing prospect for tumor diagnosis and surgical navigation. In this study, we developed a novel probe IR808-DOTA for tumor-targeted PET/NIRF imaging, image-guided surgery, and photothermal therapy. This construct had better water solubility and pharmacokinetics than IR808 and had similar photophysical properties, tumor targeting ability, and photothermal anticancer effect to IR808. By a simple labeling process, IR808-DOTA was labeled with gallium-68 and applied as a PET probe for tumor imaging in MCF-7 tumor xenografted mice. IR808-DOTA itself acted as an NIRF imaging agent in the following surgery for intraoperative navigation to aid surgeons in the delineation of tumor margins and visualizing sentinel lymph nodes to facilitate a more thorough tumor resection. Irradiation by laser, IR808-DOTA could prominently inhibit tumor growth in MCF-7 subcutaneous tumor model mice by directly ablating tumor cells, inhibiting tumor proliferation, and promoting tumor cell apoptosis. In summary, 68Ga-DOTA-IR808 could enable a convenient and user-friendly workflow for tumor imaging and guided surgery, and therefore, it may have great prospects for clinical translation as a PET/NIRF dual-modal probe.

Usefulness of [68Ga]FAPI-04 and [18F]FDG PET/CT for the detection of primary tumour and metastatic lesions in gastrointestinal carcinoma: a comparative study.

OBJECTIVE: To assess and compare the diagnostic performance of gallium-68-labelled fibroblast activation protein inhibitor ([68Ga]FAPI-04) and fluorine-18 fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) in gastrointestinal cancer. METHODS: Fifty-one patients who underwent both [18F]FDG and [68Ga]FAPI-04 PET/CT for initial staging or restaging were enrolled. Histopathological findings, typical radiological appearances, and clinical imaging follow-up were used as the reference standard. The diagnostic performance of the two tracers was calculated and compared. The maximum standardised uptake value (SUVmax), mean SUV (SUVmean), tumour-to-mediastinal blood pool ratio (TBR), and tumour-to-liver ratio (TLR) of primary and metastatic lesions were measured and compared between two imaging modalities. RESULTS: In patient-based analysis, [68Ga]FAPI-04 showed much better diagnostic sensitivity than [18F]FDG in detecting primary tumour (94.44% [17/18] vs. 61.11% [11/18]), postoperative recurrence and metastases (95.65% [22/23] vs. 69.57% [16/23]), and peritoneal carcinomatosis (100% [28/28] vs. 60.71% [17/28]) (all p < 0.05). In lesion-based analysis, [68Ga]FAPI-04 showed higher sensitivity than [18F]FDG for detecting lymph node metastases. In peritoneal carcinomatosis, the median SUVmax (12.12 vs. 7.18) and SUVmean (6.84 vs. 4.11) with [68Ga]FAPI-04 were significantly higher than those with [18F]FDG (all p < 0.005). The TBR and TLR of [68Ga]FAPI-04 were significantly higher than those of [18F]FDG for detecting primary tumour, lymph node, liver, and peritoneal metastases (all p < 0.005). Therapeutic management changed in 13 patients according to [68Ga]FAPI-04 PET/CT compared with conventional imaging. CONCLUSIONS: [68Ga]FAPI-04 is superior to [18F]FDG PET/CT for detecting primary tumour, postoperative recurrence and metastasis, and peritoneal carcinomatosis in gastrointestinal cancer. KEY POINTS: • [68Ga]FAPI-04 PET/CT showed significantly higher sensitivity than [18F]FDG PET/CT in the detection of primary tumour and postoperative recurrence and metastasis in patients with gastrointestinal carcinoma. • [68Ga]FAPI-04 PET/CT had obvious advantages over [18F]FDG PET/CT in the detection of peritoneal carcinomatosis from gastrointestinal carcinoma with a much higher FAPI uptake value, TBR, and TLR. • Although the median SUVmax and SUVmean of [68Ga]FAPI-04 were similar to those of [18F]FDG for the primary tumour, lymph node metastases, and liver metastases in gastrointestinal carcinoma, the TBR and TLR of the SUVmax and SUVmean were significantly higher on [68Ga]FAPI-04 PET/CT, causing the lesions to be displayed more clearly.

68Ga-WRWWWW Is a Potential Positron Emission Tomography Probe for Imaging Inflammatory Diseases by Targeting Formyl Peptide Receptor 2.

Inflammation plays a significant role in many physiological and pathological processes. Molecular imaging could provide functional as well as anatomical information for visualizing various inflammatory diseases. Advancements in imaging tracers for inflammation would improve the accuracy of diagnosis and monitoring, thus facilitating patient care. The positron emission tomography (PET) imaging tracer, 68Ga-labeled antagonist peptide Trp-Arg-Trp-Trp-Trp-Trp (WRWWWW, WRW4), targets formyl peptide receptor 2 (FPR2), which is in turn widely distributed in a variety of tissues and is associated with many inflammatory diseases. In the current study, we aimed to investigate the potential of 68Ga-WRW4 for detecting and monitoring inflammatory lesions in mice. We established an inflammation mouse model by the intramuscular injection of turpentine oil into the left thigh. WRW4 was labeled with 68Ga with an overall radiochemical yield >90% and radiochemical purity >99%. 68Ga-WRW4 uptake in inflamed muscle peaked on day 2 (1.14 ± 0.01 percentage of the injected dose per gram of tissue (%ID/g)) and the uptake ratio of inflammatory/normal muscle also reached a maximum (12.36 ± 2.35). Strong PET signals were detected in the left thigh at 60 min after the injection of 68Ga-WRW4 in experimental mice, but weak or no signals were detected in mice in the blocking and control groups. 68Ga-WRW4 uptake was in agreement with the dynamics of immune cell infiltration during the inflammatory reaction. These results suggest that 68Ga-WRW4 is a promising PET tracer suitable for the noninvasive detection of FPR2 expression and for monitoring inflammatory activity in inflammation-bearing mice.

Palladium-catalyzed allene synthesis enabled by ß-hydrogen elimination from sp2-carbon.

The rational design based on a deep understanding of the present reaction mechanism is an important, viable approach to discover new organic transformations. ß-Hydrogen elimination from palladium complexes is a fundamental reaction in palladium catalysis. Normally, the eliminated ß-hydrogen has to be attached to a sp3-carbon. We envision that the hydrogen elimination from sp2-carbon is possible by using thoroughly designed reaction systems, which may offer a new strategy for the preparation of allenes. Here, we describe a palladium-catalyzed cross-coupling of 2,2-diarylvinyl bromides and diazo compounds, where a ß-vinylic hydrogen elimination from allylic palladium intermediate is proposed to be the key step. Both aryl diazo carbonyl compounds and N-tosylhydrazones are competent carbene precursors in this reaction. The reaction mechanism is explored by control experiments, KIE studies and DFT calculations.

Stereoselective synthesis of conjugated trienes via 1,4-palladium migration/Heck sequence.

Conjugated trienes are ubiquitous structures in natural products and organic functional molecules. An efficient 1,4-palladium migration/Heck sequence was developed for the highly stereoselective synthesis of trisubstituent 1,3,5-trienes, which were found to undergo easy E/Z isomerization in the presence of light.

Enantioselective Rhodium-Catalyzed Alkenylation of Aliphatic Imines.

An efficient, enantioselective rhodium-catalyzed addition of potassium alkenyltrifluoroborates to N-nosyl aliphatic imines has been realized. Good reaction yields and excellent enantioselectivities (94-99% ee) were obtained for a variety of aliphatic imines and nucleophilic alkenyltrifluoroborates. An active rhodium-diene catalyst and the precise reaction condition control proved to be pivotal for success.

Rhodium-catalyzed asymmetric hydrogenation of unprotected ß-enamine phosphonates.

We have successfully developed a strategy for the first time for the enantioselective Rh-TaniaPhos catalyzed asymmetric hydrogenation of unprotected ß-enamine phosphonates to free ß-amino phosphonates directly with good enantioselectivities (80%-86% ee) and high conversions (>99% conversion). The resulting chiral free ß-amino phosphonates and their derivatives are important intermediates in biochemistry and pharmaceuticals.

Highly enantioselective synthesis of chiral cyclic allylic amines via Rh-catalyzed asymmetric hydrogenation.

Highly regioselective and enantioselective asymmetric hydrogenation of cyclic dienamides catalyzed by an Rh-DuanPhos complex has been developed, which provides a readily accessible method for the synthesis of chiral cyclic allylic amines in excellent enantioselectivities (up to 99% ee). The products are valuable chiral building blocks and could be easily transformed to multisubstituted cyclohexane derivatives.