A case of testicular tumor and respiratory failure caused by choriocarcinoma syndrome managed through modified chemotherapy and extracorporeal membrane oxygenation.

Introduction: Choriocarcinoma syndrome with multiple lung metastases has a poor prognosis and causes respiratory failure due to alveolar hemorrhage. We encountered a case where the introduction of extracorporeal membrane oxygenation effectively sustained oxygenation until chemotherapy took effect on lung metastases of testicular tumors. Case presentation: A 35-year-old man with dyspnea was referred to our hospital. He showed left testicular tumor with multiple lung metastases. Serum human chorionic gonadotropin level was also elevated. Reduced chemotherapy was initiated and extracorporeal membrane oxygenation was administered because of low oxygen levels on the fourth day. Chemotherapy successfully reduced the size of the lung masses, and extracorporeal membrane oxygenation was discontinued. Respiratory status improved substantially, but the patient died of brain metastases 4 months later. Conclusion: Extracorporeal membrane oxygenation may be a useful option for managing respiratory failure resulting from choriocarcinoma syndrome until the respiratory condition is improved by chemotherapy for testicular tumors.

Simultaneous epicardial ablation based on intraoperative electroanatomic mapping during left ventricular assist device implantation.

Intraoperative ventricular tachycardia (VT) ablation targeting the epicardial substrate using three-dimensional electroanatomic mapping (EAM) was performed during left ventricular assist device (LVAD) implantation. We proved that EAM can be safely performed during LVAD implantation and that an ablation strategy based on electrophysiological information may reduce VT recurrence after LVAD implantation.

Outcomes of active surveillance for Japanese patients with prostate cancer (PRIAS-JAPAN).

OBJECTIVE: To report the outcomes of repeat biopsies, metastasis and survival in the Prostate Cancer Research International: Active Surveillance (PRIAS)-JAPAN study, a prospective observational study for Japanese patients, initiated in 2010. PATIENTS AND METHODS: At the beginning, inclusion criteria were initially low-risk patients, prostate-specific antigen (PSA) density (PSAD) <0.2, and ≤2 positive biopsy cores. As from 2014, GS3+4 has also been allowed for patients aged 70 years and over. Since January 2021, the age limit for Gleason score (GS) 3 + 4 cases was removed, and eligibility criteria were expanded to PSA ≤20 ng/mL, PSAD <0.25 nd/mL/cc, unlimited number of positive GS 3 + 3 cores, and positive results for fewer than half of the total number of cores for GS 3 + 4 cases if magnetic resonance imaging fusion biopsy was performed at study enrolment or subsequent follow-up. For patients eligible for active surveillance, PSA tests were performed every 3 months, rectal examination every 6 months, and biopsies at 1, 4, 7 and 10 years, followed by every 5 years thereafter. Patients with confirmed pathological reclassification were recommended for secondary treatments. RESULTS: As of February 2024, 1302 patients were enrolled in AS; 1274 (98%) met the eligibility criteria. The median (interquartile range) age, PSA level, PSAD, and number of positive cores were 69 (64-73) years, 5.3 (4.5-6.6) ng/mL, 0.15 (0.12-0.17) ng/mL, and 1 (1-2), respectively. The clinical stage was T1c in 1089 patients (86%) and T2 in 185 (15%). The rates of acceptance by patients for the first, second, third and fourth re-biopsies were 83%, 64%, 41% and 22%, respectively. The pathological reclassification rates for the first, second, third and fourth re-biopsies were 29%, 30%, 35% and 25%, respectively. The 1-, 5- and 10-year persistence rates were 77%, 45% and 23%, respectively. Six patients developed metastasis, and one patient died from prostate cancer. CONCLUSION: Pathological reclassification was observed in approximately 30% of the patients during biopsy; however, biopsy acceptance rates decreased over time. Although metastasis occurred in six patients, only one death from prostate cancer was recorded.

Mechanistic understanding of the thermal-assisted photocatalytic oxidation of methanol-to-formaldehyde with water vapor over Pt/SrTiO3.

Anaerobic thermal-assisted photocatalytic methanol conversion in the gas phase in the presence of water vapor has been suggested as an interesting way to generate formaldehyde as a valuable coupled product in addition to H2 production. Here, the reaction mechanism and photocatalyst deactivation are investigated in detail using in situ diffuse reflectance infrared fourier transform (DRIFTS) and electron paramagnetic resonance (EPR) spectroscopy. EPR shows that paramagnetic oxygen vacancies are not involved in the reaction mechanism over undoped SrTiO3. Instead, on an optimized 0.1 wt% Pt/SrTiO3 photocatalyst, methoxy species are formed by dissociative adsorption of methanol leading to formaldehyde formation while the formation of CO, CO2 (via a formate intermediate) and methyl formate occurs through three concurrent reactions from formyl species. Our findings suggest that CO adsorbed on Pt is a spectator species not perturbing the reaction kinetics, and deactivation is shown to be strongly correlated with the accumulation of formate groups on SrTiO3, which is more pronounced at high reaction temperatures. The mechanistic understanding provided here forms the basis for the further optimization of photocatalysts to increase methanol conversion and improve formaldehyde selectivity.

Chemodivergent Synthesis of Polycyclic Aromatic Diarylamines and Carbazoles by Thermal/Photochemical Process-Controlled Dephosphinylative Functionalizations of Amino(phosphinyl)arenes.

A chemodivergent synthesis of polycyclic aromatic diarylamines and carbazoles was established by employing thermally or photochemically controlled processes using KOtBu/1,10-phenanthroline. The synthetic processes involved the dephosphinylation of 9-amino-10-(phosphinyl)phenanthrenes, which were obtained through a regioselective palladium-catalyzed direct [4 + 2] benzannulation of phosphinyl ynamines with 2-iodobiphenyls. When the dephosphinylation was conducted under heating conditions (∼100 °C), it proceeded to yield 9-aminophenanthrene. However, when the reaction was performed under the illumination of purple light (LEDs, λmax = ca. 390 nm), KOtBu/1,10-phenanthroline promoted single-electron-transfer-triggered dephosphinylation followed by cyclization, producing the corresponding π-expanded carbazoles. We successfully synthesized a highly π-expanded dicarbazole through a dual dephosphinylative cyclization. Additionally, we present the optical properties of a series of amino compounds produced through the dephosphinylative processes.

Validity and reliability of the palliative care needs assessment tool in Japanese patients with heart failure.

AIMS: Although patients with heart failure (HF) frequently experience considerable symptom burden and require significant care, most HF patients do not receive timely intervention due to the absence of a standardized method for identifying those in need of palliative care. The Needs Assessment Tool: Progressive Disease-Heart Failure (NAT: PD-HF) assesses the palliative care needs of patients with HF. However, its validity and reliability have yet to be fully examined. We aimed to assess the validity and reliability of the NAT: PD-HF in Japanese patients with HF. METHODS: We prospectively enrolled 106 consecutive patients with chronic HF admitted to our university hospital between February 2023 and July 2023. Their caregivers (n = 95) and healthcare providers (n = 17) were also included. The NAT: PD-HF was translated from English to Japanese using a forward-backward translation procedure and adapted based on Japanese cultural and medical backgrounds by our professional multidisciplinary team. We assessed the internal consistency of the Japanese NAT: PD-HF version with Cronbach's alpha coefficient and the inter-rater and test-retest reliabilities with Cohen's kappa coefficient. After using the tool, all participants were asked to complete a questionnaire about the tool to determine its validity. RESULTS: The proportion of female patients in this study was 47 (44%). The median age was 72 years [interquartile range (IQR) 59-81]. The median time spent assessing the patients' and their caregivers' needs using the Japanese NAT: PD-HF was 14 min (IQR 12-17). The Cronbach's alpha coefficient was 0.82, and the minimum kappa coefficient was 0.77 for inter-rater reliability and 0.88 for test-retest reliability. In total, 103 patients (97%) and all caregivers responded that the tool was easy to understand. One hundred (94%) patients and 89 (94%) caregivers felt that the tool would improve the quality of care, and 102 (96%) patients and 91 (96%) caregivers indicated that the discussions using this tool allowed them to confide in all their burdens and care needs. All healthcare providers expressed that this tool is helpful in understanding the burden and care needs of both patients and caregivers comprehensively. CONCLUSIONS: The NAT: PD-HF is a reliable and valid tool for Japanese patients with HF and their caregivers. This tool was very well accepted by patients, caregivers and healthcare providers to identify burdens and care needs.

A case of Adult-onset Acute Flaccid Myelitis Accompanied by Rhombencephalitis which First Presented with Prominent Psychiatric Symptoms and Dysautonomia Mimicking Anti-N-methyl-d-aspartate Receptor Encephalitis.

A 44-year-old woman with a subacute onset of an altered mental status, urinary retention, and fluctuating blood pressure was initially diagnosed with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, meeting the criteria of Graus et al. Cardiac arrest occurred, which required pacemaker placement. She subsequently showed profound flaccid limb paralysis, with magnetic resonance imaging demonstrating focal necrotic lesions localized in the anterior horn of the longitudinal segments of the spinal cord and in the pontine tegmentum. Enteroviruses or autoimmune encephalitis-associated autoantibodies were not detected. We herein report a case of acute flaccid myelitis with profound psychiatric symptoms and dysautonomia, resembling NMDAR encephalitis.

Identification of Critical Amino Acid Residues of a Two-Component Sensor Protein for Signal Sensing in Porphyromonas gingivalis Fimbriation via Random Mutant Library Construction.

Porphyromonas gingivalis (Pg) utilizes FimA fimbriae to colonize the gingival sulcus and evade the host immune system. The biogenesis of all FimA-related components is positively regulated by the FimS-FimR two-component system, making the FimS sensory protein an attractive target for preventing Pg infection. However, the specific environmental signal received by FimS remains unknown. We constructed random Pg mutant libraries to identify critical amino acid residues for signal sensing by FimS. Optimized error-prone polymerase chain reaction (PCR) was used to introduce a limited number of random mutations in the periplasmic-domain-coding sequence of fimS, and expression vectors carrying various mutants were generated by inverse PCR. More than 500 transformants were obtained from the fimS-knockout Pg strain using the Escherichia coli-Pg conjugal transfer system, whereas only ~100 transformants were obtained using electroporation. Four and six transformant strains showed increased and decreased fimA expression, respectively. Six strains had single amino acid substitutions in the periplasmic domain, indicating critical residues for signal sensing by FimS. This newly developed strategy should be generally applicable and contribute to molecular genetics studies of Pg, including the elucidation of structure-function relationships of proteins of interest.

Nitrate reduction enables safer aryldiazonium chemistry.

Aryldiazonium salts remain a staple in organic synthesis and are still prepared largely in accord with the protocol developed in the 19th century. Because of the favorable reactivity that often cannot be achieved with other aryl(pseudo)halides, diazonium chemistry continues to grow. Facile extrusion of dinitrogen contributes to the desired reactivity but is also reason for safety concerns. Explosions have occurred since the discovery of these reagents and still result in accidents. In this study, we report a diazonium chemistry paradigm shift based on nitrate reduction using thiosulfate or dihalocuprates as electron donors that avoids diazonium accumulation. Because nitrate reduction is rate-limiting, aryldiazoniums are produced as fleeting intermediates, which results in a safer and often more efficient deaminative halogenation in a single step from anilines.

The impact of second transurethral resection on survival outcomes in patients with non-muscle-invasive bladder cancer treated with bacillus Calmette-Guérin therapy.

OBJECTIVE: Several guidelines recommended that second transurethral resection should be performed in patients with diagnosis of high-risk non-muscle-invasive bladder cancer. However, therapeutic benefits of second transurethral resection before bacillus Calmette-Guérin intravesical instillation were conflicting amongst previous studies. We investigated the prognostic impact of second transurethral resection before bacillus Calmette-Guérin instillation in high-risk non-muscle-invasive bladder cancer patients. METHODS: This retrospective study included 3104 non-muscle-invasive bladder cancer patients who received bacillus Calmette-Guérin instillations between 2000 and 2019 at 31 collaborative institutions. Univariate and multivariate Cox proportional hazards models were used to assess the risk factors of intravesical recurrence, disease progression, cancer-specific mortality and overall mortality. RESULTS: In the entire population, patients undergoing second transurethral resection (33%, 1026/3104) had a lower risk of intravesical recurrence on univariate analysis (hazard ratio 0.85, 95% confidence interval 0.73-0.98, P = 0.027), although it did not remain significant on multivariate analysis (hazard ratio 0.90, 95% confidence interval 0.76-1.07, P = 0.24). Subgroup analysis revealed that, in pT1 patients (n = 1487), second transurethral resection was significantly correlated with a lower risk of intravesical recurrence on multivariate analysis (hazard ratio 0.80, 95% confidence interval 0.64-1.00, P = 0.048), but lower risks of disease progression (hazard ratio 0.75, 95% confidence interval 0.56-1.00, P = 0.049), cancer-specific mortality (hazard ratio 0.54, 95% confidence interval 0.35-0.85, P = 0.007) and overall mortality (hazard ratio 0.73, 95% confidence interval 0.55-0.97, P = 0.027) on univariate analysis. CONCLUSIONS: Second transurethral resection confers accurate pathological staging and could be used to safely select good candidates for intravesical bacillus Calmette-Guérin instillation. We further confirm that second transurethral resection could confer an oncological benefit in pT1 bladder cancer patients treated by bacillus Calmette-Guérin instillation, and so strongly recommend second transurethral resection in this patient population.

Globo-series Gb4 activates ERK and promotes the proliferation of osteoblasts.

OBJECTIVES: Globo-series Gb4 (globoside) is involved in the immune system and disease pathogenesis. We recently reported that systemic Gb4 deficiency in mice led to decreased bone formation due to a reduction in osteoblast number. However, it remains unclear whether Gb4 expressed in osteoblasts promotes their proliferation. Therefore, we investigated the role of Gb4 in osteoblast proliferation in vitro. METHODS: We examined osteoblast proliferation in Gb3 synthase knockout mice lacking Gb4. We investigated the effects of Gb4 synthase knockdown in the mouse osteoblast cell line MC3T3-E1 on its proliferation. Furthermore, we administered Gb4 to MC3T3-E1 cells in which Gb4 was suppressed by a glucosylceramide synthase (GCS) inhibitor and evaluated its effects on their proliferation. To elucidate the mechanisms by which Gb4 promotes osteoblast proliferation, the phosphorylated extracellular signal-regulated kinases 1 and 2 (ERK1/2) levels were measured in MC3T3-E1 cells. RESULTS: Osteoblast proliferation was lower in Gb3 synthase knockout mice lacking Gb4 than in wild-type mice. Proliferation was inhibited by Gb4 synthase knockdown in MC3T3-E1 cells. Furthermore, the administration of Gb4 to MC3T3-E1 cells, in which a GCS inhibitor suppressed Gb4, promoted their proliferation. Moreover, it increased the phosphorylated ERK1/2 levels in MC3T3-E1 cells. CONCLUSIONS: Our results suggest that Gb4 expressed in osteoblasts promotes their proliferation through ERK1/2 activation.

Contemplation of the Effect of Nivolumab Plus Cabosantinib Therapy on Cerebral Hemorrhage in Patients with Brain Metastasis of Renal Cell Carcinoma: A Case Report.

Although the response to combination therapy has been reported in patients with brain metastases from advanced renal cancer, treatment-related cerebral hemorrhage has not been adequately studied. The CheckMate 9ER clinical trial of nivolumab and cabozantinib excluded patients with brain metastases. Therefore, the associated treatment outcomes in these patients with brain metastases are unclear. Herein, we report a case of bleeding from brain metastases in a patient with advanced renal cancer after gamma knife combination therapy with nivolumab and cabozantinib. Fortunately, the cerebral hemorrhage of the patient was alleviated by conservative treatment. Despite treatment interruption, the metastatic lesions reduced in size, and treatment was gradually resumed. In this case study, we report the risk of cerebral hemorrhage in combination therapy for brain metastasis cases, how to manage hemorrhage cases, and their prognosis.

Exercise Capacity and Clinical Outcomes in Chronic Heart Failure Patients with Mild Tricuspid Regurgitation.

AIM: The present study aimed to investigate the impact of mild tricuspid regurgitation (TR) on the exercise capacity or clinical outcomes in patients with chronic heart failure (CHF). METHODS AND RESULTS: The study enrolled 511 patients with CHF who underwent cardiopulmonary exercise testing (CPET) between 2013 and 2018. The primary outcome was a composite of heart failure hospitalization and death. Patients with mild TR (n = 324) or significant TR (moderate or greater; n = 60) displayed worse NHYA class and reduced exercise capacity on CPET than those with non-TR (n = 127), but these were more severely impaired in patients with significant TR. A total of 90 patients experienced events over a median follow-up period of 3.3 (interquartile range 0.8-5.5) years. Patients with significant TR displayed a higher risk of events, while patients with mild TR had a 3.0-fold higher risk of events than patients with non-TR (hazard ratio (HR) 3.01; 95% confidence interval (CI), 1.50-6.07). Multivariate Cox regression analysis showed that, compared with non-TR, mild TR was associated with increased adverse events, even after adjustment for co-variates (HR 2.97; 95% CI, 1.35-6.55). CONCLUSIONS: TR severity was associated with worse symptoms, reduced exercise capacity, and poor clinical outcomes. Even patients with mild TR had worse clinical characteristics than those with non-TR.

Association of coronary plaque morphology with inflammatory biomarkers and target lesion revascularization in patients with chronic coronary syndrome: an optical coherence tomography study.

BACKGROUND: The characteristics of high-risk coronary atherosclerosis evaluated using optical coherence tomography (OCT) can have a prognostic role. Inflammatory biomarkers may be related to the severity of coronary artery disease. This study investigated the association of high-risk morphological features of coronary plaques on OCT with circulating levels of inflammatory biomarkers and target lesion revascularization (TLR). MATERIALS AND METHODS: We prospectively analyzed the data of 30 consecutive patients with chronic coronary syndrome who underwent percutaneous coronary intervention (PCI) using OCT. The levels of interleukin-6, tumor necrosis factor-alpha, high-sensitivity C-reactive protein, pentraxin 3, vascular endothelial growth factor, and monocyte chemoattractant protein-1 (MCP-1) were measured in plasma samples. Coronary plaque characteristics were scored quantitatively in the form of coronary plaque risk score (CPRS). The estimated high-risk plaque characteristics for TLR were plaque rupture, plaque erosion, calcified nodule, lipid-rich plaque, thin-cap fibroatheroma, cholesterol crystals, macrophage infiltration, microchannels, calcification angle >90°, and microcalcifications. Each high-risk feature carries 1 point. Patients were defined as having a low CPRS (CPRS ≤3) or a high CPRS (CPRS ≥4). RESULTS: The primary outcome was TLR. TLR occurred in 6 (20%) patients within 15 months of PCI. High CPRS on OCT was directly correlated with TLR (P=0.029). In logistic regression analysis, CPRS was associated with TLR (odds ratio, 10.0; 95% confidence interval, 1.34-74.5). Serum MCP-1 level was significantly correlated with the CPRS (P=0.020). CONCLUSIONS: In patients with chronic coronary syndrome, CPRS may be a surrogate predictor of TLR. Serum MCP-1 may aid in the detection of high-risk coronary atherosclerosis.

Differences in blood flow dynamics between balloon- and self-expandable valves in patients with aortic stenosis undergoing transcatheter aortic valve replacement.

BACKGROUND: The differences in pre- and early post-procedural blood flow dynamics between the two major types of bioprosthetic valves, the balloon-expandable valve (BEV) and self-expandable valve (SEV), in patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR), have not been investigated. We aimed to investigate the differences in blood flow dynamics between the BEV and SEV using four-dimensional flow cardiovascular magnetic resonance (4D flow CMR). METHODS: We prospectively examined 98 consecutive patients with severe AS who underwent TAVR between May 2018 and November 2021 (58 BEV and 40 SEV) after excluding those without CMR because of a contraindication, inadequate imaging from the analyses, or patients' refusal. CMR was performed in all participants before (median interval, 22 [interquartile range (IQR) 4-39] days) and after (median interval, 6 [IQR 3-6] days) TAVR. We compared the changes in blood flow patterns, wall shear stress (WSS), and energy loss (EL) in the ascending aorta (AAo) between the BEV and SEV using 4D flow CMR. RESULTS: The absolute reductions in helical flow and flow eccentricity were significantly higher in the SEV group compared in the BEV group after TAVR (BEV: - 0.22 ± 0.86 vs. SEV: - 0.85 ± 0.80, P < 0.001 and BEV: - 0.11 ± 0.79 vs. SEV: - 0.50 ± 0.88, P = 0.037, respectively); there were no significant differences in vortical flow between the groups. The absolute reduction of average WSS was significantly higher in the SEV group compared to the BEV group after TAVR (BEV: - 0.6 [- 2.1 to 0.5] Pa vs. SEV: - 1.8 [- 3.5 to - 0.8] Pa, P = 0.006). The systolic EL in the AAo significantly decreased after TAVR in both the groups, while the absolute reduction was comparable between the groups. CONCLUSIONS: Helical flow, flow eccentricity, and average WSS in the AAo were significantly decreased after SEV implantation compared to BEV implantation, providing functional insights for valve selection in patients with AS undergoing TAVR. Our findings offer valuable insights into blood flow dynamics, aiding in the selection of valves for patients with AS undergoing TAVR. Further larger-scale studies are warranted to confirm the prognostic significance of hemodynamic changes in these patients.

Impact of Cardiac Power Output on Exercise Capacity and Clinical Outcome in Patients With Chronic Heart Failure.

Less data are available regarding the impact of cardiac power output on exercise capacity or clinical outcome in patients with chronic heart failure (CHF). The study enrolled 280 consecutive patients with CHF referred for cardiopulmonary exercise testing and right-sided heart catheterization between 2013 and 2018. The primary outcome was composite of heart failure hospitalization or death. Cardiac power output was calculated as (mean arterial pressure × CO) ÷ 451. Patients with low cardiac power output (<0.53 W, n = 99) were older and had a higher brain natriuretic peptide level than patients with high cardiac power output (≥0.53W, n = 181). Cardiac power output was correlated with peak oxygen consumption (peak V̇O2), peak workload achievement, and ventilatory efficiency (V̇E/V̇CO2 slope) in cardiopulmonary exercise testing, whereas each of cardiac output or mean arterial pressure was not. There were 48 patients with events over a median follow-up period of 3.5 (interquartile range 1.0 to 6.0) years. Patients with low cardiac power output had about a 2-fold higher risk of events than those with a high cardiac power output (hazard ratio 1.97, 95% confidence interval 1.12 to 3.48). In the multivariable Cox regression, a 0.1-W decrease in cardiac power output was associated with 19% increased adverse events (hazard ratio 0.81, 95% confidence interval 0.67 to 0.99). In conclusion, cardiac power output was associated with reduced exercise capacity and poor clinical outcome, suggesting that cardiac power output is useful for risk stratification in patients with CHF. Further study is required to identify therapies targeting cardiac power output to improve the exercise capacity or clinical outcome in patients with CHF.

Improving compliance with guidelines may lead to favorable clinical outcomes for patients with non-muscle-invasive bladder cancer: A retrospective multicenter study.

OBJECTIVES: Clinical guidelines recommend that patients with non-muscle-invasive bladder cancer (NMIBC) should be treated with appropriate adjuvant therapy. However, compliance with guideline recommendations is insufficient, and this may lead to unfavorable outcomes. We aimed to investigate the level of adherence to guideline recommendations in patients with NMIBC and evaluate the outcomes of those who did and did not receive guideline-recommended therapies. METHODS: We performed a retrospective analysis of patients with histologically diagnosed NMIBC. The percentage of patients with intermediate- and high-risk tumors who received adjuvant intravesical therapy or second transurethral resection (TUR) was calculated. Recurrence-free survival was assessed in patients who did and did not receive the therapies. We conducted a propensity score-matched analysis to compare outcomes between patients with intermediate-risk and T1 NMIBC who did and did not undergo guideline-recommended therapies. RESULTS: Overall, 1204 patients from the Tohoku Urological Evidence-Based Medicine Study Group and Kyoto University Hospital were included. Of patients with intermediate- and high-risk tumors, 91.0% and 74.0% did not receive maintenance bacillus Calmette-Guérin (BCG), respectively. In both groups, significantly better recurrence-free survival was found for patients treated with maintenance BCG. Among patients with T1 NMIBC, only 16.7% underwent guideline-recommended therapies, that is, a second TUR and maintenance BCG. Significantly greater recurrence-free survival was observed in patients who received guideline-recommended therapies compared with propensity-matched patients who did not. CONCLUSIONS: Guideline-recommended therapies may contribute to improvements in outcomes for patients with NMIBC, suggesting that improvements in adherence to clinical guidelines may lead to favorable outcomes.

Synthesis, optical properties and crystal structure of (E,E)-1,3-(3,4:9,10-dibenzododeca-1,11-diene-5,7-diyne-1,12-di-yl)benzene.

The de-hydro-benzannulene (E,E)-1,3-(3,4:9,10-dibenzododeca-1,11-diene-5,7-diyne-1,12-di-yl)benzene, C26H16, was successfully synthesized via photocatalyst-assisted stereoselective reductive de-sulfonyl-ation of 1,3-bis-{1-phenyl-sulfonyl-2-[2-(tri-methyl-silylethyn-yl)phen-yl]ethen-yl}benzene, C44H42O4S2Si2, and subsequent desilylative cyclization of the resulting (E,E)-bis-silyl-protected dienyne, C32H34Si2. The structure of the de-hydro-benzannulene thus obtained was confirmed by single-crystal X-ray analysis; three benzene rings are connected to one another by a 1,3-butadiynylene and a pair of ethenylene arrays. Although the π-system expanded efficiently in the de-hydro-benzannulene, it was observed that the butadiynylene and ethenylene arrays were strained, showing smaller [171.3 (2)-172.6 (2) °] and larger bond angles [122.5 (2)-131.9 (2)°] than the conventional bond angles, respectively. In CHCl3, the de-hydro-benzannulene showed the longest absorption band at 377 nm. When irradiated by UV light, it emitted fluorescence at 468 nm (ΦF = 0.26) and 504 nm (ΦF = 0.24) in CHCl3 and in the powdered state, respectively.