43 research outputs found
Synthesis of Polycyclic Imidazolidinones via Amine Redox-Annulation
α-Ketoamides undergo redox-annulations
with cyclic secondary
amines, such as 1,2,3,4-tetrahydroisoquinoline, pyrrolidine, piperidine,
and morpholine. Catalytic amounts of benzoic acid significantly accelerate
these transformations. This approach provides polycyclic imidazolidinone
derivatives in typically good yields
Synthesis of Polycyclic Imidazolidinones via Amine Redox-Annulation
α-Ketoamides undergo redox-annulations
with cyclic secondary
amines, such as 1,2,3,4-tetrahydroisoquinoline, pyrrolidine, piperidine,
and morpholine. Catalytic amounts of benzoic acid significantly accelerate
these transformations. This approach provides polycyclic imidazolidinone
derivatives in typically good yields
Selective Fluorescence Detection of Cysteine over Homocysteine and Glutathione Based on a Cysteine-Triggered Dual Michael Addition/Retro-aza-aldol Cascade Reaction
In this work, a cysteine (Cys)-triggered
dual Michael addition/retro-aza-aldol
cascade reaction has been exploited and utilized to construct a fluorescent
probe for Cys for the first time. The resulting fluorescent probe
8-alkynylBodipy <b>1</b> contains an activated alkynyl unit
as Michael receptor and a Bodipy dye as fluorescence reporter and
can highly selectively detect Cys over homocysteine (Hcy)/glutathione
(GSH) as well as other amino acids with a significant fluorescence
offâon response (âŒ4500-fold) and an ultralow detection
limit (0.38 nM). The high selectivity of <b>1</b> for Cys could
be attributed to a kinetically favored five-membered cyclic intermediate
produced by the dual Michael addition of Cys with the activated alkynyl
unit of <b>1</b>. The big fluorescence offâon response
is due to the subsequent retro-aza-aldol reaction of the five-membered
cyclic intermediate that results in the release of a highly fluorescent
8-methylBodipy dye <b>2</b>. The probe has been successfully
used to detect and image Cys in serum and cells, respectively
A Naphthalimide-Based Glyoxal Hydrazone for Selective Fluorescence Turn-On Sensing of Cys and Hcy
A fluorescent turn-on probe for Cys/Hcy based on inhibiting the Cî»N isomerization quenching process by an intramolecular hydrogen bond was reported. The probe exhibited higher selectivity toward Cys/Hcy over other amino acids as well as thiol-containing compounds
Alternative Sm(II) Species-Mediated Cascade Coupling/Cyclization for the Synthesis of Oxobicyclo[3.1.0]hexane-1-ols
The allylSmBr/HMPA/MsOH system has
been found to be an efficient
reagent for the âester-alkeneâ coupling/cyclization
cascade of readily available α-allyloxy esters. Oxobicyclo[3.1.0]Âhexane-1-ols
were thus prepared in good to excellent yields and diastereoselectivities.
Investigation on the mechanism suggested the possible existence of
a new SmÂ(II) species, namely, CH<sub>3</sub>SO<sub>3</sub>SmBr, which
resulted from the reaction between allylSmBr and MsOH and may be the
actual SET reagent
Additive Tuned Selective Synthesis of Bicyclo[3.3.0]octan-1-ols and Bicyclo[3.1.0]hexan-1-ols Mediated by AllylSmBr
The
selective construction of bicyclo[3.3.0]Âoctan-1-ols and bicyclo[3.1.0]Âhexan-1-ols
was achieved by using an allylSmBr/additive(s) system. By employing
HMPA as the only additive, the momoallylation/ketoneâalkene
coupling occurred preferably and afforded bicyclo[3.3.0]Âoctan-1-ols
in good yields with high diastereoselectivities. While the esterâalkene
coupling predominated to generate bicyclo[3.1.0]Âhexan-1-ols in moderate
yields with excellent diastereoselectivities in the presence of a
proton source, such as pyrrole as the coadditive with HMPA. The tunable
reactivity of allylSmBr by additive(s) would make it a versatile reagent
in organic synthesis
One-Pot Synthesis of PyrroloÂ[3,2,1-<i>kl</i>]phenoÂthiazines through Copper-Catalyzed Tandem Coupling/Double Cyclization Reaction
A novel and efficient synthesis of
pyrroloÂ[3,2,1-<i>kl</i>]ÂphenoÂthiazines has been
developed through a CuÂ(I)-catalyzed
tandem CâS coupling/double cyclization process. Using 2-alkynyl-6-iodoanilines
and <i>o</i>-bromoÂbenzenethiols as the starting materials,
a wide range of pyrroloÂ[3,2,1-<i>kl</i>]ÂphenoÂthiazine
derivatives were facilely and efficiently generated in one pot under
CuÂ(I) catalysis
Additive Tuned Selective Synthesis of Bicyclo[3.3.0]octan-1-ols and Bicyclo[3.1.0]hexan-1-ols Mediated by AllylSmBr
The
selective construction of bicyclo[3.3.0]Âoctan-1-ols and bicyclo[3.1.0]Âhexan-1-ols
was achieved by using an allylSmBr/additive(s) system. By employing
HMPA as the only additive, the momoallylation/ketoneâalkene
coupling occurred preferably and afforded bicyclo[3.3.0]Âoctan-1-ols
in good yields with high diastereoselectivities. While the esterâalkene
coupling predominated to generate bicyclo[3.1.0]Âhexan-1-ols in moderate
yields with excellent diastereoselectivities in the presence of a
proton source, such as pyrrole as the coadditive with HMPA. The tunable
reactivity of allylSmBr by additive(s) would make it a versatile reagent
in organic synthesis
DataSheet_1_Construction and validation of nomograms based on the log odds of positive lymph nodes to predict the prognosis of lung neuroendocrine tumors.docx
BackgroundThis research aimed to investigate the predictive performance of log odds of positive lymph nodes (LODDS) for the long-term prognosis of patients with node-positive lung neuroendocrine tumors (LNETs).MethodsWe collected 506 eligible patients with resected N1/N2 classification LNETs from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2015. The study cohort was split into derivation cohort (n=300) and external validation cohort (n=206) based on different geographic regions. Nomograms were constructed based on the derivation cohort and validated using the external validation cohort to predict the 1-, 3-, and 5-year cancer-specific survival (CSS) and overall survival (OS) of patients with LNETs. The accuracy and clinical practicability of nomograms were tested by Harrellâs concordance index (C-index), integrated discrimination improvement (IDI), net reclassification improvement (NRI), calibration plots, and decision curve analyses.ResultsThe Cox proportional-hazards model showed the high LODDS group (-0.79â€LODDS) had significantly higher mortality compared to those in the low LODDS group (LODDSConclusionsWe created visualized nomograms for CSS and OS of LNET patients, facilitating clinicians to bring individually tailored risk assessment and therapy.</p
DataSheet_1_Cotton Fusarium wilt diagnosis based on generative adversarial networks in small samples.pdf
This study aimed to explore the feasibility of applying Generative Adversarial Networks (GANs) for the diagnosis of Verticillium wilt disease in cotton and compared it with traditional data augmentation methods and transfer learning. By designing a model based on small-sample learning, we proposed an innovative cotton Verticillium wilt disease diagnosis system. The system uses Convolutional Neural Networks (CNNs) as feature extractors and applies trained GAN models for sample augmentation to improve classification accuracy. This study collected and processed a dataset of cotton Verticillium wilt disease images, including samples from normal and infected plants. Data augmentation techniques were used to expand the dataset and train the CNNs. Transfer learning using InceptionV3 was applied to train the CNNs on the dataset. The dataset was augmented using GAN algorithms and used to train CNNs. The performances of the data augmentation, transfer learning, and GANs were compared and analyzed. The results have demonstrated that augmenting the cotton Verticillium wilt disease image dataset using GAN algorithms enhanced the diagnostic accuracy and recall rate of the CNNs. Compared to traditional data augmentation methods, GANs exhibit better performance and generated more representative and diverse samples. Unlike transfer learning, GANs ensured an adequate sample size. By visualizing the images generated, GANs were found to generate realistic cotton images of Verticillium wilt disease, highlighting their potential applications in agricultural disease diagnosis. This study has demonstrated the potential of GANs in the diagnosis of cotton Verticillium wilt disease diagnosis, offering an effective approach for agricultural disease detection and providing insights into disease detection in other crops.</p