The absolute configurations of some hydroxy-fatty acids were examined by the modified Mosher's method proposed by Ohtani et al. The absolute configurations of the major components were determined from NMR data of their ΜΤΡΑ esters and 2-ΝΜΑ esters. The application of Mosher's method for the anti-glycol is discussed.
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http://dx.doi.org/10.1271/bbb.61.881 | DOI Listing |
J Org Chem
December 2024
Department of Pharmacy, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China.
Nine new structurally diverse filicinic acid-based meroterpenoids (-) with four kinds of carbon skeletons were isolated from the rhizomes of . Their structures, including the absolute configurations, were elucidated by comprehensive analysis of spectroscopic data, quantum chemical calculations, and single-crystal X-ray diffraction. Structurally, compounds - feature an unprecedented 6/6/5/6/6/6 hexacyclic system with a rare oxaspiro[4.
View Article and Find Full Text PDFSci Rep
December 2024
School of Mechanical and Electrical Engineering, Qiqihar University, Qiqihar, 161006, China.
A prediction model of the pig house environment based on Bayesian optimization (BO), squeeze and excitation block (SE), convolutional neural network (CNN) and gated recurrent unit (GRU) is proposed to improve the prediction accuracy and animal welfare and take control measures in advance. To ensure the optimal model configuration, the model uses a BO algorithm to fine-tune hyper-parameters, such as the number of GRUs, initial learning rate and L2 normal form regularization factor. The environmental data are fed into the SE-CNN block, which extracts the local features of the data through convolutional operations.
View Article and Find Full Text PDFBioorg Chem
December 2024
CSIR- Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India. Electronic address:
Alantolactone and isoalantolactone are two isomeric sesquiterpene lactones that were isolated from Innula recemosa. Here, we are used for the semisynthesis of novel isoxazolidine hybrids of alantolactone and isoalantolactone through a two-step process: nitrone synthesis followed by nitrone 1,3-dipolar cycloaddition. The formation of the cycloadduct was well characterized via modern spectroscopic techniques such as HRMS, H NMR, C NMR, DEPT-90, DEPT-135, and 2D NMR.
View Article and Find Full Text PDFMar Drugs
December 2024
CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Nanhai Road 7, Qingdao 266071, China.
Six new sesquiterpenes, including four eremophilane derivatives fureremophilanes A-D (-) and two acorane analogues furacoranes A and B ( and ), were characterized from the culture extract of the cold-seep derived fungus CS-280 co-cultured with autoclaved QDIO-4. All the six compounds were highly oxygenated especially and with infrequent epoxyethane and tetrahydrofuran ring systems. The structures of - were established on the basis of detailed interpretation of 1D and 2D NMR and MS data.
View Article and Find Full Text PDFMar Drugs
November 2024
Jiangsu Key Laboratory for Functional Substances of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China.
Cembranoid diterpenes are characteristic compounds of soft corals with diverse structures and significant activities, making them an important source of drug lead compounds. In this paper, five new cembranoid diterpenes, meijicrassolins A-E (-), were isolated from the soft coral , along with five previously reported compounds (-). The structures and absolute configuration for new compounds - were assigned by extensive spectroscopic analysis, single-crystal X-ray crystallography, quantum mechanical nuclear magnetic resonance (QM-NMR), and time-dependent density functional theory/electronic circular dichroism (TDDFT/ECD) calculations.
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