ABSTRACT
Residual dipolar couplings (RDC) emerged to be an important structural parameter for organic and biomolecules. Herein, a new helical polyisocyanopeptide (l,l-PIAF-OBn) that forms lyotropic liquid crystals (LLC) in CDCl3 is proposed as a novel weakly orienting medium for acquiring residual dipolar couplings (RDCs) of organic molecules. We demonstrate its application for the structural elucidation of strychnine and triptolide.
Subject(s)
Liquid Crystals/chemistry , Peptides/chemistry , Diterpenes/chemistry , Epoxy Compounds/chemistry , Magnetic Resonance Spectroscopy , Molecular Conformation , Phenanthrenes/chemistry , Strychnine/chemistryABSTRACT
Residual dipolar couplings (RDCs) have attracted attention in light of their great impact on the structural elucidation of organic molecules. However, the effectiveness of RDC measurements is limited by the shortage of alignment media compatible with widely used organic solvents, such as DMSO. Herein, we present the first liquid crystal (LC) based alignment medium that is compatible with pure DMSO, thus enabling RDC measurements of polar and intermediate polarity molecules. The liquid crystals were obtained by grafting polymer brushes onto graphene oxide (GO) using free radical polymerization. The resulting new medium offers several advantages, such as absence of background signals, narrow line shapes, and tunable alignment. Importantly, this medium is compatible with π-conjugated molecules. Moreover, sonication-induced fragmentation can reduce the size of GO sheets. The resulting anisotropic medium has moderate alignment strength, which is a prerequisite for an accurate RDC measurement.
ABSTRACT
Dalesindole, an antibacterial and anti-inflammatory indole alkaloid with an undescribed carbon skeleton, was stereoselectively constructed by Daldinia eschscholzii through class II aldolase catalyzed Michael addition of fungal chromone with 3,3'-diindolylmethane (DIM) formed in situ from indole-3-carbinol (I3C) under catalyses of monooxygenase and 8-amino-7-oxononanoate synthase (AONS). Dalesindole isomerizes via a retro-Michael reaction to give stereoisomers with bioactivities. The work provides an access to new bioactive hybrids of fungal oligoketide with microbially decorated exogenous chemistry.
Subject(s)
Chromones/metabolism , Indole Alkaloids/metabolism , Chromones/chemistry , Indole Alkaloids/chemistry , Models, Molecular , Molecular StructureABSTRACT
OBJECTIVE: To explore the prevalence, distribution type and impact of atrial fibrillation on prognosis of hospitalized patients with congestive heart failure (CHF) with left ventricular ejection fraction (LVEF)>or=0.50. METHODS: The medical records of 417 unselected consecutive patients with CHF were retrospectively reviewed. Patients were categorized as LVEF<0.50 or LVEF>or=0.50. And they were also categorized by the past history of atrial fibrillation and divided into three groups: paroxysmal atrial fibrillation, continuous atrial fibrillation and onset of atrial fibrillation after admission. Then the vicious events, the number of readmission due to CHF and the interval between discharge and readmission were observed and recorded. RESULTS: Male patients were prevalent with CHF whose LVEF<0.50. The occurrence of acute myocardial infarction in the 1st year [15.6% (34/218)] was higher than that of CHF with LVEF>or=0.5 [8.0% (16/199), P<0.01]. The occurrence of cerebral stroke in patients with atrial fibrillation [24.3% (27/111)] was higher than that of patients without atrial fibrillation [8.4% (9/107), P<0.05). The numbers of acute coronary syndrome and cardiac death were also increased. In the patients with CHF whose LVEF>or=0.50 the incidence atrial fibrillation occurring after readmission was significantly higher than that of patient with CHF whose LVEF<0.50 (51 vs. 30, P<0.05). Atrial fibrillation could be found in nearly 2/3 of patients. And the number of readmission (2.78+/-1.79 vs. 2.00+/-1.35, P<0.01) was increased, while the interval between discharge and readmission [(117+/-107) days vs. (154+/-130) days, P<0.05] was shorter. CONCLUSION: Atrial fibrillation occurs more likely in patients with CHF whose LVEF>or=0.50, leading to a shorter interval of readmission. Therefore the importance of treatment of atrial fibrillation should be emphasized.
