44 research outputs found
Synthesis based on cyclohexadienes. Part 22. Formal syntheses of patchouli alcohol and norpatchoulenol
The preparation of 6-endo-formyl-1,3,3-trimethylbicyclo[2.2.2]octan-2-one 7 and 6-endo-acetyl-1,3,3-trimethylbicyclo[2.2.2]octan-2-one 8, the two key intermediates for the synthesis of patchouli alcohol 1 and norpatchoulenol 2, is reported by a simple and short method from 2-methylbenzoic acid
Finite Element Analysis of Propeller Shaft for Automotive and Naval Application
The Drive shaft is mainly used for power transmission from the engine to the rear differential. Parts are created by using creo software and the assembled model is exported to analysis Parasolid file and various analysis are performed. Structural analysis of drive shaft to with stand a torque of 10000nm at one where other side is fixed. Use of conventional steel for manufacturing of drive shaft has many disadvantages such as low specific stiffness and strength. Conventional drive shaft is made up into two parts to increase its fundamental natural bending frequency. Two-piece drive shaft increases the weight of drive shaft which is not desirable in today’s market. Many methods are available at present for the design optimization of structural systems and these methods based on mathematical programming techniques involving gradient search and direct search. These methods assume that the design variables are continuous. But in practical structural engineering optimization, almost all the design variables are discret
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
Recent advances in cascade Enyne/RCM in organic synthesis
A concise highlight on recent advances in cascade/enyne RCM reactions of a range of substrates is discussed. Some of the reported strategies led to total synthesis of biologically active natural products
A concise total synthesis of (+)-cladospolide D
A short and convergent total synthesis of (+)-cladospolide D is delineated, which involves olefin cross metathesis and furan oxidation to access the γ-oxo-α,β-unsaturated acid and Yamaguchi lactonization to construct the 12-membered ring as key steps
An expedient enyne metathesis approach to dysidiolide
A short and efficient enyne metathesis route is reported for the construction of a key intermediate required in the synthesis of dysidiolide thus completing its formal synthesis.© Elsevie
First enantioselective total synthesis of the angucyclinone-type antibiotic YM-181741
A simple and efficient strategy for angucyclinone antibiotics is described with the disclosure of first total synthesis of YM-181741
A ring-closing metathesis approach to a synthesis of the B ring of eleutherobin
A short and efficient RCM route is reported for the construction of the key nine-membered B ring of eleutherobin starting from the readily available 1,2,5,6-diisopropylidene-D-glucose
Efficient metathesis route to the B-ring of eleutherobin and other medium-sized cyclic ethers
A short and efficient RCM route is reported for the synthesis of the B-ring of eleutherobin and other medium-sized cyclic ethers from readily available 1,2,5,6-diisopropylidene-D-glucose. This strategy is successfully extended to the synthesis of a few bicyclic ethers, which may find applications in the synthesis of novel bicyclic nucleosides
A one-pot, copper-catalyzed cascade route to 2-indolyl-C-glycosides
An efficient and high-yielding, one-pot, Cu-catalyzed synthesis of 2-indolyl-C-glycosides is delineated. The sequence involves a cascade Sonogashira type coupling and a hydroamination reaction between sugar-derived alkynes and N-tosyl-o-iodoaniline followed by removal of the N-tosyl group to provide a library of 2-indolyl-C-glycosides in moderate to excellent yields