ChemInform Abstract: A New Approach to the Synthesis of Antitumor Benzophenanthridine Alkaloids. Formal Synthesis of Nitidine.

The thujone-derived chiral synthon 1 is converted, via selenium chmistry, to the important cross-conjugated dienone 2 and the latter is then convertible to the unsaturated cardenolide analogue 3, which through known methodology (3 → 26 → 27 → 4), completes a formal synthesis of digitoxigenin (4). Extensive studies to afford 2 from androstenedione (5) are also described and a new approach to elaborate the essential butenolide ring system, characteristic of the cardiac active steroids, is developed. Keywords: thujone, steroid synthesis, digitoxigenin.

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Automated and Formal Synthesis of Neural Barrier Certificates for Dynamical Models

Tools and Algorithms for the Construction and Analysis of Systems - Lecture Notes in Computer Science ◽

10.1007/978-3-030-72016-2_20 ◽

2021 ◽

pp. 370-388

Author(s):

Andrea Peruffo ◽

Daniele Ahmed ◽

Alessandro Abate

Keyword(s):

Neural Network ◽

State Of The Art ◽

The State ◽

Dynamical Models ◽

Safety Verification ◽

Data Set ◽

New Approach ◽

Formal Synthesis ◽

Numerical Robustness ◽

Set Up

AbstractWe introduce an automated, formal, counterexample-based approach to synthesise Barrier Certificates (BC) for the safety verification of continuous and hybrid dynamical models. The approach is underpinned by an inductive framework: this is structured as a sequential loop between a learner, which manipulates a candidate BC structured as a neural network, and a sound verifier, which either certifies the candidate’s validity or generates counter-examples to further guide the learner. We compare the approach against state-of-the-art techniques, over polynomial and non-polynomial dynamical models: the outcomes show that we can synthesise sound BCs up to two orders of magnitude faster, with in particular a stark speedup on the verification engine (up to three orders less), whilst needing a far smaller data set (up to three orders less) for the learning part. Beyond improvements over the state of the art, we further challenge the new approach on a hybrid dynamical model and on larger-dimensional models, and showcase the numerical robustness of our algorithms and codebase.

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Palladium-catalyzed synthesis of 2-alkenyl-3-arylindoles via a dual α-arylation strategy: formal synthesis of the antilipemic drug fluvastatin

Organic & Biomolecular Chemistry ◽

10.1039/c5ob01632k ◽

2015 ◽

Vol 13 (45) ◽

pp. 10995-11002 ◽

Cited By ~ 11

Author(s):

Ajit Prabhakar Kale ◽

Gangam Srikanth Kumar ◽

Manmohan Kapur

Keyword(s):

Enol Ethers ◽

New Approach ◽

Formal Synthesis ◽

Palladium Catalyzed

A new approach has been developed for the synthesis of substituted 2-alkenyl-3-arylindoles utilizing a palladium-catalyzed dual α-arylation of TES-enol ethers of enones as the key step.

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A New Approach to Highly Substituted Cyclopentanoids from a Concise Formal Synthesis of (+)-Roseophilin

Organic Letters ◽

10.1021/ol300332b ◽

2012 ◽

Vol 14 (7) ◽

pp. 1740-1743 ◽

Cited By ~ 23

Author(s):

Daniel J. Kerr ◽

Bernard L. Flynn

Keyword(s):

New Approach ◽

Formal Synthesis

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The O–C diagrams of minor planets − a new approach to modelling the rotation

International Astronomical Union Colloquium ◽

10.1017/s0252921100031407 ◽

1999 ◽

Vol 173 ◽

pp. 185-188

Author(s):

Gy. Szabó ◽

K. Sárneczky ◽

L.L. Kiss

Keyword(s):

Error Analysis ◽

Time Dependence ◽

Theoretical Work ◽

Minor Planet ◽

Minor Planets ◽

New Approach ◽

Preliminary Results ◽

Ccd Observations

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.

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