Development of Petri Net-Based Dynamic Model for Improved Production of Farnesyl Pyrophosphate by Integrating Mevalonate and Methylerythritol Phosphate Pathways in Yeast

In this case study, we designed a farnesyl pyrophosphate (FPP) biosynthetic network using hybrid functional Petri net with extension (HFPNe) which is derived from traditional Petri net theory and allows easy modeling with graphical approach of various types of entities in the networks together. Our main objective is to improve the production of FPP in yeast, which is further converted to amorphadiene (AD), a precursor of artemisinin (antimalarial drug). Natively, mevalonate (MEV) pathway is present in yeast. Methyl erythritol phosphate pathways (MEP) are present only in higher plant plastids and eubacteria, but not present in yeast. IPP and DAMP are common isomeric intermediate in these two pathways, which immediately yields FPP. By integrating these two pathways in yeast, we augmented the FPP synthesis approximately two folds higher (431.16 U/pt) than in MEV pathway alone (259.91 U/pt) by using HFPNe technique. Further enhanced FPP levels converted to AD by amorphadiene synthase gene yielding 436.5 U/pt of AD which approximately two folds higher compared to the AD (258.5 U/pt) synthesized by MEV pathway exclusively. Simulation and validation processes performed using these models are reliable with identified biological information and data.     

Third‐order WENO scheme with a new smoothness indicator

In this article, we have devised a new reference smoothness indicator for third‐order weighted essentially non‐oscillatory (WENO) scheme to achieve desired order of convergence at critical points. In the context of the weighted essentially non‐oscillatory scheme, reference smoothness indicator is constructed in such a way that it satisfies the sufficient condition on the weights for the third‐order convergence. The goal is to construct a reference smoothness indicator such that the resulted scheme have to achieve the required order of accuracy even if the first two derivatives vanish but not the third derivative. The construction of such reference smoothness indicator is not possible through a linear combination of local smoothness indicators only. We have proposed a reference smoothness indicator to be of the fourth order of accuracy on three‐point stencil that contains the linear combination of the first derivative information of the local and global stencils. The performance enhancement of the WENO scheme through this reference smoothness indicator is verified through the standard numerical experiments. Numerical results indicate that the new scheme provides better results in comparison with the earlier third‐order WENO schemes like WENO‐JS and WENO‐Z. Copyright © 2017 John Wiley & Sons, Ltd.     

Synthesis and Characterization of the First Pyrrolidine‐Based Chiral Ionic Liquids

The first example of pyrrolidine‐based room‐temperature chiral ionic liquids using 2‐aminobutanol as chiral auxiliary is described.     

Urea and thiourea derivatives of 3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1, 2, 4]triazolo[4,3-a]pyrazine: Synthesis,characterization, antimicrobial activity and docking studies

Abstract

An efficient and robust synthetic procedure was developed primarily for the synthesis of a precursor compound; 3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1, 2, 4]triazolo[4,3-a]pyrazine (11), from 2-chloropyrazine (7) through the chemical transformations such as hydrazine substitution, trifluoroacetyl group induction, cyclization and pyrazine ring reduction. A new series of urea derivatives 13a-e and thiourea derivatives 13f-j of compound 11 have been synthesized and the structures of all the compounds were confirmed using spectroscopic analyses such as IR, ¹H NMR, ¹³C NMR, LC-MS and HRMS. The newly synthesized compounds were screened for their in vitro antimicrobial activity against five bacteria and two fungi, in which compounds 13d, 13i and 13j displayed potential activity against bacterial strains and 13a, 13d, 13g and 13j against fungal strains with the MIC values in the range of 6.25–25.0 µg/mL. An overall comparison of the activity results revealed that thiourea derivatives contain better activity than that of urea compounds. Molecular docking studies on poly (ADP-ribose) polymerase 15 (ARTD7, BAL3) demonstrated that all the synthesized compounds possess significant binding energies (-8.1 to -9.8?kcal/mol) with no adverse effect in the active site of protein.     

Synthesis of New Benzoxazaphosphinine/Benzoxazaphosphole/Diazaphosphaphenalene‐2‐sulfides using Lawesson's Reagent

Synthesis of new benzoxazaphosphinine/benzoxazaphosphole/diazaphosphaphenalene 2‐sulfides were accomplished by the reaction of Lawesson's reagent (LR) with 4‐bromo‐2‐[(phenylamino) methyl]phenol (1a), 4‐bromo‐2‐[(4‐chloro/bromo/methoxy/methylphenyl‐amino)methyl]phenol (1b–e), 4‐bromo‐2‐[(benzylamino)methyl]phenol (1f), 2‐amino‐4‐chlorophenol (2a)/2‐amino‐4‐methylphenol (2b), 1,8‐diaminonaphthalene (3) respectively in anhydrous toluene. Products 4a–f, 5a–b and 6 were characterized by IR, ¹H, ¹³C, ³¹P NMR and Mass spectra.     

Sequential 1,3-Dipolar Cycloadditions in the Synthesis of Novel Tri-spiro Cyclohexanones and Piperidin-4-ones

The sequential 1,3-dipolar cycloadditions of azomethine ylide and nitrile oxide to a series of 2,6-bis[(E)-arylmethylidene]cyclohexanones and 1-methyl-3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones afforded novel tri-spiro heterocycles comprising isoxazoline, pyrrolidine and acenaphthylen-1(2H)-one rings in good yields and stereoselectivity.