ceverelst

Nature, Published online: 13 March 2024; doi:10.1038/d41586-024-00727-z

A hiring manager reveals the lessons he learnt when transitioning from a PhD programme to industry.

Paracetamol can be produced from p-hydroxybenzamide at >95 % purity in 90 % yield. Aqueous ammonia treatment of poplar or oil palm empty fruit bunches forms p-hydroxybenzamide. Under continuous processing conditions, a Hofmann rearrangement converts p-hydroxybenz-amide to p-aminophenol, then liquid/liquid extraction combined with acid/base chemistry and acetylation purifies, forms, and isolates paracetamol.

Abstract

As we work to transition the modern society that is based on non-renewable chemical feedstocks to a post-modern society built around renewable sources of energy, fuels, and chemicals, there is a need to identify the renewable resources and processes for converting them to platform chemicals. Herein, we explore a strategy for utilizing the p-hydroxybenzoate in biomass feedstocks (e. g., poplar and palm trees) and converting it into a portfolio of commodity chemicals. The targeted bio-derived product in the first processing stage is p-hydroxybenzamide produced from p-hydroxybenzoate esters found in the plant. In the second stage a continuous reaction process converts the p-hydroxybenzamide to p-aminophenol via the Hofmann rearrangement and recovers the unreacted p-hydroxybenzamide. In the third stage the p-aminophenol can be acetylated to form paracetamol, which is readily isolated by liquid/liquid extraction at >95 % purity and an overall p-hydroxybenzamide-to-paracetamol process yield of ~90 %. We explore how utilization of protecting groups alters the challenges in this process and expands the portfolio of possible products to include p-(methoxymethoxy)aniline and N-acetyl-p-(methoxymethoxy)aniline. These target compounds could become value-added renewably-sourced platform chemicals that could be used to produce biodegradable plastics, pigments, and pharmaceuticals.

Publication aims to help chemists develop standard operating procedures for working with this potentially dangerous reagent

Synthesis
DOI: 10.1055/a-2241-6858

This short review showcases the developing field of C–H activation reactions, with a particular focus on green catalysis through the use of environmentally friendly solvents. It evaluates the effects of these solvents on reaction outcomes, environmental aspects and general efficacy, highlighting their advantages that lead to greater selectivity, lower levels of toxicity and enhanced reaction rates. Water and biobased alternatives such as polyethylene glycols, glycerol, 2-methyltetrahydrofuran, γ-valerolactone, methanol, ethanol, p-cymene and diethyl carbonate are representative examples of such solvents. The scope of this short review encompasses studies of different methodologies, catalysts, and reaction conditions that help to develop C–H activation reactions utilizing green solvents.1 Introduction2 Water3 Polyethylene Glycols (PEGs)4 Glycerol5 2-Methyltetrahydrofuran (2-MeTHF)6 γ-Valerolactone (GVL)7 Methanol8 Ethanol9 p-Cymene10 Diethyl Carbonate11 Conclusion
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Article in Thieme eJournals:
Table of contents  |  Abstract  |  Full text

Publication date: April 2024

Source: Chemical Engineering Research and Design, Volume 204

Author(s): Vinicius Lima Ferreira, Marco Aurélio Suller Garcia, Donato Alexandre Gomes Aranda, Pedro Nothaft Romano

Nature Synthesis, Published online: 06 February 2024; doi:10.1038/s44160-023-00478-1

Collaboration between synthesis laboratories requires procedures that are reproducible despite differences in equipment. Now, a digital standard for automated chemical synthesis reproduces results between distinct laboratory systems almost half a world apart.

Herein, we report an approach for generating thionyl fluoride (SOF2) from the commodity chemicals thionyl chloride (SOCl2) and potassium fluoride (KF). The methodology relies on a microfluidic device that can efficiently produce and dose this toxic, gaseous reagent under extremely mild and safe conditions. Subsequently, the in situ generated thionyl fluoride is reacted with an array of structurally and electronically differing carboxylic acids, leading to the direct and efficient synthesis of highly sought-after acyl fluorides. Importantly, our investigation also highlights the inherent modularity of this flow-based platform. We demonstrate the adaptability of this approach by not only synthesizing acyl fluorides, but also directly converting carboxylic acids into a diverse array of valuable compounds such as esters, thioesters, amides, and ketones. This versatility showcases the potential of this approach for a wide range of synthetic applications, underscoring its significance in the realm of chemical synthesis.

We proposed a Minisci-type strategy for the alkylation of heterocycles with a variety of boron species under low cost and easily scale-up conditions without the use of transition-metal or organo-catalysts. The extension of this strategy to other systems will provide green approaches for the post-modifications of drug molecules and complex natural products.

Abstract

This manuscript describes a general strategy for the easily scale-up alkylation of heterocycles with a wide variety of boronic acids, boronates, and trifluoroborate salts under low-cost and simple conditions without using any transition-metal or organo-photocatalysts. The key additive of catechol plays an important role in this method which in-situ activated a variety of boron-base species to alkylboronic esters (R-BCat) with a low oxidation potential. The transformation is distinguished by a broad scope, such as drug molecules and natural products. Furthermore, the methodology proves easily scalable under standard batch conditions, enhancing its practicality and accessibility.

Nature, Published online: 23 January 2024; doi:10.1038/d41586-024-00165-x

Flavour variations are mainly the result of changes at the chromosome level, sequencing effort finds.