Pharmaceutically relevant (hetero)cyclic compounds and natural products from lignin-derived monomers:Present and perspectives

Lignin, the richest source of renewable aromatics on the planet, is an intriguing raw material for the construction of value-added aromatics. In the past decade, much progress has been made regarding the development of efficient lignin depolymerization methods, able to produce specific monophenol derivatives in high-enough selectivity and yields. This now serves as an excellent basis for developing powerful downstream conversion strategies toward a wide range of products, including fine chemical building blocks. The inherent structural features of lignin-derived platform chemicals undoubtedly inspire the development of novel, creative, atom-economic synthetic routes toward biologically active molecules or natural products. In this perspective we attempt to bridge the structural features of lignin-derived platform chemicals with existing synthetic strategies toward the construction of heterocycles and provide a summary of efforts for the production of natural products from aromatics that can be, in principle, obtained from lignin. Last, we comment on the latest efforts that present entire value-chains from wood to valuable pharmaceutically relevant compounds

Process considerations of a biorefinery producing value-added products from corn fibre

Corn fibre, a co-product of corn wet milling, can be a suitable raw material of a biorefinery producing biofuels and value-added chemicals. The simulated process is able to produce bioethanol, biomethane and xylitol synergistically, while it also covers its own heat demand. The proposed plant consists of the following process steps: fractionation, enzymatic hydrolysis and ethanol fermentation, distillation and dehydration, anaerobic digestion, biogas upgrading, aerobic waste water treatment, combined heat and power production, xylitol fermentation and recovery. Various scenarios of the biorefinery were investigated and the process configurations were compared in terms of energy efficiency, or mass flows of the products. Incineration of the sludge and production of district heat are found to be effective methods to increase the energy efficiency, on which aerobic sludge yield has a great effect. The solid-liquid separations, which are carried out in filterpress, have a curial role in terms of energy efficiency . Combustion of the solid part of cellulose hydrolysis residue is favourable compared with the anaerobic digestion, except if the dry matter content of the filterpressed solid was set to 30% instead of 40%. The amounts of the produced xylitol and biomethane are variable, which ensures the ability of market adaptation for the biorefinery

Amination of beta-hydroxyl acid esters via cooperative catalysis enables access to bio-based beta-amino acid esters

beta-amino acid esters are important scaffolds in medicinal chemistry and valuable building blocks for materials synthesis. Surprisingly, the waste-free construction of such moieties from readily available or renewable starting materials has not yet been addressed. Here we report on a robust and versatile method for obtaining beta-amino acid esters by direct amination of beta-hydroxyl acid esters via the borrowing hydrogen methodology using a cooperative catalytic system that comprises a homogeneous ruthenium catalyst and an appropriate Bronsted acid additive. This method allows for the direct amination of esters of 3-hydroxypropionic acid, a top value-added bio-based platform chemical, opening a simple route to access beta-amino acid esters from a range of renewable polyols including sugars and glycerol

Neue amine-n-oxide compounds

The invention relates to amine-N-oxide compounds of formula (I) or (II):wherein R1 is selected from hydrocarbon radicals having 4 to 26 C atoms and optionally at least one O or s atom; R2, R3 and R5 each independently selected from hydrogen, R1- O-, R8 and in formula (I) also from -CH2- N+(O-)R6R6 wherein R8 represents a hydrocarbon radical having 1 to 26 C atoms and optionally at least one O or s atom; R4 is selected from hydrogen and R8 is selected; and the R6 are each independently selected from hydrocarbon radicals having from 1 to 6 carbon atoms and optionally at least one n, O or s atom; wherein optionally two radicals R6 are connected to one another to form a nitrogen-containing ring or where, if desired, one or both radicals R.6 a grouping -N+(O-)R6R6 with one or both radicals R6 of such a grouping of another molecule of the formula (I) and are bonded to the structurewherein the dashed line represents an optional bond between the two R 'S6 and the asterisks indicate the bonds of the bridge to the two aromatic rings, form a Dimer according to formula (II); and a preparation process therefor and their use as surfactants

Novel sulfonate compounds

The invention relates to novel sulfonate compounds of formula (I) or (II): wherein the R1 are selected from hydrocarbon radicals having 4 to 26 C atoms and optionally at least one O or s atom; R2 to R5 are each independently selected from hydrogen and hydrocarbon radicals having from 1 to 26 carbon atoms and optionally at least one O or s atom; the R6 are each independently selected from hydrogen and hydrocarbon radicals having from 1 to 6 carbon atoms, wherein the two radicals R.6 optionally, as indicated by the dashed line, are joined together to form a five-or six-membered ring comprising the carbonyl carbon; and each X is independently selected from monovalent and polyvalent cations X.n+, wherein n ≥ 1, including H.+In formula (I), both X together optionally represent a polyvalent cation; and a process for their preparation and their use as surfactants

Primary amines from lignocellulose by direct amination of alcohol intermediates, catalyzed by RANEY® Ni

Primary amines are crucially important building blocks for the synthesis of a wide range of industrially relevant products. Our comprehensive catalytic strategy presented here allows diverse primary amines from lignocellulosic biomass to be sourced in a straightforward manner and with minimal purification effort. The core of the methodology is the efficient RANEY® Ni-catalyzed hydrogen-borrowing amination (with ammonia) of the alcohol intermediates, namely alkyl-phenol derivatives as well as aliphatic alcohols, obtained through the two-stage LignoFlex process. Hereby the first stage entails the copper-doped porous metal oxide (Cu20PMO) catalyzed reductive catalytic fractionation (RCF) of pine lignocellulose into a crude bio-oil, rich in dihydroconiferyl alcohol (1G), which could be converted into dihydroconiferyl amine (1G amine) in high selectivity using ammonia gas, by applying our selective amination protocol. Notably also, the crude RCF-oil directly afforded 1G amine in a high 4.6 wt% isolated yield (based on lignin content). Finally it was also shown that the here developed Ni-catalysed heterogeneous catalytic procedure was equally capable of transforming a range of aliphatic linear/cyclic primary/secondary alcohols – available from the second stage of the LignoFlex procedure – into their respective primary amines

Neue amine-n-oxide compounds

The invention relates to amine-N-oxide compounds of formula (I) or (II):wherein R1 is selected from hydrocarbon radicals having 4 to 26 C atoms and optionally at least one O or s atom; R2, R3 and R5 each independently selected from hydrogen, R1- O-, R8 and in formula (I) also from -CH2- N+(O-)R6R6 wherein R8 represents a hydrocarbon radical having 1 to 26 C atoms and optionally at least one O or s atom; R4 is selected from hydrogen and R8 is selected; and the R6 are each independently selected from hydrocarbon radicals having from 1 to 6 carbon atoms and optionally at least one n, O or s atom; wherein optionally two radicals R6 are connected to one another to form a nitrogen-containing ring or where, if desired, one or both radicals R.6 a grouping -N+(O-)R6R6 with one or both radicals R6 of such a grouping of another molecule of the formula (I) and are bonded to the structurewherein the dashed line represents an optional bond between the two R 'S6 and the asterisks indicate the bonds of the bridge to the two aromatic rings, form a Dimer according to formula (II); and a preparation process therefor and their use as surfactants

Novel sulfonate compounds

The invention relates to novel sulfonate compounds of formula (I) or (II): wherein the R1 are selected from hydrocarbon radicals having 4 to 26 C atoms and optionally at least one O or s atom; R2 to R5 are each independently selected from hydrogen and hydrocarbon radicals having from 1 to 26 carbon atoms and optionally at least one O or s atom; the R6 are each independently selected from hydrogen and hydrocarbon radicals having from 1 to 6 carbon atoms, wherein the two radicals R.6 optionally, as indicated by the dashed line, are joined together to form a five-or six-membered ring comprising the carbonyl carbon; and each X is independently selected from monovalent and polyvalent cations X.n+, wherein n ≥ 1, including H.+In formula (I), both X together optionally represent a polyvalent cation; and a process for their preparation and their use as surfactants

One-Pot Catalytic Conversion of Lignin-Derivable Guaiacols and Syringols to Cyclohexylamines

Cyclic primary amines are elementary building blocks to many fine chemicals, pharmaceuticals, and polymers. Here, a powerful one-pot Raney Ni-based catalytic strategy was developed to transform guaiacol into cyclohexylamine using NH3 (7 bar) and H2 (10 bar) in up to 94 % yield. The methodology was extendable to the conversion of a wider range of guaiacols and syringols into their corresponding cyclohexylamines. Notably, a crude bio-oil originating from the reductive catalytic fractionation of birch lignocellulose was transformed into a product mixture rich in 4-propylcyclohexylamine, constituting an interesting case of catalytic funneling. The isolated yield of the desired 4-propylcyclohexylamine reached as high as 7 wt % (on lignin basis). Preliminary mechanistic studies pointed at the consecutive occurrence of three key catalytic transformations, namely, demethoxylation, hydrogenation, and amination

A well-defined diamine from lignin depolymerization mixtures for constructing bio-based polybenzoxazines

The demand for high-performance materials is increasing, and most of these materials are petrol based. Therefore, the development of highly efficient and selective catalytic methods that allow access to industrially relevant polymer building blocks from complex biomass depolymerization mixtures is essential. Here, we report on a robust catalytic strategy to obtain the industrially relevant 4,4′-methylenebiscyclohexanamine (MBCA) from lignin oxidation mixtures and its use for constructing fully bio-based polybenzoxazines. The strategy consists of two challenging catalytic steps: 1) the funneling of lignin-derived bisphenol mixtures into 4,4′-methylenebiscyclohexanol (MBC) and 2) the highly selective amination of MBC with ammonia to obtain MBCA. The renewable polybenzoxazines were prepared from MBCA and phenolic lignin platform chemicals. The most promising, cured poly (S-MBCA), shows high glass transition temperature Tg of 315°C, outstanding thermal stability (T10% = 400°C), and good storage modulus (E′25°C = 3.8 GPa), which is competitive with commercial resins