Bio-based Aromatic Amines from Lignin-Derived Monomers

A new approach to synthesize valuable 3,4- dialkoxyanilines and alkyl propionates from lignin-derived 4- propylguaiacol and -catechol with overall isolated yields up to 65% has been described. The strategy is based on the introduction of nitrogen via a Beckmann rearrangement. Amino introduction therefore coincides with a C-defunctionalization reaction; overall a replacement of the propyl chain by an amino group is obtained. The process only requires cheap bulk chemicals as reagents/reactants and does not involve column chromatography to purify the reaction products. Furthermore, all carbon atoms from the biorenewable lignin-derived monomers are transformed into valuable compounds. Greenness was assessed by performing a Green Metrics analysis on two dialkoxyanilines. A comparison was made with literature routes for these compounds starting from a petrochemical substrate.status: publishe

Bio-based aromatic amines from lignin-derived monomers

A new approach to synthesize valuable 3,4-dialkoxyanilines and alkyl propionates from lignin-derived 4-propylguaiacol and -catechol with overall isolated yields up to 65% has been described. The strategy is based on the introduction of nitrogen via a Beckmann rearrangement. Amino introduction therefore coincides with a <i>C</i>-defunctionalization reaction; overall a replacement of the propyl chain by an amino group is obtained. The process only requires cheap bulk chemicals as reagents/reactants and does not involve column chromatography to purify the reaction products. Furthermore, all carbon atoms from the biorenewable lignin-derived monomers are transformed into valuable compounds. Greenness was assessed by performing a Green Metrics analysis on two dialkoxyanilines. A comparison was made with literature routes for these compounds starting from a petrochemical substrate

A nitrilase-mediated entry to 4-carboxymethyl-β-lactams from chemically prepared 4-(cyanomethyl)azetidin-2-ones

(3R, 4S)-3-Alkoxy/aryloxy-4-(cyanomethyl) azetidin-2-ones were efficiently prepared from readily available 1,2: 5,6-di-D-isopropylidene-D-mannitol by means of a classical organic synthesis approach via 4-hydroxymethyl-beta-lactams as key intermediates. The corresponding 4-carboxymethyl-beta-lactams were subsequently obtained after selective hydrolysis of the nitrile functionality by means of a nitrilase enzyme without affecting the sensitive four-membered ring system, hence overcoming the difficulties associated with the chemical hydrolysis approach. Thus, the implementation of a biocatalytic step allows a convenient synthetic route to new 4-carboxymethyl-beta-lactams as versatile building blocks for further elaboration

Bronsted Acid Catalyzed Tandem Defunctionalization of Biorenewable Ferulic acid and Derivates into Bio-Catechol

An efficientconversionof biorenewableferulicacidintobio-catechol hasbeendeveloped.Thetransformationcomprisestwoconsecutivedefunctionalizationsof the sub-strate,that is,C@O(demethylation)andC@C(de-2-carbox-yvinylation)bondcleavage,occurringin one step.The processonlyrequiresheatingof ferulicacidwithHCl(or H2SO4)ascatalystin pressurized hot water(25088C, 50 bar N2). Theversatilityis shownon avarietyof other(biorenewable)substratesyieldingup to 84%di- (catechol, resorcinol,hydro-quinone)andtrihydroxybenzenes(pyrogallol,hydroxyqui-nol),in mostcasesjust requiringsimpleextractionas work-up.status: publishe