Fredrik Heen Blindheim

Mr. Fredrik Heen Blindheim


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 June 2023 in Polymers
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FBFredrik Heen Blindheim
Fredrik Heen Blindheim
Jost RuwoldtJost Ruwoldt
Jost Ruwoldt
The characterization and quantification of functional groups in technical lignins are among the chief obstacles of the utilization of this highly abundant biopolymer. Although several techniques were developed for this purpose, there is still a need for quick, cost-efficient, and reliable quantification methods for lignin. In this paper, three sampling techniques for fourier transform infrared (FTIR) spectroscopy were assessed both qualitatively and quantitatively, delineating how these affected the resultant spectra. The attenuated total reflectance (ATR) of neat powders and DMSO-d6 solutions, as well as transmission FTIR using the KBr pelleting method (0.5 wt%), were investigated and compared for eight lignin samples. The ATR of neat lignins provided a quick and easy method, but the signal-to-noise ratios in the afforded spectra were limited. The ATR of the DMSO-d6 solutions was highly concentration dependent, but at a 30 wt%, acceptable signal-to-noise ratios were obtained, allowing for the lignins to be studied in the dissolved state. The KBr pelleting method gave a significant improvement in the smoothness and resolution of the resultant spectra compared to the ATR techniques. Subsequently, the content of phenolic OH groups was calculated from each FTIR mode, and the best correlation was seen between the transmission mode using KBr pellets and the ATR of the neat samples (R2 = 0.9995). Using the titration measurements, the total OH and the phenolic OH group content of the lignin samples were determined as well. These results were then compared to the FTIR results, which revealed an under-estimation of the phenolic OH groups from the non-aqueous potentiometric titration, which was likely due to the differences in the pKa between the lignin and the calibration standard 4-hydroxybenzoic acid. Further, a clear correlation was found between the lower Mn and the increased phenolic OH group content via SEC analyses. The work outlined in this paper give complementary views on the characterization and quantification of technical lignin samples via FTIR.

22 July 2022 in Antibiotics
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COCecilie Elisabeth Olsen
Cecilie Elisabeth Olsen
FBFredrik Heen Blindheim
Fredrik Heen Blindheim
CSCaroline Krogh Søgaard
Caroline Krogh Søgaard
LRLisa Marie Røst
Lisa Marie Røst
ASAmanda Holstad Singleton
Amanda Holstad Singleton
Bård Helge HoffBård Helge Hoff
Bård Helge Hoff
Currently, there is a world-wide rise in antibiotic resistance causing burdens to individuals and public healthcare systems. At the same time drug development is lagging behind. Therefore, finding new ways of treating bacterial infections either by identifying new agents or combinations of drugs is of utmost importance. Additionally, if combination therapy is based on agents with different modes of action, resistance is less likely to develop. The synthesis of 21 fused pyrimidines and a structure-activity relationship study identified two 6-aryl-7H-pyrrolo [2,3-d] pyrimidin-4-amines with potent activity towards Staphylococcus aureus. The MIC-value was found to be highly dependent on a bromo or iodo substitution in the 4-benzylamine group and a hydroxyl in the meta or para position of the 6-aryl unit. The most active bromo and iodo derivatives had MIC of 8 mg/L. Interestingly, the most potent compounds experienced a four-fold lower MIC-value when they were combined with the antimicrobial peptide betatide giving MIC of 1–2 mg/L. The front runner bromo derivative also has a low activity towards 50 human kinases, including thymidylate monophosphate kinase, a putative antibacterial target.

5 November 2024 in ChemSusChem
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FBFredrik Heen Blindheim
Fredrik Heen Blindheim
Jost RuwoldtJost Ruwoldt
Jost Ruwoldt
As society is rapidly converting from fossil‐based materials to greener alternatives, the valorization of lignin through chemical modification has been given considerable attention. Characterizing this highly heterogeneous biopolymer is a constant challenge, and an emerging strategy for dealing with variations in material characteristics is combining traditional analytical techniques with chemometrics, such as Fourier‐transform infrared (FTIR) spectroscopy with partial least squares regression (PLSR). Here, a calibration data set was built based on FTIR spectra and the total carbon‐hydrogen bond (CHB) content of mixtures of technical lignins and alkanes, meant to emulate esterified samples. From this data, a PLSR model was built which predicted the CHB content of esterified lignin reaction products with an RMSECV=5.685 mmol/g and RMSEPred=5.827 mmol/g, and from which the weight percentage of ester‐to‐lignin was determined. When compared to wet‐chemical analysis, good agreement between the techniques was found with an obtained RMSEPred=8.3 % and a R2Train=0.9752 for the degree of esterification. This indicates high model predictability and goodness of fit, and that the calibration data set successfully emulated esterified lignin samples.

2 December 2021 in ChemistrySelect
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FBFredrik Heen Blindheim
Fredrik Heen Blindheim
AMAne Thoresen Malme
Ane Thoresen Malme
BDBjørn Dalhus
Bjørn Dalhus
ESEirik Sundby
Eirik Sundby
Bård Helge HoffBård Helge Hoff
Bård Helge Hoff
To front emergence of antibiotic resistance there is an urgent need for new therapeutics, and one seemingly relevant target is thymidylate monophosphate kinase (TMPK). Serendipitously, we discovered a naphthyl substituted pyrrolopyrimidine possessing activity towards E. coli TMPK. Based on this hit, synthesis, and screening of 61 fused pyrimidines were undertaken. The most potent derivatives were also counter assayed towards the human variant of the enzyme. Two of the inhibitors possessed promising drug‐like properties and selectivity for E. coli TMPK. Although the initial pyrrolopyrimidine hit failed to have cellular activity, two alternative scaffolds were discovered providing starting points for further work.

4 November 2018 in Catalysts
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FBFredrik Heen Blindheim
Fredrik Heen Blindheim
MHMari Bergan Hansen
Mari Bergan Hansen
SESigvart Evjen
Sigvart Evjen
WZWei Zhu
Wei Zhu
Elisabeth Egholm JacobsenElisabeth Egholm Jacobsen
Elisabeth Egholm Jacobsen
Clenbuterol is a β2-agonist used in the veterinary treatment of asthma in several countries. The drug is listed on the World Antidoping Agency’s prohibited list due to its effect on increased protein synthesis in the body. However, racemic clenbuterol has recently been shown to reduce the risk of Parkinson’s disease. In order to reveal which one (or both) of the enantiomers that cause this effect, pure enantiomers need to be separately studied. (R)-1-(4-Amino-3,5-dichlorophenyl)-2-bromoethan-1-ol has been synthesised in 93% enantiomeric excess (ee) by asymmetric reduction of the corresponding ketone catalysed by a ketoreductase and nicotinamide adenine dinucleotide phosphate (NADPH) as the cofactor in dimethyl sulfoxide (DMSO). (S)-N-(2,6-Dichloro-4-(1-hydroxyethyl)phenyl)acetamide has been synthesised in >98% ee by the same system. Both synthons are potential precursors for clenbuterol enantiomers.

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MHMari Bergan Hansen
Mari Bergan Hansen
ATAnna Lifen Tennfjord
Anna Lifen Tennfjord
FBFredrik Heen Blindheim
Fredrik Heen Blindheim
LBLucas Bocquin
Lucas Bocquin
Elisabeth Egholm JacobsenElisabeth Egholm Jacobsen
Elisabeth Egholm Jacobsen
(S)-Atenolol ((S)-2-(4-(2-Hydroxy-3-(isopropylamino)propoxy)phenyl)acetamide) has been synthesized in >99% enantiomeric excess (ee) with the use of Candida antarctica lipase B from Syncozymes (Shanghai, China), in a kinetic resolution of the corresponding racemic chlorohydrin. A catalytic amount of base was used in deprotonation of the phenol building block. The enantiopurity of the chlorohydrin building block remained unchanged upon subsequent amination to yield the final drug. All four steps in the synthesis protocol have been optimized compared to previously reported methods, which makes this new protocol more sustainable and in accordance with green chemistry principles. The overall yield of (S)-atenolol was 9.9%, which will be further optimized.