Forsøk på syntese av (all-Z)-hentriakonta-3,6,9,12,15, 19,22,25,28-nonan

Målet med oppgaven var å syntetisere hydrokarbonet (3Z,6Z,9Z,12Z,15Z,19Z,22Z,25Z,28Z)-hentriakonta-3,6,9,12,15,19,22,25,28-nonan (1). Dette hydrokarbonet er et lang kjedet, flerumettet hydrokarbon (LC-PUCH) som er funnet i flere mikroorganismer, blant annet slekten Shewanella. Syntesen av 1 er basert på kommersielt tilgjenngelige fettsyren eicosapentaensyre-((5Z,8Z,11Z,14Z,17Z)-eikosa-5,8,11,14,17-pentaensyre) som startmateriale for C-31 hydrokarbonet. Dette blir gjort via en addisjonsreaksjon av aldehydet 17 og alkynet 18 til propargylalkoholen 16 med et utbytte på 39 %. Propargylalkoholen ble forsøkt redusert på flere måter, blant annet ved bruk av Appel- og Barton-McCombie-reaksjonen, men uten hell. Propargylalkoholen 16 ble omsatt til propargyljodid 22 via mesylatet 23 med gode utbytter. For å fullføre syntesen ble det forsøkt flere forskjellige strategier. Direkte semi-hydrogenering av 22 med Lindlar katalysatorer med håp om at dette skulle lede til hydrogenolyse av jod-bindingen ga kun reduksjon av dobbeltbindingen til alkenjodidet 25. Fjerning av halogenet med Bu3SnH fra mesylatet 23 ga heller ikke ønsket produkt. Det ble da forsøkt å redusere propargyljodidet 22 til tilsvarende alkyn 15, men dette resulterte i dannelse av allenet 26. Allenet 26 ble til sist forsøkt redusert med to metoder, med Lindlar katalysator og med en 10 % Pd-C katalysator. Hydrogenering ble kun observert ved sistnevnte katalysator, men dessverre med mye overhydrogenering og målmolekylet 1 ble ikke syntetisert. Videre undersøkelse av en mer optimalisert hydrogenering vil trolig føre til en syntese av 1. På grunn av tid ble ikke dette forsøkt i denne oppgaven. Med bakgrunn i arbeidet som er gjort og forslagene til videre arbeid, kan detteføre frem til en god syntesevei av målmolekylet 1. Abstract Synthetic studies towards the long chaind polyunsaturated hydrocarbon (LC-PUCH), (3Z,6Z,9Z,12Z,15Z,19Z,22Z,25Z,28Z)-hentriaconta-3,6,9,12,15,19,22,25,28-nonane (1). The LC-PUCH in this thesis have been found in several microorganisms, including the genus Shewanella. The synthesis of 1 is based on commercially avaiable fatty acid eicosapentaenoic acid ((5Z,8Z,11Z,14Z,17Z)-eicosa-5,8,11,14,17-pentanoic acid) as the starting material for the C-31 hydrocarbon. This is done by an addition reaction of the aldehyde 17 and the alkyne 18 to the alcohol 16 with a yield of 39%. The alcohol 16 was attempted reduced in several ways, including using Appel- and Barton-McCombie reaction without luck. The alcohol 16 was converted into the iodide 22 through mesylate 23 with good yields. To complete the synthesis there was several attempted strategies, one was direct semi-hydrogenation of 22 with Lindlar catalysts, with the hope that this would lead to hydrogenolysis of the iodine bond. Only reduction of the tripple bond to give alkeniodide 25 was achieved. Removal of the halogen with Bu3SnH from mesylate 23 did not give the desired product. It was then attempted to reduce iodide 22 to the corresponding alkyne 15, but this resulted in the formation of allene 26. Allene 26 was at the end attempted to be reduced by two different methods, using Lindlar and a 10% Pd/C catalyst. Hydrogenation was only observed with the latter, but unfortunately this gave a lot of over hydrogenation and the target molecule 1 was not synthesized. Further examination of a more optimized hydrogenation is likely to lead to a synthesis of 1. Unfortunately because of limited time this was not attempted in this paper. Based on the work done and suggestions for future work, it should be possible to synthesis the target molecule 1

Synthesis towards (all-Z)-hentriaconta-3,9,12,15,19,22,25,28- nonane

Målet med oppgaven var å syntetisere hydrokarbonet (3Z,6Z,9Z,12Z,15Z,19Z,22Z,25Z,28Z)-hentriakonta-3,6,9,12,15,19,22,25,28-nonan (1). Dette hydrokarbonet er et lang kjedet, flerumettet hydrokarbon (LC-PUCH) som er funnet i flere mikroorganismer, blant annet slekten Shewanella. Syntesen av 1 er basert på kommersielt tilgjenngelige fettsyren eicosapentaensyre-((5Z,8Z,11Z,14Z,17Z)-eikosa-5,8,11,14,17-pentaensyre) som startmateriale for C-31 hydrokarbonet. Dette blir gjort via en addisjonsreaksjon av aldehydet 17 og alkynet 18 til propargylalkoholen 16 med et utbytte på 39 %. Propargylalkoholen ble forsøkt redusert på flere måter, blant annet ved bruk av Appel- og Barton-McCombie-reaksjonen, men uten hell. Propargylalkoholen 16 ble omsatt til propargyljodid 22 via mesylatet 23 med gode utbytter. For å fullføre syntesen ble det forsøkt flere forskjellige strategier. Direkte semi-hydrogenering av 22 med Lindlar katalysatorer med håp om at dette skulle lede til hydrogenolyse av jod-bindingen ga kun reduksjon av dobbeltbindingen til alkenjodidet 25. Fjerning av halogenet med Bu3SnH fra mesylatet 23 ga heller ikke ønsket produkt. Det ble da forsøkt å redusere propargyljodidet 22 til tilsvarende alkyn 15, men dette resulterte i dannelse av allenet 26. Allenet 26 ble til sist forsøkt redusert med to metoder, med Lindlar katalysator og med en 10 % Pd-C katalysator. Hydrogenering ble kun observert ved sistnevnte katalysator, men dessverre med mye overhydrogenering og målmolekylet 1 ble ikke syntetisert. Videre undersøkelse av en mer optimalisert hydrogenering vil trolig føre til en syntese av 1. På grunn av tid ble ikke dette forsøkt i denne oppgaven. Med bakgrunn i arbeidet som er gjort og forslagene til videre arbeid, kan detteføre frem til en god syntesevei av målmolekylet 1. Abstract Synthetic studies towards the long chaind polyunsaturated hydrocarbon (LC-PUCH), (3Z,6Z,9Z,12Z,15Z,19Z,22Z,25Z,28Z)-hentriaconta-3,6,9,12,15,19,22,25,28-nonane (1). The LC-PUCH in this thesis have been found in several microorganisms, including the genus Shewanella. The synthesis of 1 is based on commercially avaiable fatty acid eicosapentaenoic acid ((5Z,8Z,11Z,14Z,17Z)-eicosa-5,8,11,14,17-pentanoic acid) as the starting material for the C-31 hydrocarbon. This is done by an addition reaction of the aldehyde 17 and the alkyne 18 to the alcohol 16 with a yield of 39%. The alcohol 16 was attempted reduced in several ways, including using Appel- and Barton-McCombie reaction without luck. The alcohol 16 was converted into the iodide 22 through mesylate 23 with good yields. To complete the synthesis there was several attempted strategies, one was direct semi-hydrogenation of 22 with Lindlar catalysts, with the hope that this would lead to hydrogenolysis of the iodine bond. Only reduction of the tripple bond to give alkeniodide 25 was achieved. Removal of the halogen with Bu3SnH from mesylate 23 did not give the desired product. It was then attempted to reduce iodide 22 to the corresponding alkyne 15, but this resulted in the formation of allene 26. Allene 26 was at the end attempted to be reduced by two different methods, using Lindlar and a 10% Pd/C catalyst. Hydrogenation was only observed with the latter, but unfortunately this gave a lot of over hydrogenation and the target molecule 1 was not synthesized. Further examination of a more optimized hydrogenation is likely to lead to a synthesis of 1. Unfortunately because of limited time this was not attempted in this paper. Based on the work done and suggestions for future work, it should be possible to synthesis the target molecule 1.M-KJEM

Effects of pH on steam explosion extraction of acetylated galactoglucomannan from Norway spruce

Background: Acetylated galactoglucomannan (AcGGM) is a complex hemicellulose found in softwoods such as Norway spruce (Picea abies). AcGGM has a large potential as a biorefinery feedstock and source of oligosaccharides for high-value industrial applications. Steam explosion is an effective method for extraction of carbohydrates from plant biomass. Increasing the reaction pH reduces the combined severity ( R′ 0 ) of treatment, affecting yields and properties of extracted oligosaccharides. In this study, steam explosion was used to extract oligosaccharides from Norway spruce wood chips soaked with sodium citrate and potassium phosphate buffers with pH of 4.0–7.0. Yields, monosaccharide composition of released oligosaccharides and biomass residue, their acetate content and composition of their lignin fraction were examined to determine the impact of steam explosion buffering on the extraction of softwood hemicellulose. Results: Reducing the severity of steam explosion resulted in lower yields, although the extracted oligosaccharides had a higher degree of polymerization. Higher buffering pH also resulted in a higher fraction of xylan in the extracted oligos. Oligosaccharides extracted in buffers of pH > 5.0 were deacetylated. Buffering leads to a removal of acetylations from both the extracted oligosaccharides and the hemicellulose in the residual biomass. Treatment of the residual biomass with a GH5 family mannanase from Aspergillus nidulans was not able to improve the AcGGM yields. No hydroxymethylfurfural formation, a decomposition product from hexoses, was observed in samples soaked with buffers at pH higher than 4.0. Conclusions: Buffering the steam explosion reactions proved to be an effective way to reduce the combined severity ( R′ 0 ) and produce a wide range of products from the same feedstock at the same physical conditions. The results highlight the impact of chemical autohydrolysis of hemicellulose by acetic acid released from the biomass in hydrothermal pretreatments. Lower combined severity results in products with a lower degree of acetylation of both the extracted oligosaccharides and residual biomass. Decrease in severity appears not to be the result of reduced acetate release, but rather a result of inhibited autohydrolysis by the released acetate. Based on the results presented, the optimal soaking pH for fine-tuning properties of extracted AcGGM is below 5.0

Effects of pH on steam explosion extraction of acetylated galactoglucomannan from Norway spruce

Background: Acetylated galactoglucomannan (AcGGM) is a complex hemicellulose found in softwoods such as Norway spruce (Picea abies). AcGGM has a large potential as a biorefinery feedstock and source of oligosaccharides for high-value industrial applications. Steam explosion is an effective method for extraction of carbohydrates from plant biomass. Increasing the reaction pH reduces the combined severity ( R′ 0 ) of treatment, affecting yields and properties of extracted oligosaccharides. In this study, steam explosion was used to extract oligosaccharides from Norway spruce wood chips soaked with sodium citrate and potassium phosphate buffers with pH of 4.0–7.0. Yields, monosaccharide composition of released oligosaccharides and biomass residue, their acetate content and composition of their lignin fraction were examined to determine the impact of steam explosion buffering on the extraction of softwood hemicellulose. Results: Reducing the severity of steam explosion resulted in lower yields, although the extracted oligosaccharides had a higher degree of polymerization. Higher buffering pH also resulted in a higher fraction of xylan in the extracted oligos. Oligosaccharides extracted in buffers of pH > 5.0 were deacetylated. Buffering leads to a removal of acetylations from both the extracted oligosaccharides and the hemicellulose in the residual biomass. Treatment of the residual biomass with a GH5 family mannanase from Aspergillus nidulans was not able to improve the AcGGM yields. No hydroxymethylfurfural formation, a decomposition product from hexoses, was observed in samples soaked with buffers at pH higher than 4.0. Conclusions: Buffering the steam explosion reactions proved to be an effective way to reduce the combined severity ( R′ 0 ) and produce a wide range of products from the same feedstock at the same physical conditions. The results highlight the impact of chemical autohydrolysis of hemicellulose by acetic acid released from the biomass in hydrothermal pretreatments. Lower combined severity results in products with a lower degree of acetylation of both the extracted oligosaccharides and residual biomass. Decrease in severity appears not to be the result of reduced acetate release, but rather a result of inhibited autohydrolysis by the released acetate. Based on the results presented, the optimal soaking pH for fine-tuning properties of extracted AcGGM is below 5.0

Characterization of Pseudo-Lignin from Steam Exploded Birch

There is a growing interest in a more wholesome utilization of biomass as the need for greener chemistry and non-mineral oil-based products increases. Lignin is the largest renewable resource for aromatic chemicals, which is found in all types of lignocellulosic biomass. Steam-explosion of lignocellulosic biomass is a useful pretreatment technique to make the polymeric material more available for processing. However, this heat-based pretreatment is known to result in the formation of pseudo-lignin, a lignin-like polymer made from carbohydrate degradation products. In this work, we have analyzed steam-exploded birch with a varying severity factor (3.1−5.0) by pyrolysis−gas chromatography−mass spectrometry, 2D-NMR, and Fourier transform infrared spectroscopy. The main results reveal a consumption of acetic acid at higher temperatures, with the increase of furan components in the pyrolyzate. The IR and NMR spectral data support these results, and there is a reason to believe that the conditions for humin formation are accomplished under steam explosion. Pseudo-lignin seems to be a humin-like compound.Characterization of Pseudo-Lignin from Steam Exploded BirchpublishedVersio

Effects of pH on steam explosion extraction of acetylated galactoglucomannan from Norway spruce

Background: Acetylated galactoglucomannan (AcGGM) is a complex hemicellulose found in softwoods such as Norway spruce (Picea abies). AcGGM has a large potential as a biorefinery feedstock and source of oligosaccharides for high-value industrial applications. Steam explosion is an effective method for extraction of carbohydrates from plant biomass. Increasing the reaction pH reduces the combined severity ( R′ 0 ) of treatment, affecting yields and properties of extracted oligosaccharides. In this study, steam explosion was used to extract oligosaccharides from Norway spruce wood chips soaked with sodium citrate and potassium phosphate buffers with pH of 4.0–7.0. Yields, monosaccharide composition of released oligosaccharides and biomass residue, their acetate content and composition of their lignin fraction were examined to determine the impact of steam explosion buffering on the extraction of softwood hemicellulose. Results: Reducing the severity of steam explosion resulted in lower yields, although the extracted oligosaccharides had a higher degree of polymerization. Higher buffering pH also resulted in a higher fraction of xylan in the extracted oligos. Oligosaccharides extracted in buffers of pH > 5.0 were deacetylated. Buffering leads to a removal of acetylations from both the extracted oligosaccharides and the hemicellulose in the residual biomass. Treatment of the residual biomass with a GH5 family mannanase from Aspergillus nidulans was not able to improve the AcGGM yields. No hydroxymethylfurfural formation, a decomposition product from hexoses, was observed in samples soaked with buffers at pH higher than 4.0. Conclusions: Buffering the steam explosion reactions proved to be an effective way to reduce the combined severity ( R′ 0 ) and produce a wide range of products from the same feedstock at the same physical conditions. The results highlight the impact of chemical autohydrolysis of hemicellulose by acetic acid released from the biomass in hydrothermal pretreatments. Lower combined severity results in products with a lower degree of acetylation of both the extracted oligosaccharides and residual biomass. Decrease in severity appears not to be the result of reduced acetate release, but rather a result of inhibited autohydrolysis by the released acetate. Based on the results presented, the optimal soaking pH for fine-tuning properties of extracted AcGGM is below 5.0.Effects of pH on steam explosion extraction of acetylated galactoglucomannan from Norway sprucepublishedVersio