| 1. |
- Dubol, Manon, et al.
(författare)
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Acute nicotine exposure blocks aromatase in the limbic brain of healthy women : A [11C]cetrozole PET study
- 2023
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Ingår i: Comprehensive Psychiatry. - : Elsevier. - 0010-440X .- 1532-8384. ; 123
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Tidskriftsartikel (refereegranskat)abstract
- Background: Of interest to women's mental health, a wealth of studies suggests sex differences in nicotine addiction and treatment response, but their psychoneuroendocrine underpinnings remain largely unknown. A pathway involving sex steroids could indeed be involved in the behavioural effects of nicotine, as it was found to inhibit aromatase in vitro and in vivo in rodents and non-human primates, respectively. Aromatase regulates the synthesis of oestrogens and, of relevance to addiction, is highly expressed in the limbic brain.Methods: The present study sought to investigate in vivo aromatase availability in relation to exposure to nicotine in healthy women. Structural magnetic resonance imaging and two [11C]cetrozole positron emission tomography (PET) scans were performed to assess the availability of aromatase before and after administration of nicotine. Gonadal hormones and cotinine levels were measured. Given the region-specific expression of aromatase, a ROI -based approach was employed to assess changes in [11C]cetrozole non-displaceable binding potential.Results: The highest availability of aromatase was found in the right and left thalamus. Upon nicotine exposure, [11C]cetrozole binding in the thalamus was acutely decreased bilaterally (Cohen's d =-0.99). In line, cotinine levels were negatively associated with aromatase availability in the thalamus, although as non-significant trend.Conclusions: These findings indicate acute blocking of aromatase availability by nicotine in the thalamic area. This suggests a new putative mechanism mediating the effects of nicotine on human behaviour, particularly relevant to sex differences in nicotine addiction.
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| 2. |
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| 3. |
- Roslin, Sara
(författare)
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Exploring Palladium-Mediated 11C/12C-Carbonylation Reactions : PET Tracer Development Targeting the Vesicular Acetylcholine Transporter
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work presented herein describes the utilization and exploration of palladium-mediated incorporations of carbon monoxide and/or [11C]carbon monoxide into compounds and structural motifs with biological relevance.The first part of the thesis describes the design, synthesis and 11C-labeling of prospective PET tracers for the vesicular acetylcholine transporter (VAChT), a target affected in several neurodegenerative diseases. Different parts of the benzovesamicol scaffold were modified in papers I and II to probe the binding to VAChT. The key motif was an amide functional group, which enabled the use of palladium-mediated 11C/12C-carbonylations to synthesize and evaluate two different sets of structurally related ligands.The second part of the thesis describes the exploration of different aspects of palladium-mediated 11C/12C-carbonylation reactions. The utilization of unactivated alkyl iodides and bromides as coupling partners in a carbonylative Suzuki-Miyaura reaction was described in paper III. The combination of palladium-catalysis together with visible light irradiation enabled their functionalization via an alkyl radical. The mild conditions, namely the ambient temperature and pressure of carbon monoxide, and the accessible reaction set-up further added to the utility of the method. A palladium(II)-mediated oxidative 11C-carbonylation for synthesis of 11C-labeled ureas was described in paper IV. Utilizing only amines in addition to a palladium-source and [11C]carbon monoxide, the method proved to be facile and robust, thus representing a simplification in relation to methods using other 11C-synthons for synthesis of 11C-labeled ureas. Finally, a palladium(0)-catalyzed carbonylation reaction for synthesis of acylamidines was presented in paper V. The versatility of the method was demonstrated by one-pot cyclizations to form oxadiazoles and triazoles together with the corresponding 11C-carbonylation reaction to produce 11C-labeled acylamidines and an oxadiazole.The work described herein has thus contributed structural information in the search for a PET tracer for VAChT and identified a viable lead structure for future investigations. Furthermore, investigation of reaction conditions that would allow use of either elusive or accessible substrates led to the development of methods for synthesis and/or 11C-labeling of various carbonylated compounds.
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| 4. |
- Roslin, Sara, et al.
(författare)
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Palladium and Visible-Light Mediated Carbonylative Suzuki-Miyaura Coupling of Unactivated Alkyl Halides and Aryl Boronic Acids
- 2017
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 53:51, s. 6895-6898
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Tidskriftsartikel (refereegranskat)abstract
- Herein, a simple and efficient method for the palladium-catalyzed carbonylation of aryl boronic acids with unactivated alkyl iodides and bromides under visible-light irradiation, ambient temperature and low CO-pressure is presented. Notably, the procedure uses readily available equipment and an inexpensive palladium catalyst to generate the key alkyl radical intermediate. These mild conditions enabled the synthesis of a range of functionalized aryl alkyl ketones including the antipsychotic drug, melperone.
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| 5. |
- Roslin, Sara, et al.
(författare)
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Reaction of 11C‐benzoyl chlorides with metalloid reagents: 11C‐labeling of benzyl alcohols, benzaldehydes, and phenylketones from [11C]CO
- 2018
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Ingår i: Journal of Labelled Compounds and Radiopharmaceuticals. - : Wiley. - 0362-4803 .- 1099-1344. ; 61:5, s. 447-454
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we describe the carbonâ€11 (11C, t1/2 = 20.4 minutes) labeling of benzyl alcohols, benzaldehydes, and ketones using an efficient 2-€step synthesis in which 11C-€carbon monoxide is used in an initial palladium-€mediated reaction to produce 11C-€benzoyl chloride as a key intermediate. In the second step, the obtained 11C-€benzoyl chloride is further treated with a metalloid reagent to furnish the final 11C-€labeled product. Benzyl alcohols were obtained in moderated to high nonâ€isolated radiochemical yields (RCY, 35%-90%) with lithium aluminum hydride or lithium aluminum deuteride as metalloid reagent. Changing the metalloid reagent to either tributyltin hydride or sodium borohydride, allowed for the reliable syntheses of 11C-€benzaldehydes in RCYs ranging from 58% to 95%. Finally, sodium tetraphenylborate were utilized to obtain 11C-€phenyl ketones in high RCYs (77%-95%). The developed method provides a new and efficient route to 3 different classes of compounds starting from aryl iodides or aryl bromides.
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| 6. |
- Roslin, Sara, et al.
(författare)
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Synthesis and In Vitro Evaluation of 5-Substituted Benzovesamicol Analogs containing N-Substituted Amides as Potential Positron Emission Tomography Tracers for the Vesicular Acetylcholine Transporter
- 2017
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Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 25:19, s. 5095-5106
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Tidskriftsartikel (refereegranskat)abstract
- Herein, new ligands for the vesicular acetylcholine transporter (VAChT), based on a benzovesamicol scaffold, are presented. VAChT is acknowledged as a marker for cholinergic neurons and a positron emission tomography tracer for VAChT could serve as a tool for quantitative analysis of cholinergic neuronal density. With an easily accessible triflate precursor, aminocarbonylations were utilized to evaluate the chemical space around the C5 position on the tetrahydronaphthol ring. Synthesized ligands were evaluated for their affinity and selectivity for VAChT. Small, preferably aromatic, N-substituents proved to be more potent than larger substituents. Of the fifteen compounds synthesized, benzyl derivatives (+/-)-7i and (+/-)-7l had the highest affinities for VAChT. Compound (+/-)-7i was chosen to investigate the importance of stereochemistry for binding to VAChT and selectivity toward the sigma(1) and sigma(2) receptors. Enantiomeric resolution gave (+/-)-7i and (-)-7i, and the eutomer showed seven times better affinity. Although racemate (+/-)-7i was initially promising, the affinity of (-)-7i for VAChT was not better than 56.7 nM which precludes further preclinical evaluation. However, the nanomolar binding together with the ready synthesis of [C-11]-(+/-)-7i shows that (-)-7i can serve as a scaffold for future optimizations to provide improved C-11-labelled VAChT PET tracers.
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| 7. |
- Roslin, Sara, et al.
(författare)
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Visible-Light Photocatalysis as an Enabling Tool for the Functionalization of Unactivated C(sp(3))-Substrates
- 2017
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Ingår i: European Journal of Organic Chemistry. - : WILEY-V C H VERLAG GMBH. - 1434-193X .- 1099-0690. ; 2017:15, s. 1993-2007
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Forskningsöversikt (refereegranskat)abstract
- Over the past decade, visible-light photocatalysis has emerged as one of the brightest and most dynamic fields in modern organic chemistry. By employing a transition-metal- or organic-dye-based photocatalyst in conjunction with a low-energy visible-light source, this synthetic manifold allows the facile generation of radical intermediates that can subsequently be directed through a wide range of transformations. Although initial studies focused largely on the functionalization of stabilized radical intermediates, over the past few years significant efforts have been directed towards the functionalization of challenging unactivated radical precursors. In this review we summarize the recent developments in the use of visible-light photocatalysis for the functionalization of unactivated C(sp(3))-substrates.
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| 8. |
- Rydfjord, Jonas, et al.
(författare)
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Acyl Amidines by Pd-Catalyzed Aminocarbonylation : One-Pot Cyclizations and C-11 Labeling
- 2023
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 88:8, s. 5078-5089
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Tidskriftsartikel (refereegranskat)abstract
- A protocol for the carbonylative synthesis of acyl amidines from aryl halides, amidines, and carbon monoxide catalyzed by Pd(0) is reported herein. Notably, carbon monoxide is generated ex situ from a solid CO source, and several productive palladium ligands were identified with complementary benefits and substrate scope. Furthermore, sequential one-pot, two-step protocols for the synthesis of 1,2,4-triazoles and 1,2,4-oxadiazoles via acyl amidine intermediates are reported. In addition, this approach was extended to isotopic labeling using [11C]carbon monoxide to allow, for the first time, synthesis of 11C-labeled acyl amidines as well as a 11C-labeled 1,2,4-oxadiazole.
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| 9. |
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| 10. |
- Rydfjord, Jonas, et al.
(författare)
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Palladium-Mediated Synthesis of [Carbonyl-11C]acyl Amidines from Aryl Iodides and Aryl Bromides and Their One-Pot Cyclization to 11C-Labeled Oxadiazoles
- 2022
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 88:8, s. 5118-5126
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Tidskriftsartikel (refereegranskat)abstract
- Positron emission tomography (PET) is a highly valuable imaging technique with many clinical applications. The possibility to study physiological and biochemical processes in vivo also makes PET an important tool in drug discovery. Of importance is the possibility of labelling the compound of interest with a positron-emitting radionuclide, such as carbon-11. Carbonylation reactions with [11C]carbon monoxide ([11C]CO) has been used to label a number of molecules containing a carbonyl derivative, such as amides and esters, with carbon-11. Presented herein is the palladium-mediated carbonylative synthesis of [carbonyl-11C]acyl amidines and their subsequent cyclization to 11C labeled 1,2,4-oxadiazoles. Starting from amidines, [11C]CO, and either aryl iodides or aryl bromides, [carbonyl-11C]acyl amidines were synthesized and isolated in good to very good radiochemical yields (RCY). The 11C-labeled 1,2,4-oxadiazoles were synthesized without the isolation of the intermediate [carbonyl-11C]acyl amidines and isolated in useful RCYs, including the NF-E2-related factor 2 activator DDO-7263. 3-Phenyl-5-(4-tolyl)-1,2,4-(5-11C)oxadiazole was synthesized and isolated with a clinically relevant molar activity. The broadened substrate scope, together with the good RCY and high Am, demonstrates the utility of this method for the incorporation of carbon-11 into acyl amidines and 1,2,4-oxadiazoles, structural motifs of pharmacological interest.
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