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Journal of the American Chemical Society Sep 2023α,β-Dehydrogenation of aliphatic acids has been realized through both enolate and β-C-H metalation pathways. However, the synthesis of isolated β,γ-unsaturated...
α,β-Dehydrogenation of aliphatic acids has been realized through both enolate and β-C-H metalation pathways. However, the synthesis of isolated β,γ-unsaturated aliphatic acids via dehydrogenation has not been achieved to date. Herein, we report the ligand-enabled β,γ-dehydrogenation of abundant and inexpensive free aliphatic acids, which provides a new synthetic disconnection as well as a versatile platform for the downstream functionalization of complex molecules at remote γ-sites. A variety of free aliphatic acids, including acyclic and cyclic systems with ring sizes from five-membered to macrocyclic, undergo efficient dehydrogenation. Notably, this protocol features good chemoselectivity in the presence of more accessible α-C-H bonds and excellent regioselectivity in fused bicyclic scaffolds. The utility of this protocol has been demonstrated by the late-stage functionalization of a series of bioactive terpene natural products at the γ-sites. Further functionalization of the β,γ-double bond allows for the installation of covalent warheads, including epoxides, aziridines, and β-lactones, into complex natural product scaffolds, which are valuable for targeted covalent drug discovery.
Topics: Fatty Acids; Ligands; Carboxylic Acids
PubMed: 37698388
DOI: 10.1021/jacs.3c06423 -
Transplantation and Cellular Therapy Aug 2023Second allogeneic hematopoietic stem cell transplantation (HSCT) is a treatment option for patients with acute leukemia who relapse after a first HSCT. Although...
Second allogeneic hematopoietic stem cell transplantation (HSCT) is a treatment option for patients with acute leukemia who relapse after a first HSCT. Although myeloablative conditioning (MAC) regimens before the first HSCT are considered superior to reduced- intensity conditioning (RIC) in terms of disease control in acute leukemia patients, the optimal conditioning regimen for the second allogeneic HSCT remains controversial. The most important prognostic factors are the remission disease phase at the time of the second HSCT and an interval >12 months from the first HSCT to the second HSCT. Total marrow irradiation (TMI) is an advanced high-precision radiation treatment that delivers therapeutic doses over extensively selected targets while substantially reducing radiation to vital organs compared to conventional total body irradiation (TBI). Here we report the results of a retrospective analysis of second allogeneic HSCT treated with TMI as an MAC regimen with the intent of limiting toxicity. We investigated the efficacy of high dose per fraction TMI in combination with thiotepa, fludarabine, and melphalan in 13 consecutive patients with acute leukemia who had relapsed after a first allogeneic HSCT treated between March 2018 and November 2021. Donor type was haploidentical in 10 patients, unrelated in 2 patients, and HLA-identical sibling in 1 patient. The conditioning regimen consisted of 8 Gy TMI in 5 patients on days -8 and -7 and 12 Gy TMI in 8 patients on days -9 to -7, plus thiotepa 5 mg/kg on day -6, fludarabine 50 mg/day on days -5 to -3, and melphalan 140 mg/day on day -2. The TMI was delivered at the dosage og 4 GY for 2 consecutive days (total = 8 GY) or for 3 consecutive days (total = 12 GY). The median patient age was 45 years (range, 19 to 70 years); 7 patients were in remission, and 6 had active disease at the time of their second allogeneic HSCT. The median time to a neutrophil count of >.5 × 10/L was 16 days (range, 13 to 22 days), and the median time to a platelet count of >20 × 10/L was 20 days (range, 14 to 34 days). All patients showed complete donor chimerism on day +30 post-transplantation. The cumulative incidence of grade I-II acute graft-versus-host disease (GVHD) was 43%, and that of chronic GVHD was 30%. The median duration of follow-up was 1121 days (range, 200 to 1540 days). Day +30 and +100 transplantation-related mortality (TRM) was 0. The overall cumulative incidence of TRM, relapse rate, and disease free-survival were 27%, 7%, and 67%, respectively. This retrospective study demonstrates the safety and efficacy of a hypofractionated TMI conditioning regimen in patients with acute leukemia undergoing second HSCT with encouraging outcomes in terms of engraftment, early toxicity, GVHD, and relapse.
Topics: Humans; Young Adult; Adult; Middle Aged; Aged; Retrospective Studies; Bone Marrow; Melphalan; Thiotepa; Leukemia, Myeloid, Acute; Hematopoietic Stem Cell Transplantation; Graft vs Host Disease; Acute Disease; Recurrence
PubMed: 37094701
DOI: 10.1016/j.jtct.2023.04.014 -
Archiv Der Pharmazie Jul 2023The ubiquitin-proteasome pathway (UPP) represents the principal proteolytic apparatus in the cytosol and nucleus of all eukaryotic cells. Nowadays, proteasome inhibitors...
The ubiquitin-proteasome pathway (UPP) represents the principal proteolytic apparatus in the cytosol and nucleus of all eukaryotic cells. Nowadays, proteasome inhibitors (PIs) are well-known as anticancer agents. However, although three of them have been approved by the US Food and Drug Administration (FDA) for treating multiple myeloma and mantel cell lymphoma, they present several side effects and develop resistance. For these reasons, the development of new PIs with better pharmacological characteristics is needed. Recently, noncovalent inhibitors have gained much attention since they are less toxic as compared with covalent ones, providing an alternative mechanism for solid tumors. Herein, we describe a new class of bis-homologated chloromethyl(trifluoromethyl)aziridines as selective noncovalent PIs. In silico and in vitro studies were conducted to elucidate the mechanism of action of such compounds. Human gastrointestinal absorption (HIA) and blood-brain barrier (BBB) penetration were also considered together with absorption, distribution, metabolism, and excretion (ADMET) predictions.
Topics: Humans; Proteasome Endopeptidase Complex; Structure-Activity Relationship; Antineoplastic Agents; Proteasome Inhibitors; Neoplasms
PubMed: 37119396
DOI: 10.1002/ardp.202300174 -
Journal of Neuro-oncology Mar 2024Leptomeningeal disease (LMD) secondary to high grade glioma (HGG), such as glioblastoma (GBM), are characterized by the spread of tumor cells to the leptomeninges which... (Review)
Review
BACKGROUND
Leptomeningeal disease (LMD) secondary to high grade glioma (HGG), such as glioblastoma (GBM), are characterized by the spread of tumor cells to the leptomeninges which further complicates treatment approaches. Intrathecal (IT) chemotherapy has surfaced as a potential strategy to bypass the blood-brain barrier and address the challenges posed by disseminated disease. Here, we present a review of the safety and efficacy of IT chemotherapy in the treatment of LMD secondary to HGG.
METHODS
A systematic review following PRISMA guidelines was conducted searching PubMed and Embase from January 1995 to September 2022 using specified terms related to IT chemotherapy for LMD. Included articles involved patients diagnosed with LMD from HGG, treated with intrathecal chemotherapy, and provided survival data. Data, including demographics, tumor characteristics, treatment, and survival information, were collected and independently extracted.
RESULTS
A total of 68 patients across 10 clinical studies were diagnosed with LMD from HGG and included in the review. Among these patients, the average age at diagnosis was 44.2 years. GBM was the most common tumor type (n = 58, 85.3%). A majority of the patients presented with recurrent disease (n = 29, 60.4%). The review encompassed various IT chemotherapy regimens, including mafosfamide, thio-TEPA, 5-fluoro-2'-deoxyuridine (FdUrd), methotrexate (MTX), and cytarabine; however, dosages and frequencies were inconsistently reported. The mean progression-free survival (PFS) and overall survival (OS) for this cohort were 7.5 months and 11.7 months, respectively. Common side effects of IT chemotherapy included headaches, nausea, and vomiting, with more severe complications such as myelotoxicity, disseminated intravascular coagulopathy, meningitis, and gastrointestinal toxicity reported in some cases.
CONCLUSION
LMD continues to be an uncommon complication associated with HGG with a poor prognosis. This article provides an overview of the presently available literature on IT chemotherapy for LMD secondary to HGG, and their respective treatment protocols with overall survival attributes. Additional research is warranted to ascertain how to maximize the potential efficacy of IT chemotherapy as a treatment option.
Topics: Humans; Adult; Brain Neoplasms; Glioma; Glioblastoma; Thiotepa; Meninges
PubMed: 38294637
DOI: 10.1007/s11060-024-04582-w -
Frontiers in Chemistry 2023Aziridine had different regioselective ring openings depending on the functional group of its alkyl substituent. In the case of the alkyl group bearing γ-ketone at the...
Aziridine had different regioselective ring openings depending on the functional group of its alkyl substituent. In the case of the alkyl group bearing γ-ketone at the C2 substituent of aziridine, the ring opening by the hydroxy nucleophile from HO occurred by attacking the aziridine carbon at the C2 position. This reaction proceeded efficiently in the presence of CFCOH. Interestingly, the same starting aziridine ring bearing the alkyl substituent at the C2 position with the γ-silylated hydroxy group instead of γ-ketone led to the ring-opening reaction by the same oxygen nucleophile at the unsubstituted C3 position, with the breakage of the bond between aziridine N1 nitrogen and carbon at C3. These reaction products were cyclized to afford substituted pyrrolidine and piperidine rings with representative examples of congeners of pseudoconhydrine and monomorine.
PubMed: 37927563
DOI: 10.3389/fchem.2023.1280633 -
Angewandte Chemie (International Ed. in... Oct 2023An unprecedented Pd-catalyzed fluorinative bifunctionalization of aziridines and azetidines was successfully developed via regioselective C-C and C-F bond cleavage of...
An unprecedented Pd-catalyzed fluorinative bifunctionalization of aziridines and azetidines was successfully developed via regioselective C-C and C-F bond cleavage of gem-difluorocyclopropanes, leading to various β,β'-bisfluorinated amines and β,γ-bisfluorinated amines. This reaction was achieved by incorporating a 2-fluorinated allyl group and a fluorine atom scissored from gem-difluorocyclopropane in 100 % atom economy for the first time. The mechanistic investigations indicated that the reaction underwent amine attacking 2-fluorinated allyl palladium complex to generate η -coordinated N-allyl aziridine followed by fluoride ligand transfer affording the final β- and γ-fluorinated amines.
PubMed: 37572320
DOI: 10.1002/anie.202310283 -
ACS Omega Aug 2023-2-iminothiazolidines and -thiazolidine-2-iminium tetrafluoroborates were successfully produced from --alkyl aziridine-2-carboxylates and phenyl/alkyl isothiocyanates...
Zinc Tetrafluoroborate-Mediated Ring Expansion of -Aziridine-2-carboxylates to -2-Iminothiazolidines and -Thiazolidine-2-iminium Tetrafluoroborates and Evaluation of Antimicrobial Activity.
-2-iminothiazolidines and -thiazolidine-2-iminium tetrafluoroborates were successfully produced from --alkyl aziridine-2-carboxylates and phenyl/alkyl isothiocyanates mediated by zinc tetrafluoroborate in refluxing DCE. Reactions were performed via a complete regio- and stereoselective process to give the title iminothiazolidines and -thiazolidine-2-iminium salts in moderate to good yields (35 to 82%) with a wide substrate scope. In addition, the antibacterial activity evaluation of these compounds, as well as the minimum inhibitory concentration (MIC) determination, revealed that only four -thiazolidine-2-iminium salts showed growth inhibition against .
PubMed: 37636906
DOI: 10.1021/acsomega.3c03531 -
Journal of Chromatography. A Sep 2023In this work, tetraethylenepentamine (TEPA) was used as precursor and reaction medium to prepare tetraethylenepentamine-functionalized carbon dots (TEPACDs), the...
In this work, tetraethylenepentamine (TEPA) was used as precursor and reaction medium to prepare tetraethylenepentamine-functionalized carbon dots (TEPACDs), the resultant mixture was subsequently silanized and then grafted on the surface of bare silica. The obtained tetraethylenepentamine-functionalized carbon dots and tetraethylenepentamine co-modified silica stationary phase (Sil-TEPA/CDs) was characterized by multiple ways, such as Fourier transformed infrared spectroscopy (FTIR), elemental analysis and transmission electron microscope, which revealed the successful preparation of the mixed stationary phase and higher density of functional groups on co-modified stationary phase than precursor single-modified stationary phase. The synergistic effect of TEPACDs and TEPA was proved by comparing the separation performance of Sil-TEPA/CDs and Sil-TEPA toward amino acids, nucleosides, and nucleobases, which distinctly enhanced the selectivity of Sil-TEPA/CDs. Thus, 12 nucleosides and nucleobases and 11 amino acids was nicely separated on Sil-TEPA/CDs. By study the influences of the changes of mobile phase composition, mobile phase buffer concentration and buffer pH on the retention behaviors of Sil-TEPA and Sil-TEPA/CDs, it was found that both hydrophilic partitioning and adsorption of analytes on Sil-TEPA/CDs were enhanced benefit from the co-existence of TEPA and TEPACDs, which provided the analytes better separation performance. By comparing the column quality of Sil-TEPA/CDs with four commercially available columns, Sil-TEPA/CDs exhibited the best peak asymmetry of 0.98, and second best column efficiency of 43895 m using guanosine as analyte. The RSD (n = 9) of the retention times of five selected analytes on Sil-TEPA/CDs were within 0.30-0.61% during 40 h of continuously elution, which implied excellent stability of prepared packing material.
Topics: Nucleosides; Amino Acids; Carbon; Chromatography; Silicon Dioxide; Triethylenephosphoramide
PubMed: 37639850
DOI: 10.1016/j.chroma.2023.464325 -
Journal of Enzyme Inhibition and... Dec 2023In this study, we report a series of newly synthesised sulphonamides of aziridine-2-carboxylic acid (Az-COOH) ester and amide analogues as potent protein disulphide...
In this study, we report a series of newly synthesised sulphonamides of aziridine-2-carboxylic acid (Az-COOH) ester and amide analogues as potent protein disulphide isomerase (PDI, EC 5.3.4.1) inhibitors. The inhibitory activity on PDI was determined against recombinant human PDIA1 and PDIA3 proteins using an insulin reduction assay. These compounds in low micromolar to low nanomolar concentrations showed the effective inhibitory properties of PDIA1 with weaker effects on PDIA3. Complexes of N- and N,C- uniformly labelled recombinant human PDIA1a with two PDIA1 inhibitors were produced and investigated by a protein nuclear magnetic resonance (NMR) spectroscopy. It was found that both C53 and C56 of the PDIA1 enzyme were involved in covalent binding. Finally, in a range of pharmacological studies, we demonstrated that investigated compounds displayed anti-cancer and anti-thrombotic activity. These findings demonstrate that sulphonamides of Az-COOH derivatives are promising candidates for the development of novel anti-cancer and anti-thrombotic agents.
Topics: Humans; Aziridines; Protein Disulfide-Isomerases; Sulfonamides
PubMed: 37070480
DOI: 10.1080/14756366.2022.2158187 -
The Journal of Organic Chemistry Jul 2023We have developed a highly stereospecific cyclization of aziridine silanols into 1'-amino-tetrahydrofurans. Our protocol of stirring a substrate with 10 mol % Sc (OTf)...
We have developed a highly stereospecific cyclization of aziridine silanols into 1'-amino-tetrahydrofurans. Our protocol of stirring a substrate with 10 mol % Sc (OTf) and 1 equivalent of NaHCO in CHCl is mild and compatible with a range of activating aziridine -substituents (including tosylates, mesylates, and carbamates) and functional groups on the alkyl chains (including substituted aryl rings, alkyl bromides, and alkyl ethers). In all cases examined, di-substituted aziridine silanols give products with an configuration; conversely, di-substituted aziridine silanols give products with a configuration. While literature syntheses of 1'-amino-tetrahydrofurans exist, only one example, contemporaneous with our work, uses a similar cyclization for their construction. Control experiments demonstrate that, for this transformation, the silanol is not particularly privileged, and a variety of protecting groups on the alcohol (including other silicon protecting groups, benzyl ethers, and MOM ethers) are compatible with product formation.
Topics: Furans; Stereoisomerism; Ethers; Aziridines
PubMed: 37253098
DOI: 10.1021/acs.joc.3c00763