The epoxidation, the addition of hypobromous acid, and the hydroboration of 3-methoxy-13α-estra-1,3,5(10),16-tetraene 1 with diborane, catecholborane, and 9-BBN were investigated in order to determine the stereochemical outcome and to synthesize new 13α-estra-1,3,5(10)-trienes for biological a...
The primary hydroxy functions of 16α-hydroxymethyl-3-methoxy-13α-estra-1,3,5(10)-trien-17β-ol (3a) and 16β-hydroxymethyl-3-methoxy-13α-estra-1,3,5(10)-trien-17α-ol (4a) were stereoselectively transformed into good leaving groups. On alkaline methanolysis of the 16-halomethyl or 16-tolylsul...
Treatment of diols, 11,12-seco-12-nor-11,13-dihydroxy-3-methoxy-17-vinylestra-1,3,5(10)-triene and the 18-fluoro-substituted derivatives, with phosphorus oxychloride led after rearrangement to (±)-B(9a)-homo-C-nor-3-methoxy-12-oxa-17-vinylestra-1,3,5(10)-triene and the 18-fluoro-substituted der...
Publisher SummaryThis chapter presents data for chemical resistance tests, test conditions, and test results for the materials acetal and acetal homopolymer (POM Homopolymer). This data has also been made available online on Science Direct. It provides information related to exposure medium, con...
Simple and efficient MW-assisted cleavage of acetal and ketal is proposed in deionized water and in a very short time.
New routes to N-(diethoxyphosphoryl)imines derived from enolizable carbonyl compounds have been investigated. Three different procedures were studied: (i) the aza-Claisen condensation of ethyl-[N-(diethoxyphosphoryl)]-formimidate with enolizable ketones, (ii) the reaction between diethyl N-sulfi...
In the presence of a catalytic amount of mesoporous aluminosilicate (Al-MCM-41), both allyltrimethylsilane and silyl enol ether reacted with various acetals under mild reaction conditions to afford the corresponding homoallyl ethers and β-alkoxy ketones, respectively. The catalyst was easily re...
Diastereoface differentiating m-chloroperbenzoic acid oxidation of the chiral enol ether prepared from cyclohexanone and optically active 2,4-pentanediol proceeded from −72 to 39 °C to give a diastereomeric mixture of the corresponding 2-hydroxycyclohexanone acetal. The diastereomeric excess of...
A comprehensive review of the reports concerning the synthesis of symmetrical and, particularly, mixed acetals and orthoesters with transition metal compounds and complexes as catalysts is presented. The following methods for the synthesis of symmetric and mixed acetals are discussed: acetalizat...
A mesoporous aluminosilicate (Al-MCM-41) was found to be an effective heterogeneous catalyst for the reaction of both aldehydes and acetals with silyl enol ethers or ketene silyl acetals to give the corresponding aldol adducts in moderate to high yields. The remarkable high catalytic activity of...
A novel Cu(I)-catalyzed photochemical reaction of diethyl ether with vicinal diols and their ketals is reported. The most remarkable feature is the transformation of 1,2-diols and their ketals to acetals of acetaldehyde under totally neutral condition without using acetaldehyde.
We investigated the effects of serum on lysophospholipid-induced cytotoxicity in Jurkat T cells. We found that sphingosylphosphorylcholine (SPC, also known as lysosphingomyelin) induced cytotoxicity and that albumin in serum could protect cells by binding directly to SPC. Furthermore, we also fo...
Inflammation in de-endothelialised arteries contributes to the development of cardiovascular diseases. The process that initiates this inflammatory response is the adhesion of monocytes/macrophages to exposed vascular smooth muscle cells, typically stimulated by cytokines such as tumour necrosis...
Sphingosylphosphorylcholine (SPC), a lipid mediator with putative second messenger functions, has been reported to regulate ryanodine receptors (RyRs), Ca2+ channels of the sarco/endoplasmic reticulum. RyRs are also regulated by the ubiquitous Ca2+ sensor calmodulin (CaM), and we have previously...
The critical micelle concentrations (CMC) of lysophosphatidic acid (LPA) and sphingosylphosphorylcholine (SPC) were measured by isothermal titration calorimetry. The CMC of LPA decreases with salt concentration and acyl chain length. In water at 25 °C, the CMC values of 1-acyl-2-lyso-sn-glycero...
Sphingosylphosphorylcholine (SPC) participates in several cellular processes including metastasis. SPC induces keratin reorganization and regulates the viscoelasticity of metastatic cancer cells including PANC-1 cancer cells leading to enhanced migration and invasion. The role of SPC and the rel...
The sphingomyelin metabolite, sphingosylphosphorylcholine (SPC) has been the subject of much recent interest and controversy. Studies have indicated that SPC naturally occurs in plasma and a constituent of lipoproteins. Synthesis is also increased in some pathological conditions. Research has de...
Autophagy, evoked by diverse stresses including myocardial ischemia/reperfusion (I/R), profoundly affects the development of heart failure. However, the specific molecular basis of autophagy remains to be elucidated. Here we report that sphingosylphosphorylcholine (SPC), a bioactive sphingolipid...
Sphingosylphosphorylcholine (SPC) is a bioactive sphingolipid which regulates many cancer-related processes, including cellular proliferation. The Hippo signaling pathway consists of a cascade of tumor suppressive kinases Mst1/2 and Lats1/2 and their downstream targets YAP and TAZ which are gene...
Sphingosylphosphorylcholine (SPC) is a phosphorylcholine-containing lysophospholipid. It has been proposed to act as both an extracellular mediator and intracellular messenger. The precise intracellular role of SPC is unknown. As an extracellular mediator, SPC is reported to interact with three …
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