Synthesis of Fluorine-Containing Analogues of 1-Lysoglycerophospholipids via Horner–Wadsworth–Emmons Reaction

This article describes an efficient method of synthesizing fluorine-containing analogues of 1-lysoglycerophospholipids (1-LPLs) by introducing a palmitoyl moiety starting from bis(2,2,2-trifluoroethyl)phosphonoacetate (Still-Gennari reagent). Our method effectively employs Horner-Wadsworth-Emmons reagents as masked 1-LPL derivatives to prepare a series of analogues of 1-lysophosphatidic acid (1-LPA), 1-lysophosphatidylethanolamine (1-LPE), and 1-lysophosphatidylcholine (1-LPC)

N4-methylation changes the conformation of (3S,6S)-3-alkyl-6-benzylpiperazine-2,5-diones from folded to extended

N4-Methylation of (3S,6S)-3-alkyl-6-benzylpiperazine-2,5-diones (S,S)-1a–c was found to change their folded conformation to an extended conformation. Conformational aspects of N1- and/or N4-methylated (S,S)-1a–c were revealed by single crystal X-ray crystallography and 1H NMR spectroscopy

Synthesis of Erythrochelin : A Hydroxamate-Type Siderophore from Saccharopolyspora erythraea

Erythrochelin, a hydroxamate-type siderophore produced by Saccharopolyspora erythraea, is synthesized for the first time. A key building block of erythrochelin containing the 2,5-diketopiperazine ring is prepared by intramolecular cyclization of the corresponding dipeptide precursor derived from two kinds of protected δ-N-hydroxy-L-ornithines. Consecutive condensation of the building block with protected D-serine and protected δ-N-hydroxy-D-ornithine, followed by deprotection, furnishes erythrochelin

Synthesis of Allenyl Esters by Horner-Wadsworth-Emmons Reactions of Ketenes Mediated by i-PrMgBr

The synthesis of conjugated allenyl esters (trisubstituted allenes) was achieved by the Mg(II)-mediated Horner-Wadsworth-Emmons reaction of methyl bis(2,2,2-trifluoroethyl)phosphonoacetate with di-substituted ketenes. In addition, a novel access to α-fluorinated allenyl carboxamides (tetra-substituted allenes) is presented

Enzymatic synthesis of chiral P-stereogenic phosphonoacetates

In this data article, we describe the enzymatic kinetic resolution of a series of racemic mixed phosphonoacetates, which were successfully prepared from methyl bis(2,2,2-trifluoroethyl)phosphonoacetate (Still-Gennari reagent) by alcoholysis with σ-symmetrical secondary alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Porcine liver esterase (PLE)-catalyzed kinetic resolution of some of these racemic mixed phosphonoacetates proceeded in a highly stereoselective manner to furnish the chiral P-stereogenic phosphonoacetates (up to >99% ee)

Synthesis of Novel Phosphorus-Substituted Stable Isoindoles by a Three-Component Coupling Reaction of ortho-Phthalaldehyde, 9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-Oxide, and Primary Amines

A three-component coupling reaction of ortho-phthalaldehyde, 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide, and various primary amines readily afforded novel phosphorus-substituted stable isoindoles in good to excellent yields. The importance of the reversible ring-opening of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide by methanolysis in the three-component coupling reaction became apparent

Facile Two-Step Synthesis of Methyl Bis(2,2,2-trifluoroethyl)phosphonoacetate by Exploiting Garegg–Samuelsson Reaction Conditions

A facile two-step synthesis of methyl bis(2,2,2-trifluoroethyl)phosphonoacetate (Still–Gennari reagent) has been developed by exploiting Garegg–Samuelsson reaction conditions. Starting from trimethyl phosphonoacetate, Still–Gennari reagent was prepared in 94% yield via methyl 2-{bis[(trimethylsilyl)oxy]phosphoryl}acetate intermediate. This synthetic procedure was also used to prepare some kinds of Horner–Wadsworth–Emmons reagents and related compounds

Development of a novel tocopheryl ester for suppression of lipid accumulation without cytotoxicity by optimization of dicarboxylic ester moiety

Tocopheryl succinate (Tsuc) is a succinic acid ester of the well-known antioxidant α-tocopherol (T). Tsuc exhibits various biological activities, including tumor growth suppression via activation of cell signaling and prevention of lipid accumulation in mouse adipocyte 3T3-L1 cells. The latter findings suggest that Tsuc may be a drug candidate for the treatment of obesity. However, Tsuc was found to induce apoptosis of normal cells (in addition to cancer cells), demonstrating the need to reduce the cytotoxicity of Tsuc without losing the suppression effect on lipid accumulation. Based on our previous findings, we focused on the ester structure of Tsuc for controlling cytotoxicity. Herein, we examined the cytotoxicity and lipid accumulation suppression effect of various T ester derivatives. We found that the terminal carboxylic group is necessary for suppression of lipid accumulation. We synthesized tocopheryl glutarate (Tglu) and tocopheryl adipate (Tadi) by elongation of carbon atoms 1 and 2 of the dicarboxylic moiety, respectively. Tglu and Tadi did not show any cytotoxicity, and both esters suppressed lipid accumulation, although their suppression activities were weaker than that of Tsuc. Tadi showed a more potent lipid accumulation inhibitory effect than Tglu. Although Tadi inhibited lipogenesis and promoted lipolysis, lipolysis was induced at lower concentrations than inhibition of lipogenesis, suggesting that Tadi mainly affects lipolysis. Taken together, we succeeded in the reduction of cytotoxicity, without loss of the suppression effect on lipid accumulation, by elongation of the dicarboxylic moiety of Tsuc. Tadi may be a promising candidate as an anti-obesity drug

Synthesis of Sterically Protected Isoindoles from ortho-Phthalaldehyde

o-Phthalaldehyde (OPA) reacts with O-protected tris(hydroxyalkyl) aminomethanes in the presence of 1-propanethiol to afford a novel class of stable isoindoles. Steric protection provided by the bulkiness of C3-symmetric primary amines derived from tris(hydroxymethyl)aminomethane could be significant for the stabilization of 1-alkylthio-2-alkyl-substituted isoindoles derived from OPA. A plausible reaction mechanism is proposed to explain the formation of the isoindole and an isoindolin-1-one by-product