Sphingosine mediates FTY720-induced apoptosis in LLC-PK1 cells

FTY720, a synthetic sphingoid base analog, was examined as a new sphingosine kinase inhibitor, which converts endogenous sphingosine into its phosphate form. With 20 microM of FTY720, sphingosine accumulated in the LLC-PK(1) cells in a time- and dose-dependent manner. The FTY720 treated cells showed a high concentration of fragmented DNA, a high caspase-3 like activity and TUNEL staining cells. It was also found that the sphingosine and sphinganine level increased in a time- and dose-dependent manner within 12 h after the FTY720 treatment. The sphingosine kinase activity was reduced by FTY720 as much as other sphingosine kinase inhibitors, N, N-dimethylsphingosine (DMS), dl-threo-dihydrosphingosine (DHS). The fragmented DNA content as a result of the 20 microM of FTY720 treatment and by 5 microM of the exogenously added BSA-sphingosine complex indicated typical apoptosis. Under similar conditions, the accumulated sphingosine concentration in all the cells was almost identical even though the sphingosine distribution inside the cells was somewhat different. These results indicate that the FTY720 induced apoptosis is associated with the inhibition of the sphingosine kinase activity and is strongly associated with the successive accumulation of sphingosine.     

Iron-catalyzed cross-coupling reactions. A scalable synthesis of the immunosuppressive agent FTY720

A chemo- and regioselective cross-coupling reaction of the functionalized aryl triflate 5 with octylmagnesium bromide catalyzed by cheap, nontoxic, and environmentally benign Fe(acac)(3) sets the basis for a practical and scaleable synthesis of the octylbenzene derivative 6, which serves as a key building block for the preparation of FTY720 (1). This 2-amino-1,3-propanediol derivative shows highly promising immunosuppressive properties and is currently in human clinical phase III trials.     

Synthesis and spectral properties of cholesterol- and FTY720-containing boron dipyrromethene dyes

Two analogues (1, 2) of free cholesterol and one analogue (3) of the immunosuppressive sphingolipid FTY720 containing a boron dipyrromethene chromophore (BODIPY) were synthesized. The synthetic routes involved preparation of boron dipyrromethene moieties (5, 11), bearing a phenylethynyl group at different positions of the chromophore, and lipids (13, 20) bearing an azido group. The dye was tethered to the lipid via a 1,2,3-triazole in the linker by the click reaction. Analogues derived from 11 [in which an (E)-styrylethynyl moiety is bonded to C-5 of BODIPY] exhibited a marked red shift (approximately 70-80 nm) compared with those derived from 5 (in which a phenylethynyl moiety is bonded to C-8 of BODIPY).     

A photoreactive analogue of the immunosuppressant FTY720

An azido group was incorporated into the immunomodulatory agent FTY720, accomplishing the first synthesis of a photoactivatable analogue of this ligand (2) in 9 steps from 2-(4-hydroxyphenyl)ethanol and in 34% overall yield. The key steps are formation of a primary amine at a quaternary center of aniline derivative 13 followed by selective diazotization of the arylamine.     

Synthesis of the key intermediate, diethyl 2-acetylamino-2-(2-(4-octanoylphenyl)ethyl)propane-1,3-dioate, of the immunomodulatory agent FTY720 (fingolimod)

The key intermediate, diethyl 2-acetylamino-2-(2-(4-octanoylphenyl)ethyl)propane-1,3-dioate (13), for the immunomodulatory agent FTY720 (2: fingolimod) was synthesized via Michael addition of diethyl(acetylamino)malonate (6) to 4-octanoylstyrene (12).     

Efficient chromatography-free synthesis of the oxy-analogue of fingolimod

Fingolimod (FTY720) and its analogue derivatives are not only promising therapeutics in sphingolipid signaling but also valuable tools for understanding the roles of sphingolipids in (patho)physiological conditions. A practical method for the synthesis of the ether analogue of FTY720 is described. Our final synthetic approach allows high yield and efficient synthesis of O-FTY in only four steps without chromatographic purifications.     

Direct mono-phosphorylation of 1,3-diols. A synthesis of FTY720-phosphate

A novel method for selective and direct phosphorylation of various 1,3-diols using silver(I) oxide, tetrabenzyl pyrophosphate (TBPP), and tetrahexylammonium iodide affording mono-phosphates was developed. We applied the present method to the synthesis of FTY720-phosphate.     

A convergent synthesis of the immunosuppressant FTY720 employing aqueous Wittig chemistry

A short, convergent synthesis of the immunosuppressant FTY720 is described involving the use of 4-hydroxymethylbenzaldehyde as a pivotal intermediate. A double Wittig strategy was developed to connect this dual-functional aldehyde with an alkyl-tether and to a readily available TRIS-derivative leading to an efficient synthesis of the target molecule.     

A convenient synthesis of the immunosuppressive agent FTY720

Abstract  

This paper describes a practical synthetic approach to preparation of an immunosuppressant, FTY720. The key steps involve an iron-catalyzed cross-coupling reaction and a Wittig reaction. The advantages of this synthesis include readily available starting materials, inexpensive reagents, simple operations and good yields.     

Synthesis of fluorinated analogues of the immunosuppressive drug FTY720

Four fluorinated derivatives of the immunosuppressive drug FTY720 were synthesized by a convergent strategy, using the Sonogashira coupling as the key reaction to assemble the two major fragments.     

Determination of glyoxylic acid in urine by liquid chromatography with fluorescence detection, using a novel derivatization procedure based on the Petasis reaction

The Petasis reaction is the multi-component reaction of a carbonyl compound, amine, and arylboronic acid to form an α-amino acid or a β-aminoalcohol. In this work, as the first analytical application of the Petasis reaction, a high-performance liquid chromatographic (HPLC) method with fluorescence detection was developed for determination of glyoxylic acid. The glyoxylic acid was derivatized with 1-pyreneboronic acid, as fluorescent arylboronic acid, in the presence of N-methylbutylamine, as amine, to give a fluorescent α-amino acid. HPLC separation of the fluorescent derivative was performed within 30 min on an octyl column eluted with a gradient prepared from acetonitrile and 50 mmol L(-1) acetate buffer (pH 4.0). The detection limit (S/N=3) for glyoxylic acid was 5.0 nmol L(-1) (20 fmol/injection). The method can be used to determine the concentration of glyoxylic acid in human urine without interference from biological components.     

Asymmetric synthesis of α,α-disubstituted α-amino alcohol derivatives

We herein report an asymmetric synthesis of α,α-disubstituted α-amino alcohol derivatives 3, key intermediates of a novel immunomodulator, using enzymatic desymmetrization of 2-alkyl-2-tert-butoxycarbonylamino-1,3-propanediols 1a and 1b. This method makes it possible to prepare a chiral analogue of FTY720 4. These synthetic procedures allow for a broad structure variation in order to evaluate structure–activity relationships and the mechanism of action for sphingosine 1-phosphate-1 (S1P₁) receptor agonist.     

A monoselective sphingosine-1-phosphate receptor-1 agonist prevents allograft rejection in a stringent rat heart transplantation model

FTY720 is an immunomodulator with demonstrated efficacy in a phase II trial of relapsing multiple sclerosis. FTY720-phosphate, the active metabolite generated upon phosphorylation in vivo, acts as a potent agonist on four of the five known sphingosine-1-phosphate (S1P(1)) receptors. AUY954, an aminocarboxylate analog of FTY720, is a low nanomolar, monoselective agonist of the S1P(1) receptor. Due to its selectivity and pharmacokinetic profile, AUY954 is an excellent pharmacological probe of S1P(1)-dependent phenomena. Oral administration of AUY954 induces a profound and reversible reduction of circulating lymphocytes and, in combination with RAD001 (Certican/Everolimus, an mTOR inhibitor), is capable of prolonging the survival of cardiac allografts in a stringent rat transplantation model. This demonstrates that a selective agonist of the S1P(1) receptor is sufficient to achieve efficacy in an animal model of transplantation.     

Synthesis of pyrimidinyl arylglycines through subsequent Mitsunobu and Petasis reactions

The synthesis of highly functionalized pyrimidinyl arylglycines is presented. The highlight in our synthetic sequence includes selective O-alkylation of 2-(benzylsulfanyl)-4(3H)-pyrimidinones with N-Boc β-aminoalcohols under Mitsunobu conditions, Petasis reaction with glyoxylic acid and phenylboronic acid and nucleophilic ipso-substitution of the activated sulfur with morpholine. The unexpected spontaneous Smiles rearrangement of several pyrimidinyl amines is also discussed.     

Diastereoselective Petasis Mannich reactions accelerated by hexafluoroisopropanol: a pyrrolidine-derived arylglycine synthesis

A diastereoselective synthesis of pyrrolidine-derived arylglycines has been developed using the Petasis boronic acid Mannich reaction. High diastereoselectivities in the reactions of chiral amines, aryl boronic acids, and glyoxylic acid monohydrate have been demonstrated for the first time. Key to the implementation of this method is the discovery that hexafluoroisopropanol accelerates the Petasis process, reducing reaction times from multiple days to less than 24 h.     

Catalytic diastereoselective petasis reactions

Multicomponent Petasis reactions: The first diastereoselective Petasis reaction catalyzed by chiral biphenols that enables the synthesis of syn and anti?β-amino alcohols in pure form has been developed. The reaction exploits a multicomponent approach that involves boronates, α-hydroxy aldehydes, and amines.     

Asymmetric petasis reactions catalyzed by chiral biphenols

Chiral biphenols catalyze the enantioselective Petasis reaction of alkenyl boronates, secondary amines, and ethyl glyoxylate. The reaction requires the use of 15 mol % of (S)-VAPOL as the catalyst, alkenyl boronates as nucleophiles, ethyl glyoxylate as the aldehyde component, and 3 A molecular sieves as an additive. The chiral alpha-amino ester products are obtained in good yields (71-92%) and high enantiomeric ratios (89:11-98:2). Mechanistic investigations indicate single ligand exchange of acyclic boronate with VAPOL and tetracoordinate boronate intermediates.     

Synthesis of indoles via alkylidenation of acyl hydrazides

Indoles have been synthesised via alkylidenation of acyl phenylhydrazides using phosphoranes and the Petasis reagent, followed by in situ thermal rearrangement of the product enehydrazines. The Petasis reagent provides an essentially neutral equivalent of the [acid-catalysed] Fischer indole synthesis, but with acyl phenylhydrazides as starting substrates. Alkylidene triphenylphosphoranes convert aroyl phenylhydrazides to indoles, but acyl phenylhydrazides derived from aliphatic carboxylic acids undergo a Brunner reaction to form indolin-2-ones.     

Theoretical Study on the Mechanism of the Petasis‐type Boronic Mannich Reaction of Organoboronic Acids,Amines, and α‐Hydroxy Aldehydes

The mechanism of a typical Petasis‐type boronic mannich reaction (the styrylboronic acid, dibenzylamine, and α‐hydroxylpropionaldehyde) has been investigated using density functional theory calculations. According to our calculations, the reaction is most likely to proceed through the following steps: 1) the nucleophilic addition of the amine to the aldehyde to form the carbinolamine; 2) the dehydration of the carbinolamine; 3) the formation of the tetra‐coordinated borate intermediate; 4) the C? C bond formation by the intramolecular transfer of the styryl group; 5) the hydrolysis of the resulting intermediate to give the final products. The highest point on the energy profile is the transition state for the C? C bond formation (118.8 kJ·mol^?1 above the reactants in ethanol). Our results can give reasonable explanations on some experimental facts observed for many Petasis‐type boronic Mannich reactions.