Synthesis and properties of a maleimide fluorescent thiol reagent derived from a naphthopyranone

N-(2-Carbomethoxy-9-methoxy-3-oxo-3H-naphtho[2,1-b]pyran-10-yl)maleimide 2 was designed and synthesized as a new maleimide fluorescent thiol reagent. The optical properties of 2 were investigated with and without the addition of glutathione, GSH. We have found 2 is twice as sensitive as DACM and is of comparable sensitivity to CPM for detection of thiols. The emission maximum for the GSH adduct of 2 is 513 nm which is at longer wavelength than the GSH adducts of both DACM and CPM.     

含咔唑和偶氮苯的乙炔衍生物的合成

采用Sonagashira偶联反应和N-烷基化反应合成了含有咔唑和偶氮苯的乙炔衍生物:3-乙炔基-9-(4-[4-(硝基)苯基偶氮苯]氧)亚丁基咔唑3.其结构通过IR,1H NMR,13C NMR,元素分析和X-射线单晶衍射法测定.标题化合物属单斜晶系,P21/c空间群;a=9.238(3),b=28.240(8),c...     

Synthesis and characteristics of polydepsipeptide with pendant thiol groups

To obtain water-soluble oligodepsipeptide with pendant thiol groups, the alternating co-oligomer [oligo(Glc-alt-Cys)], consisting of glycolic acid (Glc) and L -cysteine (Cys) residues as α-hydroxy acid and α-amino acid residues, respectively, was prepared by means of ring-opening homo-oligomerization of cyclo[Glc-Cys(MBzl)] and subsequent deprotection of methoxybenzyl groups. Moreover, to modify the properties of poly(lactic acid) [poly(LA)] and to introduce pendant thiol groups to poly(LA), the terpolymer of LA, Glc, and Cys {poly[LA-(Glc-Cys)]} was synthesized through ring-opening and copolymerization of L -lactide with the protected cyclodepsipeptide, cyclo[Glc-Cys(MBzl)] and subsequent deprotection of methoxybenzyl groups. By changing the mol fraction of (Glc-Cys) unit, the solubility, thermal transition, degradation behavior of the modified poly(LA), and the water contact angle of its film could be varied. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1283–1290, 1998     

Synthesis of a simple chiral auxiliary derived from levoglucosenone and its application in a Diels-Alder reaction

The synthesis of a chiral alcohol derived from levoglucosenone has been studied. The alcohol was employed as chiral template in an asymmetric Diels-Alder reaction of the corresponding acrylic ester derivative with cyclopentadiene, and was shown to be an efficient asymmetric inductor. The oxidation reaction detected during the hydrogenation of a secondary allylic alcohol intermediate with Pd/C was also investigated.     

HPLC determination of thiol drugs in pharmaceutical formulations using ethacrynic acid as a precolumn ultraviolet derivatization reagent

Summary A high performance liquid chromatographic method has been developed for the determination of aliphatic thiol drugs, such as N-acetyl-L-cysteine, captopril and mercaptopropionylglycine in pharmaceutical formulations. The procedure involves a precolumn derivatization of the thiol drug with ethacrynic acid followed by reversedphase HPLC separation and UV detection. The conditions for a rapid and selective reaction of the thiols with ethacrynic acid have been investigated. The method proved to be suitable for a reliable and selective quality control of commercial dosage forms of the examined thiol drugs.     

Synthesis of the C-terminal tetrapeptide of the oxytocin sequence using various protective groups for the cysteine thiol function

The synthesis of amides of tetrapeptides with the 6–9 sequence of oxytocin containing various protective groups for the thiol function has been performed by 2+2 and 1+3 schemes. Relationships between the yield of tetrapeptide and the structures of the protective groups have been obtained. An advantage of trityl and benzyl protective groups for masking the tiol function of cysteine has been shown. The signals of the¹³C NMR spectra of the compounds obtained have been interpreted.All-Union Scientific-Research Institute of Blood Substitutes and Hormone Preparations, Moscow. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 400–406, May–August, 1992.     

Synthesis and fluorescent properties of a new photostable thiol reagent “BACM”

The 3-maleimidocoumarin BACM ( 2d ) is a new tag designed to react with thiols in biological materials to form fluorescent derivatives whose emission is in the 500 nm (green) region with good resistance to fading. The fluorescence properties of its N-acetyl-L-cysteine derivative are described. BACM itself is non-fluorescent, as is its predecessor, DACM ( 1a ). A synthesis of BACM is reported which avoids the formation of nitrocoumarin isomers obtained in the reported synthesis of DACM. The synthesis of the related 3-(4-maleimidophenyl)coumarin is also described.     

Addition of a chiral copper reagent derived from propargylic oxazolidininone to aldehydes

[reaction: see text] The copper reagent arising from an optically pure propargylic oxazolidinone was found to react regio- and diastereoselectively with aldehydes, leading, in a one-pot procedure, to the anti homopropargylic amino alcohols derivatives in good yields.     

Allyl tetrahydropyranyl ether: a versatile alcohol/thiol protecting reagent

Allyl tetrahydropyranyl ether (ATHPE) can be used as a versatile protecting reagent. In combination with NBS/I₂, O-allyl group can easily be replaced by hydroxyls (including tertiary-OH) or thiols, in the molecules comprising other reactive functional groups such as halogen, nitro, acetonide and alkene under mild reaction conditions (near neutral pH and ambient temperature).     

Synthesis of silver metal nanodispersions using Tollens reagent

It is shown that silver metal nanodispersions can be produced through the silver mirror reaction using the Tollens reagent in Aerosol OT-stabilized water-in-oil microemulsions using glucose as a reducing agent. The ranges of the formation of microemulsions and their droplet sizes, as well as component ratios and reaction conditions that yield stable nanodispersions, are determined.     

New chiral auxiliary: Optically active thiol derived from camphor

A new camphor based mercapto chiral auxiliary has been prepared, and demonstrated to induce very high chiral inductions in the diastereoselective reductions of -sulfinylketones, in the presence of bivalent Lewis acids.     

Synthesis and reactions of diphosphenes carrying bulky aryl and phenoxy groups

Unsymmetrical diphosphenes carrying bulky aryl and phenoxy groups were prepared by the reaction of lithium 2,4,6-tri-t-butylphenylphosphide with the corresponding phenyl phosphorodichloridites, followed by the dehydrochlorination reaction with 1,8-diazabicyclo[5.4.0]undec-7-ene. The diphosphenes were isolated as stable compounds. The reactions of these diphosphenes with elemental sulfur or selenium afforded the corresponding thiadiphosphiranes or selenadiphosphiranes, respectively. The diphosphenes also reacted with dichlorocarbene to give dichlorodiphosphiranes.     

Synthesis of photo- and electroactive stilbenoid dendrimers carrying dibutylamino peripheral groups

[structure: see text]. A novel convergent synthetic route for the preparation of functionalized and fluorescent stilbenoid dendrons built on the 1,3,5-benzene core and endowed with a periphery of dibutylamino groups has been developed. Long alkyl chains have been incorporated on the peripheral amino moieties to increase the solubility of the final products. Good donor ability of the new dendrimers has been observed by cyclic voltammetry measurements as a result of the presence of the peripheral dibutylaniline moieties.     

Determination of thiol groups with o-diacetoxy-iodobenzoate

o-Diacetoxyiodobenzoate is used for determining thiol groups by two procedures. In the first, thiols are titrated directly with the reagent at pH 6-8, with leuco-2,6-dichlorophenolindophenol and potassium iodide as indicator. In the second, thiols are treated at pH 7 with an excess of the reagent, the surplus being determined by reaction with excess of mercaptoacetic acid followed by back-titration of the latter with iodine. Both procedures yield results within 0.2% of the theoretical.     

Methylsulfonyl benzothiazole (MSBT): a selective protein thiol blocking reagent

A new thiol blocking reagent, methylsulfonyl benzothiazole, was discovered. This reagent showed good selectivity and high reactivity for protein thiols.     

A simple synthesis of thiol esters from copper-I-mercaptides and acyl chlorides

Thiol esters are obtained from acyl chlorides and copper-I-mercaptides in excellent yields.