β-(Trimethylsilyl)ethoxymethyl chloride. A new reagent for the protection of the hydroxyl group

Reactions of β-(trimethylsilyl)ethoxymethyl chloride with alcohols afford the corresponding ethers in high yield. Deprotection using n-Bu₄NF in THF or HMPA cleanly regenerates the hydroxyl function.     

Trimethylsilyl tetrafluoroborate a convenient reagent for solvolysis reactions

Conversions of cyclopropyl carbinols (or their acetates) and ketones into homoallyl and γ-substituted ketone derivatives, respectively, are accomplished by trimethylsilyl tetrafluoroborate efficiently and under mild conditions.     

The 2-phenylsulfonylethylcarbonyl (PSEC) group for the protection of the hydroxyl function

The PSEC group may be used to protect the hydroxyl function in conjunction with a variety of acid and base labile protecting groups; the PSEC group may be removed by treatment of triethylamine (15 equiv.) in dry pyridine solution within 20 h at 20°C while other base labile protecting groups remained intact.     

Chemically removable derivatization reagent for liquid chromatography I. 2-(N-Phthalimido)ethyl 2-(dimethylamino)ethanesulfonate

A sulfonate derivatization reagent, 2-(N-phthalimido)ethyl 2-(dimethylamino)ethanesulfonate, was synthesized and examined for use in liquid chromatography. The reagent contains two key moieties, a chromophore (phthalimido) necessary for detection and a dimethylamino function that is chemically removable after derivatization. The reagent was applied to the derivatization of 2,4,6-trichlorophenol as a model analyte. The results indicated that the reagent can be readily removed after derivatization by simple acid treatment.     

A convenient synthesis of ethyl 2-(4-nitrophenyl)-3,4-disubstituted and c-fused thiophene-5-carboxylates

A convenient one step synthesis of the hitherto unknown ethyl 2-(4-nitrophenyl)-3,4-disubstituted and c-fused thiophene-5-carboxylates was achieved by the condensation of ethyl 4-nitrobenzylthioacetate with a variety of 1,2-dicarbonyl compounds using sodium ethoxide in refluxing ethanol.     

Chloromethylaluminum 2 (2-propenyl)anilide - a convenient reagent for the conversion of lactones into protected hydroxy acids

The title reagent reacts with γ and δ lactones to provide hydroxy amides which can be easily converted into protected N-acyl indoles. Mild saponification provides indole and the protected hydroxy acid.     

A convenient synthesis of 2-(alkylamino)pyridines

The synthesis of a series of 2-(alkylamino)pyridines (1) in three steps from 2-aminopyridine (4) is reported. The products were obtained in 67-91% overall yield from 4.     

Determination of biogenic amines by RPHPLC with fluorescent detection after derivatization with 2-(9-carbazole)ethyl chloroformate (CEOC)

Summary The use of 2-(9-carbazole)ethyl chloroformate (CEOC) for pre-column derivatization of biogenic amines (BA) has been tested for the first time. The reagent reacts completely with BA within 3 min at ambient temperature in acetonitrile solution to form stable derivatives that are readily analyzed by reversed-phase HPLC. Study of the derivatization conditions revealed derivatization yields to be excellent in borate buffer over the pH range 9.0–10.0. Maximum yields were obtained by use of a three- to fourfold molar excess of reagent. The reaction is extremely tolerant of common buffer salts, no decrease in reaction yield is discernible in well-buffered samples. The emission maximum for the CEOC-derivatives is 360 nm (λ _ex = 293 nm). All the derivatives fluoresced strongly and direct injection of the reaction mixture was possible, with no significant disturbance from the major fluorescent reagent degradation by-products, 2-(9-carbazole)ethanol (CEOC-OH) and bis-(2-(9-carbazole)ethyl) carbonate (CEOC)₂. Separation of the derivatized BA by high-performance liquid chromatography with gradient elution was tested on a Hypersil BDS C18 column. Excellent response linearity was observed over the concentration range from 0.25 to 94.6 μmol L⁻¹ for the labeled BA. Detection limits were 117–840 fmol at a signal-to-noise ratio of 3∶1. Analysis of BA in a shrimp sauce extract was conducted to demonstrate the applicability of the technique to real sample matrixes; results were satisfactory.     

氨基酸的咔唑-9-乙基氯甲酸酯柱前衍生高效液相色谱分析

采用一种新型氯甲酸酯类荧光衍生试剂咔唑－9－乙基氯甲酸酯（CEOC）对氨基酸进行柱前衍生，并通过荧光检测的方法进行高效液相色谱（HPLC）分析；在Hypersil BDS C18柱上对19种氨基酸衍生物进行了分离，衍生物的激发和发射波长分别为λex=293nm,λem=365nm,当衍生化缓冲液pH为9．0，衍生试剂总量（摩尔数）为氨基酸总量的4倍时，衍生化产率最大，平均检出限可达22．8fmol。     

Trimethylsilyl fluorosulfonyldifluoroacetate (TFDA): a new, highly efficient difluorocarbene reagent

TFDA is readily prepared from the reaction of fluorosulfonyldifluoroacetic acid with trimethylsilyl chloride, and it is a very effective and efficient source of difluorocarbene for use in addition reactions to alkenes of a broad scope of reactivities. Acid-sensitive substrates may require an additional purification step involving treatment of the distilled TFDA with sufficient Et₃N to remove the acid impurity. Other trialkylsilyl fluorosulfonyldifluoroacetates can also be prepared, and they have been found to have reactivities similar to TFDA. The triethyl derivative, TEFDA is more convenient to prepare in a pure state and has similar reactivity to TFDA. Thus, it may prove to be a superior reagent.     

Trimethylsilyl trichloroacetate: a new reagent for salt-free silylations

Trimethylsilyl trichloroacetate ($\text{1}$) is a convenient reagent for the silylation of phenols, carboxylic acids, mercaptans, amides, acetylenes, and β-keto esters, while the reaction of $\text{1}$ with aldehydes and ketones affords silylated trichloromethyl carbinols ($\text{5}$).     

1-(Trimethylsilyl)-1,2,4-triazene: A Novel Free Radical Initiator

The reaction of 1-(trimethylsilyl)-1,2,4-triazene with trifluoromethylsulfenyl chloride in dry n-pentane furnishes a complex mixture containing 11 compounds. All but six of them are derived from the reaction of the thiyl or chlorine radicals with n-pentane. The probable mechanism of their formation and mass spectral characterization are presented in this article.     

Trimethylsilyl isothiocyanate (TMSNCS): an efficient reagent for the one-pot synthesis of mercapto-1,2,4-triazoles

A mild, convenient, and efficient one-pot synthesis of mercapto-1,2,4-triazoles is described. Various hydrazides efficiently reacted with trimethylsilyl isothiocyanate (TMSNCS) under basic condition to give mercapto-1,2,4-triazoles in high yields.     

A convenient reagent for aldehyde to alkyne homologation

A convenient reagent for the one-carbon homologation of an aldehyde to the corresponding alkyne is reported. This reagent allows this conversion to conveniently be carried out on a large scale under ambient conditions.