Trichloroacetic Anhydride Research Articles

Intramolecular cyclization of N-cyano sulfoximines by N-CN bond activation.

Metal-free halogenated anhydrides promote the intramolecular cyclization of N-cyano sulfoximines. Trifluoro- or trichloroacetic anhydride (TFAA or TCAA, respectively) activate the N-cyano groups of N-cyano sulfoximines, leading to the intramolecular cyclization of 2-benzamide-N-cyano sulfoximines 1. This method results in excellent yields of thiadiazinone 1-oxides 2. A full intramolecular cyclization pattern was suggested by (i) labeling experiments with 13C, (ii) isolating of N-trifluoroacetyl sulfoximine 1ac, and (iii) confirming the generation of the intermediate 1ad by LC/MS analysis.

ChemInform Abstract: Lipase-Catalyzed Resolution: Enantioselective Esterification of 2- Propanol Amines.

Abstract Porcine pancreatic lipase catalyzes the specific hydroxyl acylation of 2-propanol amines with enantioselectivity employing trichloroacetic anhydride in organic solvents.

Solvent-Free Friedel–Crafts Cyclization with Trichloroacetic Anhydride

Friedel–Crafts cyclization products were obtained using 1.1 equivalents of environmentally benign trichloroacetic anhydride as sole reagent and solvent. The resulting ketones included benzothiepins, benzothiopyrans, benzoxepins, dibenzothiepins, dibenzoxepins, and tetralones.

Regioselective and stereospecific acylation across oxirane- and silyloxy systems as a novel strategy to the synthesis of enantiomerically pure mono-, di- and triglycerides

A trifluoroacetate-catalyzed opening of the oxirane ring of glycidyl derivatives bearing allylic acyl or alkyl functionalities with trifluoroacetic anhydride (TFAA), provides an efficient entry to configurationally homogeneous 1(3)-acyl- or 1(3)-O-alkyl-sn-glycerols. Selective introduction of tert-butyldimethylsilyl- (TBDMS), or triisopropylsilyl- (TIPS) transient protections at the terminal sites within these key intermediates secures 1(3)-acyl- or 1(3)-O-alkyl-3(1)-O-TBDMS (or TIPS)-sn-glycerols as general bifunctional precursors to 1,2(2,3)-diacyl-, 1(3)-O-alkyl-2-acyl- and 1,3-diacyl-sn-glycerols and hence triester isosters. Incorporation of a requisite acyl residue at the central carbon of the silylated synthons with a subsequent Et(3)N.3HF-promoted, direct trichloroacetylation across the siloxy system by trichloroacetic anhydride (TCAA), followed by cleavage of the trichloroacetyl group, affords the respective 1,2(2,3)-diacyl- or 1(3)-O-alkyl-2-acyl-sn-glycerols. Alternatively, a reaction sequence involving: (i) attachment of a trichloroacetyl fragment at the stereogenic C2-centre of the monosilylated glycerides; (ii) replacement of the silyl moiety by a short- or long-chain carboxylic acid residue by means of the acylating agent: tetra-n-butylammonium bromide (TBABr)-carboxylic acid anhydride (CAA)-trimethylsilyl bromide (TMSBr); and (iii) removal of the trichloroacetyl replacement, provides pure 1,3-diacyl-sn-glycerols. The TBABr-CAA-TMSBr reagent system allows also a one-step conversion of 1,2-diacylglycerol silyl ethers into homochiral triglycerides with predefined asymmetry and degree of unsaturation. These compounds can also be accessed via a two-step one-pot approach where the trichloroacetyl derivatives of 1,2(2,3)- or 1,3-diacyl-sn-glycerols serve as triester building blocks for establishing the third ester bond at preselected C3(1)- or C2-positions within the glycerol skeleton at the very last synthetic stage. In all instances, the target compounds were produced under mild conditions, in high enantiomeric purity, and in practically quantitative yields.

A direct transformation of O-silyl groups into O-trichloroacetates. A novel synthetic approach to protein kinase C ligands: 1-oleoyl-2-acetyl- and 1-hexadecyl-2-acetyl- sn-glycerols

A fluoride ion-promoted direct esterification of tert-butyldimethylsilyl- (TBDMS), or triisopropylsilyl (TIPS)-protected glycerol derivatives by means of trichloroacetic anhydride (TCAA), followed by removal of the trichloroacetyl transient protection, provides a new, efficient entry to stereochemically pure 1-oleoyl-2-acetyl- and 1- O-hexadecyl-2-acetyl- sn-glycerols.

Derivatisation of 4-nonylphenol and bisphenol A with halogenated anhydrides

The aim of this work is to synthesize and characterise the halogenated derivatives of the endocrine disrupting compounds (EDCs) 4-nonylphenol (4-NP) and bisphenol A (BPA). Characterisation was performed after gas chromatographic (GC) separation on-line coupled to mass spectrometric (MS) detector and a Fourier Transform Infrared (FTIR) spectroscopic detector. Further structure elucidation was done applying Nuclear Magnetic Resonance spectroscopy (NMR). Two different approaches for the preparation of derivatives were evaluated. At first trifluoroacetyl derivatives were synthesized by the reaction of trifluoroacetic acid (TFA) anhydride and the EDCs in acetonitrile at a temperature of 50 degrees C for 30 minutes. In a second step the 4-NP was derivatised using trichloroacetic acid anhydride and triethylamine in diethyl ether at 20 degrees C for 30 minutes. After synthesis the halogenated NP and BPA derivatives were characterised applying GC/MS, GC/FTIR and NMR. Three indices for a successful derivatisation were observed: El-GC/MS proved a complete derivatisation presenting a characteristic fragmentation pattern for each derivative. The IR spectra obtained by GC/FTIR after derivatisation and separation confirmed the loss of the phenolic O-H stretching vibration at 3,600 cm(-1) while typical absorptions for halogenated compounds now were observed. The NMR-spectra contained the predicted resonance signals.

Guanidine-annelated Heterocycles XV. Synthesis of 2-Substituted 4-Phenylamino[1,2,4]triazolo-[2,3-a]quinazolin-5(4H)-ones as Potential Antihypertensive Agents^1

Starting from isatoic anhydride (1) and via one-pot process to 2-methylthio-3-phenylamino-quinazolin-4(3H)-one (4) was isolated in excellent yield. Hydrazinolysis of 4 converted it into the hydrazino derivative 5. Cyclocondensation of 5 with appropriate carboxylic acid orthoesters 6a-c, N,N’-carbonyl-, N,N’-thiocarbonyldiimidazole (6d,e), ethyl chloroformate, carbon disulfide, trifluoro- and trichloroacetic anhydride (6h,i) under elevated temperature gave 4-phenylamino-1「1,2,4」triazolo「2,3-a」 quinazolin-5(4H)-one (8a) and its 2-substituted derivatives 8b-g in different yields. These compounds activated satisfactory antihypertensive activity after the pharmacological evaluation on anesthetized rats.

Synthesis of 4‐Functionalized Aryl‐3,5‐diacyl‐1,4‐dihydropyridines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Nucleophilic addition to chiral pyridinium salts: stereoselective synthesis of (−)- Na-methylervitsine

Chiral non-racemic 4-substituted 3,5-diacyl-1,4-dihydropyridines 8 are prepared by the regio- and diastereoselective addition of organocopper reagents to chiral pyridinium salt 2, followed by acylation with trichloroacetic anhydride and subsequent haloform reaction. Additionally, (−)- N a -methylervitsine is synthesized by reaction of the enolate derived from 2-acetylindole 9 with pyridinium salt 2, followed by electrophile (Me 2N +CH 2I −)-induced cyclization and subsequent elaboration of the 16-methylene and (20 E)-ethylidene substituents.

Anhydride and halogenated-anhydride trihalogenacetic acid interaction with thymidine-5'-phosphate: ways to new activating reagents in nucleotide phosphorylation reactions

The interaction of thymidine 5'-phosphate with trichloroacetic anhydride, trichloroacetyl chloride, and tribromoacetyl bromide was studied in dimethylformamide and acetonitrile in the presence of tertiary amines. The first two reactions gave the mixed anhydride of trichloroacetic and thymidylic acids (acyl phosphate) as the major product and P1, P2-dithymidine 5'-pyrophosphate as the byproduct. The third reaction proceeded by a more complicated mechanism and mainly led to substituted polyphosphates. The subsequent treatment of the reaction mixtures with morpholine resulted in thymidine 5'-phosphoromorpholidate in a high yield. The phosphorylating activities of the trichloroacetyl and tribromoacetyl phosphates were 77 and 89%, respectively.

Synthesis of 4-functionalized aryl-3,5-diacyl-1,4-dihydropyridines

The valuable N-unsubstituted 4-aryl-3,5-diacyl-1,4-dihydropyridines 12b– f , bearing an electron-withdrawing substituent at the benzene ring, have been synthesized by the copper-mediated addition of functionalized arylmagnesium reagents 2b– f to N-benzhydrylpyridinium salt 9 , followed by acylation with trichloroacetic anhydride and the subsequent haloform reaction and N-deprotection.

Addition of organocopper reagents to N-alkylpyridinium salts. A flexible access to polysubstituted dihydropyridines

The addition of a series of organocopper (alkyl, vinyl, allyl, and ethynyl) reagents to 3-acyl- N-alkylpyridinium salts, followed by acylation of the intermediate 1,4- or 1,2-dihydropyridines with trichloroacetic anhydride has been studied.

Reaction of Trialkyl Phosphites with Monoacylals of Dichloro- and Trichloroacetic Acids

We found a new reaction between trialkyl phosphites I and 1-ethoxyethyl dichloroand trichloroethanoates II, resulting in formation of 1-ethoxyethylphosphonates III and alkyl dichloroand trichloroethanoates IV. This result differs radically from the previously reported results of reactions of compounds I with ethyl trichloroacetate [1], halogen-substituted acetyl chlorides [2], and trichloroacetic anhydride and its diacylal [3], the major products of which were substituted vinyl phosphates.

A short procedure for the preparation of highly functionalized di- and tetrahydropyridines

The addition of a series of stabilized carbon nucleophiles to 3-acyl-1-alkylpyridinium salts. followed by acylation of the intermediate dihydropyridines with trichloroacetic anhydride has been studied. The C-4 adducts resulting from the addition of α-(methylsulfanyl)ester enolates have been converted into synthetically useful 1,2,3,4-tetrahydropyridines.

Novel Dehydrative Glycosylation by Using Acid Anhydride and TMSClO4

Abstract Novel dehydrative glycosylation with 1-hydroxy sugars as glycosyl donors was achieved. Combination of trifluoroacetic anhydride or trichloroacetic anhydride as dehydrating agents with TMSClO4 as a Lewis acid afforded desired glycosides in good yields. t-Butyldiphenylsilyl and trichloroethoxycarbonyl groups at the 6-position of donors enhance α-selectivity of the glycosylation.

Synthesis of 3,5-diacyl-4-phenyl-1,4-dihydropyridines

3,5-Diacyl-4-phenyl-1,4-dihydropyridines have been synthesized via a regio- and chemoselective addition of Ph 2Cu(CN)Li 2 to β-substituted N-alkylpyridinium salts, followed by acylation of the intermediate 1,4-dihydropyridines with trichloroacetic anhydride and subsequent haloform-type reaction. A similar sequence using an N-silylpyridinium salt and PhMgBr allows the preparation of the corresponding N-unsubstituted dihydropyridines.

Reaction of Imines with Trichloroacetic Esters or Anhydride Promoted by Iron Carbonyl or Microwave Irradiation. Preparation of 3,3-Dichloro-β-Lactams

The synthesis of 3,3-dichloroazetidin-2-ones by the reaction of imines and methyl or trimethylsilyl trichloroacetate promoted by diiron nonacarbonyl or by microwave irradiation of imines and trichloroacetic anhydride is described.

ChemInform Abstract: Reaction of Polyhalogenated Compounds with Metals and Electrophilic Reagents. Part 22. Reaction of Trichloroacetic Anhydride and Mixed Anhydrides of Trichloroacetic Acid and Aliphatic Acids with Zinc and Acyl Chlorides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of 2-amino-5-(5R-1,2,4-oxadiazolyl-3)-1,3,4-oxadiazoles

The interaction of 2-amino-1,3,4-oxadiazole-5-carboxamidoxime with nitriles in the presence of ZnCl2 and HCl or with trichloroacetic anhydride affords 2-amino-5-(5R-1,2,4-oxadiazolyl-3)-1,3,4-oxadiazoles. Their reactions with N-nucleophiles have been studied.

Simultaneous Analysis of Amphetamine, Methamphetamine, and 3,4-Methylenedioxymethamphetamine (MDMA) in Urine Samples by Solid-Phase Extraction, Derivatization, and Gas Chromatography/Mass Spectrometry

A rapid and effective solid-phase extraction procedure using Bond Elute Certify bonded silica sorbent cartridges was adopted to extract amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy) from urine samples. The extract was derivatized with trichloroacetic anhydride prior to gas chromatography/mass spectrometry (GC/MS) analysis with selected ion monitoring of the following ions: 190, 91, 188; 204, 91, 202; 162, 135, 202; 194, 123; and 211, 209 for the derivatized amphetamine, methamphetamine, MDMA, d5-amphetamine, and d9-methamphetamine, respectively. The first of the ions listed for each compound was used for quantitation. The compound d5-amphetamine was used as the internal standard for amphetamine, and d9-methamphetamine was used for methamphetamine and MDMA. Results showed a higher than 65% recovery and a reproducibility with less than a 5% coefficient of variation. When a sample size of 2 mL was used, the lowest detectable concentration was about 50 ng/mL, and a near-perfect fit can be obtained (within the 250 to 4000-ng/mL concentration range studied) using a second-order polynomial model.