A mild and general one-pot preparation of cyanoethyl-protected tetrazoles

Described herein is a mild and general one-pot procedure for the conversion of cyanoethyl amides to cyanoethyl-protected tetrazoles with azidotrimethylsilane via the intermediacy of imidoyl chlorides generated in situ with phosphorus pentachloride. This synthetic sequence works well with sterically hindered amides and is compatible with acid sensitive functionality.     

Ruthenium‐Catalyzed Reductive Arylation of N‐(2‐Pyridinyl)amides with Isopropanol and Arylboronate Esters

A new three‐component reductive arylation of amides with stable reactants (iPrOH and arylboronate esters), making use of a 2‐pyridinyl (Py) directing group, is described. The N‐Py‐amide substrates are readily prepared from carboxylic acids and PyNH₂, and the resulting N‐Py‐1‐arylalkanamine reaction products are easily transformed into the corresponding chlorides by substitution of the HN‐Py group with HCl. The 1‐aryl‐1‐chloroalkane products allow substitution and cross‐coupling reactions. Therefore, a general protocol for the transformation of carboxylic acids into a variety of functionalities is obtained. The Py‐NH₂ by‐product can be recycled.     

Colorimetric determination of organic compounds by formation of hydroxamic acids

Carboxylic acids, their chlorides, anhydrides, esters, lactones, amides, lactams and imides react with hydroxylamine to give hydroxamic acids which are then treated with iron(III). Other compounds or groups of compounds can also be determined after a prior conversion into hydroxylamine-reactive derivatives. The calorimetric applications of these reactions are reviewed. The effect of various factors is discussed. A selective procedure for determination of acid chlorides and anhydrides and an improved procedure for determination of carboxylic esters and lactones are presented.     

Mild and direct conversion of quinoline N-oxides to 2-amidoquinolines with primary amides

[reaction: see text] A simple, one-pot procedure is described for the direct conversion of quinoline N-oxides to alpha-amidoquinolines with primary amides. This methodology is complimentary to the Abramovich reaction, which is limited to the introduction of secondary amides via imidoyl chlorides. Although reaction conditions are quite similar, omission of the base is key for successful reaction with primary amides, which were found not to proceed through the intermediacy of an imidoyl chloride but rather through an acyl isocyanate.     

Convenient One-Pot Synthesis of Aldehydes from Carboxylic Acid Chlorides with Sodium Diethyldihydroaluminate

Carboxylic acid chlorides and acids were converted into the corresponding aldehydes conveniently in one-pot process with sodium diethyldihydroaluminate (SDDA) in moderate to good yields.     

A mild method for the formation and in situ reaction of imidoyl chlorides: conversion of pyridine-1-oxides to 2-aminopyridine amides

[reaction: see text] A mild, practical, one-pot method for the generation of imidoyl chlorides and their subsequent in situ reaction with pyridine-1-oxides is described. The imidoyl chlorides were formed from the reaction of secondary amides with a stoichiometric amount of oxalyl chloride and 2,6-lutidine in CH(2)Cl(2) at 0 degrees C. Upon warming of the reaction mixture to room temperature in the presence of pyridine-1-oxides, a rapid conversion to 2-aminopyridine amides was observed in moderate to excellent isolated yields.     

4-Functionally Substituted 3-heterylpyrazoles: XII. 4-Chlorothieno[2,3-c]pyrazole-5-carbonyl Chlorides

3-(4-Pyrazolyl)acrylic acids reacted with excess thionyl chloride in the presence of benzyltriethylammonium chloride affording 4-chlorothieno[2,3-c]pyrazole-5-carbonyl chlorides which were converted into the corresponding acids, esters, and amides.     

An efficient procedure for chemoselective amidation from carboxylic acid and amine (ammonium salt) under mild conditions

Presented here is an efficient one-pot and catalyst-free procedure for the synthesis of amides starting from carboxylic acids and amine/ammonium salts using 2,2-dichloro-1,3-diisopropylimidazolidine-4,5-dione as the coupling agent. Reactions can proceed smoothly even with those bearing thermosensitive group(s) at ambient temperature, and the corresponding products of primary, secondary and tertiary amides can be afforded in moderate to excellent yields of up to 96%.     

Preparation of α,ω-ditriazinylperfluoroalkane derivatives

The synthesis of 2-oxa and 2-thiaperfluoroglutaric acids and their corresponding ethyl esters, amides, nitriles, acid chlorides, and also 2-thiaperfluoroglutaric anhydride are described. These compounds were prepared as precursors to α,ω-ditriazinylperfluoroalkane derivatives containing a heteroatom in the perfluoroalkylene chain. The ditrazinylpropanes were prepared most satisfactorily from the diacid chlorides rather than the dinitriles.     

A family of simple amide-derived air-stable P,O-ligands for Suzuki cross-coupling of unactivated aryl chlorides

A family of air-stable amide-derived phosphine (Aphos) ligands engineered on simple N,N-dialkyl aryl amide scaffolds has been designed and prepared by one-pot synthesis from the amides in high yields. The Aphos ligands have been used, in analogous to their atropisomeric variations, as hemilabile bidentate P,O-ligands in various Pd-catalyzed C-N and C-C bond forming reactions. We present here our results on the highly efficient Suzuki cross-coupling reactions of unactivated and/or sterically hindered aryl chlorides with arylboronic acids and a relationship of Aphos structures with catalytic efficacy.     

Transformation of 3-(3-arylalkylcarbamoyl-4-hydroxy-2-oxo-1,2-dihydroquinolin-1-yl)propanenitriles into amides and acids

A mixture of hydrochloric and acetic acids depleted in water was proposed to effect stepwise transformation of 3-(3-arylalkylcarbamoyl-4-hydroxy-2-oxo-1,2-dihydroquinolin-1-yl)propanenitriles into the corresponding amides and then into the acids. The procedure turned out to be efficient with 3-[(2-phenylethyl)-carbamoyl] derivatives, whereas the reactions with benzylcarbamoyl analogs were accompanied by partial or complete debenzylation.     

Isoquinoline derivatives VI. Synthesis and pharmacological properties of 4,6,7-substituted 1(2)-arylalkyl-1,2,3,4-tetrahydroisoquinolines and their analogs

The condensation of 6,7-dimethoxy-1,2.3.4-tetrahydroisoquinoline (II) with diphenylacetyl and diphenylpropionyl chlorides gave the corresponding amides (III). Reduction of III with lithium aluminum hydride converted them to tertiary amines IV, which were characterized as their hydrochlorides. The condensation of equimolecular amounts of amines I with the acid chlorides of substituted phenylacetic and diphenylpropionic acids gave amides V. The reduction of amides V with lithium aluminum hydride gave secondary amines VI. The corresponding tetrahydroisoquinolines (VII) were obtained by the cyclization of amides V and subsequent reduction with lithium aluminum hydride, The condensation of 1-diphenylethyl-6,7-dimethoxy-l,2,3,4-tetrahydroisoquinoline with formalin gave VIII. The IR spectra of the synthesized compounds were examined. The effect of these compounds on the arterial blood pressure and the coronary blood flow was studied.See [1] for communication V.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1683–1687, December, 1971.     

Efficient amidation from carboxylic acids and azides via selenocarboxylates: application to the coupling of amino acids and peptides with azides

A facile one-pot procedure for the coupling of carboxylic acid and azide via selenocarboxylate and selenatriazoline has been developed and successfully applied to the coupling of amino acids and peptides with azides. Selenocarboxylates are readily prepared by the reaction of the activated carboxylic acids with LiAlHSeH under mild conditions. The selenocarboxylates formed in situ are used to react directly with azides to form the corresponding amides via a selenatriazoline intermediate. Excellent yields were obtained for electron-deficient azides, and moderate to good yields were obtained for electron-rich azides. The selenocarboxylate/azide amidation reaction is clean and chemoselective. It provides an attractive alternative method to the conventional acylation of amines when an amide bond needs to be formed without going through an amine intermediate.     

Synthesis of 6-phenanthridinones and their heterocyclic analogues through palladium-catalyzed sequential aryl-aryl and N-aryl coupling

[reaction: see text] 6-Phenanthridinones and their heterocyclic analogues were synthesized through a one-pot procedure based on consecutive Pd-catalyzed aryl-aryl and N-aryl coupling from iodoarenes ortho-substituted by electron-releasing substituents and amides of o-bromoarene- and heteroarenecarboxylic acids.     

4-Functionally Substituted 3-Heterylpyrazoles: III. 3-Aryl(heteryl)pyrazole-4-carboxylic Acids and Their Derivatives

3-Aryl(heteryl)-4-formylpyrazoles were cleanly oxidized by potassium permanganate in water-pyridine medium to afford in high yield 3-aryl(heteryl)pyrazole-4-carboxylic acids, that were further converted into the corresponding chlorides and amides.     

One-pot synthesis of Weinreb amides employing 3,3-dichloro-1,2-diphenylcyclopropene (CPI-Cl) as a chlorinating agent

The synthesis of N^α-protected amino alkyl Weinreb amides starting from the corresponding α-amino acids as well as carboxylic acids has been delineated through the in situ generation of acid chlorides using CPI-Cl as a chlorinating agent. The protocol is simple; the reaction conditions employed were mild, and compatible with all the three commonly used urethane protecting groups namely, Boc, Cbz and Fmoc groups. The resulting Weinreb amides are obtained in good yields as optically pure products.     

Formamide as an Ammonia Synthon in Amination of Acid Chlorides

The use of formamide as a convenient source of ammonia has been explored for the direct transformation of acid chlorides to primary amides. Various aliphatic, alicyclic aromatic, and heterocyclic acid chlorides are converted to the corresponding carboxamides in good yields (75–94%).     

Diastereoselective Zwitterionic Aza-Claisen Rearrangement: The Synthesis of Bicyclic Tetrahydrofurans and a Total Synthesis of (+)-Dihydrocanadensolide

The zwitterionic Claisen rearrangement of optically-active N-allyl pyrrolidines and various acid chlorides proceeds with high simple diastereoselection (internal asymmetric induction) and high 1,2-asymmetric induction, generating a new C-C bond adjacent to a chiral C-O function. The resulting gamma,delta-unsaturated amides were cyclized to the corresponding optically active gamma-butyrolactones, which are useful intermediates in natural product synthesis. On one hand, a diastereoselective iodocyclization of several lactones led to tetrahydrofurans with a substitution pattern representing a key intermediate of an oxa-prostaglandin synthesis. On the other, a one-pot procedure of a Swern oxidation and consecutive Grignard reaction of one gamma-lactone allowed a diastereoselective chain elongation. The final oxidation/cyclization sequence completed a highly efficient synthesis of the (+)-dihydrocanadensolide or its C-3 epimer, respectively.     

A catalyst that plays multiple roles: asymmetric synthesis of beta-substituted aspartic acid derivatives through a four-stage, one-pot procedure

We report a new method for the catalytic, asymmetric synthesis of beta-substituted aspartic acid derivatives in which the nucleophilic catalyst serves up to four discrete roles in a one-pot procedure: catalytic dehydrohalogenation of acid chlorides to form ketenes; catalytic dehydrohalogenation of alpha-chloroamines to form the corresponding imines; catalyzed [2 + 2]-cycloaddition to produce intermediate acyl beta-lactams; and finally, nucleophilic ring opening to afford optically enriched beta-substituted aspartic acids in high enantioselectivity and diastereoselectivity.     

Reactions of amides of arylphosphorous acids with acyl chlorides

Conclusions The reactions of amides of arylphosphorous acids with acyl chlorides take place with replacement of the amide group and formation of amides of carboxylic acids and the corresponding aryl chlorophosphates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2131–2133, September, 1968.