Synthesis and Complexation Studies of a Tetra(N,N-dimethyl) Aminoethylamide p-tert-butyl Calix[4]arene and Its Tetramethylammonium Derivative

We describe the synthesis of two functionalised p-tert-butyl calix[4]arenes: tetra(N,N-dimethyl) aminoethylamide derivative 1 and related tetramethylammonium 2. Their complexation properties towards alkali and zinc metal cations are reported along with complexation of perchlorate anion by 2.     

A Novel Synthesis of N-Aryl-6-methylsulfanyl-4-pyrimidinones and Purine Analogues: The Reaction of Dimethyl N-Cyanodithioiminocarbonate with Cyanoacetanilides

Abstract

A novel and efficient method for the synthesis of N-aryl-6-methylsulfanyl-4-oxopyrimidine-5-carbonitriles via the reaction of dimethyl N-cyanodithioiminocarbonate with substituted cyanoacetanilides has been investigated. (3)N-Aryl-2,5-diamino-7H-pyrazolo[3,4-d]-pyrimidin-4(3H)-one have also been prepared from the reaction of 6-sulfanylthio-N-aryl-4-pyrimidinones with hydrazines.     

Synthesis of N-(2-Hydroxy-1-phenoxyacetyl)- prolylproline and Related Cation Binding and Molecular Mechanics Studies

The synthesis of N-(2-hydroxy-1-phenoxyacetyl)prolylproline 2 from 2-acetoxyphen-oxyacetic acid is described. A firstsynthesis led toN-(2-acetoxy-1-phenoxyacetyl)prolylproline methylester 8b that fragmented upon attempted esterhydrolysis with 1N NaOH. A second synthesis gave thecorresponding benzyl ester 13, which wasconverted to 2 by deacylation of the phenolicacetoxy group with pyrrolidine followed byhydrogenolysis of the ester. Cation binding by 2 in methanol and related molecular mechanics (MM)geometric optimizations are discussed.     

BASE-CATALYZED CONDENSATION OF BIS(DIETHYLPHOSPHONOMETHYL)-PHOSPHINIC AMIDES WITH ALDEHYDES1

Abstract

The reaction of the mono anion of bis(diethylphosphonomethyl)phosphinic amides (3) with aldehydes gives varying amounts of diethyl alkyl- or arylethenylphosphonates (10) and diethylphosphonomethylalkyl- or arylethenylphosphinic amides (7). When R in 3 is N,N-di-n-propylamino or N-cydohexyl-N-methylamino, the predominate product is 7 and this condensation is a satisfactory synthesis of vinylphosphinic amides which are potential antimetabolites of organic pyrophosphates.     

Convenient Synthesis of N,N′‐bis‐protected‐3,3′‐diiodo‐2,2′‐biindoles

A convenient synthesis of N,N′‐bis‐protected 3,3′‐diiodo‐2,2′‐biindoles 4–7 from 2,2′‐biindole (1) is described.     

Synthesis of substituted N-phenylmaleimides and use in a Diels–Alder reaction: a green multi-step synthesis for an undergraduate organic chemistry laboratory

ABSTRACT

This paper describes the design and implementation of a minimally hazardous, environmentally friendly, and energy efficient sequential reaction sequence within a sophomore level Organic Chemistry lab course to efficiently synthesize N-phenylmaleimide precursors for a Diels–Alder reaction. Substituted N-phenylmaleimides are a class of very expensive precursors of considerable interest due to their biological properties and use as intermediates in synthesis. The synthesis described herein produces a substituted N-phenylmaleimide in two steps from maleic anhydride and a substituted aniline followed by its Diels–Alder reaction with 2,5-dimethylfuran. The experiment exposes students to the green chemistry principles of atom economy, use of safer chemicals, design for energy efficiency, waste reduction, and inherently safer chemistry for accident prevention and enables students to use ¹H NMR spectroscopy to characterize the products.     

Synthesis of a new intercalating nucleic acid analogue with pyrenol insertions and the thermal stability of the resulting oligonucleotides towards DNA over RNA

Abstract  

A new intercalating nucleic acid monomer Y was obtained via alkylation of pyren-1-ol with (S)-(+)-2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethanol under Mitsunobu conditions followed by hydrolysis with 80% aqueous acetic acid to give a diol which was tritylated with 4,4′-dimethoxytrityl chloride followed by treatment with 2-cyanoethyltetraisopropylphosphordiamidite in the presence of N,N′-diisopropylammonium tetrazolide. In this way the monomer Y was obtained as its dimethoxytrityl-protected phosphoramidite building block for standard DNA synthesis. The corresponding oligonucleotides from Y have nearly identical hybridization properties with those of intercalating nucleic acid (INA) where neighboring oxygen and carbon atoms are interchanged in the linker. The synthesis of monomer Y avoids the use of allergic intermediates which are a problem in the synthesis of INA.     

An Efficient Acylation of Free Glycosylamines for the Synthesis of N-Glycosyl Amino Acids and N-Glycosidic Surfactants for Membrane Studies

Abstract

Treatment of free glycosylamines with 3-acyl-5-methyl-1,3,4-thiadiazole-2 (3H)-thiones 6 or with acids and 5-methyl-2-thioxo-1,3,4-thiadiazole-3(2H)-carbothioic acid S-(5-methyl-1,3,4-thiadiazol-2-yl) ester 7 in hydroorganic media afforded N-acylglycosylamines in high yields and without any competitive deglycosylation. This reaction found applications in the synthesis of N-glycopeptide building blocks and of glycosidic non ionic surfactants. Results concerning surface activities of two N-acylglycosylamines are reported. The new non ionic N-octanoyl-β-D-glucosylamine surfactant exhibited efficacy and selectivity in the extraction of membrane proteins, enhanced the activity of a membrane succinate dehydrogenase and proved thus useful for membrane studies.     

New Synthetic Approach to 4-N-Arylaminoazuleno[2,1-d]pyrimides

1-Cyano-2-N,N-dimethylformamidinylazulenes as new synthons directed to heterocycle-fused azulenes were obtained by the condensation of 2-amino-1-cyanoazulenes and N,N-dimethylformamide dimethyl acetal (DMFDMA). 1-Cyano-2-N,N-dimethylformamidinylazulene (2a) and 1-bromo-3-cyano-2-N,N-dimethylformamidinylazulene (2b) reacted with anilines (3a–h) to give 4-N-arylaminoazuleno-[2,1-d]pyrimidines in moderate yields. This reaction provides a new procedure for synthesis of pyrimidine-fused azulenes.     

Synthesis of Derivatives of ω-Isocyanato-α-methylamino, ω-Ureido-α-methylamino, and Nα-Methyl-α, ω-diamino Acids

 Homochiral N^α-methyl-2,3-diaminopropionic and N^α-methyl-2,4-diaminobutyric acid derivatives 8a,b were obtained via a stereoconservative four-step synthesis starting from hexafluoroacetone protected L-aspartic and L-glutamic acid 2a,b, respectively. Hexafluoroacetone protected ω-isocyanato-α-methylamino acids 4a,b– the key intermediates of the synthesis – are versatile building blocks for amino acid and peptide modification and promising candidates for combinatorial chemistry. Upon reaction with alcohols, compounds 4 give activated N ^ω-urethane protected ω-amino-α-methylamino acid derivatives 5–7; upon reaction with amines, ω-ureido-α-methylamino acid derivatives 10–12 and 3-methylamino-pyrrolidin-2-ones 13 are available.     

A Facile Synthesis of 3,4‐Benzo‐β‐carbolines

Abstract

A convenient method for the synthesis 3,4‐benzo‐β‐carbolines (10) from the corresponding N‐phenylsulfonyl‐3‐bromo‐N′‐arylisogramines (5) via radical mediated cyclization methodology has been reported.     

A New Hybrid Cmpo/Nopopo Ligand: Synthesis and Selected Lanthanide Coordination Chemistry

Abstract

A two-step synthesis for 2,6-bis[(diphenyl)-N,N-diethylcarbamoylmethylphosphine oxide]pyridine N-oxide (3) from 2,6-bis[(diphenylphosphinoyl)methyl]pyridine is reported along with coordination chemistry with Dy(III) and Yb(III). Crystal structure determinations for the ligand 3_S,S and 1:1 complexes [Dy(3_R,S )(NO₃)₃]·(Me₂CO) and [Yb(3_R,S )(NO₃)₃]·(Me₂CO) are described. In these complexes, the pentafunctional ligand 3 coordinates in a tridentate NOPOPO chelate mode.     

Halo-substituted (S)-N-(2-benzoylphenyl)-1-benzylpyrolidine-2-carboxamides as new chiral auxiliaries for the asymmetric synthesis of (S)-α-amino acids

The synthesis of new chiral auxiliaries (S)-N-(2-benzoylphenyl)-1-(3,4-dichlorobenzyl)-pyrrolidine-2-carboxamide (1a), (S)-N-(2-benzoylphenyl)-1-(pentafluorobenzyl)pyrrolidine-2-carboxamide (1b), and (S)-N-(2-benzoylphenyl)-1-(4-isopropoxytetrafluorobenzyl)pyrrolidine-2-carboxamide (1c) and their application in the asymmetric synthesis of amino acids using Ni^II complexes of their Schiff"s bases with alanine and glycine are described. Compound 1a is particularly appropriate for highly stereoselective synthesis of -methyl--amino acids with high enatiomeric purity (ee >95%).     

Microwave-Assisted Efficient Methylation of Alkyl and Arenesulfonamides with Trimethylsulfoxonium Iodide and KOH

Abstract

A solvent-free synthesis of N-methyl and N,N-dimethylsulfonamides has been achieved by treating the primary and secondary sulfonamides with Me₃S⁺OI^? and KOH under microwave irradiation on alumina support.     

An Efficient Synthesis of 2-(((9-Fluorenylmethoxycarbonyl)amino)methyl)benzoic Acid

An efficient, two-step syntesis of the title compound 3 in 61% overall yield is presented. The synthesis involves hydrazine removal of the N-phthalimide protecting group of α-phthalimido-o-toluic acid (6), followed by N-Fmoc formation with (9-fluorenylmethyl)succinimidyl carbonate.     

2-HALOVINYL ARYL SULFONES: NEW COUPLING REAGENTS FOR CARBOXAMIDE FORMATION1

Abstract

E-2-Chlorovinyl p-nitrophenyl sulfone 6 and 2-bromo-2-trifluoromethylvinyl phenyl sulfone 7a reacted with carboxylic acids in the presence of a molar equiv of Et₃N affording the corresponding 2-acyloxyvinyl sulfones 8, 11, 17, 18, 22, 25, 28 and 29. The latter, on treatment with amines, gave amides 9, 13, 19, 23 and 26 and peptides 30 and 32. These reagents 6 and 7a were also used for the formation of N-methylanilides 13d, 13e, 19d, 23 and 26. Particularly, 6 was successfully used for synthesis of a macrocyclic lactam 23 involving a N-methylanilide moiety. The amidation reactions proceeded under essentially neutral conditions. Therefore, base-sensitive β-hydroxycarboxy-N-methylanilides such as 26, whose structural unit was involved in maytansine 5, could be prepared by the present method. The reagent 6 was also effective for the preparation of peptides such as Val-N-MeVal derivatives (e.g. 32), which were difficult to prepare by other methods.     

Microwave-Assisted Synthesis of N,N-Dialkyl-P-Alkylphosphonamidic Anhydrides

A new rapid, efficient, solvent-free, microwave-assisted, and high-yielding method for the synthesis of N,N-dialkyl-P-alkylphosphonamidic anhydrides has been developed. The method involves the use of 4-dimethylaminopyridine and water under microwave irradiation. The reaction of N,N-dialkylaminoalkyl/phenyl phosphonochloridates 2a–h with 4-dimethylaminopyridine (DMAP) gave pyridinium salts, which were converted into N,N-dialkyl-P-alkylphosphonamidic anhydrides 4a–h.     

Efficient Syntheses of Methyl 2-Amino-2-Deoxy-3,4,6-Tri-O-Benzyl-α-D-Glucopyranoside and its 2-tert-Butoxycarbonylamino- and 2-Methylamino Derivatives from N-Acetyl-D-Glucosamine

ABSTRACT

The synthesis of the title compounds started with N-acetylglucosamine which was converted into the corresponding methyl glycoside and O-protected with benzyl groups. Subsequent N-protection as its N-BOC-N-acetyl derivative and sequential removal of the N-acetyl group and of the BOC group led in good yield to the target compounds in multigram amounts.     

Synthesis of Derivatives of ω-Isocyanato-α-methylamino, ω-Ureido-α-methylamino,and N<Superscript>α</Superscript>-Methyl-α, ω-diamino Acids

Summary.  Homochiral N^α-methyl-2,3-diaminopropionic and N^α-methyl-2,4-diaminobutyric acid derivatives 8a,b were obtained via a stereoconservative four-step synthesis starting from hexafluoroacetone protected L-aspartic and L-glutamic acid 2a,b, respectively. Hexafluoroacetone protected ω-isocyanato-α-methylamino acids 4a,b– the key intermediates of the synthesis – are versatile building blocks for amino acid and peptide modification and promising candidates for combinatorial chemistry. Upon reaction with alcohols, compounds 4 give activated N ^ω-urethane protected ω-amino-α-methylamino acid derivatives 5–7; upon reaction with amines, ω-ureido-α-methylamino acid derivatives 10–12 and 3-methylamino-pyrrolidin-2-ones 13 are available. Received November 17, 1999. Accepted November 26, 1999     

INDANE FOR SYNTHESIS OF N-ALKYL DIARYLAMINES AND N-ACYLCYCLOPENTA[4,5-b]- PHENOTHIAZINES

ABSTRACT

The synthesis of new N-alkyl-N-aryl-5-indanamines is reported. 5-Aminoindane was first N-alkylated with different alkyl halides, and the resulting N-alkyl-5-indanamines were N-phenylated with organolead or organobismuth reagents to afford the corresponding diarylamines. Direct N-acylation of linear fused 1,2,3,10-tetrahydrocyclopenta-[b]phenothiazines provided the final N-acyl tetracyclic products.