Isomerization of N-[α-(Alkylthio)alkyl]- and N-[α-(Arylthio)alkyl]benzotriazoles

The thermal isomerizations of N-[α-(alkylthio)alkyl]- and N-[α-(arylthio)alkyl]benzotriazoles have been investigated under N₂ atmospheres (i) in toluene, xylene, MeOH, or EtOH, in the presence of acid catalysts and (ii) in the absence of solvent. The sulfide isomerization rates depend on the number of H-atoms carried by the C-atom attached to the N-atom of the benzotriazole: tertiary (no hydrogen) > secondary (1 hydrogen) > primary (2 hydrogens). The results support an isomenzation mechanism involving a heterolytic N? C bond cleavage with formation of sulfonium/carbonium and benzotriazolate ions.     

Synthesis and Properties of N-(2,2,2-Trichloroethylidene)trifluoromethanesulfonamide and Its Derivatives

The reaction of N,N-dichloromethanesulfonamide with trichloroethylene gave N-(2,2,2-trichloro- ethylidene)trifluoromethanesulfonamide which showed high reactivity toward oxygen- and nitrogen-centered nucleophiles, as well as in C-alkylation of aromatic compounds.     

Substitution of the Benzotriazolyl Group in N -(α-Amidoalkyl)benzotriazoles and N -(α-Sulfonamidoalkyl)benzotriazoles with Allylsamarium Bromide

Abstract

The nucleophilic substitution of the benzotriazolyl group in the N-(α-benzotriazol-1-ylalkyl)amides and N-(α-benzotriazol-1-ylalkyl) sulfonamides with allylsamarium bromide was investigated, and the corresponding homoallylamides or homoallylsulfonamides were obtained in good to excellent yields.     

The synthesis of N-[2-(D-glucos-3-O-yl)propionyl]-l-alanine and N-[(d-glucos-3-O-yl)acetyl]-l-alanine

N-[2-(D-Glucos-3-O-yl)propionyl]-L-alanine ( 7a ) was synthesized, which has a glucose residue instead of N-acetylglucosamine residue in the muramyl peptide. N-[(D-Glucos-3-O-yl)acetyl]-L-alanine ( 7b ) was also synthesized as a glycolyl analog of 7a in order to determine the relationship between the structure of propionyl moiety in the carbohydrate analog ( 7a ) and the adjuvant activity. These simple analogs are compounds prepared for the purpose of introduction into a synthetic polymer with the view of producing polymeric drugs.     

Derivatives of 3-Deoxy-3-(N-Hydroxyamino)-D-Ribose

Abstract

A series of 3-(N-arylmethyl-N-hydroxyamino)-l,2-O-cyclopentylidene-3-deoxy-5-O-toluoyl-α-D-riboses has been prepared. The blocking groups used were chosen to allow an easy nucleosidation of these compounds to spin labelled analogs of natural nucleosides. The conformational behavior of the N-arylmethyl-N-hydroxyamino group has been studied using ³/_CH NMR coupling data and molecular mechanics computations. Upon spontaneous oxidation, these hydroxylamines led to the corresponding aminoxyl free radicals which were submitted to EPR spectroscopy and quantum mechanical computations at a semiempirical level (PM3).     

Stereoisomerism of N-(1-Propenyl)thiobenzamide

A prototropic rearrangement of N-prop-2-enylbenzocarbothioamide afforded two stereoisomeric N-prop-1-enylbenzocarbothioamides (IIa, b) isolated as individual compounds. The stereoisomerism is due to hindered rotation around thioamide bond C(S)-N and also to -diastereoisomerism. The configuration of the isolated isomers was investigated by IR spectroscopy, AM1 and PM3 methods. In the molecules occurs the p,-conjugation with participation of nitrogen atom and multiple bonds resulting in formation of a united delocalized MO in the planar fragment C(S)-NC = C.     

Ringerweiterungsreaktionen von N-(2-Aminoäthyl)-, N-(4-Aminobutyl)-, N-(6-Amino-4-aza-hexyl)- und N-(8-Amino-4-aza-octyl)-lactamen. 7. Mitteilung über Umamidierungsreaktionen

Ring Enlargement Reactions of N -(2-Aminoethyl)- , N -(4-Aminobutyl)- , N -(6-Amino-4-aza-hexyl)- and N -(8-Amino-4-aza-octyl)-lactames The N-aminoalkyl-lactams 1 , 3 , 4 , 10 (Scheme 2) and 13 (Scheme 3) have been synthesized. In the presence of KAPA (potassium 3-aminopropylamide in 1,3-propanediamine) 1 is stable, whereas 3 , 4 and 10 rearrange under ring enlargement to 5 , 8 and 11 , respectively. The 4-aminobutyl derivate 13 rearranges in a fast reaction to 14 ; after a longer reaction time the 22membered ring 16 and the ring opened product 18 are formed. Hence it may be concluded that the 7membered lactam ring is more stable than the 10membered one, and the 11membered lactam ring is more stable than the 8 membered one. Moreover, the 5- and 6 membered ring intermediates of these transamidation reactions are prefered to the 7membered ring intermediates (cf. [10]).     

Synthesis of N-(2-(Methylamino)ethyl) Derivatives of 2H-Phthalazin-1-ones

A series of new alkyl, tosyl, acetyl, and tert-butoxycarbonyl derivatives of 2-(2-aminoethyl)-phthalazinones were efficiently synthesized by reaction of lactams with N-Boc-, N-acetyl-, or N,O-ditosyl derivatives of N-methylethanolamine in the presence of MeONa or under Mitsunobu reaction conditions. Selected compounds were converted into corresponding 2-[2-(methylamino)ethyl]phthalazinones in good yields.     

Polymerization of N-(fluoro phenyl) maleimides

Poly(N-aryl maleimide)s of characteristic structures have been synthesized and some of their physical properties studied. These include N-(2-fluoro phenyl), N-(3-fluoro phenyl), N-(4-fluoro phenyl), N-(2,4-difluoro phenyl), N-(2,5-difluoro phenyl), N-(2,3,5,6-tetrafluoro phenyl), and N-(pentafluoro phenyl). The polymerization of N-(fluoro phenyl) maleimides by free-radical initiation in bulk or in solution and by anionic catalyst have been studied to compare the characteristics of polymerization by γ-ray irradiation with that by free-radical initiation. The polymers were characterized by elemental analysis, intrinsic viscosity, spectroscopy (IR and NMR), programmed thermogravimetric analysis, and x-ray diffraction. Spectra of polymers prepared by radiation and anionic polymerization were nearly identical with those of polymers prepared by free-radical polymerization initiated by AIBN in bulk or in solution and by the self-initiated thermal polymerization. A variety of reaction conditions were tried, but all attempts to change the molecular structure of the polymers were unsuccessful. Rates of thermal degradation for poly[N-(fluoro phenyl) maleimide]s have been analyzed by using a multiple-heating-rate procedure. Overall activation energy, order of reaction, and frequency factor have been evaluated. On the basis of the comparison between the overall activation energy of the thermal degradation of poly[N-(fluoro phenyl) maleimide]s and NMR spectra of their corresponding monomers, it can be concluded that the ¹H shifts due to ethylenic protons are so characteristic in sign and magnitude as to be useful in thermal stability elucidation. Some qualitative explanations were given on the stability of these polymers as affected by the type and size of the substituent. The x-ray diffractograms of all samples show two rather broad peaks indicative of noncrystalline structures. The location of the peaks does not depend upon preparation conditions and temperature. Poly(N-maleimide)s of fluoroanilines have not been hitherto described.     

Synthesis of Conformationally Restricted Carbocyclic Nucleosides: The Role of the O(4′)-Atom in the Key Hydration Step of Adenosine Deaminase

Conformationally restricted carbocyclic nucleosides with either a northern(N)-type conformation, i.e., N-type 2′-deoxy-methanocarba-adenosine 8 ((N)MCdAdo), or a southern(S)-type conformation, i.e. S-type 2′-deoxy-methanocarba-adenosine 9 , ((S)MCdAdo), were used as substrates for adenosine deaminase (ADA) to assess the enzyme's preference for a fixed conformation relative to the flexible conformation represented by the carbocyclic nucleoside aristeromycin ( 10 ). Further comparison between the rates of deamination of these compounds with those of the two natural substrates adenosine (Ado; 1 ) and 2′-deoxyadenosine (dAdo; 2 ), as well as with that of the conformationally locked nucleoside LNA-Ado ( 11 ), which, like the natural substrates, has a furanose O(4′) atom, helped differentiate between the roles of the O(4′) anomeric effect and sugar conformation in controlling the rates of deamination by ADA. Differences in rates of deamination as large as 10000 can be attributed to the combined effect of the O(4′) atom and the enzyme's preference for an N-type conformation. The hypothesis proposed is that ADA's preference for N-type substrates is not arbitrary; it is rather the direct consequence of the conformationally dependent O(4′) anomeric effect, which is more efficient in N-type conformers in promoting the formation of a covalent hydrate at the active site of the enzyme. The formation of a covalent hydrate at the active site of ADA precedes deamination. A new and efficient synthesis of the important carbobicyclic template 14a , a useful intermediate for the synthesis of (N)MCdAdo ( 8 ) and other conformationally restricted nucleosides, is also reported.     

Nucleotides. Part LXXII

The synthesis of various N‐methylated nucleosides (m⁶A, m³C, m⁴C, m³U) is described. These minor nucleosides can be obtained by simple methylation with diazomethane of [2‐(4‐nitrophenyl)ethoxy]carbonyl(npeoc)‐protected nucleosides. These methylated compounds are easily further derivatized to fit into the scheme of the [2‐(dansyl)ethoxy]carbonyl (dnseoc) approach for RNA synthesis (dansyl=[5‐(dimethylamino)naphthalen‐1‐yl]sulfonyl). Various oligoribonucleotides containing N⁶‐methyladenosine were synthesized, underlining the usefulness of the dnseoc approach, especially for the synthesis of natural tRNA‐derived oligoribonucleotide sequences.     

Synthesis and characterization of new poly(N-1-adamantylmaleimide) and poly(N-1-diamantylmaleimide)

N-l-Diamantylmaleimide was synthesized by reaction of maleic anhydride with 1-aminodiamantane, followed by dehydration with acetic anhydride and sodium acetate. Poly(N-1-adamantylmaleimide) ( IIa ) and poly(N-l-diamantylmaleimide) ( IIb ) were polymerized using 2,2′-azobisisobutyronitrile (AIBN) as an initiator under different experimental conditions such as various initiator concentrations, solvents, polymerization temperatures, and polymerization times. Polymerizations of N-l-adamantylmaleimide in benzene at 60°C or in bulk gave polymers with molecular weights (2000–9500). The experimental results indicated that the propagation may be interrupted by steric hindrance of bulky and rigid substituents such as the adamantyl or diamantyl groups. In addition, the effect of chain transfer to monomer contributes to the relatively low activation energy. The glass transition temperatures of Ia and Ib were 204 and 216°C, respectively. The temperatures at 5% weight loss of the polymers IIa and IIb were above 412°C. © 1996 John Wiley & Sons, Inc.     

Reaction of N-(2-pyridylmethyl)-3,5-dimethylbenzamide and N-(3-pyridylmethyl)-3,5-dimethylbenzamide N-oxides with acetic anhydride

As a continuation of our work on the reaction of N-pyridylmethyl-3,5-dimethylbenzamide N-oxides with acetic anhydride, we now report a study of the reaction of N-(2-pyridylmethyl)-3,5-dimethylbenzam.de N-oxide ( 5 ) and N-(3-pyridylmethyl)-3,5-dimethylbenzamide N-oxide ( 6 ) with acetic anhydride. Compound 5 gave N,N′-di(3,5.dimethylbenzoyl)-1,2-di(2.pyridyl)ethenediamine ( 7 ) and 3,5-dimethylbenzamtde ( 8 ). Compound 6 afforded three products formulated as 2-acetoxy-3-(3,5-dimethylbenzoylaminomethyl)pyridine ( 12 ), 3-(3,5-dimethylbenzoylaminomethyl)-2-pyridone ( 13 ) and 5-(3,5-dimethylbenzoylaminomethyl)-2-pyridone ( 14 ). Analytical and spectral data are presented which support the structures proposed.     

Potassium Tellurocyanate Mediated Coupling Reactions of N-(1-Chloroethylidene)Arylamines

Abstract

The reaction of potassium tellurocyanate (prepared in situ) with N-(1-chloroethylidene)arylamines (i.e., 4-RC₆H₄N = C(CH₃)Cl, where R = H, Cl, CH₃ and NO₂) in DMSO solution gave unexpectedly, after hydrolysis, the corresponding N-(3-(arylamino)butan-2-ylidene)arylamines in 63–78%. Reaction of N-(3-(arylamino)butan-2-ylidene)arylamines with SOCl₂ or with Br₂ resulted in the substitution of a halogen on the aromatic rings. The presence of a water molecule within the structure of the synthesized diimines was rationalized theoretically by Density Functional Theory (DFT). All compounds were characterized by elemental analysis, IR, NMR and mass spectroscopic data.     

Synthesis and Properties of N-(2,2,2-Trichloroethylidene)- and N-(2,2,2-Trichloroethyl)nitrobenzenesulfonamides

Highly reactive N-(2,2,2-trichloroethylidene)nitrobenzenesulfonamides were synthesized by reaction of N,N-dichloronitrobenzenesulfonamides with trichloroethylene. Reactions of N-(2,2,2-trichloroethylidene)nitrobenzenesulfonamides with oxygen and nitrogen nucleophiles gave products of addition at the double CÍN bond; with arenes and haloarenes, the corresponding C-amidoalkylation products were obtained.     

Oxidation of N-(1-Hydroxypolychloroethyl)sulfonamides

N-(2,2,2-Trichloro-1-hydroxyethyl)- and N-(2,2-dichloro-1-hydroxy-2-phenylethyl)arenesulfonamides are oxidized with chromium(VI) oxide to give, respectively, N-(arylsulfonyl)trichloroacetamides and N-(arylsulfonyl)dichloro(phenyl)acetamides. Under analogous conditions N-(2,2,2-trichloro-1-hydroxyethyl)trifluoromethanesulfonamide is converted into 1,1,1-trichloro-2,2-bis(trifluoromethylsulfonylamino)ethane.     

Elektronenstossinduzierte Cyclisierung Durch Nachbargruppenwechselwirkung bei N-(O-Nitrobenzyl)-Aminen

Electron-impact-induced oxygen transfer plays only a minor part in the fragmentation of N-(o-nitrobenzyl) amines. By investigation of ²H-labelled compounds, it could be established that the most important ions are formed by neighbouring group participation which leads to cyclisation of the fragment ions.     

Synthèse de N-2 alkyl (aryl) dioxo-3,5 oxadiazolidine-1,2,4

The synthesis of new 3,5 dioxo-1,2,4 oxadiazolidines whixh are N-2 substituted bioisosters of biologically active carboxylic compounds was studies. Nitro compounds were used as starting materials, and triton B as the cyclizing base. The expected N-2 allyl and aryl substituted derivatives were obtained in satisfactory yields.     

A tandem mass spectrometric investigation of N-(3-ferrocenyl-2-naphthoyl) dipeptide ethyl esters and N-(6-ferrocenyl-2-naphthoyl) dipeptide ethyl esters

N‐(3‐Ferrocenyl‐2‐naphthoyl) dipeptide ethyl esters 1–4 and N‐(6‐ferrocenyl‐2‐naphthoyl) dipeptide ethyl esters 5–8 were prepared by coupling either 3‐ferrocenylnaphthalene‐2‐carboxylic acid or 6‐ferrocenylnaphthalene‐2‐carboxylic acid to the dipeptide ethyl esters GlyGly(OEt) (1, 5), AlaGly(OEt) (2, 6), GlyPhe(OEt) (3, 7) and GlyLeu(OEt) (4, 8), using the standard N‐(3‐dimethylaminopropyl)‐N'‐ethylcarbodiimide hydrochloride, 1‐hydroxybenzotriazole protocol. Electrospray ionization mass spectrometry (ESI‐MS) and laser desorption ionization mass spectrometry (LDI‐MS) were employed in conjunction with tandem mass spectrometry in the analysis of N‐(3‐ferrocenyl‐2‐naphthoyl) dipeptide ethyl esters 1–4 and N‐(6‐ferrocenyl‐2‐naphthoyl) dipeptide ethyl esters 5–8. Radical cations, [M]^+? and [M + H]⁺ species were both observed in the mass spectra. Intense sodium [M + Na]⁺ and potassium [M + K]⁺ adducts were also present. An important diagnostic ion at m/z [M–65]⁺ was observed in both the MS and MS/MS spectra of the N‐(3‐ferrocenyl‐2‐naphthoyl) dipeptide derivatives. Sequence‐specific ions were generally not observed in the MS/MS spectra of the N‐(3‐ferrocenyl‐2‐naphthoyl) series due to formation of the diagnostic [M–65]⁺ ion. Sequence‐specific ions were observed in the MS/MS spectra of the N‐(6‐ferrocenyl‐2‐naphthoyl) dipeptide esters with charge retention on the derivatized N‐terminal of the dipeptide. Both series of compounds could be successfully analyzed by MALDI without the use of a matrix (LDI). Copyright © 2011 John Wiley & Sons, Ltd.     

Physical and chemical properties of N-(2-hydroxyethyl)alkylamines

Physical and chemical properties of N-(2-hydroxyethyl)alkylamines were studied, isotherms of a surface tension of homologous series of these compounds on a liquid-gas interface in water and hydrochloric acid were obtained.