Cyclic Diamines Research Articles

Studies of the protonation in aqueous solution of 1-thia-4,7-diazacyclononane, 1-thia-4,8-diazacyclodecane and 5-thia-2,8-diazanonane

The acid–base properties of 1-thia-4,7-diazacyclononane, 1-thia-4,8-diazacyclodecane and of 5-thia-2,8-diazanonane have been investigated in aqueous solution (25 °C, 0.1 mol dm–3 KNO3) by pH potentiometry, adiabatic calorimetry and 1H NMR spectroscopy. The cyclic diamines show a less effective solvation by water in the first protonation step with respect to the open-chain diamine. The presence of an internal hydrogen bond in the first protonation step of 1-thia-4,8-diazacyclodecane is evidenced.

Potentiometric, calorimetric and nuclear magnetic resonance studies of the protonation in aqueous solution of 1-thia-4,7-diazacyclononane- N, N′-diacetic acid, 1-thia-4,8-diazacyclodecane- N, N′-diacetic acid and related open-chain diaminocarboxylic acids

The acid-base properties in aqueous solution of 1-thia-4,7-diazacyclononane - N, N′-diacetic acid (TNODA) and 1-thia-4,8-diazacyclodecane- N, N′-diacetic acid (TDEDA) have been investigated in 0.1 mol dm −3 KNO 3 at 25°C. The protonation constants were determined by conventional pH potentiometry. The protonation enthalpy changes were obtained by adiabatic calorimetry. The corresponding entropy changes were calculated. For TNODA: log K H 1 = 11.63, log K H 2 = 4.05, log K H 3 = 1.8; Δ H° 1 = −41.4 kJ mol −1, Δ H° 2 = −0.5 kJ mol −1, Δ H° 3 = 4.2 kJ mol −1; Δ S° 1 = 83.5 J mol −1 K −1, Δ S° 2 = 75.8 J mol −1 K −1, Δ S° 3 = 48.5 J mol −1 K −1. For TDEDA: log K H 1 = 12.9, log K H 2 = 3.95, log K H 3 = 2.0; Δ H° 2 = 0.2 kJ mol −1, Δ H° 3 = 3.2 kJ mol −1; Δ S° 2 = 76.2 J mol −1 K −1, Δ S° 3 = 50 J mol −1 K −1. The protonation sequence of the cyclic diaminocarboxylates was established by 1H NMR spectroscopy. The results indicate that the first proton is added to a tertiary amino group, whereas the second and the third are added to the two carboxylate groups. The second amino group of TDEDA is only protonated in strong acid medium. Reduced solvation of the cyclic diaminocarboxylates as compared with their open-chain counterparts explains the increase in basicity at the first protonation step upon acetate substitution on the second amino group of the parent cyclic diamines. The acid-base properties of the open-chain diaminocarboxylates 2,5-diazahexane- N, N′-diacetic acid and 5-thia-2,8-diazanonene- N, N′-diacetic acid were also investigated under the same experimental conditions for comparison purposes.

Novel ring enlargement of lactams via quinazolinone annelation. A facile route to benzoannelated large-membered cyclic 1,5-diamines

A novel route to benzoannelated large-membered cyclic 1,5-diamines from lactams is described. Thus, n-membered lactams 1 were N-acylated by o-azidobenzoyl chloride 5 to afford the corresponding imides 4. These were treated with tributylphosphine and underwent an intramolecular aza-Wittig reaction to give n-membered ring-fused quinazolinones 2 in 84-96% yield. By reductive cleavage of 2 with BH 3 •THF, (n+4)-membered cyclic diamines 3 were obtained in 52-95% yield

The rate of ethylene polymerization initiated by various chelating tertiary diamine : n‐butyllithium complexes

AbstractThe initial rates of ethylene polymerization initiated by 13 chelating tertiary diamine:n‐butyllithium complexes were determined under a standard set of conditions. Complexes of the cyclic diamines 1,2‐dipyrrolidinoethane, sparteine, and 1,2‐dipiperidinoethane resulted in higher polymerization rates and larger ultimate polymer yields than did complexes of acyclic diamines such as N,N,N′,N′‐tetramethylethylenediamine. The rates of polymerization and also the polymer yields were also strongly affected by the length of the chain segment connecting the two amino groups in the diamine. Two carbon segments were superior to three carbon segments which were better than one or four carbon segments. The decomposition rate of n‐butyllithium was also strongly accelerated by the presence of many of these diamines.

Asymmetric synthesis using chiral piperazines. Part 3. Enantioselective addition of dialkylzincs to aryl aldehydes catalysed by chiral piperazines

The use of chiral piperazines (cyclic diamines) 1 as chiral catalysts for the enantioselective addition of dialkylzincs to aldehydes is described. (2S,5S)-2,5-Dialkyl substituted piperazines 1 catalysed the enantioselective addition of dialkylzincs to aryl aldehydes. It was found that the presence of the dilithium salt of 1 was more effective in producing the corresponding alcohols in high e.e.s (up to 96% e.e.) and that the catalyst 1 with branched carbon chains as the substituents on the piperazine ring was effective for highly enantioselective reaction.

ChemInform Abstract: Synthesis and Structure‐Activity Relationships of New 7‐(3‐(Fluoromethyl)piperazinyl)‐ and ‐(Fluorohomopiperazinyl)quinolone Antibacterials.

AbstractReaction of the 6,7‐difluorodihydroquinolinecarboxylic acids (I) with the cyclic diamines (II) yields the novel piperazinyl‐ or homopiperazinylquinolone antibacterials (III).

Kinetics of Acid-Hydrolysis of Nickel(II) and Copper(II) Compounds With the Cyclic Diamines 1,5-Diazocane and 4,4-Dimethyl-7-(5,5,7-trimethyl-1,4-diazepan-1-Yl)-5-azaheptan-2-ol

The kinetics of acid-promoted hydrolysis reactions of nickel(II) and copper(ll) complexes of the cyclic diamines 1,5-diazocane ( daco ) and 4,4-dimethyl-7-(5,5,7-trimethyl-1,4-diazepan-1-yl)-5-azaheptan-2-ol (pyaz) in NaCl/HCl media ([Cl-] = 2 mol dm-3) are reported. For [Ni( daco )2]2+, beyond small [H+], an acid-limited rate constant of 2.0×10-5 S-l, involving dissociation of the first daco ligand, and for [Cu( daco )2]2+ a similarly acid-limited rate constant of 1.5×10-2 s-l, involving dissociation of the second daco ligand, were measured at 50°C. For [Ni( pyaz )]2+ and [Cu ( pyaz )2+ the rates of the hydrolysis reactions are again acid-limited, effectively independent of acid with rate constant of 1.0×10-2 s-1 for [Ni( pyaz )]2+ while for [Cu( pyaz )]2+ the rate follows the expression kobs , = 6.0×10-2[H+]/(l+4.6[H+]) S-l, both measured at 25°C.

ChemInform Abstract: Thermal Investigation and Stereochemical Studies of Some Cyclic Diamine Complexes of Nickel(II), Zinc(II), and Cadmium(II) in the Solid State.

AbstractThe complexes (I)‐(IV) are prepared from corresponding metal(II) thiocyanates and cyclic diamines in ethanol.

ChemInform Abstract: Host‐Guest Complexation. Part 38. Cryptahemispherands and Their Complexes.

AbstractReaction of the diacid Chloride (I) with the cyclic diamines (II) produces the cyclic diamides (IIIa)‐(IIId) [(IIIb) and (IIIc) are obtained as separable mixture].

Host-guest complexation. 38. Cryptahemispherands and their complexes.

Syntheses and crystal structures are reported for a new class of hosts, their complexes, and their precursors. The cryptahemispherands are composed of molecular modules that are half spherand and half cryptand. They were synthesized by the reactions of diacid chloride and cyclic diamines to produce diamides, reduction of which gave the desired hosts. Cryptahemispherands form a variety of complexes with the alkali metal cations. Crystal structures were determined for the isomeric diamides for the hydroborane complex, and for alkali cation complexes.

Metal complexes of cyclic diamines, dissociation kinetics of bis(1,5-diazacyclo-octane)nickel(II) in acidic and basic solution, and electrochemical studies

The preparation of the planar yellow [Ni([8]aneN 2) 2](ClO 4) 2 is described. The complex dissociates in basic solution, with rate = k OH[NiL][OH −] (L = 1,5-diazacyclo-octane). At 25 °C, k OH = 4.5 x 10 −2 M −1 s −1 and the corresponding activation parameters are ΔH ≠ = 69.2 kJ mol −1 and ΔS 298 ≠ = −38.6 J K −1 mol −1. Acid catalysed dissociation in quite slow even in strongly acidic solutions. The kinetic data in this case can be fitted to the expression K obs = k o + K H[H +], where k o relates to a solvolytic pathway and k H to the acid catalysed pathway. At 60 °C, K o = 2 x 10 −5 s −1 and k H is 2 x 10 −5 M −1 s −1. Possible mechanisms for these reactions are considered. The Ni(II)/Ni(III) redox couple for NiL n+ is irreversible on Pt using MeCN as solvent.

Synthesis of medium-ring bicyclic bridgehead diamines from monocyclic diamines via α-aminoammonium ions

Condensation of 4-chlorobutanal and 5-chloropentanal with six cyclic diamines gave twelve α-aminoammonium salts; cleavage of these with LiAlH 4 gave medium-ring bicyclic diamines.

Synthesis and structural studies of transition metal complexes of cyclic amidines

Cyclic amidines PHZ and MPHZ (shown below) can be viewed as eight-membered cyclic diamines with two of the methylene carbons fused to the benzene rings. Although the axial positions in the bis-complexes of PHZ and MPHZ are open for fifth and sixth coordination, only four-coordinated complexes with copper(II), cobalt(II), nickel(II) and zinc(II) could be prepared. The molecular structures of these compounds and of some palladium(II), platinum(II) and platinum(IV) compounds are explained on the basis of their analytical, spectroscopic, magnetic and conductance data. Thermogravimetric analyses were carried out to explain mode of decomposition. The results show that complexation of cyclic amidines is not only sterically controlled, but factors such as unusual chelate bite angle, multiple chelate ring formation and crystal field stabilization play important role in affecting the stability and coordination number of the complexes.

Complexes of Cellulose with Cyclic Amines and Diamines

Several aromatic amines and one heterocyclic amine were applied to cotton cellulose in an attempt to form hydrogen bonded complexes. The complexes formed with aniline, benzylamine, and furfurylamine were relatively unstable, but that formed with p-phenylenediamine was relatively stable. All samples required pretreatment with ethylamine to form the product. The complexes were characterized by x-ray diffraction techniques in which the distension of the 101 planes was compared to that of the aliphatic amine-cellulose complexes. Similarity was noted between d(101) of cyclic amine- celluloses and of aliphatic amine-celluloses when computed molecular lengths of the amines were similar. A 1:1 ratio of amine to anhydroglucose units in the furfurylamine-cellulose was indicated by thermogravimetric analysis. The p phenyl enediamine-cellulose decomposed between 150 and 300°C and had a 1:2 ratio of diamine to AHG units.

Relations between the Structure and Reactivity of Bis-quinolizidine Derivatives and Other Cyclic Diamines

Relations between the Structure and Reactivity of Bis-quinolizidine Derivatives and Other Cyclic Diamines

INHIBITION AND ENHANCEMENT OF SINGLET OXYGEN (‘Ag) DIMOL CHEMILUMINESCENCE

Abstract— Various nitrogen containing compounds have previously been shown to quench singlet oxygen (10z). When measuring the dimol 1O2 light emission arising from the H2O2/OCI‐ reaction, we found that certain cyclic diamines increase the emission of light, while other amines were inhibitory. This increase of light emission was seen with both 1, 4diazabicyclo[2.2.2]octane and N, N'‐dimethylpi‐perazine but not with acyclic analogues. Sodium azide inhibited both the normal and enhanced light emission. The enhanced light emission shows spectral properties characteristic of lO2 dimol emission.

Interfacial polycondensation. VI. Polyamides based on 4,4′‐sulfonyldibenzoic acid

AbstractThe preparation of eleven soluble polyamides based on 4,4′‐sulfonyldibenzoic acid by interfacial polycondensation with the use of aliphatic and alicyclic diamines is reported. Polymer melt temperatures of those polyamides prepared from aliphatic diamines decreased with increasing chain length and amount of chain branching in the diamine. The usual odd‐even alternation of melting points was noted. Cyclic secondary diamines gave higher‐melting polyamides than straight‐chain diamines, despite the lack of hydrogen bonding. Solubility decreased with increasing melting point, except for the polyamides based on cyclic diamines, which were both soluble and high‐melting. Fiber properties are reported for those polymers which were spun.