Nitrogen Atoms In Compounds Research Articles

Synthesis, Characterization and biological ,antioxidant activity of Some New Heterocyclic Compoundsusing Mesalazin Drug Derivatives

In this research work new heterocyclic derivatives containing triazolidine have been prepared. The most available (mesalazine) has been used with benzaldehyde to get the starting material to prepare the alkyl triazolidine. All the synthesized compounds have been identified using FT-IR and 1H-NMR spectrum. (Scheme 1) shows that, from simple and available material mesalazine with benzaldehyde in basic media compound (H1) containing Schiff base prepared. A ring closer reaction has been made to compound W using ethylene glycol and hydrazine to get (H2) compound. The nitrogen atom of compound (H2) also alkylated by chloroacetic acid to give (H4) compound then H4 compound reacted with thionyl chloride to get acetyl chloride (H5compound). Compound H5 treated with amino acid (glycine) to get (H6) compound. (H7) Compound has been synthesis by reacting (H6) compound with aromatic aldehyde in the presence of acetic anhydride to get Oxazole ring (H7 compound). Also, (H2) compound reacted with malic anhydride to prepare triazolidine diacetic acid derivative H3 compound. These synthesized compounds had also been assessed by (DPPH) method, the compounds (H1-H7) evaluated for their antimicrobial activity and antioxidant activity, the compounds have strong antioxidant activity comparable to that of the well known (ascorbic acid) (IC50=31.95 μg/mL) used.

Chemoselective Detection of 2,4,6‐trinitrophenol by Ground State Adduct Formation via Protonation of Quinoline Moiety of Non‐heme Ligands with Structural Evidence

AbstractFour quinoline based non‐heme tetradendate ligands viz. N,N′‐di(quinolin‐8‐yl)ethane‐1,2‐diamine (BQENH2) 1, N,N′‐di(quinolin‐8‐yl)propane‐1,3‐diamine 2 (BQPNH2), N,N′‐di(quinolin‐8‐yl)butane‐1,4‐diamine (BQEBNH2) 3 and N,N′‐di(quinolin‐8‐yl)hexane‐1,6‐diamine (BQEHNH2) 4 are structurally characterized and used in selective detection of 2,4,6‐trinitrophenol (TNP) with high quenching constants. The plausible reaction mechanism involves ground state protonation of quinoline nitrogen atoms in compounds 1–4 by TNP with formation of picrate adducts (1 a‐4 a). The protonation of 1–4 is confirmed by infrared, 1H‐NMR spectroscopies, powder XRD and the single crystal structure analysis of 1 a and 4 a. Crystal structures further infer that after protonation, 1 a and 4 a are stabilized by intramolecular hydrogen bonding.

A Zn(II)‐Containing Coordination Polymer: Synthesis, Crystal Structure and pH Fluorescent Sensing

AbstractIn this work, a Zn(II)‐containing coordination polymer, [Zn2(2,4′‐tmbpt)2(o‐bdc)2]·5H2O (1) [2,4′‐tmbpt = 1‐((1H‐1,2,4‐triazol‐1‐yl)methyl)‐3‐(4‐pyridyl)‐5‐(2‐pyridyl)‐1,2,4‐triazole and o‐H2bdc = 1,2‐benzenedicarboxylic acid] has been synthesized hydrothermally. The structure of the compound has been characterized by single crystal X‐ray crystallography, elemental analysis, infrared spectra, thermogravimetric analysis and powder X‐ray diffraction analysis. Compound 1 features a 2D layer structure formed by the cross‐link of the wave‐like chains and helical chains. Because the uncoordinated nitrogen atoms in compound 1 can bind H+, the luminescent spectra of compound 1 in aqueous solutions of different pH from 1 to 7 have been investigated. The result indicates that this compound can be used as a sensitive and efficient pH fluorescent sensor, which can be further used for the design of molecular logic gate in the narrow pH range of 2–3. The pH response mechanism of compound 1 may be the disturbance of the conjugated system resulting from the protonation of the 2,4′‐tmbpt ligand in the compound, which has been proved by the UV‐vis absorption spectra and density functional theory (DFT) calculation.

Spectral properties of protonated naphthylpyridine in the presence of cyclodexrins

Electronic absorption and fluorescence spectroscopy showed that the addition of 2-hydroxypropyl cyclodextrin derivatives (HP-α-CD, HP-β-CD, and HP-γ-CD) to an aqueous solution of 4-(2-naphthyl)pyridinium perchlorate (2) results in its partial deprotonation and formation of an inclusion complex of 4-(2-naphthyl)pyridine (1) with the cavitand. The stoichiometry and stability of the inclusion complexes of compounds 1 and 2 and 1-methyl-4-(2-naphthyl)-pyridinium perchlorate (3) with cyclodextrins and their hydroxypropyl derivatives (logK = = 1.5–2.7) were studied by 1H NMR titration. Cyclodextrins with the neutral form 1 form more stable complexes than with ionic compounds 2 and 3. The protonation of the nitrogen atom of compound 2 in aqueous solutions can occur in both the ground and excited states, and the fluorescence spectrum exhibits only the band of the protonated form. Quantum chemical simulation of the deprotonation/protonation processes in an aqueous solution of compound 2 in the absence and presence of HP-β-CD was performed. A tendency for shifting the acid-base equilibrium towards the formation of deprotonated form 1 is observed upon the addition of 2-hydroxypropyl cyclodextrin derivatives to the solution.

Spectroscopic characterization and Ab initio calculations of new diazaphosphole and diazaphosphorinane

Phosphoryl chloride is used as a starting material to synthesize new diazaphosphole, Open image in new window (1) and diazaphosphorinane, Open image in new window (2). The products are characterized by 1H, 13C, 31P NMR, and IR spectroscopy. A high value 2J(PNH) = 17.0 Hz, 17.2 Hz is measured for two non-equivalent NH protons of endocyclic nitrogen atoms in compound 1, while it greatly decreases to 4.5 Hz in 2. Also, great amounts are obtained for two 2J(P,C) as well as two 3J(P,C) in the 13C NMR spectrum of 1, but they are zero in 2. Here, the effect of ring strain and ring size on the structural and spectroscopic parameters is observed. The 31P NMR spectra reveal that δ(31P) of compound 1 is far much more downfield (12.63 ppm) relative to that of compound 2 (−10.39 ppm). Furthermore, ab initio quantum chemical calculations are performed to optimize the structures of these molecules by density functional theory (B3LYP) and Hartree-Fock (HF) methods, using the standard 6−31+G** basis set. The stabilization energies are calculated by the equation ΔEstabilization = Emolecule − ΣEi, where i = atom. To obtain the atomic hybridizations, NBO computations are made at the B3LYP/6−31+G** level. Also, by NMR calculations the 1H, 13C, 31P chemical shifts are obtained and compared with the experimental ones.

Synthesis, Structure and Magnetic Differences of Two a-Nitronyl Nitroxide Isomers

The two isomeric organic nitronyl nitroxide free radicals 2-(2'-hydroxyl-3'-methoxy-phenyl)-4, 4, 5, 5-tetramethyl-4, 5-dihy- dro-1H-imidazoyl-1-oxyl-3-oxide, 1, and 2-(3'-hydroxyl-4'-methoxy- phenyl)-4, 4, 5, 5-tetramethyl-4, 5-dihydro-1H-imidazoyl-1-oxyl-3- oxide, 2, have been synthesized and their structures determined by X-ray diffraction. Structure 1 has three dimensional, strong, intra- molecular hydrogen bonds in addition to intermolecular interactions favoring sheets. The structure of radical 2 also shows strong hydrogen bonds both intra- and intermolecular. Some of these bonds are with a lattice water molecule, yielding a three-dimensional crystal structure. An important structural difference between both radicals is that in compound 1, one of the nitrogen atoms of the radical shows smaller angles than the other atom in the same radical and than both nitrogen atoms in compound 2. This suggests that in 1, one of the nitrogen atoms has a higher sp 3 character than the other. This proposal is sup- ported by the N-O bond length which is significantly longer in the sp 3 nitrogen side. Both isomers show quite different magnetic behavior. In 1 there are both ferromagnetic (JF/k = + 0.11 ± 0.01 K) and anti- ferromagnetic (JAF/k = - 0.81 ± 0.10 K) interactions, whereas 2 only shows antiferromagnetism (JAF/k = - 1.60 ± 0.02 K) with a phase transition at Tc = 2.48 K.

New 1,3,2-diazaphosphorinanes; synthesis, spectroscopic characterization, X-ray crystallography andab initiocalculations

Using phosphoryl chloride as a starting material, new 1,3,2-diazaphosphorinanes with formula (1 – 6) where [X[dbnd]F (1), Cl (2), Br (3), I (4), OCH3 (5); Y[dbnd]CH3] and [X[dbnd]OCH3, Y[dbnd]H (6)] were synthesized and characterized by 1H, 13C, 31P NMR, IR spectroscopy and elemental analysis. The structures of compounds 1, 2, 5 and 6 have been determined by X-ray crystallography. Compound 1 exists as two symmetrically independent molecules in the crystalline lattice. The endocyclic nitrogen atoms in compounds 1, 1′ and 6 are very close to planar, but in 2 and 5 are distorted from planarity. These structures form two-dimensional polymeric chains through [sbnd]P[dbnd]O…H[sbnd]N[sbnd] hydrogen bonds. 1H NMR spectra of compounds 1 – 5 indicate high value 3 J(PNCH) coupling constants about 25.0 Hz which is related to H equatorial with P[sbnd]N[sbnd]C[sbnd]H torsion angle near to 180° obtained from X-ray crystallography. Ab initio quantum chemical calculations were performed with Gaussian 98 program at HF leve...

Phosphorus–nitrogen compounds. spiro- and crypta-phosphazene derivatives: synthesis and spectral investigations. Structure of butane- N, N′-bis(1,4-oxybenzyl)- spiro(propane-1,3-diamino)tetrachlorocyclo-2λ 5, 4λ 5, 6λ 5-triphosphazatriene. Part VII

The condensation reactions between trimer, N 3P 3Cl 6, and diamines, 2 and 4 and {1-{ N-[1-(2-hydroxynaphthylmethyl)aminomethylidene]}-2(1H)-naphthalenone, 3, yielded the new spiro-cyclic- ( 5 and 8) and the novel spiro-phosphazene ( 7) derivatives, respectively. The fully substituted phosphazene ( 6) was also obtained from the reaction of 5 with the excess of pyrrolidine. Compounds ( 4– 8) have been characterized by elemental analyses, FTIR, 1H-, 13C-, 31P-NMR, HETCOR, COSY and MS. The structure of crypta-phosphazene, 8, has been examined crystallographically. Compound 8 is the first example of the crypta-phosphazene derivatives. The 31P-NMR spectra of compounds 7 and 8 indicate that, both of the compounds have anisochronism because of the stereogenic centers. The pyramidal geometry of two spiro-cyclic nitrogen atoms in compound 8, gives rise to stereogenic property. The sums of the bond angles around N 4 and N 5 nitrogens are 350.6(2) and 349.6(3)°, respectively. Compound 8 crystallizes in the triclinic space group P 1 with a=8.798(3), b=10.498(3) and c=15.689(4) Å; α=91.35(2), β=103.39(4) and γ=102.88(4)°; V=1369.9(7) Å 3, Z=2 and D x=1.491 g cm −3. It consists of a non-centrosymmetric, non-planar phosphazene ring with a bulky dibenzo-diazacrown etheric side group.

Phosphorus?nitrogen compounds. spiro- and crypta-phosphazene derivatives: synthesis and spectral investigations. Structure of butane-N,N$prime;-bis(1,4-oxybenzyl)-spiro(propane-1,3-diamino)tetrachlorocyclo-2$lambda;5, 4$lambda;5, 6$lambda;5-triphosphazatriene. Part VII

The condensation reactions between trimer, N3P3Cl6, and diamines, 2 and 4 and {1-{N-[1-(2-hydroxynaphthylmethyl)aminomethylidene]}-2(1H)-naphthalenone, 3, yielded the new spiro-cyclic- (5 and 8) and the novel spiro-phosphazene (7) derivatives, respectively. The fully substituted phosphazene (6) was also obtained from the reaction of 5 with the excess of pyrrolidine. Compounds (4–8) have been characterized by elemental analyses, FTIR, 1H-, 13C-, 31P-NMR, HETCOR, COSY and MS. The structure of crypta-phosphazene, 8, has been examined crystallographically. Compound 8 is the first example of the crypta-phosphazene derivatives. The 31P-NMR spectra of compounds 7 and 8 indicate that, both of the compounds have anisochronism because of the stereogenic centers. The pyramidal geometry of two spiro-cyclic nitrogen atoms in compound 8, gives rise to stereogenic property. The sums of the bond angles around N4 and N5 nitrogens are 350.6(2) and 349.6(3)°, respectively. Compound 8 crystallizes in the triclinic space group P1 with a=8.798(3), b=10.498(3) and c=15.689(4) Å; α=91.35(2), β=103.39(4) and γ=102.88(4)°; V=1369.9(7) Å3, Z=2 and Dx=1.491gcm−3. It consists of a non-centrosymmetric, non-planar phosphazene ring with a bulky dibenzo-diazacrown etheric side group.

Synthesis of 2-imidazolidinylidene propanedinitrile derivatives as stimulators of gastrointestinal motility—III

Recently, we reported that a ranitidine derivative 2 (fumarate: KW-5092), which had a 2-imidazolidinylidene propanedinitrile moiety (A), showed potent gastrointestinal motility enhancing activity. We have also found that introduction of substituents such as benzyl or 4-fluorobenzyl (i.e., giving 3 or 4) at the N-3 position of the moiety (A) significantly increased this activity. In this study, novel 2-imidazolidinylidene propanedinitrile derivatives possessing a thioether 5–15 were prepared and evaluated for in vitro assays; acetylcholinesterase (AChE) inhibitory activity and potentiating action on electrically induced contractions of guinea pig ileum. Compound 5, in which a nitrogen atom of compound 2 was replaced by a sulfur atom, was more potent than 2 in these tests. Also, in a series of thioether derivatives, introduction of substituents at the N-3 position of the 2-imidazolidinylidene propanedinitrile moiety markedly influenced both activities. In particular, compounds 12 and 13, which showed an excellent potency during in vitro study (AChE IC 50 = 3.6 and 2.7 nM; ES. EC 30 = 2.1 and 2.5 nM, respectively), were found to be more active in the enhancement of gastrointestinal motility in anesthetized rabbits than their corresponding parent compounds 3 and 4, respectively. In addition, compounds 12 and 13 showed lower affinity for the histamine H 2-receptor than ranitidine. Therefore, these compounds may be potent and selective stimulators of gastrointestinal motility.

Relative basicities of nitrogen atoms in compounds of the 2-aminopyridine and 1-alkyl-2(1H)-pyridonimine types

1. It has been shown, by comparisons of the absorption spectra of compounds of the 2-aminopyridine series and the 2(1H)-pyridonimine series in various media, that the salt-forming center in bases of the first type is to be found at the ring nitrogen atom, whereas in bases of the second type it is to be found at the side-chain nitrogen. 2. When substituted 2(1H)-pyridonimizes are dissolved in dilute acid or in alcohol (or water [5]_. they assume structure of the 2-aminopyridium salt type.