Synthesis and Pharmacological Activity of 4-Aryl-1,5-benzo[b]diazepine-2-carboxylic Acid Arylamides
It was reported that 1,5-benzodiazepine derivatives possess antiinflammatory [1] and analgesic [2, 3] activity. This study was aimed at developing pathways for the synthesis of 1,5-benzo[b]diazepine derivatives and characterization of their pharmacological activity. The traditional method of synthesis of 1,5-benzo[b]diazepine derivatives is based on the reaction of o-phenylenediamine with -dicarbonyl compounds. However, 4-aryl2,4-dioxobutanoic acids and their esters interact with o-phenylenediamine in inert solvents only with the formation of 3-phenacylidene-3,4-dihydro-2-quinoxalones [4 – 6]. According to [6], 4-aryl-2,4-dioxobutanoic acid arylamides (I) do not react with o-phenylenediamine in solvents but interact with this agent in the melt with the formation of both quinoxalones and 4-aryl-1,5-benzo[b]diazepin-2-carboxylic acid arylamides (II). Analogous dual reactivity of arylamides I was observed in [7]. The kinetics of reactrions between arylamides (I) and o-phenylenediamine with the formation of only 2-quinoxalones was studied in [8]. In this context, we have studied the reactions of arylamides Ia – If with o-phenylenediamine in aqueous ethanol solutions (see scheme) in a broad range of pH. It was established that these reactions (Method A) at pH 5.8 lead to the formation of the corresponding 4-aryl-1,5-benzo[b]diazepine-2-carboxylic acid arylamides (IIa – IIf) with yields from 82 to 90% (Table 1). The UV spectra of arylamides IIa – IIf exhbit intense bands with max = 260 – 270 nm (log = 4.75 – 4.90). The IR spectra of compounds IIa – IIf (Table 1) contain absorption bands due to NH groups in the region of 3311 – 3348 cm – , the bands of amide carbonyl groups in the region of 1682 – 1691 cm – , and (for compounds IIb, IId – IIf) the bands of ester carbonyls at 1710 – 1718 cm – . The H NMR spectra of compounds IIa, IIc – IIf (Table 1) display the signals from protons of methylene groups at = 3.69 and 3.82 ppm), representing singlets broadened due to inversion of the seven-member cycle. This inversion is analogous to that observed for 1,4-benzodiazepines [9] and 4-methyl-1,2-dihydro-3H-1,5-benzodiazepin-2-one [10]. The presence of an electron-acceptor substituted in ortho position of aromatic ring of the amide fragment (compound IIe) leads to a shift of the amide proton singlet by 2.10 – 2.16 ppm to weaker fields as compared to the case of para-substituted amides (IId, IIf). In contrast to the data of [7], our syntheses using method A showed no influence of the character of substituents in the aroyl or arylamide fragments on the yield of compounds II. It should be noted that the synthesis of benzo [b]diazepines by method A requires strict observation of the time schedule, since an increase in the reaction time leads to accumulation of 2-quinoxalone derivatives in the reaction mixture. Compounds IId and IIf were also obtained via interaction of the corresponding arylamides, Id and If, with o-phenylene-bis-triphenylphosphinimine on heating in toluene (method B). The product yields in this case are reduced to 15 and 27% yields, respectively, because the process of isolation and purification of the target compounds is accompanied by the formation of 2-quinoxalones.
Protonenresonanz-Untersuchungen an siebengliedrigen Ringverbindungen I. Intramolekulare Beweglichkeit von Azepinen und Diazepinen
Die Protonenresonanz-Spektren der ungesattigten Siebenringe 2, 6, 7, 8, 9, 10 und 11 wurden in Abhangigkeit von der Temperatur gemessen. Diese Azepine und Diazepine liegen in der Wannenform vor, die ein rasches Umklappen der Molekule, z. B. von 3 in 4, erlaubt. Die freien Enthalpien ΔG= der Aktivierung dieses Vorgangs wurden zu den sterischen und elektronischen Verhaltnissen in Beziehung gebracht. Der ΔG=-Wert des Dibenzamils (2) ist um 4 kcal/Mol hoher als der des Cycloheptatriens. Auch fur das Azepin 13 wurde ein Umklappen wannenformiger Molekule wahrscheinlich gemacht.
Selective etching of InP in NaF solution
Abstract The crossing porous structure of InP has been obtained by electrochemical etching in NaF solutions. The behavior of the periodic oscillation occurs at different potential ranges for the different concentrations of solutions, and it will disappear with the concentration of the solution decreased. The scanning electron microscope (SEM) image shows that the pores have two directions on the surface and are perpendicular to each other. The two directions are assigned to [0 1 1] and [ 0 1 ¯ 1 ], respectively. The SEM image of the cross-section also shows that the two directions are assigned to [1 1 1]B and [ 1 1 ¯ 1 ¯ ]B. Both are due to the selective etching of F− ions. The crossing porous structure of InP is a very promising feature for the three-dimensional structure of III–V compound semiconductors for photonic band gap materials.