SYNTHESIS OPTIMIZATION OF 6-NITRO-3,4-DIHYDROQUINAZOLINE-4-ONE

A method for the synthesis of the substance 6-nitro-3,4-dihydroquinazolin-4-one has been developed. Quantitative determination of the target product was carried out spectrophotometrically using an SF-46 instrument. As a solvent, 0.1 mol/l HCl was used. A 0.1 mol/l hydrochloric acid solution was used as a comparison solution. The optical density of the standard and test samples was measured at a wavelength of 254 nm. The synthesis conditions of 6-nitro-3,4-dihydro-quinazolin-4-one were studied. The structure of the obtained product was studied by IR, Mass, 1H, 13C NMR spectroscopy, and the structure of the synthesized compound was also established. The main factors that influence the process of producing 6-nitro-3,4-dihydroquinazolin-4-one are identified. The process is optimized by the method of mathematical planning of the experiment. A mathematical model is drawn up. And the regression equation is calculated. A steep ascent along the response surface was carried out and optimal process conditions were found: temperature, time, quantitative ratio of the starting materials. It has been established that the main factor affecting the nitration process of 3,4-dihydroquinazolin-4-one is the temperature of 40 ºC and the reaction time is 4.5 h. Note that at a higher temperature, according to the analysis, a significant amount of dinitro derivative is formed, as a reaction byproduct.

Azo-linked corner porphyrin systems: synthesis, crystal structures and spectroscopic investigation

1,2-bis[10,15-di(3,5-di-tert-butyl)phenylporphyrinatonickel(II)-5-yl]diazene was synthesised via copper-catalyzed coupling of aminated nickel(II) 5,10-diarylporphyrin ("corner porphyrin") and its X-ray crystal structure was determined. Two different crystals yielded different structures, one with the free meso-positions in a trans-like orientation, and the other with a cis-like disposition. The free meso-positions of the obtained dimer have been further functionalized while the synthesis of a zinc analog has so far been unsuccessful. The X-ray crystal structure of the dinitro derivative of the dinickel(II) azoporphyrin was determined, and the structure showed a cis-like disposition of the nitro groups.

Formation of Infinite Grids with Chiral Square Compartments by Self-Assembly of Achiral 1,1'-Biphenyl-2,2',6,6'-tetracarboxylic Acids. Effect of 4,4'-Substitution on the Grid Stacking

The achiral 1,1'-biphenyl-2,2',6,6'-tetracarboxylic acid as well as its 4,4'-dibromo and 4,4'-dinitro derivative self-assemble in crystal under formation of a two-dimensional grid set up from hydrogen-bonded cyclotetrameric compartments which are individually chiral (D4 symmetry). The roughly square cavities (ca 5.6 Å) of individual compartments partly accommodate the perpendicularly oriented benzene rings of the neighbouring grid, in dependence on the nature of the 4,4'-substituents. As a consequence, the grids are stacked in a staggered (nonconcatenated) manner.

NMR Complexation Study of Several Oxyethylated Calix[4]arenes with Lithium, Sodium and Potassium Ions

The influence of calix[4]arene upper rim substitution on the complexation with Li+, Na+, K+ was studied by 1H NMR spectroscopy. Calix[4]arenes 1-4 namely 25,26,27,28-tetrakis(3-oxapentyloxy)calix[4]arene (1), its 5,17-diamino (2) and 5,17-dinitro derivative (3) as well as 25,26,27,28-tetrakis(3,6,9-trioxadecyloxy)calix[4]arene (4) having four monoalkyloligoethylene glycol chains on the lower rim have been studied. No complexation has been observed for Li+. Two electron-donating NH2 groups on the calixarene upper rim (compound 2) improve the complexation ability for Na+ and K+ compared with parent calixarene 1. The electron-withdrawing nitro groups in 3 have the opposite influence. It seems that the complexation of alkali metal ions studied is not significantly influenced by the increasing number of donor atoms (from eight in 1 to sixteen in 4) available for complexation on the lower rim. The position of sodium cation in 1 . Na+ and 4. Na+ is supposed to be in close proximity of phenolic oxygens based on 1H and 13C NMR data. The error analysis is given for the stability constant determination from NMR data.

Electroréduction de dérivés dinitrés aromatiques. III. Rôle du sulfate de titanyle comme médiateur redox

The electrochemical behavior of titanium oxysulfate, used as a redox mediator in the reduction of 4,4′-dinitrodibenzyl, is studied in a 5 N H2SO4/EtOH 50:50 medium. The role played by electrogenerated Ti3+ ions in the chemical reduction of nitro groups is also defined. The results obtained allow the determination of the most suitable conditions leading to selective syntheses. Macroscale electrolyses at a constant potential in the presence of TiOSO4 give 4,4′-diaminodibenzyl with a great purity and a higher yield (93%) than without mediator (75%). The homogeneous chemical reduction of 4,4′-dinitrodibenzyl by first electrogenerating the Ti3+ ions, then adding the organic substrate, is particularly selective. The nature of the reduction products depends on the [Ti3+]/[dinitro derivative] ratio. The 4-amino-4′-nitrodibenzyl is synthesized in a 70% yield for a 6:1 ratio whereas the amount of diamino derivative increases and can constitute the sole reduction product for higher ratios. A comparison is made with 1,5- and 1,8-dinitronaphthalenes and 2,2′-dinitrodiphenyl. Using a 6:1 ratio, 1-amino-8-nitronaphthalene is not obtained while 45% of 1-amino-5-nitronaphthalene and 25% of 2-amino-2′-nitrodiphenyl are formed by reduction of the corresponding dinitro derivatives.

MECHANISM OF GUANIDINE NITRATION: I. AZO-BIS-NITROFORMAMIDINE

Although azo-bis-formamidine dinitrate cannot be converted to the dinitro derivative directly it can be chlorinated in water to azo-bis-chloroformamidine and thence to azo-bis-nitroformamidine in nitric acid and acetic anhydride. When the latter substance is treated with 2-methylpentadiene-1,3 an alkali-soluble compound is obtained which is specified as 1-imino-3-nitrimino-4,6(or 5,7)-dimethyl-2,8,9-triaza-4,6,8,9-tetrahydroindandione-1,3. The characteristics of this reaction indicate that azo-bis-nitroformamidine exists as the nitrimino tautomer. The Diels-Alder reaction with 2-methylpentadiene-1,3 has its counterpart in the similar reaction whereby azo-bis-formamidine is converted to 1,3-diimino-4,6-dimethyl-2,8,9-triaza-4,6,8,9-tetrahydroindandione-1,3mononitrateand ammonium nitrate. The entire sequence of reactions is offered as evidence that the imino group in guanidines is the site of nitration, and its chemistry of nitration is analogous with that of aliphatic secondary amines.

COMPARISON OF THE NITROLYSIS OF 1, 3-DICYCLOHEXYLIMIDAZOLIDINE WITH THAT OF HEXAMETHYLENETETRAMINE

The nitrolysis of N,N′-dicyclohexylimidazolidine has been effected with formation of the nitrate salt, the nitroso derivative, and the aceto derivative of N,N′-dicyclohexyl-N-nitro-1,2-diaminoethane. The absence of the dinitro derivative suggests that demethylolation is not related to nitramine formation. When formaldehyde splits off to leave a weakly basic amine, as in hexamethylenetetramine nitrolysis, then subsequent nitration will occur; but it will not take place if the resulting amine is strongly basic. Nitrolysis will depend also on reactivity of nitric acid, which can be decreased by addition of ammonium nitrate. This decrease will prevent esterification of intermediate N-methylolamines but not nitrolysis of hexamethylenetetramine types. However both nitrolysis and esterification are thus prevented with dicyclohexylimidazolidine. On the other hand the two nitrolyses are related by the fact that both are accelerated by electropositive chlorine.