SOME REACTIONS OF Α-HYDROXY- AND Α- DIMETHYLAMINOFORMYLIDINE – 2,3-POLYMETHYLENE-3,4-DIHYDROQUINAZOLIN-4-ONES

Аннотация

The nitration reactions of 2,3-polymethylene-3,4-dihydroquinazolin-4-one and quinazolines were studied . The reaction conditions for the substitution of hydrogen atoms in positions 6 and 8 of the aromatic ring were shown. It turned out that it is impossible to introduce a second nitro group into the quinazoline ring without using an excess amount of the nitrating mixture (1:4) and under relatively complex conditions (heating to 90-100 0C). The synthesized compounds were studied for the first time and it was found that such organic substances have biological activity. 2,3-Polymethylene-3,4-dihydroquinazolin-4-one was nitrated under special conditions to obtain several different nitro derivatives and their properties (reduction, substitution reactions) were studied. This nitration process was first carried out on three-ring quinazolineand quinazolinerings, and theirproperties were studied. Key words:2,3-polymethylene-3,4-dihydroquinazolin-4-ones, ichinazolines , nitration, amination,transamination ,enamine,acetone cyanohydrin ,bromination. VISIONS Previously [1,3] we studied some electrophilic substitution reactions of 2,3- polymethylene-3,4-dihydroquinazolin-4 – ones . Some of the synthesized compounds have growth-regulating , hypnotic, muscle-relaxing , narcotic action. Therefore, they are of certain practical interest. On the other hand, the presence of several reaction centers (pyridine nitrogen atom, aromatic ring, etc.) make them interesting in chemical terms. Before our research, there are almost no data on nitration reactions of quinazalines in the literature . Therefore, the study ofthesereactions is ofgreat scientific interest. Purposeofthework: To date, there are no data in the literature on the electrophilic substitution of 2,3- polymethylene-3,4-dihydroquinazolin-4-ones. There is only information on the nitration of the simplest representative of the quinazoline series - quinasolone-4 and some of its derivatives. [1] It was therefore of interest to investigate the nitration reactions of 2,3-polymethylene-3,4- dihydroquinazolin-4-ones and quinazolines . For this purpose, we studied [2,3,4,5] the nitration of 2,3-polymethylene-3,4- dihydroquinazolin-4-ones (I-III). The reaction proceeds smoothly when I-III, IV are treated with a nitrating mixture (reagent ratio 1:2.3) and leads to 6-nitro-2,3-polymethylene-3,4- dihydroquinazolin-4-ones (V-XIII). page1697 INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE ISSN:2692-5206,ImpactFactor:12,23 AmericanAcademicpublishers,volume05,issue05,2025 Journal: https://www.academicpublishers.org/journals/index.php/ijai O O O N C 2 C N (CH ) N (CH ) 2 n 2 n C C N N V-VIII I-III, IV IV n=1; IV -VIn=2; X, VII n=3; IV, VIII n=4 Compounds I-III, IV react with a mixture of nitric and sulfuric acids and give V-VIII under mild conditions. However, it is not possible to introduce a second nitro group into the quinazoline ring even when using an excess of the nitrating mixture (1:4.6) and under relatively harsh conditions (heating to90-100 0). The position of the nitro group of 6-nitro-2,3-polymethylene-3,4-dihydroquinazolin-4- ones has been proven by spectral data, their counter synthesis from 5- nitroanthranilic acid, and also by reduction with tin chloride to the corresponding 6-amino-2,3-polymethylene-3,4- dihydroquinazolin-4-ones [XI]. The latter are reduced with zinc in hydrochloric acid at room temperature and yield 6-amino-2,3-polymethylene-3,4-dihydroquinazolines XII. O O O 2 N C N (CH 2 ) n H 2 N C N (CH 2 ) n O 2 N N (CH 2 ) n C C N C N N V XI XII The nitration reaction of 2,3-trimethylene-3,4-dihydroquinazoline (XIII) proceeds differently. When using a 1:1 reagent ratio, a mono nitro product is formed – 6-nitro-2,3- polymethylene-3,4-dihydroquinazoline (XIV), and at 1:2 – 6,8-dinitro-2,3-trimethylene-3,4- dihydroquinazoline(XV). page1698 INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE ISSN:2692-5206,ImpactFactor:12,23 AmericanAcademicpublishers,volume05,issue05,2025 Journal: https://www.academicpublishers.org/journals/index.php/ijai O N 2 O N 2 N N N C C C N N N NO 2 XIII XIV XV The possibility of introducing two nitro groups into the molecule of 2,3-trimethylene- 3,4-dihydroquinazoline is apparently explained by an increase in nucleophilicity benzene ring during the transition from 2,3-trimethylene-3,4-dihydroquinazolone-4 to the corresponding quinazoline , which is associated with the withdrawal of electrons from the aromatic ring by the amidecarbonyl . Reduction of the nitro group of 6'-nitro-2,3-trimethylene-3,4-dihydroquinazoline gives 6'-amino-2,3-trimethylene-3,4-dihydroquinazoline, which is identical to the product obtained from 6'-nitro-2,3-trimethylene-3,4-dihydroquinazolin-4-one. In the mass spectrum of XIV there is an intense peak of the molecular ion with m/e 262(M +), 215(M +-47), 182(M +-80), 169(M +-93), 149(M +-113), 103(M +-159), the relative intensityofwhich is100,25,12,54,10,9%, respectively. In the PMR spectrum of compounds XIV and XV, the met