Nitrogen bridgehead compounds. 44. New antiallergic 4H-pyrido[1,2-a]pyrimidin-4-ones. 4

Abstract

The weak antiallergic activity of 6-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-3-carbox yli c acid (1) in the rat reaginic passive cutaneous anaphylaxis test was enhanced by the introduction of an (arylamino)methylene moiety into position 9 of the pyridopyrimidine ring. Compound 34, (+)-6(S)-methyl-9-[(m-methylphenyl)-hydrazono]-4-oxo-4H-pyrido[1,2 -a] pyrimidine-3-carboxylic acid, displayed about 10 000 times the activity of the starting compound 1. A structure-activity relationship study of 9-[(arylamino)methylene]tetrahydropyridopyrimidine-3-carb ox ylic acids resulted in conclusions similar to those found for the 9-(arylhydrazono)tetrahydro-and 9-(arylamino)dihydropyridopyrimidine series. Replacement of the 3-carboxy group of 9-(phenylhydrazono)-tetrahydropyridopyrimidin-4-ones with an acrylic acid moiety caused slight increases in potency. In the 6-methyl-substituted series, a high stereospecificity was observed between the enantiomers with 6S and 6R absolute configurations, the former being responsible for the antiallergic activity. The effects of some 9-[(arylamino)-methylene]tetrahydropyridopyrimidine-3-car box ylic acids on the rat passive peritoneal anaphylaxis test were also investigated.

Synthesis and Preliminary Antimicrobial Activity of New Schiff Bases of Pyrido [1,2-A] Pyrimidine Derivatives with Certain Amino Acids

“…It was reported that such tautomeric forms were observed in the synthesis of compounds 1a and 1b [22]. This situation was also previously observed for synthesis of pyridopyrimidine derivatives [23][24][25][26]. For compounds 1-6, there are even further tautomeric forms that are formed between C 2 -C 4 and at C 3 and the imine formed with the amino acids (scheme 2).…”

A Green Synthesis of 7‐amino‐5‐(4‐aroyl)‐1,3‐dimethyl‐2,4‐dioxo‐1,2,3,4,5,8‐hexahydropyrido[2,3‐d]pyrimidine‐6‐carbonitrile Derivatives by a One‐pot Three‐component Reaction

“…Recently, the pyrido[2,3‐ d ]pyrimidine derivatives have received considerable attention because of their biological and pharmacological activities such as anti‐AIDS , antifungal , antileishmanial , tuberculostatic , antimicrobial , antitumor , tyrosin ekinase , anti‐inflammatory , antiallergic , analgesic , antibronchitic , hepatoprotective , antihypertensive , calcium channel antagonists , and antibacterial .…”

Electrocatalytic multicomponent assembling of aminouracils, aldehydes and malononitrile: An efficient approach to 7-amino-pyrido[2,3-d]pyrimidine-6-carbonitrile derivatives

“…Uracil and its derivatives, such as pyrido [2,3-d]pyrimidines, have received considerable attention over the past years because of their biological activities, such as dihydrofolate reductase inhibiting, 1 antibacterial, 2 antiallergic, 3 antimicrobial, 4 tyrosine kinase inhibiting, 5 anti-inflammatory, 6 analgesic, 7 calcium channel antagonists, 8 antihypertensive, 9 antitubercular, 10 antileishmanial 11 and antifungal. 12 Several synthetic methodologies for the synthesis of 7-aminopyrido[2,3-d]pyrimidine-6-carbonitrile derivatives have been reported.…”