title: Synthesis and antimicrobial activity of some new pyrimidinone and oxazinone derivatives fused with thiophene rings using 2-chloro-6-ethoxy-4-acetylpyridine as starting material.
abstract: A series of pyridines, pyrimidinones, oxazinones and their derivatives were synthesized as antimicrobial agents using citrazinic acid (2,6-dihydroxyisonicotinic acid) as a starting material. α,β-Unsaturated ketones 3a-c were condensed with cyanothio-acetamide in the presence of ammonium acetate to give 2-cyanopyridinethiones 4a-c, which were reacted with ethyl chloroacetate to yield the corresponding cyano esters 5a-c. The esters 5a-c were cyclized by action of sodium methoxide to aminoesters 6a-c, which were aminolyzed with ammonia to corresponding aminoamide derivatives 7a-c. Also, the esters 6a-c were hydrolyzed with NaOH to the corresponding sodium salt 8a-c, which were treated with acetic anhydride to afford 2-methyloxazinones 9a-c. The latter compounds were treated with ammonium acetate to afford 2-methylpyrimidinones 10a-c, followed by methylation with methyl iodide to yield 2,3-dimethyl-pyrimidinones 11a-c. The antimicrobial screening showed that many of these compounds have good antibacterial and antifungal activities comparable to streptomycin and fusidic acid used as reference drugs.
authors.affiliation: Chemistry Department, Girls College of Science, King Khalid University, Abha 9004, Saudi Arabia. hossanaisha@yahoo.com
authors.forename: Aisha S M
authors.initials: AS
authors.lastname: Hossan
authors.forename: Hanaa M A
authors.initials: HM
authors.lastname: Abu-Melha
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Al-Omar
authors.forename: Abd El-Galil E
authors.initials: Ael-G
authors.lastname: Amr
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D000935:Antifungal Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D005658:Fungi / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006868:Hydrolysis; D007539:Isonicotinic Acids / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D010078:Oxazines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011744:Pyrimidinones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D044366:Transition Temperature
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D007539:Isonicotinic Acids; D010078:Oxazines; D011744:Pyrimidinones; C560098:citrazinic acid