Reaction of Ph3P(SCN)2with Further Orthohydroxy Carboxylic Acid Systems, Including Substituted β-Keto Acids: Synthesis of Novel 2-Thio-1,3-oxazines and Their Subsequent Transformation with Amines

Synthesis, structure elucidation, DNA-PK, PI3K, anti-platelet and anti-bacteria activity of linear 5, 6, and 10-substituted-2-morpholino-chromen-oxazine-dione and angular 3, 4, 6-substituted-8-morpholino-chromen-oxazine-2,10-dione

Coumarin, a naturally occurring or synthesised phytochemical, displays a wide range of biological activities. However, chromen-2-ones fused with 1,3-benzoxazine rings is not well documented and there is a gap in the literature which required engaging. The substituted-2-thioxo-chromen-oxazine linear compounds 14a-i and angular compounds 16a-e were synthesised from the reaction of hydroxy-substituted-chromene-carboxylic 10-13 with freshly prepared Ph₃P(SCN)₂. 2-Morpholino-substituted-chromen-oxazine-4,8-dione and 8-morpholino-substituted-chromen-oxazine-2,10-dione 15a-f and 17 were synthesised from the reaction of the corresponding oxazines 14 and 16 with morpholine. PI3K activity was observed for the hydroxy-substituted-chromene-carboxylic acid of which compound 13b showed moderate PI3Kγ (IC₅₀=5.56 μM) and PI3Kα (IC₅₀=14.7 μM) activity. Additionally, 8-morpholino-chromen-oxazine-2,10-dione 17a showed isoform selective PI3Kδ activity with IC₅₀=5.08 μM with non-DNA-PK ≥ 100 μM. Consequently compound 17a can be considered as a selective PI3Kδ inhibitor with non-DNA-PK at compound concentrations ≥100 μM.

Synthesis Characterization and Antibacterial, Antifungal Activity of N-(Benzyl Carbamoyl or Carbamothioyl)-2-hydroxy Substituted Benzamide and 2-Benzyl Amino-Substituted Benzoxazines

New N-(benzyl carbamothioyl)-2-hydroxy substituted benzamides 13, 20, and 21 were synthesized using sodium bicarbonate and benzyl amine with 2-thioxo-substituted-1,3-benzoxazines 6, 10a, b, 11c, and 12a-n. The 2-thioxo-substituted-1,3-oxazines 6, 10a-b, 11d 12a-n, and 26 were converted to the corresponding 2-methylthio-substituted-1,3-oxazines 14a-l and 24 which were then converted to 2-benzyl amino-substituted-benzoxazines 15a-i by refluxing with benzylamine. Products 15a, b, e, f, and g were also synthesized by boiling the corresponding N-(benzyl carbamothioyl)-2-hydroxy substituted benzamides 13a, b, f, l, and m in acetic acid. 2-Oxo-substituted-1,3-benzoxazines 22 and 25 were prepared by treating the corresponding 2-methylthio-substituted-1,3-oxazines 14 and 24 with dilute HCl. The N-(benzyl carbamoyl)-2-hydroxy substituted benzamide 23 was synthesized from the reaction of 2-oxo-substituted-1,3-benzoxazine 22 with benzylamine. The new products were characterized using IR, (1)H, and (13)C NMR in addition to microanalysis. Selected compounds were tested in vitro for antibacterial and antifungi activity and the most active compounds were found to be the 4-(substituted-benzylamino)-2-hydroxy benzoic acids 9a and d (M. chlorophenolicum, MIC 50 and 25 µgm L(-1), resp.), N1, N3-bis (benzyl carbamothioyl)-4,6-dihydroxy-substituted phthalamides 20a and 20c (B. subtilis MIC 12.5, 50 µgm L(-1), resp.) and 21 (M. chlorophenolicum, MIC 50 µgm L(-1)).