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Microwave (MW) irradiation allows to prepare a mini-library of pyridophenoxazinone derivatives, that are crucial intermediates in the synthesis of new antiproliferative compounds, active for human lymphoma/leukemia. The optimized procedure, consisting of a continuous input power of 50 W (80 °C) and a reaction time of 30 min, leads in very satisfactory yields to both regioisomers 5H-pyrido[2,3-a]phenoxazin-5-ones and isomeric 5H-pyrido[3,2-a]phenoxazin-5-ones, starting from readily available quinoline-5,8-dione and substituted 2-aminophenols (APhOHs). Broad functional group tolerance was observed. The availability of derivatives carrying a carboxyl group at the C-9 and C-10 positions enables the synthesis of a new family of 5H-pyridophenoxazin-5-one conjugates that were shown to exhibit good anti-cancer activity.

A weak alkaline solution of 3-hydroxykynurenine was oxidized using potassium ferricyanide. A stable epr signal was recorded, probably arising from a phenoxazine intermediate. A plausible radical mechanism for this reaction is presented.

A new series of 2-(4- and 3-substituted phenyl)-3-[3-(N,N-dimethylamino) propyl]-1,3-thiazolidin-4-ones were synthesized, characterized, and evaluated for their ability to inhibit the contractions induced by histamine on guinea pig ileum. The measurement of pA2 values suggested that the reported compounds showed H1-antagonism. The more active compounds 5, 9, and 13 exhibited activity close to that of mepyramine.

A set of substituted 1,3,4-triaryl-2-azetidinones were synthesized and characterized. Their antimicrobial activity, against Gram+ and Gram- bacteria and Fungi, was tested. The compounds 23 and 30 showed remarkable activity against Pseudomonas aeruginosa.

A series of hydroxamic acids related to the non-selective matrix metalloproteinase inhibitor Batimastat has been prepared, some members of which are potent inhibitors of the processing of the low affinity IgE receptor (CD 23). Increased activity is obtained by appropriate substitution at the α-position, whilst selectivity is gained by use of a P1′ benzyl group in conjunction with a C-terminal primary amide.

2-(Substituted-phenyl)-3-[3-(N,N-dimethylamino)propyl]-1,3-thiazolidi n-4- ones (1-15) showed dependence of the potency of the H1-histamine antagonism on the m- and p-substituents suggesting that the aromatic moiety binds the receptor by a strong pi-interaction. Electron-withdrawing substituents decrease the potency while the electron-donating alkyl substituents, enhancing the aryl HOMO energy, increase the antihistamine activity. The m-substituents with the capability to form hydrogen bonds, seems to share an extra-interaction with hydrogen accepting or donating groups of the histamine receptor and exhibits very high potency.

The ommochrome pigment present in the eyes of Loligo Vulgaris was extracted with a butanol-acetic acid-hydrochloric acid solution. The extraction mixture was examined before and after irradiation by visible light. A phenoxazinone ring opening together with a photo-induced solvent addition, causing a yellow-red batho-chromic shift, were observed and a plausible explanation of the process has been carried out and is reported on the basis of the isolated products.

The oxidation mixture of 3-hydroxykynurenine (1), treated with aqueous acetic anhydride and, subsequently, with acidic methanol, yields the 1-hydroxy-3-carbomethoxy-5-methoxy-11-(β-aspartoyl-N-acetyl-methyl ester)pyrido[3,2-a]phenoxazine (5), the 1-hydroxy-11-(β-aspartoyl-N-acetyl-methyl ester)-5.H-pyrido[3,2-a]-phenoxazin-5-one (6), the 1-methoxy-11-(β-aspartoyl-N-acetyl-methyl ester)-5H-pyrido[3,2-a]phenoxazin-5-one (6a), the l,5-dimethoxy-11-(β-aspartoyl-N-acetyl-methyl ester)pyrido[3,2-a]phenoxazine (7) and the 1-methyl-1(1′-[11-(β-aspartoyl-methyl esterimino)]ethenyl)ketal-1H,5H-pyrido[3,2-a]phenoxazin-5-one (8). A probable scheme, for the compound formation, is reported.