Santiago Romano

A new synthesis of 1,1-diphenyl-3-arylisoquinolin-4-ones by the novel cyclization of 2-azabuta-1,3-dienes.

Abstract The facile synthesis of novel 1,1-diphenyl 3-arylisoquinolin-4-ones by the cyclization of protonated 2-azabuta-1,3-dienes is reported.

The novel photochemical 1,4-addition of azadienol esters to cyclo-octa-1,3-diene

Abstract The unprecedented photocycloaddition of azadienol esters to cyclo-octa-1,3-diene (COD) yields cis- and trans-isomers of 4-aryl-2,2,5-triphenyl-5-(4′-aroyl-cis-cyclo-oct-2′-enyl)-2,5-dihydro-oxazole derivatives. The cycloaddition could arise by COD-trapping of an intermediate produced by intramolecular electron transfer in the azadienol ester.

Reaction of anions from monoimines of benzil with alkylating agents. Photochemical reactivity of some 4-alkoxy-2-aza-1,3-dienes

The reaction of benzil benzhydrylmonoimine 6a with methyl iodide or dimethyl sulphate as the electrophile affords 4-alkoxy-2-aza-1,3-dienes resulting from an O-alkylation. When benzyl chloride is employed, products of O-alkylation, C-alkylation and cyclization are produced, while with toluene-p-sulphonyl chloride only cyclization to a dihydro-oxazole takes place. Benzil α-phenylethylmonoimine 6b yields only products of C- and/or O-alkylation. In one case, when a large excess of dimethyl sulphate is used, cyclization affords N-methyl-2,3,5-triphenylpyrrole. Irradiation of the O-alkylated compounds (E)- and (Z)-4-methoxy-1,1,3,4-tetraphenyl-2-azabuta-1,3-diene and (E)-4-benzyloxy-1,1,3,4-tetraphenyl-2-azabuta,-1,3-diene in the presence of perchloric acid yields isoquinoline derivatives by a photo-Mannich reaction.

Synthesis of 1H-isoindoles by a novel rearrangement of some isoquinolin-4(1H)-ones

The isoquinolinones 8 undergo acid-induced rearrangement to yield the isomeric 1,1-dihydro-3-aroylisoindoles 9 in good yield. The reaction involves hydrolysis of the CN bond to afford a putative intermediate amino diketone 10. Cyclization within this is controlled by two factors (i) the stability of the CN group in the starting material and product and (ii) the relative reactivity of the two carbonyl groups.

A synthesis of isoquinolinones by the photochemical cyclization of 2-azabuta-1,3-dienes in the presence of acids

A study of the photochemical reactions of a series of 2-azabuta-1,3-dienes in the presence of perchloric acid or boron trifluoride–diethyl ether is reported. The photochemical reaction affords cyclization of all of the dienes to yield novel isoquinolinone derivatives. The reaction is interpreted as involving protonation, or complexation of the nitrogen lone pair. This prevents an electron transfer reaction which has been reported to yield novel dihydro-oxazole derivatives. Instead a photochemical Mannich reaction results in cyclization with the production of the isoquinolinone skeleton.