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The tricyclic-isoxazolidine analogues tetrahydrothiochromenoisoxazoles, hexahydroisoxazolequinolines and tetrahydroisoxazolepyranopyridines were prepared by an intramolecular 1,3-dipolar cycloaddition reaction of a nitrone with an alkene. For N-alkylated hexahydroisoxazolequinolines, reduction of the reaction time from two days to 40 min was achieved using microwave heating. The cyclization to form tetrahydroisoxazolepyranopyridines only proceeded when the alkene was substituted with an electron withdrawing group.

A series of 2-phenyl-3-(1H-pyrrol-2-yl)acrylonitrile derivatives were synthesized and evaluated for in vitro activity against the endoparasite Haemonchus contortus and the ectoparasite Ctenocephalides felis. Some compounds had significant in vitro activity against these parasites.

The tricyclic-isoxazolidine analogues tetrahydrothiochromenoisoxazoles, hexahydroisoxazolequinolines and tetrahydroisoxazolepyranopyridines were prepared by an intramolecular 1,3-dipolar cycloaddition reaction of a nitrone with an alkene. For N-alkylated hexahydroisoxazolequinolines, reduction of the reaction time from two days to 40 min was achieved using microwave heating. The cyclization to form tetrahydroisoxazolepyranopyridines only proceeded when the alkene was substituted with an electron withdrawing group.

N,N-dialkyl-N′-chlorosulfonylchloroformamidines 1 were treated with 2-aminothiazoline, 2-aminothiazoles, 2-aminobenzothiazoles, 2-amino-1,3,4-thiadiazoles, and 2-amino-1,3,4-oxadiazoles to give a 6,7-dihydrothiazolo[3,2-b][1,2,4,6]thiatriazine dioxide 3, a 6,7-dihydrothiazolo[2,3-c][1,2,4,6]thiatriazine dioxide 4, thiazolo[3,2-b][1,2,4,6]thiatriazine dioxides 5, [1,2,4,6]thiatriazino[3,2-b]benzothiazole dioxides 7, a [1,2,4,6]thiatriazino[3,4-b]benzothiazole dioxide 8, [1,3,4]thiadiazolo[2,3-c][1,2,4,6]thiatriazine dioxides 10, [1,3,4]thiadiazolo[3,2-b][1,2,4,6]thiatriazine dioxides 11, [1,3,4]oxadiazolo[2,3-c][1,2,4,6]thiatriazine dioxides 13, and [1,3,4]thiadiazolo[3,2-b][1,2,4,6]thiatriazine dioxides 14. Compounds 3, 4, 5, 7, 8, 10, 11, 13, and 14 are derivatives of new ring systems.

N,N-Dialkyl (N′-chlorosulfonyl)chloroformamidines 1 react regiospecifically with hydrazine derivatives to give [1,2,3,5]thiatriazole dioxides. Reaction of 1 with hydroxamic acids and N-methyl hydroxylamine gave derivatives of [1,3,2,4]oxathiadiazole dioxide 7, a new heterocycle.