Synthesis and Antibacterial Activity of Benzo[4,5]isothiazolo[2,3-a]pyrazine-6,6-dioxide Derivatives.

Using a routine procedure, a number of derivatives of the benzo[4,5]isothiazolo[2,3-]pyrazine-6,6-dioxide ring system have been synthesized from readily available starting materials. A series of chalcones were synthesized, which were subsequently reacted with chlorosulfonic acid to generate chalcone sulfonyl chlorides. The chalcone sulfonyl chlorides were then treated with bromine to generate dibromo chalcone sulfonyl chlorides.

Synthesis and Spectral Characterization of Benzo-[6,7][1,5]diazocino[2,1-a]isoindol-12-(14H)-one Derivatives.

A simple synthetic route affording 27%-85% yields of benzo[6,7][1,5]diazocino[2,1-a]isoindol-12(14H)-one ring systems from readily available 3-(2-oxo-2-phenylethyl) isobenzofuran-1(3H)-ones and 2-(aminomethyl)aniline starting materials in toluene and catalysed by p-toluene-sulfonic acid is developed. The ¹H- and (13)C-NMR spectra of the final products were assigned using a variety of one and two-dimensional NMR experiments. The distinction between the two potential isomers of the final products was made on the basis of heteronuclear multiple bond connectivity (HMBC) NMR spectra.

Synthesis and Antimicrobial Activity of 1,2-Benzothiazine Derivatives.

A number of 1,2-benzothiazines have been synthesized in a three-step process. Nine chalcones 1-9 bearing methyl, fluoro, chloro and bromo substituents were chlorosulfonated with chlorosulfonic acid to generate the chalcone sulfonyl chlorides 10-18. These were converted to the dibromo compounds 19-27 through reaction with bromine in glacial acetic acid.

Racemic 9,10-dimeth-oxy-3-methyl-6-phenyl-7,7a-dihydro-benzo[b]benzo[4,5]isothia-zolo[2,3-d][1,4]diazepine 12,12-dioxide.

There are two molecules in the asymmetric unit of the title compound, C(24)H(22)N(2)O(4)S. The conformation of the seven-membered ring is twisted boat for both molecules. The molecule is chiral, but crystal symmetry generates a recemate.

(Z)-3-Chloro-methyl-idene-5,6-dimeth-oxy-2-methyl-2,3-dihydro-1,2-benzothia-zole 1,1-dioxide.

The title compound, C(11)H(12)ClNO(4)S, adopts a Z configuration about the C=C double bond. The benzisothia-zole system is essentially planar [maximum deviation of 0.235 (2) Å for the S atom].