1-Eth-oxy-3-[4-(eth-oxy-carbon-yl)phen-yl]-3-hy-droxy-1-oxopropan-2-aminium chloride.

The title compound, CHNO ·Cl, was prepared as a racemate of ,- and ,-enanti-omers by reduction of the corresponding hy-droxy-imino-ketone. In the crystal, layers are formed hydrogen bridges of four ammonium groups to chloride ions; these lamellae are connected inter-digitated benzoic ester groups.

(10)-4,5,6,7,8,9-Cyclo-deca-[][1,2,3]selena-diazole.

The title compound, CHNSe, was prepared from a semicarbazone and selenium dioxide. The planes of the heterocycle and the double bond are almost mutually orthogonal and the hexa-methyl-ene tether is nearly strain-free.

3a,4,5,8,9,9a-Cyclo-octa-[][1,3]dioxole-2-thione.

The thio-nocarbonate of -cyclo-octenediol, CHOS, crystallizes with a 9/1 disorder in the position of the and -enanti-omers. As a result of -annulation, both rings adopt a twist conformation.

Redetermined structure of methyl 3-{4,4-di-fluoro-2-[2-(methoxy-car-bon-yl)-ethyl]-1,3,5,7-tetra-methyl-4-bora-3a,4a-di-aza--in-da-cen-6-yl}pro-pion-ate.

In the title compound, CHBFNO, a highly fluorescent boron-dipyrromethene dye, the methyl-propionate moieties have different conformations. In the crystal, weak C-H⋯F and C-H⋯O inter-actions link the mol-ecules. Some optical properties are presented.

5-[(4-Methyl-phen-yl)sulfon-yl]-1-phenyl-thio-pyrano[4,3-]indole-3(5)-thione di-chloro-methane monosolvate.

Rhodium-catalyzed [2+2+2] cyclo-addition of carbon di-sulfide to ,-dialkynyl-tosyl-anilines gives two isomeric indolo-thio-pyran-thio-nes, a violet and a red isomer. This is the first crystal structure of a red isomer, which crystallizes with one solvent mol-ecule of di-chloro-methane in the asymmetric unit, CHNOS·CHCl. In the extended structure, centrosymmetric pairs of the planar annulated system are arranged in strands and solvent mol-ecules fill the space between the strands.