Keywords: Sulfur-nitrogen heterocycles / Materials science / Liquid crystals / Radicals / Fused-ring systems 3-Amino-1H-indene-2-carbonitrile and 2-amino-3H-indene-1-carbonitrile reacted with SCl 2 , iBu 3 N and NCS to give benzocyclopenta[1,2,6]thiadiazines, and whilst 2-aminocyclopent-1-enecarbonitrile gave, under the same conditions, a cyclopenta[1,2,6]thiadiazine, its reaction with mixtures of S 2 Cl 2 , SCl 2 and iBu 3 N under different conditions gave, selectively, an isothiazolo [3,4-d]

Indene and cyclopentene enaminonitriles were reacted with SCl2, iBu3N and NCS to give the first cyclopenta[1,2,6]thiadiazines that showed unusual characteristics, one as a NIR dye and another as a liquid crystal.

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[Structure: see text]. The 1,5- and 1,7-s-hydrindacenedione dioximes reacted with S2Cl2 and iBu3N to give the first examples of bis[1,2,3]dithiazolo-s-indacenes; one of them was a near-infrared dye. In contrast, the silylated bicyclo[3.3.0]octan-2,6-dione dioxime reacted with S2Cl2 and Et3N to give a bicyclic 4-cyanoethylcyclopenta[1,2,3]dithiazole or, after addition of Li2S, a tricyclic 4-cyanoethyl-5,6-pentathiepinocyclopenta[1,2,3]dithiazole, also obtained from 2-cyanoethylcyclopentanone oxime, S2Cl2, and Hünig's base. In related reactions, 2-oxocyclopentylpropionate oxime gave the expected cyclopenta[1,2,3]dithiazole, in addition to an unexpected cyclopenta[c][1,2]thiazine that showed a reversible reduction wave in its CV at -0.95 V. Ethyl 2-oxocyclopentanecarboxylate oxime reacted with S2Cl2, Hünig's base, and Li2S to give a 5,6-tetrathiinocyclopenta[1,2,3]dithiazole derivative. Cyclopentathiophen-4-one oximes reacted with S2Cl2 and iBu3N to give thienocyclopenta[1,2,3]dithiazoles that showed UV-vis spectral bands that depended on the positions of the ring fusion.

A Facile Synthesis of 1,3,5-Trisubstituted Hydantoins via Ugi Four-Component Condensation. -The unique process involves trichloroacetic acid as a carbonic acid equivalent and is followed by a base-promoted cyclization of the adducts (V). -(IGNACIO, J. M.; MACHO, S.; MARCACCINI*, S.; PEPINO, R.; TORROBA, T.; Synlett 2005, 20, 3051-3054; Dip. Chim. Org. Ugo Schiff, Univ. Firenze, I-50121 Firenze, Italy; Eng.) -Mais 15-116

A facile access to 1,3,5-trisubstituted hydantoins is achieved by combining an Ugi four-component condensation with a base-induced cyclization. This two-step sequence, which differs from any other method, is experimentally simple and allows a wide variety in the substitution pattern. In this synthesis the acid component, namely trichloroacetic acid, acts as a carbonic acid equivalent.

Ugi reaction between arylglyoxals, anilines, cyclohexyl isocyanide and trichloroacetic acid in dichloromethane, in the presence of molecular sieves, afforded 2(3H)-oxazolone 4-carboxamides in good yields by a one-pot process that involved an in situ spontaneous cyclization of the Ugi product through an intermediate ketone enolate and the chloroacetate carbonyl group. The synthesis is based on the ability of the trichloroacetyl group to function as a masked carbonic acid surrogate.

Thiadiazine derivatives R 0660 Cyclopentathiadiazines, New Heterocyclic Materials from Cyclic Enaminonitriles. -Indene and cyclopentene enaminonitriles (I), (V) and (VII) are reacted with SCl2, iBu3N and NCS to give the first cyclopenta[1,2,6]thiadiazines (II), (VI) and (VIII), respectively. These compounds exhibit interesting properties, e.g. as NIR dye or liquid crystals. -(MACHO, S.; MIGUEL, D.; NEO, A. G.; RODRIGUEZ, T.; TORROBA*, T.; Chem. Commun. (Cambridge) 2005, 3, 334-336; Dep. Quim., Fac. Cienc., Univ. Burgos, E-09001 Burgos, Spain; Eng.) -M. Paetzel 21-175