Hard and soft electrophilic and nucleophilic dissymmetry of α-oxoketenedithioacetals and p-nitro-o-phenylenediamineexploited to achieve the regioselectivity in the synthesis of 2-thiomethyl ether substituted isomer of the privileged nucleus of 1,5-benzodiazepines over to its 4-substituted isomersAbstract. An exclusive regioselective formation of 2-thiomethyl ether substituted isomer of the privileged nucleus of 1,5-benzodiazepines was achieved from the reaction of p-nitro-o-phenylenediamine with a variety of α-oxoketene dithioacetals derived from several active methylene compounds, by exploiting the strategy based on the variation of electrophilicity of the two electrophilic centers of α-oxoketene dithioacetals and the hard and soft nucleophilic profiles of the p-nitro substituted o-phenylenediamines.Keywords. Regioselectivity in synthesis; 1,5-benzodiazepines; α-oxoketene dithioacetals; hard and soft dissymmetry of electrophilic and nucleophilic species.

Synthetic potential of the privileged molecular framework of 7‐fluoro‐1,4‐benzodiazepin‐2‐one containing a methyl carboxylate substituent at its 5‐position was exploited to develop efficient protocols to the synthesis of several novel 5‐(1′,3′,4′)oxadiazole ring incorporated analogs of medicinal interest, appended with the Mannich's base motifs at the nitrogen atom in its seven‐membered ring.

An expedient protocol for the synthesis of face 'b' pyrido-annulated analogs of 1,5-benzothiazepines, namely 4-(methylthio)-5-(1 ,3 ,4 -oxadiazol-2 -yl)-2-phenyl-5,11-dihydrobenzo[b] pyrido[2,3-e] [1,5] thiazepine-S,S-dioxides 9a-9f, of medicinal interest emerged to exploit the potential of 3-ketene dithioacetal-substituted derivatives of 4-(1 ,3 ,4 -oxadiazol-2 -yl)-2,3-dihydrobenzo[b] [1,5] thiazepin-2(1H)-one-S,S-dioxide 8. This latter compound 8 was obtained from the base-catalyzed condensation of CS 2 and MeI with 4-(1 ,3 ,4 -oxadiazol-2 -yl)-2,3-dihydrobenzo[b] [1,5] thiazepin-2(1H)-one-S,S-dioxide (7). Compound 7 was available from ethyl-2-oxo-2,3,4,5-tetrahydro-[1,5]-benzothiazepin-4-carboxylate (3) on applying established synthetic procedures, which had been previously employed in the literature on related substrates. Treatment of 8 with the anions derived from substituted acetophenones formed the diones which underwent facile cyclocondensation with NH 4 OAc in AcOH to yield the desired products 9a-9f in acceptable yields.

Im Zusammenhang mit den bekannten pestiziden Eigenschaften von Oxadiazol und Triazol‐Derivaten sowie von N‐Chloracetylarylharn‐ Stoffen werden die Arylureidooxadiazole (IV) und die Arylureidotriazole (VII) als mögliche Pestizide synthetisiert.

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