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The asymmetric unit of the title compound, C16H17ClNO2S+·HSO4 −, (I) [systematic name: (+)-(S)-5-[(2-chloro­phen­yl)(meth­oxy­carbon­yl)meth­yl]-4,5,6,7-tetra­hydro­thieno[3,2-c]pyridin-5-ium hydrogen sulfate], contains two independent cations of clopidogrel and two independent hydrogensulfate anions. The two independent cations are of similar conformation; however, this differs from that observed in ortho­rhom­bic form (II) [Bousquet et al. (2003 ▶). US Patent No. 6 504 030]. The H—N—Cchiral—H fragment shows a trans conformation in both independent cations in (I) and a gauche conformation in (II). In (I), classical inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link two independent cations and two independent anions into an isolated cluster, in which two cations inter­act with one anion only via N—H⋯O hydrogen bonds. Weak inter­molecular C—H⋯O hydrogen bonds further consolidate the crystal packing.

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Oxadiazole derivativesOxadiazole derivatives R 0290New Heterocycles with a 3-Aminofurazanyl Substituent. -The synthesis of a variety of new hetaryl-substituted 3-aminofurazans [cf. (III), (V), (VIII), (X)] starting from oxime (I), hydrazide (VII) or hydrazone (IX) is described. -(SHAPOSHNIKOV, S. D.; KOROBOV, N. V.; SERGIEVSKII, A. V.; PIROGOV, S. V.; MEL'NIKOVA, S. F.; TSELINSKII, I. V.; Russ. J. Org. Chem. 38 (2002) 9, 1351-1355; St. Petersburg State Inst. Technol., St. Petersburg 198013, Russia; Eng.) -M. Schroeter 16-125

4H,8H-Bis-(1,2,5-oxadiazolo) [3,4-b:3',4'-e]pyrazine and Some Derivatives. -Several chemical transformations of the title bisoxadiazolopyrazine (I) are studied. Compound (I) does not undergo direct nitration in the presence of nitric acid. Instead, an oxidative dehydrogenation or destruction of one furazane cycle is observed. Nitration as well as nitrosylation products (XVII) and (XIX), however, are obtained by reaction of the dipotassium salt of compound (I) with dinitrogentetra-and pentoxide. The weak NH-acid compound (I) undergoes base-mediated alkylation/arylation or addition of alkenes. Thus, with alkyl(aryl) halides (VII), the corresponding N,N'-dialkyl(aryl) derivatives (VIII) are formed and with methylvinylketone (V), the di(methylcarbonylethyl) analogue (VI) is obtained. Additionally, the dinitromethyl(ethyl) derivatives (X) and (XIV) are prepared, which can act as CH-as well as NH-acids. -(TSELINSKII, I. V.; MEL'NIKOVA, S. F.; ROMANOVA, T. V.; PIROGOV, S. V.; KHISAMUTDINOV, G. KH.; MRATKHUZINA, T. A.; KOROLEV, V. L.; KONDYUKOV, I. Z.; ABDRAKHMANOV, I. SH.; SMIRNOV, S. P.; Zh.