Darstellung und Schwingungsspektren von Dichloro- und Dibromodithiophosphat Die Kristallstrukturen von [PPh3Me] [PS2Cl2] und [PPh4] [PS2Br2]

Preparation and Vibrational Spectra of Dichloro and Dibromodithiophosphate. Crystal Structures of [PPh₃Me][PS₂Cl₂] and [PPh₄][PS₂Br₂] Dichloro and dibromodithiophosphates [Cat⁺][PS₂X₂^?] with a large organic cation can be obtained from P₄S₁₀, CatX and HX in CH₂Cl₂ (Cat⁺ = PPh₄⁺, PPh₃Me⁺; X = Cl, Br). The vibrational spectra (i.r. and Raman) of the [PS₂X₂]^? ions are reported and discussed; force constants were calculated. The crystal structures of [PPh₃Me][PS₂Cl₂] and [PPh₄][PS₂Br₂] were determined and refined with X-ray diffraction data. In both cases, simple anions [PS₂X₂]^? are present. [PPh₃Me][PS₂Cl₂]: orthorhombic, space group P2₁2₁2₁, a = 1089, b = 1334, c = 1476 pm, Z = 4, refinement to a residual index R = 0.046 for 1116 reflexions; the structure is isotopic with [PPh₃Me][VO₂Cl₂]. [PPh₄][PS₂Br₂]: tetragonal space group I4 , a = 1301, c = 721 pm, Z = 2, refinement to R = 0.065 for 357 reflexions; the structure is isotypic with [AsPh₄][FeCl₄] with [PS₂Br₂]^? ions occupying positions of 4 -symmetry with statistical orientation (statistical superposition of Br and S positions).     

Synthese und Eigenschaften von Thiazolo[3,2-a]pyrimidinen und Thiazolo [3,2-a] pyrrolo [2,3-d]pyrimidinen

From the alkali-catalysed reaction of thiouracil with bromoacetaldehyde diethyl acetal three products are isolated in nearly the same quantity: 2-(2, 2-diethoxyethylthio)-uracil ( 2 ) and two cyclization products: 3 , a thiazolo[3, 2-a]pyrimidin-5-one, and 4 , athiazolo[3, 2-a]pyrimidin7-one. By warming with acid both 2 and 4 yield 3 . Rearrangement of 4 to 3 proceeds also by heating the hydrochloride. Similar cyclizations leading to thiazolo[3, 2-d]pyrrolo[2, 3-d]pyrimidin-5-ones are also described. Bromine substitutes 3 in position 6. The bromo derivative 6 on treatment with primary or secondary amines affords 7-amino compounds.     

Stereochemie von [3.3]- und [5.5]-sigmatropischen umlagerungen

The knowledge of the stereochemical course of Cope and Claisen rearrangements is important both for mechanistic and synthetic reasons. In the first part an analysis of the possible transition state geometries (cf Table 1) for these reactions is given and methods which allow to distinguish between the various geometries are discussed (cf Schemes 1 and 2). In the second part known examples are analyzed. Generally, in Cope and Claisen rearrangements of acyclic systems a chair-like transition state (C) is favoured above a boat-like (B). Steric effects may alter this preference.     

Versuche zur Synthese von [2.2]- und [2.3]Cyclopentadienophanen

Synthetic Attempts towards [2.2]- and [2.3]Cyclopentadienophanes . The first [2.2]Cyclopentadienophane (=2,2,3,3,8,8,9,9-octamethyltricyclo[8.2.1.1^4,7]tetradecatetraene; 1b ) has been synthesized (Scheme 5) by reductive coupling of 6,6-dimethylfulvene 3 → 5 (50%) followed by base-induced twofold condensation of 1,2-di(cyclopentadienyl)-1,2-dimethylbutane 5 with acetone to give difulvene 15 (95%). Reductive coupling of 15 gives a complex mixture of tautomers of 16 , 17 , and 1b , which contains ca. 50% of the target molecule 1b . Other synthetic attempts towards [2.2]cyclopentadienophanes 1a and 1b and [2.3]cyclopentadienophane 18 are discussed.     

Hydrierte Derivate von Benz[f]- und Benz[g]isochinolinen

Zusammenfassung Aus 1- und 2-(2-Aminoalkyl)-5,6,7,8-tetrahydronaphthalin wurden durch Ringschluß nachPictet—Spengler oderBischler—Napieralski hydrierte Benz[f]- und Benz[g]isochinoline gewonnen. Einzelne dieser Verbindungen zeigen beachtliche analgetische Wirkung.

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From 1- and 2-(2-aminoalkyl)-5,6,7,8-tetrahydronaphthalene, hydrogenated benz[f]- and benz[g]isoquinolines have been obtained by cyclization according toPictet—Spengler orBischler—Napieralski. Some of these compounds exhibit remarkable analgesic activity.

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Herrn Prof. Dr.H. Bretschneider zu seinem 60. Geburtstag gewidmet.     

Synthesen und Charakterisierung von [Ni(tBuAs)6] und [Pd(tBuAs)6]

Syntheses and Characterization of [Ni(tBuAs)₆] and [Pd(tBuAs)₆] The reduction of tBuAsCl₂ with magnesium in the presence of NiCl₂ or PdCl₂ yields the complexes [Ni(tBuAs)₆] ( 2 ) and [Pd(tBuAs)₆] ( 3 ). The structure of ( 2 ) was determined by X-ray single crystal structure analysis. ( 2 ) consists of the sixmembered ring (tBuAs)₆ in chair conformation with the nickel atom in the center of this ring.     

Bildungsweise und Schwingungsspektren von Antimontetrachlorid-isocyanat [SbCl4NCO]2 und -cyanurat [SbCl4NCO]3

Formation and Vibrational Spectra of Antimony Tetrachloride Isocyanate [SbCl₄NCO]₂ and Cyanurate [SbCl₄NCO]₃ [SbCl₄NCO]₂ was obtained from K[SbCl₅NCO] and SbCl₅ in liquid SO₂. In solution it is only stable at lower temperatures (?20°C); at room temperatures or above irreversible rearrangement to [SbCl₄NCO]₃ takes place. At higher temperatures this also occurs in the solid state, so that both compounds seen to have the same melting point of 208°C. In the molten state decomposition takes place, SbCl₃ being a main product. According to its i. r. and Raman spectrum, [SbCl₄NCO]₂ is an isocyanate with bridging N-atoms. I. r. and Raman spectrum of [SbCl₄NCO]₃ show it to be a derivative of cyanuric acid. Mass spectral data of both compounds are reported.