Zur Reaktionsweise von Enaminen mit Cyclopropenonen V. Einsatz von β-Carbonyl-enaminen

Diphenylcyclopropenone ( 10 ) was heated with five different β-carbonyl-enamines, namely 4-pyrrolidino-pent-3 E-en-2-one ( 12 ), 4-dimethylamino-pent-3E-en-2-one ( 13 ), 4-dimethylamino-but-E-en-2-one ( 14 ), 3-dimethylamino-1-phenyl-prop-E-en-1-one ( 15 ) and ethyl 3-pyrrolidino-isocrotonate ( 16 ). The resulting reactions were more sluggish than those of 10 with ordinary enamines. The main reaction (between 10 and 69% yield) was in all cases a ‘C, N-insertion’. The major products were: from 12 : an inseparable mixture of 4-methyl-6-oxo-2,3-diphenyl-hepta-2E, 4E-dienoic acid pyrrolidide ( 17 ) and its 2Z, 4E-stereomer ( 18 ); from 13 : 4-methyl-6-oxo-2, 3-diphenyl-hepta-2E-dienoic acid dimethylamide ( 19 ) and its 2Z, 4E-stereomer ( 20 ); from 14 : 6-oxo-2, 3-diphenyl-hepta-2E, 4E-dienoic acid dimethylamide ( 21 ); from 15 : 6-oxo-2,3,6-triphenyl-hexa-2E, 4E-dienoic acid dimethylamide ( 22 ); and from 16 : 5-ethoxycarbonyl-4-methyl-2, 3-diphenyl-penta-2E, 4E-dienoic acid pyrrolidide ( 23 ) and its 2Z, 4E-stereomer ( 24 ). The constitutions of 17 to 24 were derived mainly from spectral properties. For these products the E-configuration at the 4,5-double bond was assigned on the assumption that the insertion of the side-chain (cyclopropenone carbons) between the enamine carbon and nitrogen atoms occurred with retention of configuration, as had been concluded earlier. This was confirmed in the cases of 21 and 22 by the trans-coupling between H? C(4) and H? C(5) in the ¹H? NMR. spectrum, the educts ( 14 and 15 ) having the E-configuration. The configurational difference between the stereomeric products 17 / 18 , 19 / 20 and 23 / 24 was, therefore attributed to the 2,3-double bond. This was confirmed by aqueous acid treatment in the case of the pair 19 / 20 : The 2E-configuration for 19 followed from its conversion to 4-acetonyl-4-methyl- 2,3-diphenyl-isocrotonolactone ( 25 ) and the 2Z-configuration of 20 by its conversion first to a mixture ol two diastereomers of (presumably) 1-acetyl-4-dimethylaminocarbonyl-2-methyl-3- phenyl-l,4-dihydronaphthalene ( 27a ) and then, under more drastic conditions, to 6-methyl-11H-benzo[a]fluorene ( 26 ).The structures of 25 and of 26 were derived from their spectral properties, and that of the 27a -mixture was made probable by the plausibility of its intermediacy on the way to 26 . A pathway for the conversion of 20 to 27a (scheme 3) and of the latter to 26 (scheme 4)is proposed. In the case of the reaction of 10 with 12 , two stereomeric basic by-products were isolated (combined yield 150/,). Their structures as traw- and cis-4-acetonyl-4,5-diphenyl-3-pyrrolidinocyclopent-2-en-ones ( 30 and 31 ) were deduced from their spectral properties and from those of their hydrochlorides 32 and 33 . The enamino-ketone function was found to be resistant to a number of reagents, among which were excess sodium borohydride, which converted 30 to the secondary alcohol 34 , and excess methyllithium, which converted 31 to the tertiary alcohol 35 . A mechanism (called ‘rearrangement’) is proposed (scheme 5) for the formation of the enaminoketones (such as 30 and 31 ), which proceeds via the same ammonio-enolate intermediate ( 36 ) which plays a role in the formation of the major products, the amides (such as 17 to 24 ). It is suggested (scheme 6) that the 3-membered ring of the ammonio-enolate 40 may open in three ways, one of which leads to the amides and another to the enamino-ketones.     

Zur Reaktionsweise von Enaminen mit Cyclopropenonen I. Einsatz von Cyclododecanon-Enamin

Monomethyl-, dimethyl-, di-n-propyl- and diphenyl-cyclopropenone ( 6 to 9 ) have been reacted with 1-(N-pyrrolidino)-cyclododecene ( 5 ) and three types of products isolated. The major products (40–7% yield) were shown to have the 3 -(cyclododec-1′-E-enyl)Z-/or E-acryl-pyrrolidide structure ( 12 , 13 / 14 , 15 / 16 , 17 ) by their spectral properties and lithium aluminium hydride reductions as well as, in one case ( 13 ), by an alternative synthesis of a stereomer ( 34 ) via 1-(cyclododec-E-ene)-carboxaldehyde ( 29 ) and a Wittig reaction. These ‘amides’ are the result of a novel reaction, called ‘C, N-insertion’. In the reactions of the symmetrical cyclopropenes 7 to 9 with 5 , the minor products (6–10%) proved to have the 2,4-disubstituted cyclopentadeca-4-E-en-1,3-dione structures 38 to 40 . These ‘β-diketones’ are considered to be the hydrolysed forms of the intermediate 1-(N-pyrrolidino)-cyclopentadeca-1,4-dien-3-ones ( 45 ).They are formed by reactions (called ‘C,C-insertions’), which represent the first cases of direct ring expansions by three carbon atoms. Such ‘C,C-insertions’ have been postulated previously by other authors. However, their products do not behave like precursors of our ‘β-diketones’ but rather like our ‘amides’. It is proposed therefore, that a reinterpretation of these reactions in the literature must be considered in the light of our ‘C, N-insertion’. In one reaction ( 8 + 5 ) a bicyclo[10. 3. 0]pentadeca-12-en-14-one dericative 42 was found in 10% yield. This type of product and reaction (called ‘condensation’) has been reported previously. A suggestion is made for a systematic representation of the several types of reactions, which cyclopropenones can undergo with enamines. – Mixing 9 + 5 in the cold produced an intermediate, which insomerised on heating to the ‘amide’ 17 . Its properties are compared with those of recently described similar ‘primary adducts’ and the latter are reexamined in the light of the new product interpretations reported in this paper. A novel structure is considered for this intermediate, that a of cycle ‘ammonium acylid’ 51 . An attempt is made at the formulation of other possible intermediates.     

Zur Reaktionsweise von Enaminen mit Cyclopropenonen IV. Einsatz von Ketenacetalen

A new interpretation – based on a reevaluation of the spectroscopic properties of products 16 to 27 – is proposed for the reaction of diphenyl-cyclopropen-one 14 and -thione 15 with ketene-A, N-diacetals 8 to 13 (A ? R₂N, RO and RS) originally reported by Sauer & Krapf. It is concluded that the previous structural assignments (see the a-structures), made on the assumption of a prevailing “C,C-insertion” reaction, must be rcplaced as follows: (1) All the “secondary adducts” are, in fact, derivatives (amides and lactams) of 2,3-diphenyl-penta-2, 4-dienoic acid and thioacid (structures 16b to 24b ); (2) the “isomerization products”, differ from the latter only in the configuration of the α,β-double bond (structures 25b and 26b ); (3) the common “hydrolysisproduct” is α,β-diphenyl-γ-methyl-γ-hydroxy-Δ^α-butenolide ( 27b ), The above cyclopropenone-ketcneacetal reactions represent, therefore, cases of “C, N-insertion”. This is rationalized with a reaction scheme, in which the “acylide” structure of the “primary adducts” plays a role.     

Umwandlung von Cardenoliden durch Mikroorganismen VI. 7β, 11α-Dihydroxydigitoxigenin und Abbau von 7β-Hydroxy-digitoxigenin zum 3β, 7β-Diacetoxy-14-hydroxy-5β, 14β, 17αH-ätiansäure-methylester. Mitteilung über Reaktionen mit Mikroorganismen [1]

Digitoxigenin ( 3 ) was transformed by a Fusarium spec. to 7β-hydroxydigitoxigenin ( 1 ) 1β, 7β-dihydroxydigitoxigenin ( 4 ) and to the hitherto unknown 7β, 11α-dihydroxydigitoxigenin ( 9 ). 7β-acetoxy-digitoxigenin ( 2 ) was degraded to methyl 3β, 7β-diacetoxy-14-hydroxy-5β, 14β, 17αH-etianate ( 11 ).     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 36. Tetrakaliumhexaphosphid: Darstellung,Struktur und Eigenschaften von α-K4P6 und β-K4P6

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 36. Tetrapotassiumhexaphosphide: Preparation, Structure, and Properties of α-K₄P₆ and β-K₄P₆ Tetrapotassiumhexaphosphide has been prepared quantitatively by reaction of the elements at 870 K in sealed Nb and Ta ampoules, respectively. Two crystalline modifications are formed: α-K₄P₆ is stable below 850 K, β-K₄P₆ is stable above this temperature. Both compounds are black semiconductors (E_G(α) = 0.55 eV) with metallic lustre. The orthorhombic structures are defect variants of the hexagonal AlB₂ type structures (K₄P₆□₂) and of a different stacking sequence of this type. Characteristic building units are planar isometric P₆ rings, formed by a specific ordering of defects in the partial structure of the major component. The short P? P distances (215.5 pm and 215.0 pm, respectively) are about 30 pm shorter than the distances compared with a single bond (221 pm). They represent one double bond which is delocalized about six bonds or an aromatic 2π-system. The thermal decomposition in tantalum crucibles, the reaction with quartz walls as well as the reaction with benzophenone in monoglyme yields quantitatively K₃P₇. The reaction with RCl ? Me₃SnCl in monoglyme at 223 K results in the formation of P₇R₃ with high yield (75%). Very probably the valence fluctuating hexaphosphene(4) system is formed at 195 K in the primary reaction step (³¹P-NMR, singulett at 473 ppm downfield).     

Selektive Reduktion von β-Jonon und Dehydro-β-jonon mit Triphenylzinnhydrid

The application of triphenyltinhydride and of triphenyltindeuteride in specific reduction of β-jonone and dehydro-β-jonone has been investigated and the preparation of pure dihydro-β-jonone,dihydro-β-jonone-d₁, dihydro-β-jonone-d₂, and dihydro-dehydro-β-jonone described.     

Chelate von β-Dicarbonylverbindungen und ihren Derivaten. XV. Komplexchemische Reaktivität von β-Mercaptovinylaldehyden

The reactivity of α-phenyl-β-mercaptocinnamaldehyde and α-(2-pyridyl)-β-mercaptocinnamaldehyde towards thiophilic metals was studied and some complexes of nickel, cobalt, copper, palladium, zinc, lead and mercury with these ligands were prepared. The chemical bonding in the complexes was examined by IR spectroscopy. The reaction of the Bis(α-phenyl-β-mercaptocinnamaldehydato)-nickel with amines gave the corresponding aldimine chelates, by the action of hydrogen sulfide the nickel chelate of α-phenyl-β-mercaptocinnamthioaldehyde was formed.     

Stabilitätskonstanten der Kupferkomplexe von Acetessigsäureamiden. I

The stability constants of the copper complexes of acetoacetdialkylamides and substituted acetoacetanilides have been determined by potentiometric pH-measurements. The variation of stability constants with phenyl substituents is interpreted.     

Sythese von α und β-Sinensal

β-Sinensal (2,6-dimethyl-10-methylene-dodeca-2,6,11-trienal) was synthesized from the diene-aldehyde 5 . This was converted into the trans- and cis-triene-aldehydes 16 and 17 , which were condensed with the phosphorane 18 to give the corresponding two geometrical isomers ( 3 and 19 ) of β-sinensal.