Synthesis of Cannabinoid Model Compounds. Part 3. (6aR, 10aR)-N-ethyl-Δ8-tetrahydrocannabinol-18-amide, (6aR, 10aR, 17 RS)-N-ethyl-17-methyl-Δ8- tetrahydrocannabinol-18-amide and (6aR, 10aR)-17,18-didehydro-Δ8-tetrahydrocannabinol

The novel cannabinoids (6aR, 10aR)-N-ethyl-Δ⁸-tetrahydrocannabinol-18-amide (15) and (6aR, 10aR, 17 RS)-N-ethyl-17-methyl-Δ⁸- tetrahydrocannabinol-18-amide (16) , designed as cannabinoid affinity ligands, were synthesized from the corresponding acids 11 and 12 via the N-hydroxysuccinimide esters. Amide 16 was tested in the rat and was generalized to Δ⁹-tetrahydrocannabinol, being 5 times less potent than the training drug. An improved synthesis of (6aR, 10aR)-17,18-didehydro-Δ⁸-tetrahydrocannabinol (23) is reported. As model reaction for the preparation of a tritiated Δ⁸-tetrahydrocannabinol, compound 23 was selectively deuterated at C(17) and C(18) in benzene/Et₃N using [(C₆H₅)₃P]₃RuCl₂ as catalyst.     

Chimie et pharmacologie de l'apiose III. Synthèse et propriétés de l'hydrate de l'O-isopropylidène-1, 2-tétrosulo-3-furannose

Ruthenium tetroxide oxidation of 1, 2-O-isopropylidene-β-D -threofuranose affords, besides the known 1, 2-O-isopropylidene-α-L -glycero-tetros-3-ulofuranose, a lactone. The tetrosulose is easily hydrated to the corresponding gem-diol whose dehydration on molecular sieves leads to a branched-chain dimer. Lead tetraacetate oxidation of 1, 2-O-isopropylidene-α-L -glycero-tetros-3-ulofuranose p-nitrophenylhydrazone leads quantitatively, to a gem-azoacetate, a new synthetic intermediate in carbohydrate chemistry. The 3-O-acetyl-1, 2-O-isopropylidene-α-L -glycero-tetr-3-enofuranose is easily obtained from the gem-diol. A highly stereoselective procedure is described to prepare the 3-O-acetyl-1, 2-O-isopropylidene-α-L -3, 4-exo-D₂-erythrofuranose.     

Collision-induced emission of O2(b1Σ → a1Δg) in the gas phase

In flow tube studies of the quenching of O₂(b¹Σ), broad band emission of O₂(b):M collision complexes was found to appear under the discrete rotational lines of the 0–0 band of the b¹Σ → a¹Δ_g electric quadrupole transition at higher oxygen pressures and on addition of foreign gases. Bimolecular rate constants for the collision-induced emission processes have been derived from the ratio of the intensities of the discrete lines and the continuum as well as from low-resolution measurements of the relative intensities of the b → a and b → X bands as a function of O₂ and added gas pressure. They range from ≈10^?21 cm³ s^?1 for He to ≈4 × 10^?19 cm³ s^?1 for PCl₃ vapor.     

Tordanone,un stéroïde replié avec une jonction de cycle A/B β-cis (5β) et B/C α-cis(8α)

Tordanone, a Twice Bent Steroid Structure with Ring A/B β-cis(5β)- and Ring B/C α-cis(8α)-Fused The 3β, 14α, 25-trihydroxy-5β, 8α-cholestan-6-one ( = tordanone; 4 ) has been prepared by stereospecific hydrogenation of 3β, 14α, 25-trihydroxy-5β-cholesta-7,22ξ-dien-6-one ( 5 ). This is the first stereospecific synthesis of a B/C cis-fused steroid belonging to the 5β, 8α -cholestane group with a H-atom at positions 5β (A/B cis-fused) and 8α. The resulting twice bent structure shows a particularly strong steric hindrance of the β-face where CH₃(18) at the C/D ring junction and H_β? C(7) of the B ring are very close to each other. Structural features and mechanistic aspects of the hydrogenation are discussed.     

Heterobimetallische phosphanido-verbrückte Zweikern-Komplexe - Synthese von cis-rac-[(η-C5H4R)2Zr{μ-PH(2,4,6−iPr3C6H2)}2M(CO)4] (RMe,MCr,Mo; RH,MMo)

Heterobimetallic Phosphanido-bridged Dinuclear Complexes - Syntheses of cis-rac-[(η-C₅H₄R)₂Zr{μ-PH(2,4,6-ⁱPr₃C₆H₂)}₂M(CO)₄] (R?Me, M?Cr, Mo; R?H, M?Mo) The zirconocene bisphosphanido complexes [(η-C₅H₄R)₂Zr{PH(2,4,6-ⁱPr₃C₆H₂)}₂] (R?Me, H) react with [(NBD)M(CO)₄] (NBD?norbornadiene, M?Cr, Mo) to give only one diastereomer of the phosphanido-bridged heterobimetallic dinuclear complexes cis-rac-[(η-C₅H₄R)₂Zr{μ-PH(2,4,6-ⁱPr₃C₆H₂)}₂M(CO)₄] [R?Me, M?Cr ( 1 ), Mo ( 2 ); R?H, M?Mo ( 3 )]. However, no reaction was observed between [(η-C₅H₅)₂Zr{PH(2,4,6-^tBu₃ C₆H₂)}₂] and [Pt(PPh₃)₄]. 1—3 were characterised spectroscopically. For 1—3 , the presence of the racemic isomer was shown by NMR spectroscopy. No reaction was observed at room temperature for 3 and CS₂, (NO)BF₄, Me₃NO or PH(2,4,6-Me₃C₆H₂)₂. With Et₂AlH or PhC?CH decomposition of 3 was observed.     

Über die Synthese von 1-Aryl-und 1-Alkyl-2, 3-dimethyl-chinoxalinium-perchloraten. 2. Mitteilung. Synthese und 1H-NMR.-Spektren von 2,3-Dimethyl-1-phenyl-6-X-chinoxalinium-perchloraten

On the Synthesis of 1-Aryl- and-1-Alkyl-2, 3-dimethyl-quinoxalinium Perchlorates. 2nd Communication

1 1. Mitt.: [1].

. Synthesis and ¹ H-NMR. Spectra of 2, 3-Dimethyl-1-phenyl-6-X-quinoxlinium Perchlorates The synthesis of the title compounds ( 5 ) which have been useful as precursors for a lot of conventional and new-type dyes [2-8] has yet been limited to examples with X?H [2] [3] [11] [15] and with electron-donating [4] [12] or at best slightly electron-accepting [1] [6] substituents X and R. We now describe a method suitable even for compounds 5 with strongly electron-accepting substituents: N-monosubstituted o-phenylendiamines 4 , were condensed with 2, 3-butanedione and perchloric acid in mixed solvents containing an excess of diethyl ether. The products - mostly substituted at position 6 of the quinoxalinium ring - are chracterized by ¹H-NMR. spectra, elemental analyses and in most cases by isolation of the corresponding bases 6 . Correlations of chemical shifts with Hammett's σ_p [18] are given by equations (1)-(5).     

The Crystal and Molecular Structure of 3-Oxo-17β-acetoxy-Δ4-14α-methyl-8α, 9β, 10α, 13α-estrene

The crystal and molecular structure of 3-oxo-17β-acetoxy-Δ⁴-14α-methyl-8α, 9β, 10α, 13α-estrene, C₂₁H₃₀O₃, has been determined by X-ray diffraction analysis. The crystals belong to the orthorhombic space group P2₁2₁2₁, with the cell dimensions a = 12.093 Å, b = 19.667 Å, c = 7.746 Å; Z = 4. Intensity data were collected at room temperature with an automatic four-circle diffractometer. The structure was solved by direct methods and the parameters were refined by least-squares analysis. All the hydrogen atoms were included in the refinement. The final R value was 0.038 for 1413 observed reflections. The conformation of ring A is intermediate between a half-chair and a 1, 2-diplanar form. The hydrogens at C(9) and C(10) are anti, the B/C ring junction is trans, and rings B and C adopt chair conformations. Ring D is cis fused and is halfway between C₂ and C_s forms.     

Hetero-Diels-Alder Additions of α,β-Unsaturated-Acyl Cyanides. Part 3. Syntheses of 3-bromo-2-ethoxy-3,4-dihydro-2H-pyran-6-carbonitriles,and about their transformation to 2-ethoxy-2H-pyrans

Cycloadditions of the α,β-unsaturated-acyl cyanides 1–3 with (Z)-or (E)-1-bromo-2-ethoxyethene ( 4 ) may be performed at moderate temperatures and provide in good yields the 3-bromo-2-ethoxy-3,4-dihydro-2H-pyran-6-carbonitriles 5–7 , respectively (Scheme 1). Diastereoisomeric pairs of products result at room temperature merely from the ‘endo’- and ‘exo’-transition states; more complex mixtures appear above 60° as a consequence of (Z)/(E)-isomerization of 4 . The relative stability of the anomers of 5 and 6 is explored by treatment with BF₃·Et₂O. Acid alcoholysis (MeOH or EtOH) of 5 leads to acetals 9a , b of 4-bromo-5-oxopentanoate. Alkyl (2Z,4E)-5-ethoxypenta-2,4-dienoates 12 , 17 , and 20 , are formed in alcoholic alkoxide solutions from 5 , 6 , and 7 , respectively, which is compatible with the intermediacy of 2-alkoxy-2H-pyrans and their valence tautomers, α,β-unsaturatedacyl cyanides. Methoxide addition to the CN group competes with dehydrobromination in case of 5 ; it leads to 3-bromo-3,4-dihydro-2H-pyran-6-carboximidate 13 (ca. 50% at ?20°) which can be hydrolyzed to the methyl carboxylate 14 . DBU (1,8-diazabicyclo[5,4,0]undec-7-ene) in benzene converts 5 to 6-ethoxy-2-oxohexa-3,5-dienenitrile ( 11 ), the ring-opening product of an obviously unstable 2-ethoxy-2H-pyran; the same reagent dehydrobrominates 6 to 2-ethoxy-4-methyl-2H-pyran-6-carbonitrile ( 15 ). HBr Elimination from 7 takes place with great ease in presence of pyridine, or even during chromatography on alumina, and leads to the stable ethyl 6-cyano-2-ethoxy-2H-pyran-4-carboxylate ( 18 ); this dimerizes at room temperature to give a 1:3 mixture of tricyclic adducts ‘endo’- 21 and ‘exo’- 21 . The structure of the latter is established by an X-ray crystallographic analysis.     

Organylarsino-substituierte Schwefeldiimide: Die Kristallstrukturanalysen von 3, 7-Di-t-butyl-3H, 7H,-1λ4, 5λ4, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocin und Bis(diphenylarsino)schwefeldiimid

Organoarsino-Substituted Sulphur Diimides: Crystal Structure Analyses of 3, 7-Di-t-butyl-3H, 7H-1λ⁴, 5λ⁴, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocine and Bis (diphenylarsino)sulphur Diimide Reaction of the salt K₂SN₂ with organoarsenic chlorides leads to sulphur diimides containing organoarsino substituents at both ends. Single crystal X-ray structure analyses were carried out for two typical compounds, i.e. the cyclic eight-membered 3, 7-di-t-butyl-3H, 7H-1λ⁴, 5λ⁴, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocine ( 1a , prepared from K₂SN₂ and (t-Bu)AsCl₂ (1:1)) and the open-chain bis(diphenylarsino)sulphur diimide ( 2a , prepared from K₂SN₂ and Ph₂AsCl (1:2)). In both compounds the sulphur diimide groups are coplanar with their directly bound arsenic atoms. This coplanarity principle leads, in the case of 1a , to about conformation (mm2(C_2v) symmetry) of the eight-membered heterocycle; the t-butyl substituents occupy quasi equatorial positions. Small deviations from mm2 symmetry and torsions around the S?N bonds up to 12° can be explained as a consequence of the transnnular repulsion of the lone pairs at the arsenic atoms (As …As distance 3.683(1) Å). In the case of the open-chain S(N? AsPh₂)₂ ( 2a , 2(C₂) symmetry), a cis, cis configuration was found at the S?N double bonds which indicates As…As interaction. The As…As distance (3.379(1) Å) is shorter than in 1a and parallells a reduced interaction of the lone pairs at the As atoms. The S?N bond lenghts (1.517(5) Å in 1 a and 1.521(3) Å in 2a ) are characteristic of sulphur diimides withoug significant π-interaction with the substituents and correspond to S^IV?N double bonds.     

Complexation of the 2, 4, 6‐Triallyloxy‐1, 3, 5‐triazine with Copper(I,II) Chlorides. Syntheses and Crystal Structures of [CuCl2·2C3N3(OC3H5)3], [Cu7Cl8·2C3N3(OC3H5)3], and [Cu8Cl8·2C3N3(OC3H5)3]·2C2H5OH

Interaction of copper(II) chloride with 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine leads to formation of copper(II) complex [CuCl₂·2C₃N₃(OC₃H₅)₃] ( I ). Electrochemical reduction of I produces the mixed‐valence Cu^{I, II} π, σ‐complex of [Cu₇Cl₈·2C₃N₃(OC₃H₅)₃] ( II ). Final reduction produces [Cu₈Cl₈·2C₃N₃(OC₃H₅)₃]·2C₂H₅OH copper(I) π‐complex ( III ). Low‐temperature X‐ray structure investigation of all three compounds has been performed: I : space group P1¯, a = 8.9565(6), b = 9.0114(6), c = 9.7291(7) Å, α = 64.873(7), β = 80.661(6), γ = 89.131(6)°, V = 700.2(2) ų, Z = 1, R = 0.0302 for 2893 reflections. II : space group P1¯, a = 11.698(2), b = 11.162(1), c = 8.106(1) Å, α = 93.635(9), β = 84.24(1), γ = 89.395(8)°, V = 962.0(5) ų, Z = 1, R = 0.0465 for 6111 reflections. III : space group P1¯, a = 8.7853(9), b = 10.3602(9), c = 12.851(1) Å, α = 99.351(8), β = 105.516(9), γ = 89.395(8), V = 1111.4(4) ų, Z = 1, R = 0.0454 for 4470 reflections. Structure of I contains isolated [CuCl₂·2C₃N₃(OC₃H₅)₃] units. The isolated fragment of I fulfils in the structure of II bridging function connecting two hexagonal prismatic‐like cores Cu₆Cl₆, whereas isolated Cu₆Cl₆(CuCl)₂ prismatic derivative appears in III . Coordination behaviour of the 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine moiety is different in all the compounds. In I ligand moiety binds to the only copper(II) atom through the nitrogen atom of the triazine ring. In II ligand is coordinated to the Cu^II‐atom through the N atom and to two Cu^I ones through the two allylic groups. In III all allylic groups and nitrogen atom are coordinated by four metal centers. The presence of three allyl arms promotes an acting in II and III structures the bridging function of the ligand moiety. On the other hand, space separation of allyl groups enables a formation of large complicated inorganic clusters.     

Diazoalcanephosphonates. Etude par RMN du proton de la configuration de Δ1-pyrazolines dérivées du norbornadiène

The NMR spectra of eleven pyrazolines 1 to 11 derived from norbornadiene are interpreted and discussed. The configurations are deduced from the vicinal P?C?C?H₁₀ coupling: this is ～20 Hz in the anti derivatives and ～6·0 Hz in their syn epimers. The long-range P,H₉ coupling is stereospecific, being maximum for a syn configuration.     

Two phosphonodehydrotripeptides: Boc0–Gly1–Δ(Z)Phe2–α‐Abu3PO3Me2 and Boc0–Gly1–Δ(Z)Phe2–α‐Nva3PO3Et2

The present paper reports the crystal structures of two short phosphonotripeptides (one in two crystal forms) containing one ΔPhe (dehydrophenylalanine) residue, namely dimethyl (3‐{[tert‐butoxycarbonylglycyl‐α,β‐(Z)‐dehydrophenylalanyl]amino}propyl)phosphonate, Boc⁰–Gly¹–Δ(Z)Phe²–α‐Abu³PO₃Me₂, C₂₁H₃₂N₃O₇P, (I), and diethyl (4‐{[tert‐butoxycarbonylglycyl‐α,β‐(Z)‐dehydrophenylalanyl]amino}butyl)phosphonate, Boc⁰–Gly¹–Δ(Z)Phe²–α‐Nva³PO₃Et₂, as the propan‐2‐ol monosolvate 0.122‐hydrate, C₂₄H₃₈N₃O₇P·C₃H₈O·0.122H₂O, (II), and the ethanol monosolvate 0.076‐hydrate, C₂₄H₃₈N₃O₇P·C₂H₆O·0.076H₂O, (III). The crystals of (II) and (III) are isomorphous but differ in the type of solvent. The phosphono group is linked directly to the last C_α atom in the main chain for all three peptides. All the amino acids are trans linked in the main chains. The crystal structures exhibit no intramolecular hydrogen bonds and are stabilized by intermolecular hydrogen bonds only.     

Synthesis and Structure of Novel Thieno[2, 3‐d]Pyrimidine Derivatives Containing 1, 3, 4‐Oxadiazole Moiety

The reaction of 5‐(1‐pyrrolyl)‐4‐methyl‐2‐phenylthieno[2, 3‐d]pyrimidine carbohydrazide 5 with CS₂ in the presence of pyridine afforded the 6‐(2, 3‐dihydro‐2‐mercapto‐1, 3, 4‐oxadiazol‐5‐yl)‐4‐methyl‐5‐(1‐pyrrolyl)‐2‐phenylthieno[2, 3‐d]pyrimidine 6 , which reacted with methyl iodide in the presence of sodium methoxide to yield the 6‐(2‐methylthio‐1, 3, 4‐oxadiazol‐5‐yl)‐4‐methyl‐5‐(1‐pyrrolyl)‐2‐phenyl‐thieno[2, 3‐d]pyrimidine 7. The 6‐(2‐substituted‐1, 3, 4‐oxadiazol‐5‐yl)‐2‐phenylthieno[2, 3‐d]pyrimidine derivatives 9, 11 and 13 were obtained by the condensation of 6‐(2‐methylthio‐1, 3, 4‐oxadiazol‐5‐yl)‐2‐phenylthieno[2, 3‐d]pyrimidine 7 with appropriate secondary amines. The structure of the new compounds was substantiated from their IR, UV‐vis spectroscopy, ¹H NMR, mass spectra, elemental analysis and X‐ray crystal analysis.     

Synthèse de sucres aminés ramifiés III. Synthèse et réactions de 1′α-amino-nitrile dérivé du di-O-isopropylidène-1,2:5,6-α-D-ribo-hexofurannosul-3-ose

The addition of cyanohydric acid to 1,2:5,6-di-O-isopropylidene-α-D -ribo-hexofurannos-3-ulose can be sterically controlled. Under kinetic conditions, the allo cyanohydrine epimer is formed, under thermodynamic conditions, the gluco epimer is formed. The configuration of these two products is proved by their chemical reactions. Hydration followed by hydrolysis of the nitrile group of the allo epimer (O-acetyl derivative) gives the 3-C-carboxy-1,2-O-isopropyloidene compound. This product forms the corresponding γ or δ-lactone with hydroxyl ( 5 ) or ( 6 ). On the other hand, after hydrolysis of 5,6-isopropylidene, the 3-O-acetyl derivative of the gluco epimer gives an acetyl migration from position 3 to position 5 and finally to position 6. By reaction of the allo epimer with NH₃ and CN^?, an aminonitrile is formed. The allo configuration is deduced from the above mentioned reaction and from IR. and NMR. data. Several acetylated and trifluoracetylated derivatives of these products are described. The oxidation of the nitrile group to the amide group is possible with both epimeric cyanohydrines and the amino-nitrile.     

Γ-Lakton-cis-anellierung an Δ2- und Δ3- Cholesten

γ-Lactone-cis-annulation to Δ²- and Δ³- Cholestene. From Δ²- and Δ³- cholestene the γ-lactones 11a , 11b , 12a , and 12b are synthesized through the dibromocarbene adducts 3 and 4 , the bromohydrines 5 and 6 , the oxapiropentanes 7 and 8 , and the cyclobutanones 9a , 9b and 10a , 10b , respectively. The ¹³C-NMR.-spectra of 1–8 and 11 as well as the ORD.-spectra of the cyclobutanones 9 and 10 are reported.     

Acyl- und Alkylidenphosphane. XXIV. (N,N-Dimethylthiocarbamoyl)trimethylsilylphosphane und 1,2-Di(tert-butyl)-3-dimethylamino-1-thio-4-trimethylsilylsulfano-1λ5,2λ3-diphosphet-3-en

Acyl- and Alkylidenephosphines. XXIV. (N,N-Dimethylthiocarbamoyl)trimethylsilyl-phosphines and 1.2-Di(tert-butyl)-3-dimethylamino-1-thio-4-trimethylsilylsulfano-1λ⁵, 2λ³-diphosphet-3-ene In contrast to bis(trimethylsilyl)phosphines R? P[? Si(CH₃)₃]₂ 1 {R ? H₃C a ; (H₃C)₃C b ; H₅H₆ c ; H₁₁C₉ d ; (H₃C)₃Si e }, the more nucleophilic lithium trimethylsilylphosphides 4 react with N,N-dimethylthiocarbamoyl chloride already at ?78°C to give (N,N-dimethylthiocarbamoyl)trimethylsilylphosphines 2 . Working up the reaction, a dismutation of the mesityl derivative 2d is observed, whereas the tert-butyl compound 2b dissolved in toluene, eliminates dimethyl(trimethylsilyl)amine to form 1,2-di(tert-butyl)-3-dimethylamino-1-thio-4-trimethylsilyl-sulfano- 1λ⁵, 2λ³-diphosphet-3-ene 6b , nearly quantitatively within several days at +20°C.     

Ringschlussreaktionen mit 2-(β-Styryl)benzylaminen 5-Phenyl-1H-2-benzazepine. 23. Mitteilung über siebengliedrige Heterocyclen

Cyclization reactions with 2-(β-styryl)benzylamines 5-Phenyl-1H-2-benzazepines Cyclization of the urea derivative 3 with POCl₃ to give 2-(4-methyl-1-piperazinyl)-4-phenylquinoline ( 4 ) was carried out in analogy to the quinoline synthesis of Foulds & Robinson. This reaction was used for the preparation of 2-benzazepines. The trisubstituted ureas 6 and 8 , derived from the 2-(β-styryl)-benzylamines 5 , were cyclized with POCl₃ to yield the 3-amino-5-phenyl-1H-2-benzazepines 7 and 9 , respectively. Similarly, cyclization of the corresponding acetyl-derivatives 10 gave the 3-methyl-5-phenyl-1H-2-benzazepines 12 . On the other hand, the disubstituted urea 15 , cyclized under the same conditions to the 1-methyl-1-phenylisoindoline derivative 16 , and 2-(β-styryl)benzylamine ( 5a ) on treatment with phosgene gave the isoindoline 17 in an analogous manner.     

Nucleoside und Nucleotide. Teil 10. Synthese von Thymidylyl-(3′-5′) -thymidylyl-(3′-5′)-1-(2′-desoxy-β-D-ribofuranosyl)-2(1 H)-pyridon

Nucleosides and Nucleotides. Part 10. Synthesis of Thymidylyl-(3′-5′)-thymidylyl-(3′-5′)-1-(2′-deoxy-β-D - ribofuranosyl)-2(1 H)-pyridone The synthesis of 5′-O-monomethoxytritylthymidylyl-(3′-5′)-thymidylyl-(3′-5′)-1-(2′-deoxy-β-D -ribofuranosyl)-2(1H)-pyridone ((MeOTr)T_dpT_dp∏_d, 5 ) and of thymidylyl-(3′-5′)-thymidylyl-(3′-5′)-1-(2′-deoxy-β-D -ribofuranosyl)-2(1 H)-pyridone (T_dpT_dp∏_d, 11 ) by condensing (MeOTr) T_dpT_d ( 3 ) and p∏_d(Ac) ( 4 ) in the presence of DCC in abs. pyridine is described. Condensation of (MeOTr) T_dpT_dp ( 6 ) with Π_d(Ac) ( 7 ) did not yield the desired product 5 because compound 6 formed the 3′-pyrophosphate. The removal of the acetyl- and p-methoxytrityl protecting group was effected by treatment with conc. ammonia solution at room temperature, and acetic acid/pyridine 7 : 3 at 100°, respectively. Enzymatic degradation of the trinucleoside diphosphate 11 with phosphodiesterase I and II yielded T_d, pT_d and p∏_d, T_dp and Π_d, respectively, in correct ratios.     

Reactions of Cyclohexyl Isocyanide with η5‐Substituted Cyclo‐pentadienyl MoMo Triply Bonded Complexes. Crystal Structure of [Mo(CO)2(η5‐C5H4CO2CH3)]2(μ‐η2‐CNC6H11)

Reactions of one or two equiv. of cyclohexyl isocyanide in THF at room temperature with Mo?Mo triply bonded complexes [Mo(CO)₂(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) gave the isocyanide coordinated Mo? Mo singly bonded complexes with functionally substituted cyclopentadienyl ligands, [Mo(CO)₂(η⁵‐C₅H₄R)]₂(μ‐η²‐CNC₆H₁₁) ( 1a , R=COCH₃; 1b , R=CO₂CH₃) and [Mo(CO)₂(η⁵‐C₅H₄R)(CNC₆H₁₁)]₂ ( 2a , R=COCH₃; 2b , R=CO₂CH₃), respectively. Complexes 1a , 1b and 2a , 2b could be more conveniently prepared by thermal decarbonylation of Mo? Mo singly bonded complexes [Mo(CO)₃(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) in toluene at reflux, followed by treatment of the resulting Mo?Mo triply bonded complexes [Mo(CO)₂(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) in situ with cyclohexyl isocyanide. While 1a , 1b and 2a , 2b were characterized by elemental analysis and spectroscopy, 1b was further characterized by X‐ray crystallography.     

Cluster chemistry. 61. Addition of HX (XCl,Br,I) or AuCl(PPh3) to an open Ru5 cluster. X-ray structures of Ru5(μ-H)(μ5-C2PPh2)(μ-PPh2)(μ-Br)(CO)13 and Ru5(μ-H)(μ5-C2PPh2)(μ3-I)(μ-PPh2)(CO)12

Reactions of aqueous HX (X?Cl, Br) or of AuCl(PPh₃) with Ru₅(μ₅-C₂PPh₂)(μ-PPh₂)(CO)₁₃ result in addition of the 4e-donor set (H + X) or (Au(PPh₃) + Cl) with concomitant opening of two Ru? Ru bonds to give complexes containing dimetallated triangular of ‘scorpion’ cores. Aqueous HI reacts similarly, but in this case the iodide ligand spans three Ru atoms, the (H + I) set acting as 6e-donor. The structures of the two title compounds were confirmed by X-ray crystallographic studies. Ru₅(μ-H)(μ₅-C₂PPh₂)(μ-PPh₂)-(μ-Br)(CO)₁₃ is triclinic, space group P1 , a = 9.689(2), b = 11.874(2), c = 20.005(4) Å, α = 84.66(2), β = 82.90(6), λ = 67.51(6)°, Z = 2; 6478 data with I > 2σ(I) were refined to R = 0.0368, R_w = 0.0362. Ru₅(μ-H)(μ₅-C₂PPh₂)(μ₃-I)(μ-PPh₂)-(CO)₁₂.CH₂Cl₂ is monoclinic, space group P2₁/n, a = 14.809(4), b = 20.721(4), c = 17.698(5) Å, β = 111.42(2)°, Z = 4; 7815 data with I > 2σ(I) were refined to R = 0.0440, R_w = 0.0416.