Perfluoroalkyl derivatives of nitrogen. Part LI [1]. Reaction of the N-halogenobistrifluoromethylamines (CF3)2NX (X=Cl,Br) with norbornadiene

Reaction of the amines (CF₃)₂NX (X=Cl,Br) with norbornadiene either in solvent (CH₂Cl₂) at ?78 °C in the dark or in the vapour phase at 20 °C in daylight gives a mixture of 3-halogeno-5-($\text{NN}$-bistrifluoromethylamino)nortricyclene ($\text{exo}$, $\text{endo}$-and $\text{exo}$, $\text{exo}$-isomers) and $\text{exo}$-5-($\text{NN}$-bistrifluoromethylamino)- $\text{anti}$-7-halogenonorbornene in quantitative yield formed $\text{via}$ halonium ion addition to the diene. The reaction of the amine (CF₃)₂NBr in solvent Me₂O or Et₂O at ?78 °C in the dark gives the same products in low yield, together with 3-bromo-5-alkoxynortricyclene ($\text{exo}$, $\text{endo}$- and $\text{exo}$, $\text{exo}$-isomers) and the amine (CF₃)₂NR (R=Me, Et) in high yield.     

The optical absorption and emission spectra of Cs2NaSmCl6

Optical absorption and emission spectra are reported for single crystals of the cubic elpasolite Cs₂NaSmCl₆. The variable temperature spectra obtained at high resolution are assigned using energies and relative intensities. Transitions from the ground level, ⁶H_{$\text{5}\text{2}$} to cystal fi levels of ⁶H_{$\text{7}\text{2}$-$\text{15}\text{2}$}, ⁶F_{$\text{1}\text{2}$-$\text{11}\text{2}$}, ⁴G_{$\text{5}\text{2}$-$\text{9}\text{2}$}, ⁴F_{$\text{3}\text{2}$,$\text{5}\text{2}$}, ⁴I_{$\text{9}\text{2}$}, and ⁶P_{$\text{3}\text{2}$, $\text{5}\text{2}$} are located and characterized. Intensity calculations are reported for magnetic dipole allowed transitions. The dominance of vibronic intensity in ⁶H_{$\text{5}\text{2}$}→⁶F _{$\text{1}\text{2}$-$\text{9}\text{2}$} and ⁶P_{$\text{3}\text{2}$, $\text{5}\text{2}$} transitions is accounted for qualitatively through the ligand polarization model involving quadrupole metal (Sm³⁺)-ligand (Cl^?) interaction mechanisms. The E_u″(⁶H_{$\text{5}\text{2}$})→E′(⁶H_{$\text{1}\text{2}$}) E_u′(⁶F_{$\text{1}\text{2}$}) no-phonon transition is postulated to be pure electric quadrupole allowed. The ground state magnetic moment is determined to be very small from magnetic circular dichroism (MCD) spectra.This study has led to the assignment of nearly all of the crystal field levels in the visible and IR region for Cs₂NaSmCl₆. A total of 27 such levels were identified, 17 from no-phonon transitions and the rest from vibronic transitions. The magnetic dipole intensity calculated using intermediate coupling O_h wavefunctions along with a crystal field analysis of the splitting pattern was used in the assignment of the levels. Vibronic bands were observed for all transitions and their vibrational symmetries were tentatively assigned. MCD data were used to determine the magnet moment of the ground state.     

An unusual chlorination of 1-phenyl-4-(2,6-dichlorophenyl)-1,3-butadiene

The diene $\text{1a}$ reacted with CHCl₃/aq. NaOH/PTC in CH₂ Cl₂ unexpectedly to give a mixture of the chlorination products $\text{2}$ and $\text{3a}$. Usual chlorination with Cl₂ yielded similarly $\text{2}$, $\text{3a}$, and $\text{3b}$ dependent on the amount of Cl₂. The formation of $\text{2}$ as well as the reaction of $\text{7}$ to give $\text{9}$ (besides $\text{8}$) shows an unusual Cl-Cl-interaction.     

Reaktionen an komplexgebundenen Liganden. XXXII.: Synthese und eigenschaften von heteronuklearen mangan-chrom-komplexen mit distickstoff- diazen- und hydrazin-brükenliganden

Synthesis and properties of C₅H₅(CO)₂Mn-N₂H₄-Cr(CC)₅$\text{(1)}$, C₅H₅(CO)₂Mn-N₂H₂-Cr(CO)₅$\text{(2)}$ and C₅H₅(CO)₂Mn-N₂-Cr(CO)₅$\text{(3)}$ are reported. $\text{(1)}$, $\text{(2)}$ and $\text{(3)}$ constitute the first series of heteronuclear complexes in which N₂, N₂H₂ and N₂H₄ are bound to identical metal centers. $\text{(1)}$ and $\text{(3)}$ are obtained by reacting C₅H₅Mn(CO)₂N₂H₄ respectively with Cr(CO)₅THF, $\text{(2)}$ by oxidation of $\text{(1)}$. $\text{(2)}$ disproportionates by addition of base yielding $\text{(3)}$ and H₂. The IR Spectrum of $\text{(2)}$ allows the assignment of five normal vibrations of the diazene ligand; in the IR spectrum of the deuterated analogue all six normal vibrations can be assigned. The ¹H-NMR spectrum of $\text{(2)}$ yields the coupling constant of protons on NN double bonds for the first time; the value of ³J_HH  23,5 Hz points to a trans structure of $\text{(2)}$.     

Methylated multibridged [2n]cyclophanes. All alternate synthesis of [26](1,2,3,4,5,6) cyclophane (superphane)

A sequence of formylation followed by a carbene insertion reaction has led to the stepwise introduction of additional ethano bridges into 4,5,7,8- tetramethyl [2₂](1,4)cyclophane ($\text{1}$), providing syntheses of 5,7,8-trimethyl- [2₃](l,2,4)cyclophane ($\text{6}$), a mixture of 5,8-dimethyl[2₄(1,2,4,5)cyclophane ($\text{10}$) and 5,7-dimethyl[2₄(1,2,3,5)cyclophane ($\text{11}$, and-4-methyl[2₅](1,2,3,4,5)-cyclophane ($\text{14}$). This route to $\text{14}$ completes a formal eight-step synthesis of [2₆](1,2,3,4,5,6)cyclophane ($\text{15}$, superphane) with an overall yield of 17%. A Birch reduction of $\text{6}$ readily gave 12,15-dihydro-5,7,8-trimethyl[2₃](1,2,4)-cyclophane ($\text{7}$) in 85% yield.     

Yield of I(2Psol:12) in the photodissociation of CH2I2

The production of I(²P_{$\text{1}\text{2}$}) in the photolysis of CH₂I₂ has been studied optoacoustically at excitation wavelengths between 365.5 and 247.5 nm. Bands found at 32200 and 47000 cm^?1 correlate with I(²P_{$\text{3}\text{2}$}) whilst those at 34700 and 40100 cm^?1, which correlate with I(²P_{$\text{1}\text{2}$}), give final ²P_{$\text{3}\text{2}$}/²P_{$\text{1}\text{2}$} ratios of 1.75 and 1.1, respectively, after curve crossing.     

The oxidation of the benzotropylium cation

Oxidation of benzotropylium ($\text{1}$) fluoborate with Na₂O₂ and KO₂ gives the benzotropones, $\text{5}$ and $\text{6}$, as the major products with no naphthalene ($\text{9}$) or other ring contracted products formed. Oxidation with $\text{m}$-chloroperoxybenzoic acid produces a small amount of naphthaldehydes ($\text{10}$ and $\text{11}$) and even less naphthalene, a long with the benzotropones, while oxidation with H₂O₂ and $\text{t}$-butyl peroxyacetate gives slightly more of the ring contracted naphthaldehydes than benzotropones, in addition to a small quantity of naphthalene. All reactions produce some 1,2-benzotropilidene ($\text{8}$)     

Organomercury compounds XX Reactions of lithium polyfluorobenzenesulphinates with mercuric salts

The lithium polyfluorobenzenesulphinates, Li O₂SR (R = C₆F₅, $\text{p}$-HC₆F₄, $\text{m}$-HC₆F₄, or $\text{o}$-HC₆F₄), and the dilithium tetrafluorobenzenedisulphinates, $\text{p}$- and $\text{o}$-(LiO₂S)₂C₆F₄, have been prepared by reaction of the appropriate polyfluoroaryllithium compounds with sulphur dioxide. All compounds were isolated as hydrates and gave the corresponding $\text{S}$-benzylthiouronium salts on treatment with $\text{S}$-benzylthiouronium chloride. From reactions of the lithium sulphinates with suitable mercuric salts in water, generally at room temperature, the derivatives RHgX (R = C₆F₅, X = Cl, Br, CH₃CO₂, or PhSO₂; R = $\text{p}$-HC₆F₄, X = Cl, Br, or CH₃CO₂; R = $\text{m}$-HC₆F₄, X = Cl or Br; R = $\text{o}$-HC₆F₄, X = Cl), $\text{p}$-(XHg)₂C₆F₄ (X = Cl, Br, or CH₃CO₂), and $\text{o}$-(XHg)₂C₆X₄ (X = Cl or Br) have been prepared. Similarly, the bispolyfluorophenylmercurials R₂Hg (R = C₆F₅, $\text{p}$-HC₆F₄, or $\text{m}$-HC₆F₄) have been prepared from the corresponding lithium sulphinates and either mercuric salts or polyfluorophenylmercuric halides in aqueous $\text{t}$-butanol. A possible mechanism for the sulphur dioxide elimination reactions is discussed.     

An electrochemical chlorinative ene-type reaction of isoprenoids

The chlorinative ene-type reaction of isoprenoids ( $\text{1}$ → $\text{2}$ ) has been performed by electrolysis in CH₂Cl₂-H₂O-NaCl system. The reaction provides useful allylic chlorides $\text{2}$ for terpene synthesis in high yields and is affected strikingly by the nature of halide ions and solvents. dl-Theaspirane $\text{2}$$\text{1}$ was prepared from α-dihydroionol $\text{via}$ the electrolysis.     

A practical synthesis of fluoromethyltriphenylphosphonium salts

A practical synthesis of [Ph₃$\text{P}\text{+}$CH₂F]BF₄^? is reported $\text{via}$ two routes, $\text{via}$ fluorination of [Ph₃$\text{P}\text{+}$CH₂OH]BF₄^? with DAST or $\text{via}$ hydrolysis of the phosphoranium salt, [Ph₃$\text{P}\text{+}$$\text{C}$F$\text{P}\text{+}$Ph₃]Br^?.     

On the mechanism of the formation of benzocyclobutene by flash vacuum pyrolysis of ortho-methylbenzyl chloride

Flash vacuum pyrolysis of $\text{o}$-methylbenzyl chloride-$\text{∝}$,$\text{∝}$-$\text{d}$₂ gives benzocyclobutene-$\text{∝}$,$\text{∝}$-$\text{d}$₂. This finding indicates that the reaction involves net δ-elimination of hydrochloric acid.     

A case of oligomerization on attempted chlorination of an α-hydroxy acetal with the triphenylphosphine tetrachloromethane reagent

Treatment of methyl 3,5-dideoxy-β-$\text{D}$-$\text{erythro}$-pentofuranoside $\text{8}$ with the Ph₃P-CCl₄ reagent gave none of the expected 2-chloro derivative but a mixture of l→2 linked oligosaccharides, $\text{9}$, $\text{10}$ with some higher homologues, terminated by αa 2-chloro-2,3,5-trideoxy-α-$\text{D}$-$\text{threo}$-pentofuranosyl unit at the non reducing end.     

Trimethymetall-urotropinaddukte des aluminiums,galliums, indiums und thalliums

Reactions of urotropine (C₆H₁₂N₄) with trimethylmetal derivatives of Al, Ga, In und Tl in various ($\text{1}\text{1}$$\text{1}\text{4}$) molar ratios lead to stable and monomeric $\text{1}\text{1}$, $\text{1}\text{2}$ or $\text{1}\text{3}$ adducts in good yields, but no $\text{1}\text{4}$ addition product could be isolated. The vibrational spectra (IR and Raman) of all compounds are recorded and partly assigned. Some characteristic frequencies of the C₆N₄-skeletons clearly show the symmetry changes in the series of the $\text{1}\text{1}$ → $\text{1}\text{2}$ → $\text{1}\text{3}$ adducts (C_3ν → C_2ν → C_3ν). The X-ray structure determinations of C₆H₁₂N₄·.GaMe₃ (MeCH₃) and C₆H₁₂N₄·.2GaMe₃, are in good agreement with the vibrational spectra. Both compounds crystallize in monoclinic space groups (P2₁ and C2/c). The GaN distances are around 214 pm, and the values for the C₆N₄-skeletons are not significantly different from those for free urotropine.     

Conformationally selective transannular cyclizations of humulene 9,10-epoxide. Synthesis of the two skeletally different cyclohumulanoids: dl-bicyclohumulenone and dl-africanol

Two cyclohumulanoids, dl-bicyclohumulenone ($\text{4}$) and dl-africanol ($\text{7}$ were synthesized through newly developed conformationally selective transannular cyclization of humulene 9,10-epoxide ($\text{2}$). The epoxide $\text{2}$ was converted to a bicyclohumulenediol diacetate $\text{3a}$ in 70% yield by treatment with BF₃·OEt₂-Ac₂O, while treatment of $\text{2}$ with trimethylsilyl trifluoromethansulfonate gave an africen-10-ol ($\text{5}$a and $\text{5}$b) in 80% yield. The two intermediates $\text{3a}$ and $\text{5a}$ furnished the natural products $\text{4}$ and $\text{7}$ in 30 and 8 % yield from $\text{2}$ respectively.     

[2+2]-Cycloadditionen von vinylkationen

The vinylbromides $\text{1a}$ and $\text{1b}$ are allowed to react ith AgBF₄ and AgPF₆ in the presence of various olefins in CH₂Cl₂ as the solvent. Except for the reaction of cyclopentene with $\text{1a}$ all other olefins used, react with vinyl cation $\text{2}$ to form the cycloaddition products $\text{7}$, $\text{8a}$ and $\text{8b}$ in high yields.     

Adenosine cyclic 3′,5′-(RP)- and (SP)-phosphoramidates,the first representatives of nucleoside cyclic 3′,5′-phosphoramidates derived from ammonia

Adenosine cyclic 3′,5′-phosphoramidate $\text{2}$ was synthesized by reacting adenosine cyclic 3′,5′-phosphate $\text{1}$ with POCl₃, in trimethyl phosphate for 1 h at O°C, followed by in situ treatment of the reaction mixture with a suspension of (NH₄)₂CO₃ in anhydrous DMF or pyridine or DMF/pyridine mixture for 30 min at 25° C. Diastereoisomers ($\text{R}$_P)-$\text{2}$ and ($\text{S}$_P)-$\text{2}$ the relative quantities of which depended on the solvent of (NH₄)₂CO₃ treatment, were separated by reversed phase partition chromatography. Hydrolysis of (R_P)-$\text{2}$ and (S_P)-$\text{2}$ proceeded with predominant (90% in 0.1 N HCl, 100% in 0.1 N NaOH) -P-O-C bond breaking.     

Thermodynamics of metal-ligand bond formation: XVI. Base adducts of some organotin compounds

Thermodynamic data have been obtained by calorimetric titration in benzene solution at 30° for reaction of organotin compounds with Lewis bases; data are reported for forty acid/base systems.Ph₃SnCl forms $\text{1}\text{1}$ adducts of low stability with pyridine (py) or 4-methyl-pyridine (4-mepy). Ph₂SnCl₂, Me₂SnCl₂, Bu₂SnCl₂ and Bu₂Sn(NCS)₂ form simultaneously $\text{1}\text{1}$ and $\text{1}\text{2}$ adducts with py or 4-mepy and $\text{1}\text{1}$ adducts with 2,2′-bipyridine or 1,10-phenanthroline (phen); the enthalpies of formation of the phen adducts are similar to those of $\text{1}\text{2}$ adducts with 4-mepy. With BuSnCl₃ and PhSnCl₃ it was not possible to obtain data for each step in addition of pyridine or 4-mepy. Adduct stabilities increase with increasing chloride substitution and in the order Bu < Me < Ph; adducts of Bu₂Sn(NCS)₂ are more stable than those of Bu₂SnCl₂.Tributylphosphine does not react with Ph₃SnCl but gives $\text{1}\text{1}$ adducts with the other tin compounds; only PhSnCl₃ adds a second molecule of this base. The $\text{1}\text{1}$ adducts are more stable than those with heterocyclic bases. Tributylamine brings about disproportionation of the compounds R₂SnX₂ to R₄Sn and SnX₄NBu₃.     

Acid-catalysed decomposition of (20 R) and (20 S)-20-azido-5α-pregnane : bis steroids Schiff base formation via imine coupling.

BF₃-OEt₂ decompostion of azides $\text{1}$ or $\text{2}$ leads to the coupling product Schiff base $\text{6}$$\text{via}$ imine intermediates.     

Etude de l''addition des organomagnesiens satures et benzyliques aux enynes conjugues, simples et fonctionnels

Saturated and benzylic organomagnesium compounds are shown to readily undergo addition reactions with the conjugated enynes H$\text{C}\text{4}$$\text{C}\text{3}$C$\text{H}\text{2}$$\text{C}\text{1}$HCH₂R′, with R′ = alkyl, OH, OC₄H₉, NHC₂₅, N(C₂H₅)₂, by refluxing for several hours in benzene or toluene.This reaction leads to both υ-acetylenic compounds (1,2-addition) and β-allenic compounds (1,4-addition).     

Micellar alkylation: a methylating surfactant

Micellar $\text{n}$-C₁₆H₃₃$\text{N}\text{+}$(CH₃)₂CH₂$\text{S}\text{+}$(CH₃)₂, 2CF₃SO₃^? rapidly methylates bound thiophenoxide ions.