Acyl- und Alkylidenphosphane. XXVIII. Synthese und Struktur von 1,3-Dibenzyl- und 1,3-Diethyl-2,4-bis(phenylimino)-1,3-diphosphetan

Acyl- and Alkylidenephosphines. XXVIII. Synthesis and Structure of 1,3-Dibenzyl- and 1,3-Diethyl-2,4-bis(phenylimino)-1,3-diphosphetane Catalyzed by small amounts of solid sodium hydroxide, the adducts 1a and 1b formed from benzyl- or ethylbis(trimethylsilyl)phosphine and phenylisocyanate, react at +20°C slowly to give hexamethldisiloxane and oligomeric [(phenylimino)methylidene]phosphines. In different solvents the benzyl compound was found to exist only as a mixture of [N,N′-(E)/(Z)]-isomeric 2,4-bis-(phenylimino)-1,3-diphosphetanes 2a with their alkyl groups at the phosphorus atoms in trans position, whereas in case of the ethyl derivative 2b a second pair of [N,N′-(E)/(Z)]-isomeric dimers with their substituents in cis position and two trimeric forms ( 3b and 4b ) could be detected in cyclopentane. [N,N′-(E)]-1r,3t-dibenzyl- ( 2a ) and [N,N′-(E)]-1r,3t-diethyl-2,4-bis(phenylimino)-1,3-diphosphetane 2b isolated from 1,2-dimethoxyethane or cyclopentane, crystallize in the monoclinic space group P2₁/c or P2₁/n, resp., with following dimensions of the unit cell determined at temperatures of measurement of +20 ± 3°C/?130 ± 3°C: a = 2145.4(1)/569.3(1); b = 568.1(2)/719.1(2); c = 1960.2(2)/2042.6(4) pm; β 99.43(1)°/95.03(2)°; Z = (2+2) and 2, resp. X-ray structure determinations (R_w = 0.034/0.041) show both molecules to be centrosymmetric. Characteristic rounded bond lengths (pm) and angles (°) are: endocyclic P? C 185/184; C? P? C 82/81; P? C? P 98/99; exocyclic P? C 186/184; C?N l27/127; C?N? C 121/11.     

Thermolyse von Arylhalogenboranen; Synthese von 1,3-Dibora- und 1,3-Borasilaindanen

The thermolysis of the 2-silylated or borylated arylboranes (3a-g, or 9a,b) has been investigated. The synthesis of the unknown starting boranes succeeds upon treatment of the (o-(dichloroboryl)phenyl)trimethylsilane (3b) with trimethylalane (giving 3e), tetramethylstannane (giving 3f) or diisopropylamine (giving 3g) and upon trimethylation of the 1,2-bis(dichloroboryl)benzene (9a) with tetramethylstannane (giving 9b). In solution 3b,c, and 9a,b “dimerize” readily in a temperature range between 45 and 135°C with the liberation of halotrimethylsilanes or chloroboranes yielding the 9,10-dibora-9,10-dihydroanthracenes. The reaction mechanism is discussed. To force intramolecular reactions exclusively, flash vacuum pyrolyses (FVP) were performed at about 650°C. When pyrolyzing 3b elimination of hydrogen chloride occurs yielding 1,1-dimethyl-3-chloro-1-sila-3-boraindane (11). After pyrolysis of 11 at 750°C intramolecular, mutual migration of a chloro and a methyl group takes place. Possible rearrangement mechanisms are discussed and have been experimentally in investigated. Hydrogen chloride is the best leaving molecule in these pyrolyses. Extrusion of methanol (from (o-(dimethoxyboryl)phenyl)trimethylsilane (3d)) or methane (from 3e) gives the corresponding borasilaindanes only at 750°C and in lower yields. The synthesis of the very sensitive 1,3-dimethyl-1,3-diboraindane also succeeds by FVP (550°C) starting with 9b. The high-field shifts of the ²⁹Si and the ¹¹B NMR signals of the borasilaindanes compared to the chemical shifts of the corresponding parent bora- and silaindane systems are considered as evidence for a through-bond interaction between both hetero atoms.     

Synthese und reaktionen von 1-germcyclohexa-2,4-dienen und 1-germacyclohexa-2,4-dien-eisentricarbonylen

1,1-Diakyl(aryl)4-alkyl(aryl)-4-methoxy-1-germacyclohexa-2,5-dienes undergo ether cleavage with sodium in n-pentane or liquid ammonia. Hydrolysis of the resulting sodium salts yields the 1,1-dialkyl(aryl)-4-alkyl(aryl)-1-germacyclohexa-2,4-dienes. Reduction of 1-chloro-4-methoxy-1-germacyclohexa-2,5-dienes with LiAlH₄ can be directed to give the 1H-1-germacyclohexa-2,4-dienes with ether cleavage.The 1H-1-germacyclohexadienes are chlorinated by PCl₅ and brominated by N-bromosuccinimide to the 1-chloro- or 1-bromo-1-germacyclohexa-2,4-dienes, respectively. 1,1-Diethyl-4-phenyl-4-methoxy-1-germacyclohexa-2,5-diene reacts with PCl₃ with ether cleavage and formation of the 6-chloro-1-germacyclohexa-2,4-diene. Ether cleavage is also possible with BCl₃, the 1-phenyl-1-chloro-4R-4-methoxy-1-germacyclohexa-2,5-dienes are transformed into the 1-phenyl-1,6-dichloro-4R-1-germacyclohexa-2,4-dienes.The Fe(CO)₃ complexes of 1,1-dialkyl(aryl)-1-germacyclohexa-2,4-dienes were synthesized.     

The vibrational spectra of some 1,3-dimethyl-1,3-diaza-2-boracyclopentanes

A detailed vibrational assignment is proposed for 1,3-dimethyl-1,3-diaza-2-boracyclopentanes:

where X = Cl, Br or NMe₂. The assignments are generally in accord with C_2v symmetry, but there is some evidence for a slight breakdown, as some A₂ modes appear in the IR. The BN₂ stretches are near 1500 cm^?1, (antisymmetric) and 1300 cm^?1 (symmetric), consistent with a large degree of π-bonding.     

Synthese,Eigenschaften und NMR-spektroskopische Untersuchungen an 2,4-Dithioxo-2,4-dimercapto-1,3-diaza-2λ5,4λ5-diphosphetidinen

Synthesis, Properties and N.M.R. Spectroscopic Studies of 2,4-Dithioxo-2,4-dimercapto-1,3-diaza-2λ⁵,4λ⁵-diphosphetidines On the reaction of py · PS₂Cl ( 1 ) or py · PS₂F ( 2 ) (py = Pyridine) with hexamethyl disilazane in a molar ratio of 1:1 the pyridinium salt of the 1,3-bis(trimethylsilyl)-2,4-dimercapto-2,4-dithioxo-1,3-diaza-2λ⁵, 4λ⁵-diphosphetidine ( 3 ) is formed. 3 reacts with MeI to the corresponding methyl ester 9 . There exist two isomers of 9 , probable with cis and trans configuration of the MeS groups, respectively. 3 and 9 have been characterized by i.r., Raman, mass, and NMR spectroscopy. 4 reacts in acetonitrilic solution in the presence of water under hydrolytic cleavage of the trimethyl silyl groups whereas the P₂N₂ ring is preserved. The hydrolysis of 9 has been studied by ¹H-, ³¹P-, and ¹³C-NMR spectroscopy.     

Synthese,Struktur und Reaktivität eines 2,4-Diphosphino-1,3-diphospha-2,4-disilacyclobutans

Synthesis, Structure, and Reactivity of a 1,3-Diphosphino-2,4-diphospha-1,3-disilacyclobutane Pentamethylcyclopentadienyltrichlorosilane reacts with Li[Al(PH₂)₄] to give the stable 1,3-diphosphino-2,4-diphospha-1,3-disilacyclobutane 4 . Treatment of 4 with Lithium alkyls affords the Lithium phosphide 5 via regiospecific metalation of a ring phosphorus atom, and reaction with t-Bu₂Hg proceeds via oxidative P? P bond formation to yield the 1,4-disila-2,3,5,6-tetraphospha-bicyclo[2,1,1]-hexane 6 . Cleavage of pentamethylcyclopentadiene is observed during thermolysis of 4 at 200°C. 4–6 were characterised by NMR-spectroscopy, and 4 by an additional crystal structure determination.     

Synthese von 1,3-dithiethanderivaten

The reactions of the anilide of β-anilinecinnamic acid and its fluoroderivatives with thiophosgene have been investigated. The acylation process gave in each case a mixture of ‘cis’ and ‘trans’ isomers of 2,4-bis-(phenylcarbamoyl-benzalaniline-methylene)-1,3-dithiethane. The structures of the new products were confirmed by spectroscopy and by alkaline hydrolysis.     

Synthese und Hydrolyse von 1,3-Dihydro-1,3,2-benzodiazaphosphol-2-oxiden

Zusammenfassung Verschiedene 1,3-Dihydro-1,3,2-benzodiazaphosphol-2-oxide und entsprechende Bisverbindungen wurden hergestellt. Einige der Verbindungen konnten nur ohne Lösungsmittel bei Temperaturen bis zu 250°C in guter Ausbeute und in großer Reinheit erhalten werden.Bei der Hydrolyse werden meist beide P–N-Bindungen gespalten, und es entsteht das Monosalz der Phosphonsäure mit dem Diamin; dieses Salz ist identisch mit dem aus den beiden Komponenten direkt erhaltenen.

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Various 1.3-dihydro-1.3.2-benzodiazaphosphole-2-oxides and the corresponding bis phosphole oxides have been prepared. Some of the compounds allowed to be prepared in satisfactory yield and high purity only in the absence of solvents at temperatures up to 250°C.Hydrolysis usually entailed cleavage of the two P–N-bonds, and interaction with the diamine yields the monosalt of phosphonic acid; this salt is identical with that obtained by direct interaction of the two reactants.

     

Synthese und Reaktionsverhalten von 6-sec-Amino-1,3-thiazin-2-thionen

The title compounds3 have been prepared by ring transformation reactions of the isomeric 2-sec-amino-1,3-thiazine-6-thiones1 via ring-opening products2 and by special cyclocondensation reactions with thiocarboxamides8, and with iminium salts10, starting from 2,2-dichlorovinyl ketones6 in all cases. The pathways differ specifically in scope and limitations. On the other hand the intermediates2 react with alkylating agents to 2,6-di-sec-amino-1,3-thiazinium salts4, which are also available via alkylation of3 to 2-methylthio-1,3-thiazinium salts11 and aminolysis. Moreover,11 serve as useful precursors for other 1,3-thiazine derivatives by nucleophilic methylthio displacement (examples12).

     

Synthese und chemie von 4R-silacyclohexa-2,5-dienen und 4R-silacyclohexa-2,4-dienen

The 1(Z),4(Z)-1,5-dilithium-3R-3-methoxypenta-1,4-dienes, available by cleavage of 1,1-di-n-butyl-4R-4-methoxy-1-stannacyclohexane-2,5-dienes with n-BuLi in ether, react with dichlorosilanes (R′R″ SiCl₂; R′, R″ = H, alkyl, aryl, alkoxy) to give 1R′,1R″,4R-4-methoxy-1-silacyclohexa-2,5-dienes.Claevage of the ether group with BBr₃, BCl₃ or PCl₃ gives 6-chloro(bromo)-1-silacyclohexa-2,4-dienes or 1,5-dichloro-1-silacyclohexane-2,4-dienes, respectively.Ether cleavage of 4R-4-methoxy-1-silacyclohexa-2,5-dienes with sodium results in the formation of 4R-1-silacyclohexadienyl anions, which can be hydrolyzed to give 1-silacyclohexa-2,4-dienes which reach further with trichloromethylsilane to give 6-trimethylsilyl-1-silacyclohexa-2,4-dienes.Phase transfer-catalyzed conversion of 1-chlorosilacyclohexadienes into the fluoro derivatives as well as further substitution reactions of 1-chlorosilacyclohexadienes are described.The ¹H NMR, ¹³C NMR, IR and mass spectra of the silacyclohexadienes are discussed.     

Zur Synthese sulfonierter Derivate von 4-Amino-1,3-dimethylbenzol und 2-Amino-1,3-dimethylbenzol

Syntheses of Sulfonated Derivatives of 4-Amino-1, 3-dimethylbenzene and 2-Amino-1, 3-dimethylbenzene Direct sulfonation of 4-amino-1, 3-dimethylbenzene (1) and sulfonation of 4-nitro-1,3-dimethylbenzene ( 4 ) to 4-nitro-1,3-dimethylbenzene-6-sulfonic acid ( 3 ) followed by reduction yield 4-amino-1,3-dimethylbenzene-6-sulfonic acid ( 2 ). The isomeric 5-sulfonic acid ( 5 ) however is prepared solely by baking the acid sulfate salt of 1 . Reaction of sulfur dioxide with the diazonium chloride derived from 2-amino-4-nitro-1,3-dimethylbenzene ( 7 ) leads to 4-nitro-1,3-dimethylbenzene-2-sulfonyl chloride ( 8 ), which is successively hydrolyzed to 4-nitro-1,3-dimethylbenzene-2-sulfonic acid ( 9 ) and reduced to 4-amino-1, 3-dimethylbenzene-2-sulfonic acid ( 6 ). Treatment of 4-amino-6-bromo-1,3-dimethylbenzene ( 12 ) and 4-amino-6-chloro-1, 3-dimethylbenzene ( 13 ), the former obtained by reduction of 4-chloro-6-nitro-1,3-dimethyl-benzene ( 10 ) and the latter from 4-chloro-6-nitro-1, 3-dimethylbenzene ( 11 ), with oleum yield 4-amino-6-bromo-1,3-dimethylbenzene-2-sulfonic acid ( 14 ) and 4-amino-6-chloro-1,3-dimethylbenzene-2-sulfonic acid ( 15 ) respectively; subsequent carbon-halogen hydrogenolyses of 14 and 15 lead also to 6 (Scheme 1). Baking the acid sulfate salt of 2-amino-1, 3-dimethylbenzene ( 17 ) gives 2-amino-1, 3-dimethylbenzene-5-sulfonic acid ( 16 ), whereas the isomeric 4-sulfonic acid ( 18 ) can be prepared by either of the following three possible pathways: Sulfonation of 2-nitro-1,3-dimethylbenzene ( 20 ) to 2-nitro-1,3-dimethylbenzene-4-sulfonic acid ( 21 ) followed by reduction or sulfonation of 2-acetylamino-1,3-dimethylbenzene ( 19 ) to 2-acetylamino-1,3-dimethylbenzene-4-sulfonic acid ( 22 ) with subsequent hydrolysis or direct sulfonation of 17 . Further sulfonation of 18 yields 2-amino 1,3-dimethylbenzene-4,6-disulfonic acid ( 23 ), the structure of which is independently confirmed by reduction of unequivocally prepared 2-nitro- 1,:3-dimethylbenzene-4,6-disulfonic acid ( 24 )(Scheme 2).