TRITHIA-DIPHOSPHABIYCLO[2.2.1]HEPTANE

Abstract

3,6-Dialkyl-2,5-Dithioxo-1,4,2λ⁵,5λ⁵-dithiadiphosphorinan-2,5-disulfides (1) react with PSCI₃, to give 3,6-Dialkyl(diaryl)-1,4-dithioxo-2,5,7-trithia-lλ⁵,4λ⁵ diphosphabicyclo[2.2.1]heptanes (2). The reaction mechanism of their formation. and the stereochemistry are discussed. By reduction of 2 with (n-C₄H₉)₃P or (C₆H₅),P 3,6-Dialkyl-2,5,7-trithia-1λ³,4λ³-diphosphabicyclo[2.2.1]heptanes (3) are formed. 2c reacts with one mole of (C₆H₅)₃P to give 3,6-Diethyl-l-thioxo-2,5,7-trithia-lλ⁵,4λ³- diphosphabicyclo(2.2.1]heptane, 4c.

3,6-Dialkyl-2,5-dithioxo-1.4,2λ⁵,5λ⁵-dithiadiphosphorinan-2,5-disulfide (I) reagieren mit PSCI₃ zu 3,6-Dialkyl(diaryl)-1,4-dithioxo-2,5,7-trithia-lλ⁵,4λ⁵-diphosphabicyclo[2.2.l]heptanen (2). Der Reaktionsmechanismus ihrer Bildung und ihre Stereochemie werden diskutiert. Die Reduktion von 2 mit (n-C₄H₉)₃,P oder (C₆H₅)₃P führt zu 3,6-Dialkyl-2,5,7-trithia-1λ³,4λ³-diphosphabicyclo[2.2.1] heptanen(3). 2c reagiert mit einer äquimolaren Menge (C₆H₅)₃,P zu 3,6-Diethyl-l-thioxo-2,5,7-trithia-lλ⁵,4λ³- diphosphabicyclo[2.2.1]heptan, 4c.     

New Approach to Synthesis of Tetrahydroisoquino[2,l-c] [1,3]-benzodiazepine

A concise and efficient synthesis of the new compounds tetrahydroisoquino [2,1-c] [1,3] benzodiazepine 5 and 7 is reported.     

Über die Kronenetherkomplexe [K(15-Krone-5)2]3[Sb3I12], [TeCl3(15-Krone-5)][TeCl5] und [TeCl3(15-Krone-5)]2[TeCl6]

On the Crown Ether Complexes [K(15-Crown-5)₂]₃[Sb₃I₁₂], [TeCl₃(15-Crown-5)][TeCl₅], and [TeCl₃(15-Crown-5)]₂[TeCl₆] Orange-coloured crystals of [K(15-crown-5)₂]₃[Sb₃I₁₂] are formed in the reaction of potassium iodide with antimony triiodide and 15-crown-5 in acetonitrile solution. An X-ray structure determination reveals severe disorder of the crown ether molecules, which coordinate to the potassium atoms in a sandwich array; so only the [Sb₃I₁₂]^3? ion and the potassium positions were ascertained. The anion is a centrosymmetric trimer (symmetry C_2h), which can be understood as central SbI₆^3? ion, coordinated by two SbI₃ molecules. (Space group C2/m), Z = 2, 3263 observed, independent reflections, R = 0.06, lattice dimensions at 20°C: a = 2541.1 pm, b = 1441.7 pm, c = 1588.4 pm, β = 113.33°. The tellurium complexes [TeCl₃(15-crown-5)] [TeCl₅] and [TeCl₃(15-crown-5)]₂[TeCl₆] are prepared by reaction of TeCl₄ with 15-crown-5 in acetonitrile solution, forming yellow-green crystals sensitive to moisture. They are characterized by their i.r. spectra.     

An Interesting Approach to Bis-calix[5]arene Analogue from Calix[6]arene

Calix [n] arenas {n = 4, 6 or 8} are easily prepared from formaldehyde and para-substituted phenols via cyclic condensation under alkaline conditions in one step. It is not surprising that the calyx [n] arene (n = 4, 6, 8) chemistry has been developing very rapidly during the latest 20 years1. However, it is not the case for calixarenes with odd benzene rings (for example, n = 5). The yield of p-tert-butylcalix [5] arene synthesized in one-step from p-tert-butylphenol and formaldehyde was a…     

Synthesis of Imidazo[1,2-c]pyrazolo [4,3-e]pyrimidines Derived From Indole and Related Heterocycles

Summary. The syntheses of the title heterocycles were achieved using 5-amino-1-(1-benzyl-1H-indol-3-ylcarbonyl)-1H-pyrazole-4-carbonitrile as starting material. These compounds were converted into the 4-imidazolinyl derivatives which were subjected to cyclization reactions to afford the title compounds.     

Phenylethinyl-[1,3,2]dithiaphospholan. Bis(dithiaphospholanyl)-[1,4]dithian

Phenylethinyl-[1,3,2]dithiaphospholane. Bis(dithiaphospholanyl)-[1,4]dithiane Nucleophilic substitution of the amino group but no cycloaddition occurs in the reaction of phenyl phenylethinyl phosphinous acid diethylamide, 5 , with 2-aminothiophenol forming compound 6 . By analogous reaction, phenylethinyl phosphonic bis(diethylamide), 7 , and ethane-1,2-dithiol form compound 8 . Cycloaddition besides nucleophilic substitution is observed, however, when acetylene bis(phosphonic diethyl-amide), 9 , and ethane-1,2-dithiol are reacted resulting in compound 11 . All new products are characterized by their nmr, mass, and i.r. spectra. Furthermore, the results of an X-ray structure analysis of 11 are reported.     

Isomerization of bicyclo[5.1.0]-2,4-octadieneiron tricarbonyl to bicyclo[4.2.0]-2,4-octadieneiron tricarbonyl

It has been shown that bicyclo[5.1.0]-2,4-octadieneiron tricarbonyl undergoes thermal isomerization to bicyclo[4.2.0]-2,4-octadieneiron tricarbonyl. The first-order rate constant for this process at 120.6° was determined to be 1.8 X 10^?5 s^?1 which corresponds to ΔF³ = 31.8 kcal/mol. Gas chromatographic results coupled with a kinetic analysis very strongly suggest that 1,3,5-cyclooctatrieneiron tricarbonyl is an intermediate in this isomerization. Two plausible mechanisms are offered to explain this rearrangement.     

Synthesis of Structurally Related Purines: Benzimidazo[1,2-a]pyridines, Benzimidazo-[1,2-c]pyrimidines, and Pyrazolo-[1,5-a]pyrimidines

Summary.  Reactions of sodium salts of 3-hydroxymethylene-2-alkanones with 2-cyanomethylbenzimidazole afforded benzimidazo[1,2-a]pyridines. Analogues reactions with 2-aminobenzimidazole and 5-aminopyrazoles afforded benzimidazo[1,2-c]pyrimidines and pyrazolo[1,5-a]pyrimidines. Received December 12, 1999. Accepted (revised) February 12, 2000     

Photochemical and thermal transformations of 7-silabicyclo[2.2.1]Heptadiene and 7-silabicyclo[2.2.1]heptene systems

2,3-Dicarbomethoxy-7,7-dimethyl-7-silabicyclo[2.2.1]hepta-2,5-diene (III) on photolysis gave dimethyl tetraphenylphthalate whereas the photolysis of 7,7-dimethyl-7-silabicyclo[2.2.1]hep-5-ene-2,3-dicarboxylic anhydride (XIa) resulted in the formation of 1,1-dimethyl-2,3,4,5-tetraphenyl-1-silacyclopentadiene (XIIIa). The thermolysis of XIa also gave rise to XIIIa. Similarly, the photolysis as well as thermolysis of 1,4,5,6,7,7-hexaphenyl-7-silabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride (XIb) led to hexaphenylsilacyclopentadiene (XIIIb). Attempts to detect radical intermediates in these thermal and photochemical transformations by carrying out the reaction in the presence of hydroquinone, hydrazobenzene, 3,6-diphenyl-1,2-dihydro-1,2,4,5-tetrazine, cumene and tolan were unsuccessful. An attempted preparation of 7-silabicyclo[2.2.1]hepta2,5-dienes by the reaction of silacyclopentadienes such as 1-methyl-1-vinyl2,3,4,5-tetraphenyl-1-silacyclopentadiene (XV) and 1-methyl-1,2,3,4,5-pentaphenyl-1-silacyclopentadiene (XVI) with dimethyl acetylenedicarboxylate resulted in the isolation of dimethyl tetraphenylphthalate indicating that the corresponding 7-silabicyclo[2.2.1]hepta-2,5-dienes are thermally unstable.     

New [g]-fused [1,2,4]triazolo[1,5-c]pyrimidines: Synthesis of pyrido[3,2-e] and [4,3-e][1,2,4]triazolo[1,5-c]pyrimidine,pyrimido[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine and [1,2,4]triazolo[1,5-c]pteridine derivatives

A number of 2-aryl-substituted pyrido[3,2-e] and [4,3-e][1,2,4]triazolo[1,5-c]pyrimidines and [1,2,4]triazolo[1,5-c]pteridines 11,12a,b,e , their corresponding 5-carbonyl derivatives 7,8a,b,e and some pyrimido[5,4-e][1,2,4]triazolo[1,5-c]pyrimidin-5-ones 7,8c,d have been synthesized, according to different pathways. The new tricyclic heterocycles were prepared with the aim of studying their possible benzodiazepine receptors affinity.     

Ringsubstituierte [1]titanocenophane

The ring-substituted bis(cyclopentadienyl)silanesMe ₂Si(C₅H₅) (MeC₅H₄) (1a) andMe ₂Si(MeC₅H₄)₂ (2a) could be prepared by the reactions ofMe ₂SiCl₂ with C₅H₅Na andMeC₅H₄Na or only withMeC₅H₄Na, respectively. Metallation of1 a or2 a withn-BuLi and following reaction with TiCl₄ led to the first ringsubstituted [1]titanocenophanes,Me ₂Si(C₅H₄) (MeC₅H₃)TiCl₂ (1 b) orMe ₂Si(MeC₅H₃)₂ TiCl₂ (2 b), respectively. On reaction with NaI,1 b yieldedMe ₂Si(C₅H₄) (MeC₅H₃)TiI₂ (1 c). Structural assignments of the compounds could be made on the basis of their¹H NMR spectra.

     

K3Au5Pb: eine Schichtstruktur mit [AuAu3/2]-Gold-Tetraedern und [Pb2/2]-Blei-Ketten

K₃Au₅Pb: Layers of [AuAu_3/2] Gold Tetrahedra and [Pb_2/2] Lead Chains Silver coloured, brittle single crystals of K₃Au₅Pb were synthesized by reaction of potassium azide with gold sponge and lead powder at T = 920 K. The structure of the compound (space group Imma, Z = 4, a = 5.646(1) Å, b = 19.500(4) Å, c = 8.412(1) Å) was determined from X-ray single-crystal diffractometry data. The gold lead partial structure consists of layers of [AuAu_3/2] tetrahedra and [Pb_2/2] zigzag chains with four-bonded lead atoms which are connected to a framework structure via Au–Pb contacts. The potassium atoms occupy channels within the gold lead partial structure.     

STUDIES ON BENZO[C]THIOPHENES

Abstract

Attempts for the synthesis of 5-tert-butylbenzo[c]thiophene 1c are described. The preparation of pure 1c by heating of sulfoxide 5 with alumina failed. However 1c could be generated in situ and trapped with N-phenylmaleimide 6. Under the conditions of mass spectroscopic measurements the cycload-ducts of 1c with 6 underwent a retro-Diels-Alder reaction which proves the existence of free 1c in the gas-phase.     

Synthesis of 7a-Aza-benzo[fg]naphthacen-7-one

Phenanthroindolizidine and phenanthroquinolizidine are closely related groups of alkaloids. Since the first isolation of tylophorine 1 in 1935, these natural products have attracted much attention because of their interesting biological activities such as antitumor activity1-3. The obvious problems such as toxicity to nerve system, instability and uneconomical synthetical pathways restrict its application. Kozma reported that C-9, C-14 of tylophorine 1 and C-9, C-15 of cryptopleurine 2 we…     

The transformation of saccharin into derivatives of lmidazo[1,2-b] [1,2]-benzisothiazole and benzo[g] [1,2,5]thiadiazocine

Reaction of 3-(2-hydroxyethylamino) benzo[d]isothiazole 1,1-dioxide ( 5a ) with thionyl chloride gives a mixture of the expected chloroethyl derivative ( 5h ) and the rearranged saccharin 2-(2-aminoethyl)-3-oxo-2,3-dihydrobenzo[d]isothiazole 1,1-dioxide hydrochloride ( 6a ). Separate treatment of the chloroethyl compound ( 5h ) with dilute alkali gives the expected cyclization product 2,3-dihydroimidazo[1,2-b] [1,2] benzisothiazole 5, 5-dioxide ( 7a ). Acidification of the liquors of the above reaction yields the ring expanded derivative 6-oxo-3,4,5,6-tetrahydro-[2H]benzo[g][1,2,5]thiadiazocine 1,1-dioxide ( 12f ), a representative of a new ring-system. Treatment of the imidazo derivative ( 7a ) with concentrated hydrochloric acid again yields the N-substituted saccharin ( 6a ) which upon treatment with alkali also produces the thiadiazocine ( 12f ). In contrast, treatment of the imidazo compound ( 7a ) with alkali leads to attack on the sulphonamide function to give 2-(2-imidazolin-2-yl)benzenesulphonic acid ( 8 ). It is suggested that the multitude of chemical interconversions which can be induced within this series of compounds (Scheme II) can only be accounted for if two separate cyclol intermediates are invoked. Related reactions observed with variously substituted derivatives of the starting saccharin derivative ( 5a ) are discussed as are the spectral properties and chemical reactivity of the new compounds prepared.     

Tetrahydrocyclopenta[e]pyrido[3,2-b][1,4]diazepine and -cyclopenta[e]pyrido[2,3-b][1,4]diazepine derivatives

In pursuing the study on compounds obtained by condensation of N-monoalkylated aromatic and hetero-aromatic diamines with α- and β-ketoesters, 7,8,9,10-tetrahydrocyclopenta[e]pyrido[3,2-b][1,4]diazepin-6(5H)-ones 4a, 4b and 5,7,8,10-tetrahydrocyclopenta[e]pyrido[2,3,-b][l,4]diazepin-9H)-ones 5a, 5b were prepared starting from 2,3-diaminopyridine or 2,3-diamino-5-chloropyridine and ethyl 2-oxo-cyclopentanecarboxylate. Compounds 4a,b and 5a,b suffer thermally induced ring contraction to the imidazolone derivatives 8a,b and 7a,b respectively and are unsuitable for preparing diazepinone derivatives. Thus the methylated diazepinones 15, 17 and 18 , stable on heating, were prepared. Compound 17 was transformed into the clozapine analogue 22 , through the diazepinthione 20 and its S-methyl derivative 21 .     

The synthesis of [1]benzothieno[2,3-c]quinolines, [1]benzothieno[2,3-c][1,2,4]triazolo[4,3-a]quinoline,and [1]benzothieno[2,3-c]tetrazolo[1,5-a]quinoline

Photocyclization of 3-chloro-N-phenylbenzo[b]thiophene-2-carboxamide 10 afforded [1]benzothieno[2,3-c]-quinolin-6(5H)-one 11 which was chlorinated to 6-chloro[1]benzothieno[2,3-c]quinoline 12 followed by dechlorination to give [1]benzothieno[2,3-c]quinoline 5 . A series of 6-substituted alkoxy and thioalkoxy[1]benzothieno[2,3-c]quinoline derivatives were prepared along with the N-methyl quaternary salt 13 of 5 . 6-Chloro[1]-benzothieno[2,3-c]quinoline 12 was converted into 6-hydrazino[1]benzothieno[2,3-c]quinoline 23 which upon treatment with formic acid yielded [1]benzothieno[2,3-c][1,2,4]triazolo[4,3-a]quinoline 6 . Treatment of 23 with nitrous acid resulted in [1]benzothieno[2,3-c]tetrazolo[1,5-a]quinoline 7 . Compounds 6 and 7 are novel heterocyclic ring systems.     

Heterocycles [h]-fused onto 4-oxoquinoline-3-carboxylic acid, Part VI [1]. Synthesis and X-ray structure of model indolo[3,2-b]- and [2,3-b]pyrido[2,3-f]quinoxaline-3-carboxylic esters

Cyclocondensation reaction of ethyl 7,8-diamino-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate with 1-methylisatin produced a separable mixture of the corresponding indolo[3,2-b]- and [2,3-b]pyrido[2,3-f]quinoxaline-3-carboxylates, of which the latter isomer predominates. On the other hand, interaction with 1H-isatin or 5-chloroisatin gave the respective indolo[2,3-b]pyrido[2,3-f]quinoxaline-3-carboxylates as the sole regiospecific products. The structures of these new pentacyclic derivatives are based on microanalytical, spectral (IR, MS, and NMR) and X-ray crystal structure data.     

New [e]-Fused Caffeines: A Simple Synthesis of 3-Substituted [1,2,4]Triazolo[4,3-e]purines

Summary.  A convenient synthesis of 3-substituted [1,2,4]triazolo[4,3-e]caffeines by oxidative cyclization of 8-arylmethylenehydrazinocaffeines with bromine in acetic acid in presence of sodium acetate is described. Corresponding author. E-mail: haney_sami@mail.com Received May 6, 2002; accepted June 13, 2002     

Synthesis of Cucurbit[5]uril-Spermine-[2]Rotaxanes

Cucurbit[5]uril and decamethylcucurbit[5]uril are cyclic pentamers built from glycoluril or dimethylglycoluril respectively. Two different experimental methods have been used for the synthesis of the different [2]rotaxanes. The formed rotaxanes are characterized using ¹H-NMR spectroscopy, mass spectrometry and elemental analysis. In contrast to cucurbit[5]uril no [2]rotaxane could be obtained with decamethylcucurbit[5]uril.