Sultan T. Abu-Orabi

Controlled synthesis of (1,3-tBu2-C5H3)2TiCl2 and (1,3-tBu2-C5H 3)TiCl3. Crystal structure and reactions of (1,3-tBu2-C5H3)TiCl3

The compounds (1,3-tBu2C5H3)2TiCl2 (I) and (1,3-tBu2C5H3)TiCl3 (II) were prepared in good yields from TiCl4 and (1,3-tBu2-C5H3)Li. Reactions of II with methanol, ethane-1,2-diol, sodium oxalate, and 2-pyrazine carboxylic acid afforded various organotitanium complexes. The crystal structure of II was determined.

Organometallic Sulfur Complexes. IVa. Synthesis and Characterization of [Fe(ButC5H4)(CO)2]2 and [Fe(1, 3-di-ButC5H3)(CO)2]2 and the S-Bonded Thiocarboxylate Derivatives, Fe(ButC5H4)(CO)2Scor and Fe(1, 3-di-ButC5H3)(CO)2Scor

Abstract The new substituted cyclopentadienyl organoiron dimers [Fe- (ButC5H4)(CO)2]2, I and [Fe(1,3-di-ButC5H3)(CO)2]2, II, were prepared from the reaction of Fe2(CO)9 with t-butylcyclopentadiene, or 1,3-di-t-butylcyclopentadiene. The equilibrium concentration of the trans-geometrical isomer decreases in the order II>I> [FeCp(CO)2]2 as a result of increasing bulkiness of Cp-substituents and increasing the steric repulsion in the cis-configurations. The 1H NMR spectra of I and II showed an anisotropic shielding effect of the bridging metal-carbonyl on the cyclopentadienyl protons.

The molecular and crystal structure of pentacarbonyl(phosphabenzene)molybdenum(0)

Abstract Pentacarbonyl(phosphabenzene)molybdenum(0) crystallizes in the Pbam space group with Z = 8, a 15.880(4), b 20.162(4) and c 7.971(3) A. The crystal structure was determined and refined from 1404 independent reflections to R 1 = 0.034. The pentacarbonylmolybdenum moiety is symmetrically coordinated to the phosphorus atom of the phosphabenzene ring, which closely resembles the free ligand in geometry.

SYNTHESIS, STRUCTURE AND FLUXIONAL BEHAVIOR OF DI-T-BUTYLCYCLOPENTADIENYL COMPOUNDS OF GROUP-15 ELEMENTS

Abstract The syntheses of di-t-butylcyclopentadienyldichlorophosphane (I), di-t-butylcyclopentadienyldiisopropylphosphane (II), di-t-butylcyclopentadienyldichloroarsane (III) and di-t-butylcyclopentadienyldichlorostibane (IV) are described. The influence of group 15 elements on the structure and the dynamic behavior (sigmatropic rearrangements) is discussed on the basis of 1H, 13C, and 13P NMR data.

1,3-Dipolar Cycloaddition Reactions of Substituted Benzyl Azides with Acetylenic Compounds

We review in this article some of our work which has been published over the last fifteen years in the area of 1,3-dipolar cycloaddition reactions of substituted benzyl azides with acetylenic compounds to form the corresponding 1,2-3-triazoles. Several triazole derivatives were transformed into triazolopyridazine and triazolo-1,3,4-oxadiazole derivatives upon their reactions with hydrazine.

Organoboration of 3-(Trinethylstannayal)-2-Propyny-1-Ethers

Abstract The reaction of 3-(trimethylstannyl)-2-propynyl-1-ethers (4, 9) with trialkylboranes (2,7) leads to different products, depending on the substituents at boron, on the presence of a Me3SnO-group as well as on the substituents at the C-1 carbon atom. In the case of the CH2OSnMe3 group (4a), the reaction with trimethyl- or triethylborane (2a,b) gives the new heterocycles, 2.3,3-trialkyl-4,4-bis(trimethylstannyl)-1,2-oxaborolanes.12. in quantitative yield (alkyl - Me, Et). In contrast, in the presence of a MeO-group (5) an alkene derivative,18, is obtained with the stannyl- and the boryl group in apposition. The analoguous products (14,15,a,b,c) are formed in the reaction between4a and trisopropylborane (2c) or B-allcyl-9-borabicyclo[3.3.1]nonane (7). If there are one or two alkyi groups as substituents at C-1 (4b,c,d) the reaction with triethylborane (2b) leads also to such alkenes.16. However, exchange of alkyl groups between the stannyl and the boryl groups takes place, leading to the alkenes17 b.c.d in which a Me2(Et)Sn- and a B(Me)Et group are in cis-position.1H-,11B-,13C- and119Sn NMR data are given.

Reactions of ring-substituted titanocene dichlorides with thiocyanate ions: Synthesis of new S-bonded thiocyanato titanocene complexes, and crystal structure of (tBuC5H4)2Ti(NCS)2

Abstract The asymmetrical titanocene dichloride (1,3- t Bu 2 C 5 H 3 )( t Bu 2 C 5 H 4 )TiCl 2 ( I ) has been prepared from (1,3- t Bu 2 C 5 H 3 )TiCl 3 and ( t BuC 5 H 4 )Li. The reactions of I and of (1,3- t Bu 2 C 5 H 3 ) 2 TiCl 2 with an excess of ammonium thiocyanate afforded the S-bonded thiocyanato complexes (1,3- t Bu 2 C 5 H 3 )( t BuC 5 H 4 )Ti(SCN) 2 ( IV ) and (1,3- t Bu 2 C 5 H 3 ) 2 Ti(SCN) 2 ( V ) respectively. A similar reaction of ( t BuC 5 H 4 ) 2 TiCl 2 with excess anmmonium thiocyanate produced the S-bonded thiocyanato complex ( t Bu C 5 H 4 ) 2 Ti(SCN) 2 ( II ) as a minor product and the N-bonded thiocyanato complex ( t BuC 5 H 4 ) 2 Ti(NCS) 2 ( III ) as the major product. Similar reaction of ( t BuC 5 H 4 ) 2 TiCl 2 with ammonium thiocyanate in 1 : 1 molar ratios gave ( t BuC 5 H 4 ) 2 Ti(Cl)(NCS) ( VI ). Crystal structure of III was determined.

Organoborierung von alkinylstannanen: XXIII. Zur Reaktion einiger C-funktionell substituierter Alkinylstannane mit Triethylboran und β-Alkyl-9-borabicyclo[3.3.1]nonanen

Abstract The influence of functional groups in R 1 on the course of the organoboration reaction of alkynylstannanes 1 , Me 3 SnCCR 1 (R 1 = OEt ( a ), 3-Methoxyphenyl ( b ), 2-Pyridyl ( c )) has been studied. The reaction of 1 with triethylborane ( 2 ) yields the products ( 4 ), with the stannyl and boryl groups always in the cis -position. In the case of the reaction between 2 and 1c it has been observed for the first time that the organoboration is followed by a Me/Et exchange between the tin and the boron atoms ( 4d ). A possible mechanism is described. The alkyne 1c reacts stereoselectively with the β-alkyl-9-borabicyclo[3.3.1]nonanes, 3 (alkyl = Me ( a ), Et ( b ), i-Pr ( c )), to give the compounds 5a, b, c in which the bicyclic system has been enlarged by one carbon atom, with the stannyl- and boryl-groups remaining in the cis -positions. 1 H, 11 B, 13 C, 119 SnN MR spectroscopy, and analytical data support the proposed structures of compounds 4 and 6 .

interaction of Organic Azides with Purified Camel Glutathione S-Transferase'

A series of organic azides was synthesized and was tested as inhibitors of purified camel glutathione S-transferases. Enzymes purified from camel liver, lung, and kidney were inhibited reversibly by these compounds in a concentration-dependent pattern. The liver glutathione S-transferase was more sensitive to inhibition by most of these compounds and the lung enzyme was the least affected. The most effective reversible inhibitors of the tested organic azides for the purified camel liver enzyme were alkyl and allyl azides. The inhibition occurred immediately upon adding the inhibitors and remained constant during a further 30-min incubation period. The tested organic azides were found to inhibit the glutathione S-transferase catalyzed conjugation of glutathione with both 1-chloro-2,4-dinitrobenzene and 4-nitrobenzyl chloride and the kinetics of these inhibitions was qualitatively different, being competitive with some inhibitors and noncompetitive with others.

Photoinduzierte umsetzungen der komplexe (η6-C6H3R3)(CO)3Cr (R = Me, Et) mit den acetylenen C2R2′ (R′ = H, C3H7, C(OEt)2H). Die molekülstruktur von (C6H3Me3)(CO)Cr(μ-CO)“;μ-C2[C(OEt)2H]2”;Cr(CO)4

Abstract The photo-induced reaction of the complexes (C 6 H 3 R 3 )(CO) 3 Cr (R = Me, Et) with acetylenes C 2 R 2 ′ (R′ = H, C 3 H 7 , C(OEt) 2 H) in solution gives the substitution products (C 6 H 3 R 3 )(CO) 2 Cr(C 2 R 2 ′). Depending on the alkyne C 2 R 2 ′ and the reaction conditions the monomeric alkyne complexes can undergo further reactions to afford the dinuclear alkyne-bridged complexes (C 6 H 3 Et 3 )(CO)Cr(C 2 H 2 )(μ-CO)Cr(CO) 4 , (C 6 H 3 R 3 )(CO)Cr(μ-CO)“;μ-C 2 [C(OEt) 2 H] 2 ”;Cr(CO) 4 , and the alkyne-free symmetric dinuclear complex [(C 6 H 3 Et 3 )(CO) 2 Cr] 2 . The tetraethoxy-substituted alkyne in the complexes (C 6 H 3 R 3 )(CO) 2 Cr“;C 2 [C(OEt) 2 H] 2 ”; eliminates Et 2 O under column chromatography on silica to give the aldehyde functionalized alkyne complexes (C 6 H 3 R 3 )(CO) 2 Cr[HC(OEt) 2 CCC(O)H]. The crystal structure of (C 6 H 3 Me 3 )(CO)Cr(μ-CO)“;μ-C 2 [C(OEt) 2 H] 2 ”;Cr(CO) 4 has been determined.