Sodium titanium isopropoxide

Further functionality (i.e., 4-oxo) has been introduced by the cyclization of a-allyloxy-carbonylnitrones, which have traditionally been problematic to obtain. Tamura and co-workers have reported that simple alkoxycarbonylnitrones (e.g., (243)) undergo transesterification and cyclization with various allylic alcohols in the presence of titanium isopropoxide (Scheme 43) <95T107, 95T119). Alternatively, allyl a-oximinocarboxylates (246) are converted in situ to nitrones (247) and further cyclized to the bicyclic heterocycles (248) (Scheme 44) <91T4495>. Tetrahydro-1 //-pyrrolo[3,4-c]isoxazoles (250) have been prepared by the condensation of C-acylnitrones with allyl amines <78AJC2013> further reduction of the bicycles (250) with sodium borohydride affords the 3-oxa-2,7-diazabicyclo[3.3.0]octane (251) (Scheme 45). 

Hydrous sodium titanate was prepared by the method of Dosch and Stephens (1). Titanium isopropoxide was slowly added to a 15 wt% solution of sodium hydroxide in methanol. The resulting solution was hydrolyzed by addition to 10 vol% water in acetone. The hydrolysis product is an amorphous hydrous oxide with a Na Ti ratio of 0.5 which contains, after vacuum drying at room temperature, approximately 13.5 wt% water and 2.5 wt% residual alcohol. The ion-exchange characteristics of the sodium titanate and the hydrolysis behavior of the nickel nitrate solutions were characterized using a combination of potentiometric titrations, inductively coupled plasma atomic emission (ICP) analysis of filtrates, and surface charge measurements obtained using a Matec electrosonic amplitude device. 

Breitenbucher and Hui (104) have recently reported the SP synthesis of a medium-large discrete library L3 of 8448 benzopyrans using the reductive amination cocktail formed from titanium isopropoxide and sodium triacetoxyborohydride, known in solution but whose applications to SP were rare and limited to single experiments (105, 106). The benzopyran scaffold is present in a number of biologically active compounds (107-110), and this library was tested in several biological assays (111). 

Titanium isopropoxide and NaOH are reacted in a molar ratio of 2 1, respectively, with the titanium isopropoxide added to the NaOH-methanol solution with stirring. Subsequently, hydrolysis is done by pouring the mixture into an acetone-water mixture containing 8.5 vol water one liter of the acetone-water mixture is required for each mole of titanium. The hydrolyzed material is coarse and can be easily and rapidly vacuum filtered through a 50 micrometer frit. After drying at ambient temperature under vacuum, dried titanate powder is then screened with the material which passes a Number bo U. S. Standard sieve and is retained on a Number l i0 U. S. Standard sieve being the desired fraction. Some properties of sodium titanate powder are listed in Table I. 

The congeners of [LiTi(0-/-Pr)5]2 (cf. Fig. 23) were identified by X-ray crystallographic studies as [NaTi(O-i-Pr)5]0o and [KTifO-i-Pr ] (184). The derivative [NaTi(0-i-Pr)5]oc (Fig. 36) consists of an infinite linear chain of alternating distorted trigonal bipyramidal titanium isopropoxide moieties and bridging highly distorted tetrahedral sodium atoms [0(5) Na 0(4) = 66.9°]. 

Preparation and Chemical Properties. The saline hydrides are prepared by direct interaction at 300-700°. For complete reaction of lithium, the temperature must be approximately 725°. Sodium normally reacts with H2 only above 200° and the reaction is slow owing to formation of a coating of an inert hydride. However, studies on continuously clean surfaces50 show that the reaction obeys first-order kinetics with an activation energy of ca. 70kJmol 1. Dispersion of sodium in mineral oil increases the reactivity, but NaH in a very reactive form can be prepared at room temperature and pressure by interaction of H2 with sodium and naphthalene (Na+CI0Hg ) in tetrahydrofuran, with titanium isopropoxide as catalyst.51... 

In the example presented here the reverse micelle was prepared by dispersion of the surfactant, sodium bis(2-ethyl hexyl) sulfosuccinate (AOT) in isooctane. The hydrolysis and sol-gel processing of titanium isopropoxide was carried out in the 5 nm size cavity of the reverse micelle to produce highly uniform Ti02 nanoparticles. These particles were redispersed in a polymer (polyimide) solution and cast as a film of the polymer composite containing Ti02 nanoparticles. 

In sodium titanium(iv) isopropoxide [Na(jLi-OPr )4Ti(OPr )] there is a linear chain comprising alternating distorted trigonal bipyramidal Ti moieties with very distorted bridging tetrahedral Na atoms." ... 

Ti02 Glycerol, sodium dodecylsulfate 400 °C in air Titanium isopropoxide [66]... 

By cyclization reactions Camphor- 10-sulfonic acid, 62 Diethoxy triphenylphosphorane, 109 Diisobutylaluminum hydride, 115 B-3-Pinanyl-9-borabicyclo[3.3.1]-nonane, 249 Sodium nitrite, 282 a,(3-Epoxy alcohols I-Butyl hydroperoxide-Dialkyl tartrate-Titanium(IV) isopropoxide, 51 I-Butyl hydroperoxide-Dibutyltin oxide, 53... 

It was noticed as early as 1925 that alkoxides of calcium, magnesium and particularly aluminum could catalyze the reduction of aldehydes by ethanol as shown in equation (65).242,243 Removal of very volatile acetaldehyde is easily achieved to drive the reaction to the right. In 1926, Ponndorf devised a method in which both aldehydes and ketones could be reduced to alcohols by adding excess alcohol and aluminum isopropoxide.244 Such reductions are today referred to as Meerwein-Ponndorf-Verley reactions. Although alkoxides of a number of metals, e.g. sodium, boron, tin, titanium and zirconium, have been used for these reactions, those of aluminum are by far the best. 

A mixture of the Step 7 product (2.3 mmol) and benzaldehyde (2.5 mmol) dissolved in 4 ml toluene was treated with titanium(IV) isopropoxide (2.8 mmol) and stirred 18 hours. The mixture was then treated with 0.80 ml ethyl alcohol followed by the portionwise addition of sodium triacetoxyborohydride (2.8 mmol) and stirred an... 

Hydrogen peroxide or t-butyl hydroperoxide may be used in the presence of a catalyst such as sodium tungstate(VI) or vanadyl acetylaceto-nate [ MeC0CH=C(0 )Me 2V0] for the epoxidation of allylic alcohols. The stereochemistry of the hydroxyl group has a profound effect on the stereochemistry of epoxidation. A system which has been applied to allylic alcohols, to make optically active epoxides, utilizes titanium(rV) isopropoxide, t-butyl hydroperoxide and either of the enantiomeric forms of diethyl tartrate. This system forms chiral epoxides of predictable stereochemistry. When the reactivity of epoxides is combined with the... 

Aluminum is used as the anode and nichrome as the cathode. There is also available in the cell a catalytic amount of titanium for fixation purposes, in addition to naphthalene, which serves a purpose again in the reduction stage. The electrolyte is tetrabutylammonium chloride. Aluminum isopropoxide increases the over-all efliciency and turns this process into a catalytic one. This system starts with titanium tetraiso-propoxide. Reduction takes place, presumably again to the titanium (II) level. We have evidence from electrochemical experiments that titanium (II) is produced and involved in the fixation. Titanium (II), once formed, picks up N2 from the atmosphere and forms the complex, which then is available for reduction by sodium naphthalenide. Naphthalene is present in a catalytic amount and is reduced at the cathode to the radical anion. In this experiment, one can actually see it as a greenish color at the cathode. Naphthalenide reduces the No compound, producing the nitride. Normally, the reaction would stop at this point. We believe that in the electrochemical process, aluminum (III) abstracts nitride from titanium and forms aluminum nitride. This nitride transfer also can be observed in nonelectrolytic reactions. Thus, aluminum nitride is stored and ammonia is available at any time, merely by protonation. Both titanium and naphthalene are catalytic and permit operation of an over-all catalytic process. 

Titanium(IV) isopropoxide, an aqueous solution of sodium hydroxide, a solution of 25 weight % tetramethylammonium hydroxide in methanol, aluminum nitrate nonahydrate and tetrapropylammonium bromide were used in the preparation of sodium CT. These chemicals were mixed to produce a white slurry. The slurry was loaded into a closed reactor and heated in an oven set at a temperature in the range of 423-473 K. The crystallization time was varied between twelve hours to two days. The synthesis details were presented by Anthony and Dosch [2]. Sodium CT was acidified by ion exchanging with an aqueous solution of HCl at pH of 2.0 for several times to remove Na+. 

The process of reducing carbonyl compounds (aldehydes or ketones) to alcohols is therefore known as the Meerwein-Ponndorf-Verley reaction. Although alkoxides of a number of metal(loid)s such as sodium, magnesium, titanium, zirconium, iron, boron, aluminium, tin, and antimony have been used for these reactions, those of aluminium are by far preferred, since they tend to give the minimum degree of side reactions. The use of aluminium isopropoxide over other alkoxides was also preferred by Young et al as well as by Adkins and Cox. ... 

Reductive amination of aldehydes with monoalkylureas in the presence of titanium(lV) isopropoxide and sodium borohydride in THF represents a viable, laboratory-scale route to unsymmetrical N,N -disubstituted ureas in 39-94% yield. 

Titanium(IV) isopropoxide (tetraisopropyl orthotitanate, Fluka Chemika, pract.), hydrochloric acid (Reanal, pro anal.), sodium hydroxide (Reanal, puriss.) and 2-propanol (Reanal, puriss.) were used as received. Similarly, a commercial sample of P25 Degussa Ti02 (25 wt% rutile, 75 wt% anatase) was used as a well-known photocatalytic reference material. Zinc(II) chloride (Reanal, pro anal.), ZnO (Reanal, puriss.), SnCl4-5H20 and Sn02 (Reanal, pro anal.) were used as received. 

Phenylsulfonyl)-3-phenyloxaziridine (1S6. Davis reagent. Figure 11.61) has been shown to react with sodium enolates of chiral carboximides of the Evans-Oppolzer type, providing a-hydroxyacyl derivatives with diastereoselectivities of 90-98% d. g 92,133 Subsequent titanium(IV) isopropoxide-mediated transesterification with benzyl alcohol and hydrogenolytic debenzylation releases the free a-hydroxy acids in enantiomerically pure form and in yields of 65-75%. This procedure was applied... 

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