Sodium, organo-, derivatives

The mutual transitions of various types of hetero cycles (recyclizations) are fairly widespread in the chemistry of azoles. Reaction of 1,4-dinitropyrazole with hydrox-ylamine liberated from corresponding salt in the presence of sodium methoxide resulted in 4-nitroisoxazole (77%) and a small amount of 5-methoxy-4-nitropyrazole [535], 4-Nitroisoxazoles, like incidentally their unnitrated analogs, are transformed into derivatives of 4-nitropyrazole by the hydrazine or its monosubstituted derivatives. Thus, 3(5)-amino-5(3)-methyl-4-nitropyrazole or its 1-organo derivative was obtained from 5-methyl-4-nitroisoxazole [28, 34, 35, 536] (Scheme 92). 

Reduction of cyanocobalamin (Figure 54(a) R = CN) with sodium borohydride affords a diamagnetic grey-green product (Vitamin 6x2 which reacts with acyl or alkyl halides and with olefins to give cobalamin o-organo derivatives. There has been some discussion whether Vitamin 6x2. is a cobaltCO anion or whether it is cobalamin hydride. Some of the... 

II Reaction with excess organo derivatives of lithium (IIA) or sodium (IIB) ... 

Reduction of cyanocobalamin with sodium borohydride or zinc and acetic acid affords a diamagnetic, grey-green product (Vitamin B12,) which reacts with acyls, alkyl halides and with olefins to ve cobalamin-[Pg.248]

The reaction of a Co(I) nucleophile with an appropriate alkyl donor is used most frequently for the formation of a Co-C bond, which also can be formed readily by addition of a Co(I) complex to an acetylenic compound or an electron-deficient olefin (5). The nu-cleophilicity of Co(I) in Co(I)(BDHC) is expected to be similar to that in the corrinoid complex, as indicated by their redox potentials. The formation of Co-C a-bond is the attractive criterion for vitamin Bi2 models. Sodium hydroborate (NaBH4) was used for the reduction of Co(III)(CN)2(BDHC) in tetrahydrofuran-water (1 1 or 2 1 v/v). The univalent cobalt complex thus obtained, Co(I)(BDHC), was converted readily to an organometallic derivative in which the axial position of cobalt was alkylated on treatment with an alkyl iodide or bromide. As expected for organo-cobalt derivatives, the resulting alkylated complexes were photolabile (17). 

An interesting example of an application of this method pertains to the synthesis of pharmacologically active synthetic A1 -tetrahydrocannabinoids 134) of the type 267 which have a lipophilic tertiary alkyl side-chain. Equation 84 shows that organo-titanium chemistry provides a versatile means to prepare the precursors 264 (65-80 %)133). Demethylation of 264 using trimethylsilyl chloride and sodium iodide affords the resorcinol derivatives 265 ( 95%)133>. Compounds of this type have been previously condensed with 266 in the presence of acids to form the A1(6)-isomers of 267, which in turn can be converted into 267135). It should be mentioned that the meta-substitution pattern of 265 prohibits simple Friedel-Crafts alkylation of resorcinol, which is the reason why alternative multistep syntheses of 264 have had to be developed l34 136>. 

Lithium alkanetellurolates, prepared from tellurium and an alkyl lithium compound or dialkyl ditellurium derivatives and hthium, and sodium arenetellurolates, obtained from diaryl ditellurium compounds and sodium borohydride ", reacted with triorganosilyl, -germyl, -stannyl, and -plumbyl chlorides to produce, for instance, organo triorganosilyl tellurium compounds. 

The three elements lithium, sodium, and potassium bear little resemblance to copper, silver, and gold in their inorganic derivatives but, with the exception of gold, they show more resemblance in their organo-metallic compounds. 

A/ "-Hexamethylguanidiniuin chloride (542 Scheme 100) is readily reduced by means of NaH in the presence of sodium alkoxyaluminates, boronic acid esters or aluminum alkoxides J Organo-metallic derivatives such as phenyllithium, 2-thienyllithium or 2-furanyllithium or sodium acetylides add to the guanidinium salt to give the corresponding orthoamides. From tetrakis(dimethylamino)methane and phenylacetylene l-phenyltris(dimethylamino)-l-propyne (543 equation 242) was prepared. ... 

Si CP/MAS-NMR was used to characterise mesoporous materials derived from sodium silicate and organotrialkoxysilanes.493 Multinuclear NMR studies have been reported on periodic mesoporous organosilicas.494,495 13C and 29Si MAS-NMR spectra were used to characterise ordered macroporous organo-silica materials.496 A similar study has been made of mesoporous organosilica/ clay heterostructures.497... 

Organotin compounds of this type can be further treated with Grignard reagents or organo-lithium or -sodium compounds, thus yielding a variety of mixed organotin derivatives for example, trialkyl- and tri(cyclohexyl)-tin... 

Arsenic derivatives of the types R2R As and RR R"As,495 including very varied dialkyl- and diaryl-alkynylarsines,401,496 have been synthesized by stepwise Grignard reagents or by isolated reactions of organic arsenic halides with organo-sodium, -lithium, or -magnesium derivatives. 

Organoalkali Initiators In general, the simple organoal-kali metal derivatives other than lithium are not soluble in hydrocarbon media. However, higher homologs of branched hydrocarbons are soluble in hydrocarbon media. The reaction of 2-ethylhexyl chloride and sodium metal in heptane produces soluble 2-ethylhexylsodium [60]. This initiator copolymerizes mixtures of styrene and butadiene to form styrene-butadiene copolymers with high (55-60%) vinyl microstructure [61, 62]. 

Elemental analysis for tin was conducted as described in reference 12 except that one drop of water and concentrated nitric acid (10 drops) are added subsequent to the sodium fusion and this mixture is heated until brown fumes are evolved. Also, the stannic sulfide is heated in air converting it to stannic oxide which is weighed and this weight utilized in determining the percentage tin. This process is not suitable for extremely volatile organo-stannanes such as dibutyltin dichloride, but is suitable for tin polyesters, polyethers and polyamines. Tin polyesters were utilized as test compounds. Thus, the polyester derived from disodium adipate and dibutyltin dichloride was found to contain 31 percent tin and the calculated value is 31 percent. 

The first organo-substituted tetrahydroborate to appear in the literature was M [BH(C6H5)3] (M = Li, Na, K), obtained by addition of tri-phenylborane to an alkali-metal hydride. Alternatively, the sodium derivative was prepared by the methanolysis of sodium triphenylborane (228). Since then, many other organotetrahydroborates have been prepared and some of their chemical reactions studied. These are summarized in Eqs. (67H89). 

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