Tri-n-butyltin azide

Organometallic azides, for example, tri-n-butyltin azide and triphenyltin azide, also react with phenylisothiocyanate to give N=C adducts [Eq. (18))35°,35i jhe organometallic group could readily be removed to give the 1,5-disubstituted tetrazole by treatment with cold dilute HC1.350 In... 

Tetrazoles are usually prepared by the reaction of an azide with a nitrile, or an activated amide tri-n-butyltin azide and trimethylsilyl azide are more convenient and safer reagents than azide anion is some cases. The second example shown illustrates the use of a cyanoethyl group as a removable protecting group for amide nitrogen. Other variations on this method from nitriles include the use of triethylammonium chloride (instead of ammonium chloride) to avoid the possible sublimation of potentially explosive azides, and the use of micelles as reaction media. Amides can be activated with trifluoromethanesulfonic anhydride, or via formation of the thioamide, or by the use of triphenylphosphine with diethyl azodicarboxylate the equivalent imidochloride will react under phase transfer conditions. ... 

A useful tetrazole preparation is the addition of NaN3 (under acidic conditions) to nitrUes. Similar processes occur with Tri-n-butyltin Azide or TMSNs. ... 

The reaction of diisothiocyanates with sodium azide in water at reflux temperature within 4 hours provides bis(tetrazoHne-5-thiones) as difunctional compounds [136]. If organotin azides hke tri-n-butyltin azide (181) or triph-... 

The combination of PhSiH3 with a catalytic amount of bis(tri-n-butyltin) oxide reduces azides to primary amines in excellent yields (Eq. 3 33).556 The reducing agent is (n-Bu)3SnH formed in situ by the silane. Azides are converted into Boc-protected primary amines with the PMHS/Pd/C reagent (Eq. 3 34).557,558... 

Dichlorobis(l-methyltetrazole) zinc(II) has been reported and its structure determined.111 The geometry around the zinc atom was that of a distorted tetrahedron. The tetrazoles were monodentate and again coordinated by a charge-transfer o-bond between the 4-N atom and the Zn which was coplanar with the ring.111 Cycloaddition of trialkyltin azides to nitriles or treatment of S-substituted tetrazoles with bis(tri-n-butyltin) oxide or trimethyltin hydroxide gave 2-jV-trialkyltin-5-substituted tetrazoles (67).112,113 The (tri-/i-butylstannyl)derivatives (68)... 

Thi.s relatively stable azide is prepared by the reaction of tri-n-butyltin chloride with a tonccniraled aqueous solution of sodium azide at 0° 91% yield, ... 

Tri-n-butyltin hydride/azodiisobutyronitrile Radical reductions with organotin hydrides Carboxylic acid amides from carboxylic acid azides... 

LACTAMS Di-n-butyltin oxide. Ily-droxylamine-O-sulfonic acid. Iodine azide. Sodium eyanoborohydride. (3-LAC TAMS Cyanuric chloride. Grignard reagents. Ion-exchange resins. Lithium phenylethynolate. Sodium dicarbonyl-cyclopentadienylferrate. Titanium(lll) chloride. Titanium(IV) chloride. Tri-phenylphosphino-Carbon tetrachloride. Triphenylphosphine-Die thyl azodicar-boxylate. Triphenylphosphine-2,2 -Dipyridyl disulfide. 

Reductions of C-N Bonds. An ethanolic mixture of PMHS and Pd/C will reduce oximes (eq 18) to amines and reduc-tively open aziridines (eq 19). Either (a) PMHS plus catalytic w-butyltin tris(2-ethylhexanoate) (eq 20) or (b) PMHS plus ZnCl2 reduces imines. The PMHS/DBATO combination reduces azides, while PMHS/Ti(0-i-Pr)4 can be applied to reductive aminations (eq 21). Asymmetric imine reductions via chiral titanium complexes and PMHS are also viable, but very substrate dependent with nonaromatic imines working best (69-99% ee vs. 6-97% ee for aromatic imines). ... 

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