Azidotris phosphonium bromide

Conversion of aromatic amines to azides was studied by Scechter et al. <2002TL8421> and these studies lead to the recognition of a new approach to tetrazolo[l,5- ]pyridine. Thus, reaction of 2-aminopyridine 142 with butyl-lithium followed by treatment with azidotris(diethylamino)phosphonium bromide gave rise to tetrazolo[l,5- ]pyr-idine 1 in 80% yield. The first intermediate is obviously the azide 7. 

Two reaction intermediates were generated neither of which were isolated. The first, azi-dotris(diethylamino)phosphonium bromide, (Et2N)3P+N3Br , was formed by the reaction of hexaethyl phosphorous triamide, bromine and sodium azide. It has also been prepared starting with phosphorous trichloride (1). The second reaction intermediate, dimethyl /3-keto-o -diazo phosphate (I), is the base catalysis product of azidotris(diethylamino)-phosphonium bromide and dimethyl-2-oxopropyl phosphate. 

McGuiness, M., Schechter, H. Azidotris(diethylamino)phosphonium bromide a self-catalyzing diazo transfer reagent. Tetrahedron Lett. 

Azidotris(diethylamino)phosphonium Bromide with Lithium Hydrazinides... 

Lithium derivatives of aromatic and heteroaromatic amines react with azidotris(diethylamino)phosphonium bromide (267) to give the corresponding azides (e.g. 268 and 269) in high yield (Scheme 3.39). ... 

Scheme 3.39 Aryl azides from amines by treatment with n-butyllithium and azidotris (diethylamino)phosphonium bromide ...

Diazo TVansfer Reagent. The related compound dotris(diethylamino)phosphonium bromide has been used for the preparation of diazo products. Active methylene compounds react with azidotris(diethylamino)phosphonium bromide in dry diethyl ether in the presence of only catalytic amounts of base, such as Potassium t-Butoxide or other alkoxide, yielding the corresponding diazo products in good yields (70-78%) (eq 4). 

PEPTIDES Azidotris(dimethylamino)phosphonium hexafluorophosphate. Benzotriazole-N-hydroxytris(dimethyIamino)phophoniuin hexafluorophosphate. Cyanogen bromide. Dicyclohexylcarbodiimide. Diethyl phophorocyanidate. 2-Ethyl-7-hydroxybenzis-oxazolium tetrafluoroborate. 1-Hydroxybenzotriazole. N-Hydroxy-S-norbornene-cndo-... 

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