Sodium azide-Dimethylformamide

Treatment of dibromides 2 with sodium azide in N,N-dimethylformamide (DMF) at room temperature resulted in the formation of two products, 3-(a-azidobenzyOchromones 2a-c,g or -1-thiochromones 2d-f and the 3-arylidenechromanones la-c,g,h or -1-thiochromanones Id-f, respectively (eqn. 2). As shown by yield data given in Table 2, the substituent at position 2 plays decisive role in the product ratio. Dibromides unsubstituted at position 2 tended to give almost exclusively azides 3a-f and only a small amount of 1 was obtained. On the contrary, the reaction of flavanone derivatives 2gjh gave 3-arylideneflavanones... 

The sulfamate ester variant of this chemistry has already been shown to be a very powerful protocol for the syntheses of 1,3-amino alcohols and related /3-amino acids (Equation (90)), as well as iminium ion equivalents (Equation (91)). The further showcases of this chemistry are the total syntheses of the bromopyrrole alkaloids, manzacidins A and C (Scheme 13).234 The cyclic sulfamidate 129 was obtained diastereospecifically from sulfamate 128 using intramolecular rhodium-catalyzed G-H insertion. It was then found to react with sodium azide in NfN-dimethylformamide at room temperature after introduction of the Boc-activating group to afford the 1,3-diamino precursor 130 in 78% yield over 3 steps. Four subsequent manipulations afford the target structure 131. 

Treatment of the epoxide 32 with sodium azide and ammonium chloride in dimethylformamide gave the azido alcohol 33 which, via the mesylate 34, could... 

It has been found32 that treatment of methyl 4,6-dichloro-4,6-dideoxy-a-D-gaIac-topyranoside 2,3-di(chlorosulfate) (8) with sodium bromide in N,N-dimethyl-formamide at room temperature affords methyl 4,6-dichloro-4,6-dideoxy-o -D-galactopyranoside and its 2- and 3-mono(chlorosulfate) derivatives. These three products were also formed, in addition to a mono(azidosulfate) derivative, when 8 was treated with sodium azide in N,N-dimethylformamide at room temperature. 

The synthesis of inosamines from bromodeoxyinositols has been achieved by way of displacement reactions with sodium azide in boiling, aqueous 2-methoxyethanol or N,N-dimethylformamide.163... 

Benzene, Arsenic trichloride. Isopentane, Aluminum chloride. Sodium bicarhonate. Sodium sulfate Ammonium nitrate. Aluminum powder. Hydrazine Dimethylformamide, Sodium azide. Chloroform, Sodium sulfate, 2,2,2-Trichloroethylamine... 

Quite analogous ring-closures occur when the 1-O-acetyl derivatives of the rhamnopyranose and talopyranose derivatives are treated with sodium azide in N,N-dimethylformamide. l-O-Acetyl-6-deoxy-2,3-0-isopropylidene-4-0-mesyl-a-L-mannopyranose is converted exclusively into l,4-anhydro-6-deoxy-2,3-0-isopropylidene-/3-L-talo-pyranose. In this instance, the azide nucleophile attacks the l-O-ace-tyl group, liberating an 0-1 oxide ion which reacts with inversion of C-4. The 4-epimeric, l-O-acetyl-6-deoxy-talose derivative gives 60% of the direct inversion product l,4-anhydro-6-deoxy-2,3-0-isopropyli-dene-a-L-mannopyranose, together with other products.50... 

Similarly, various a-D-glucopyranose derivatives having a mesyloxy group at C-4 and an acetoxyl group at C-l are also converted into 1,4-anhydro-/3-D-galactopyranose derivatives on treatment with sodium azide in such aprotic solvents as N,N-dimethylformamide.51 The use of sodium azide in N,N-dimethylformam ide under forcing conditions originated in attempts at nucleophilic displacements to form azido,... 

Interestingly, all attempts to introduce an azido group at C-6 in 13 by use of sodium azide in N,JV-dimethylformamide failed. Instead of the azido derivative, the crystalline derivative 273, containing no thiocyano, isothiocyano, methylsulfonyl, or azido group (as indicated by i.r. and H-n.m.r. spectra), was obtained.23... 

Later, it was also claimed that 3-(tetrazolyl)-4//-pyrido[ 1,2-u]pyrimidin-4-ones 159 were obtained in an one-step procedure by heating the appropriate 2-aminopyridine, ethyl (l//-tetrazol-5-yl)acetate, and triethyl orthoformate in dimethylformamide at 90°C for 1 hour, or in boiling tetra-hydrofuran for 6 hours followed by treatment with 1N potassium hydroxide at 50°C for 1 hour, or with anhydrous aluminum chloride under reflux for 6 hours (91EUP462834). 9-Methyl-3-( 1 //-tetrazolyl)-4//-pyrido[ 1,2-a]-pyrimidin-4-one 159 (R = 9-Me) could be prepared when 2-amino-3-meth-ylpyridine hydrochloride and sodium azide were suspended and stirred in dimethylformamide for 1 hour at room temperature, followed by the addition of ethyl ethoxymethylenecyanoacetate, ethoxymethylenemalo-nonitrile, ethyl cyanoacetate and triethyl orthoformate, or malononitrile and triethyl orthoformate and stirring at 90°C for 6-12 hours. Then the reaction mixture was treated with 1 N potassium hydroxide at 50°C for 1 hour, phosphoryl chloride at 90°C for 5 hours, or with concentrated hydrochloric acid at 110°C for 4 hours to give 26-62% yields. 

The cyano group of 3-cyano-, 3-cyanomethyl-, and 3-(cu-cyanoalkyl)-4//-pyrido[ 1,2-a]pyrimidinones 439 was converted to a 5-tetrazolyl group by treatment with sodium azide in boiling tetrahydrofuran for 2-23 hours in the presence of aluminum chloride or in dimethylformamide at 100-110°C for 8 hours in the presence of ammonium chloride to yield 5-tetrazolyl derivatives 440 [87EUP217673 88JAP(K)88/246375]. 3-(l H-... 

Reaction of 4-imino-4//-pyrido[l, 2-a]pyrimidine-3-carbonitriles 168 and sodium azide in the presence of ammonium chloride in dimethylformamide at 80-100°C for 1-3 hours gave 3-(2-pyridylamino)-2-(l//-tetrazol-5-yl)acrylonitriles 700 (93MIP6). 3-(2-Pyridylamino)-2-(l//-tetrazol-5-yl)acrylonitriles 700 were cyclized to 3-(l//-tetrazol-4//-pyrido[l,2-a] pyrimidin-4-ones 701 by heating in concentrated hydrochloric acid under reflux for 1 hour or by heating in polyphosphoric acid at 130-140°C for 2-4 hours (93MIP7). 

Aluminum chloride (3.51 g, 0.0263 mole) was added to cold (-30°C) tetrahydrofuran (180 ml). Sodium azide (5.12 g, 0.0788 mole) was added and the mixture heated under reflux for 30 min. The mixture was cooled to 5°C. Ethyl 2-cyano-3-(3-methyl-2-pyridylamino)acrylate (5.0 g, 0.0216 mole) was added and the mixture heated under reflux for 18 h. The tetrahydrofuran was removed under reduced pressure. The residue was treated with ice water (100 ml) and acidified to pH 3 with 6 N hydrochloric acid. The mixture was filtered and the collected solid recrystallized from N,N-dimethylformamide to give the 9-methyl-3-(lH-tetrazol-5-yl)-4H-pyrido[l,2-a]pyrimidin-4-one (2.5 g,... 

A solution of 5.00 g of sodium azide in 53 ml of water was added to a solution of benzhydryl 2-p-chloromethyl-2-a-methylpenam-3-a-carboxylate (5.13 g) in dimethylformamide (155 ml). The mixture was stirred at room temperature for 4 h. The resulting reaction mixture was poured into cooled water and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with water, dried over magnesium sulfate and concentrated to provide 4.87 g of the benzhydryl 2-p-azidomethyl-2-a-methylpenam-3-a-carboxylate as oil in 93% yield. 

A mixture of 13.1 g of 2,2-dibromomethyl-l,3-propanediol, 6.5 g of sodium azide and 750 ml of dimethylformamide was stirred and heated at 110°-120°C for 20 h, then clarified and the filtrate evaporated. The residue was extracted three times with dichloromethane. The extracts were combined and evaporated, giving 13.65 g of 2,2-bis(azidomethyl)-l,3-propanediol, compound with dimethylformamide. 

Reaction of Methyl 4,6-Dichloro-4,6-dideoxy-a-D-galactopyranoside 2,3-Di(chloro-sulfate) with Sodium Azide, and with Sodium Bromide, in A/,2V-Dimethylformamide, H. Parolis, W. A. Szarek, and J. K. N. Jones, Carbohydr. Res., 19 (1975) 97-105. 

Tse-Lok Ho 3I) has explored the effectivness of the following four nucleophiles in dequatemization reactions sodium azide, sodium thiosulphate, thiourea and tri-phenylphosphine. Among.which, triphenylphosphine turned out to be the most effective demethylating agent. A strong solvent dependence on dequatemization has been demonstrated, indicating dimethylformamide as a superior solvent in all cases. In this manner, (2B.2.1]cryptand (44) was obtained from bisquaternary salt 43 in 87% yield (Scheme 11). 

Ammonium azide is prepared by introducing a solution of ammonium chloride and sodium azide into dimethylformamide at 100 °C. 

Glycidyl azide polymer is produced in a two-step process. First, epi-chlorhydrine in the presence of bortriflouride, is polymerized into poly-epichlorhydrine. Using dimethylformamide as a solvent, the polymer is then processed with sodium azide at high temperature. Nearly all the inorganic components as well as the solvent are removed, leaving the raw final product free of low molecular weight compounds. 

Methyl 4,6-0-benzylidene-3-deoxy-a-D-ribo-hexopyranoside (56) was benzoylated, debenzylidenated, and partially p-toluenesulfon-ylated to 57 this was converted into 58 by reaction with sodium iodide, followed by catalytic reduction. The methanesulfonate of 58 was converted into 59 by reaction with sodium azide in N,N-dimethylformamide, and 59 was converted into 4-azido-3,4,6-trideoxy-a-D-xylo-hexose (60) by acetolysis followed by alkaline hydrolysis. Reduction of 60 with borohydride in methanol afforded 61, which was converted into 62 by successive condensation with acetone, meth-anesulfonylation, and azide exchange. The 4,5-diazido-3,4,5,6-tetra-deoxy-l,2-0-isopropylidene-L-ara/uno-hexitol (62) was reduced with hydrogen in the presence of Raney nickel, the resultant diamine was treated with phosgene in the presence of sodium carbonate, and the product was hydrolyzed under acidic conditions to give 63. The overall yield of 63 from 56 was 4%. The next three reactions (with sodium periodate, the Wittig reaction, and catalytic reduction) were performed without characterization of the intermediate products, and gave (+)-dethiobiotin methyl ester indistinguishable from an authentic sample thereof prepared from (+)-biotin methyl ester. 

The reaction of sodium azide with ammoitium sulfate or anunoiuum chloride in dimethylformamide at 358-393 K under reduced pressure also leads to ammoitium azide ... 

Similarly, mphenylselenenyl bromide or methylselenenyl bromide, followed by sodium azide in trifluoromethanol or lithium azide in dimethylformamide 6 8. 

The direct azido phenylselenenylation of alkenes can be accomplished by four different methods A126 reaction with phenylselenenyl chloride and sodium azide in dimethyl sulfoxide or dimethylformamide B127 reaction with diphenyldiselenide, sodium azide and iodosobenzene diacetate in dichloromethane C128 reaction with iV-phenylselenophthalimide (TV-PSP) and azidotrimethylsilane in dichloromethane D128 as in C but in the presence of 0.1 equivalent of tetrabutylammonium fluoride. 

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