Acetyl azide

Electrostatic potential maps of a typical amide (acetamide) and an acyl azide (acetyl azide) are shown. Which of the two do you think is more reactive in nucleophilic acyl substitution reactions Explain. 

DNA sequencing and. 1113 Electrospray ionization (ESI) mass spectrometry, 417-418 Electrostatic potential map, 37 acetaldehyde, 688 acetamide, 791,922 acetate ion. 43. 53, 56, 757 acetic acid. 53. 55 acetic acid dimer, 755 acetic anhydride, 791 acetone, 55, 56. 78 acetone anion, 56 acetyl azide, 830 acetyl chloride, 791 acetylene. 262 acetylide anion, 271 acid anhydride, 791 acid chloride, 791 acyl cation, 558 adenine, 1104 alanine, 1017 alanine zwitterion, 1017 alcohol. 75 alkene, 74, 147 alkyl halide, 75 alkyne. 74... 

Amine-Reactive Cascade Blue Acetyl Azide... 

One Cascade Blue derivative is available for creating linkages with amine-containing molecules. The acetyl azide functionality of this reagent reacts with primary amines at ambient temperatures or below to create amide bond derivatives (Lanier and Recktenwald, 1991 Oparka et al.,... 

Figure 9.38 The acetyl azide group of this Cascade Blue derivative has dual functions. It can react with amine groups to form amide bonds, or it can be converted to an isocyanate at high temperatures to couple with hydroxyl functional groups, creating a carbamate linkage.

At elevated temperatures (80°C in DMF), the acetyl azide group rearranges to form an isocyanate that can react with hydroxyl-containing molecules to form a urethane linkage (Figure 9.38). The Cascade Blue urethane derivatives of macromolecules are extremely fluorescent and can be detected down to femtogram quantities (Takadate et al., 1985). 

Cascade Blue acetyl azide is soluble in aqueous solution, but the reactive azide group will hydrolyze and should be used immediately in a conjugation reaction. A concentrated stock solution may be prepared in water, dissolved quickly, and an aliquot quickly added to a buffered reaction medium. For aqueous reactions, a pH range of 7-9 is optimal. Avoid amine-containing buffers. 

Acetyl azide, 0771 A-Azidocarbonylazepinc, 2728 Azidocarbonyl fluoride, 0339 Azidocarbonylguanidine, 0820 4-Azidocarbonyl-1,2,3-thiadiazole, 1069 Azidodithioformic acid, 0386 Benzene-l,3-bis(sulfonyl azide), 2210 Benzenesulfinyl azide, 2273 Benzenesulfonyl azide, 2274 Benzoyl azide, 2698... 

The photolysis of acyl azides has also been studied, and in some respects these appear to behave analogously. Pivaloyl azide, for example, adds to cyclohexene to give a 26% yield of an aziridine [Eq. (85)],321 and the assumption is that this addition again occurs via a nitrene. The photodecomposition of acetyl azide (295) in benzo-nitrile and phenylacetylene, on the other hand, affords322 2-methyl-5-phenyl-l,3,4-oxadiazole (296) and 2-methyl-5-phenyloxazole (297),... 

Acetylamino-l-oxo-2,2,6,6-tetramethylpiperidinium perchlorate, 3406b Acetyl azide, 0767 Acetyl bromide, 0724 Acetyl cyclohexanesulfonyl peroxide, 3028 Acetyldimethylarsine, 1623 Acetylenebis(triethyllead), 3665 Acetylenebis(triethyltin), 3666 Acetylenedicarboxylic acid, 1401 Acetyl hypobromite, 0725 Acetyl hypofluorite, 0748... 

Acetyl azide, 0767 Azidocarbonyl fluoride, 0338 4-Azidocarbonyl-1,2,3-thiadiazole, 1066 N- A z idocarbonyI azepi ne, 2724... 

According to the electrostatic potential maps, the carbonyl carbon of acetyl azide is more electron-poor and therefore more reactive in nucleophilic acyl substitution reactions. Resonance donation of nitrogen lone-pair electrons to the carbonyl group is greater in an amide than in an acyl azide. 

Also, reaction of sugar iminophosphoranes 73 with acetyl azide affords the sugar substituted carbodumide 74." ... 

Another promising route consists in the cycloaddition of acetyl azide to triethylphos-phoranemethylenes (306a) and subsequent hydrolysis to (306b) with yields of 60% and greater (69M1438). For further references see (7otl522S, 73t19s). 

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