Acryloyl azide

An improved method that can be easily scaled-up has been developed for the preparation of benzyl-N-vinyl carbamate 810 (Z-vinylamine), a valuable synthetic intermediate in the synthesis of p-lactam antibiotics [589]. In this method, vinyl isocyanate 809, formed by the Curtius rearrangement of acryloyl azide 808, is codistilled with a solvent such as toluene into benzyl alcohol containing a catalyst and an inhibitor. The product thus obtained can be purified by crystallization, thereby avoiding purification by high-vacuum distillation or chromatography. Potential safety issues associated with the process are important [590, 591]. 

The thermal stability of acryloyl azide has been studied in some detail. Solutions of this compound in toluene appear to be stable at sub-ambient temperatures. However, it can undergo polymerization when stored for long periods, and the crystals formed can undergo rapid decomposition when dry. Care should be exercised to avoid this polymerization by storing the solutions below 5 °C. It is strongly recommended that solutions of acryloyl azide be used soon after their preparation. 

Typical Procedure. Benzyl N-vinyl carbamate 810 [590]. Note Some of the chemicals described bdow can undergo rapid decomposition and polymerization, with evolution of gaseous products. Acryloyl azide in neat form may be dangerously explosive, and vinyl isocyanate is probably very toxic. AU experiments should be carried out behind a safety shield in a weU-ventdated hood. Extreme care should be taken to avoid injury. 

Acryloyl azide 808 All reactor was charged with 68.4 g (1.05 mol) of sodium azide, 200 ml of water, 200 ml of toluene, and 0.09 g of Adogen 464 (methyl-trialkylammonium chloride). The mixture was cooled with stirring in ice-water bath, and 90 g (1 mol) of acryloyl chloride was added dropwise over a period of 1.5 h at 0-5 °C. After the addition, the mixture was stirred for 45 min. The organic phase was separated and stored at 0-5 °C. 

Attack on Unsaturated Carbon. Numerous reports of addition of tertiary phosphites, secondary phosphites, and silyl phosphites to activated olefins have appeared. The addition of secondary phosphites to acryloyl chloride in the presence of trimethylsilyl azide provides a route to 2-isocyanato-ethylphosphonates (13). ... 

The combination of ATRP and postpolymerization modi cation by CuAAC click chemistry can be employed to prepare well-de ned tu-(meth)acryloyl macromonomers in an ef cient manner. Thus, polystyrene (PSt) can be prepared by ATRP and subsequently derivatized to contain azide end groups. The azide-terminated polymers can then be reacted with alkyne-containing (meth)acrylate monomers to achieve near-quantitative chain-end functionalization by CuAAC reaction. An ef cient synthesis route is shown in Scheme P12.1.1. 

Activation of the carboxylic acid as the acyl chloride permits direct reaction with azide anion to form the acyl azide substrates for Curtius rearrangement. Sodium azide is commonly used, and the reaction has been used on the process chemistry scale for the synthesis of benzyl-A-vinyl carbamate. Acryloyl chloride was combined with sodium azide in a biphasic system with phase-transfer catalysis (PTC), providing acyl azide 25. Upon heating, Curtius rearrangement provided vinyl isocyanate, which was distilled directly into benzyl alcohol containing phenothiazine (27) to inhibit polymerization of 26 and triethylamine to catalyze addition of the alcohol to the isocyanate. The vinyl carbamate product 28 was isolated by crystallization. As the autiior clearly pointed out, preparation and reaction of acyl azides, particularly on large scales, require appropriate safety precautions. 

Glycosyl azides are an important family of carbohydrate derivatives. They have been used as precursors of glycopeptides and heterocyclic M-glycosides. The corresponding glycosylamines, which can be obtained by reduction of the azide group, can be used as precursors to glycopolymers or hyper-branched dendrimers, after A-acryloylation. Furthermore, azide functionalities can be easily converted into... 

---