Name | nysted |
Synonyms | nysted Nysted Reagent Nystead reagent bis(bromozinciomethyl)zinc,tetrahydrofuran Nysted Reagent,cyclo-Dibromodi-μ-methylene[μ-(tetrahydrofuran)]trizinc |
CAS | 41114-59-4 |
InChI | InChI=1/C4H8O.2CH2.2BrH.3Zn/c1-2-4-5-3-1;;;;;;;/h1-4H2;2*1H2;2*1H;;;/q;;;;;;2*+1/p-2/rC4H8O.C2H4Br2Zn3/c1-2-4-5-3-1;3-6-1-5-2-7-4/h1-4H2;1-2H2 |
InChIKey | CCTHTLJWXPUNGT-UHFFFAOYSA-L |
Molecular Formula | C6H12Br2OZn3 |
Molar Mass | 456.14 |
Density | 1.186g/mLat 25°C(lit.) |
Flash Point | −15°F |
Risk Codes | R11 - Highly Flammable R14 - Reacts violently with water R19 - May form explosive peroxides R22 - Harmful if swallowed R36/37/38 - Irritating to eyes, respiratory system and skin. R40 - Limited evidence of a carcinogenic effect R36/37 - Irritating to eyes and respiratory system. |
Safety Description | S16 - Keep away from sources of ignition. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36 - Wear suitable protective clothing. S36/37 - Wear suitable protective clothing and gloves. |
UN IDs | UN 3399 4.3/PG 2 |
WGK Germany | 3 |
Application | Nast reagent is an organic synthesis reagent that realizes carbonyl methylation. Alkylation of carbonyl compounds is a very important reaction in organic synthesis, especially the methylene reaction of carbonyl groups is widely used in industry. At present, the commonly used synthesis methods still have many defects, such as Wittig reaction, which requires strict anhydrous and oxygen-free, low temperature, aprotic solvent, and harsh reaction conditions. Tebbe reagent can not only realize the methylene of carbonyl group, but also make the carbon-oxygen double bond of ester group, lactone, amide and thioester react to obtain alkenyl group. However, its disadvantage is that it is an organometallic compound, which is very sensitive to water and air, and its related operations must ensure anhydrous and oxygen-free conditions. For example, Nast reagent can be used to synthesize a class of entecavir intermediates, specifically as follows: Nast reagent (1200mL,2M, tetrahydrofuran solution) under argon protection atmosphere is added with titanium tetrachloride (240ml,1M, dichloromethane solution) at 0~5 degrees Celsius. The obtained brown-red turbid liquid was stirred at 25 degrees Celsius for 2 hours and then cooled to 0 degrees Celsius, and the intermediate compound (192g,240mmol) was slowly added. The obtained mixture was stirred at 0 degrees Celsius for 6 hours and then slowly added to the nitrogen atmosphere. Stir vigorously stirred sodium bicarbonate saturated solution (2000mL). The obtained mixture was stirred at 25 degrees Celsius for 1 hour and filtered by diatomite, and the filter cake was stirred and washed by dichloromethane (1000mL). The combined aqueous and organic phases are saturated with salt (600g) and then filtered and stratified. The separated organic phase was dried by magnesium sulfate and evaporated to dry the organic solvent to obtain the crude product of the target product (163g, yield 85%). |