Sodium Triacetoxyborohydride (STB) is a white powder with the chemical formula NaBH(OAc)₃, and its molecular weight is about 252.06 g/mol. It is solid at room temperature. It is usually in the form of needle-like crystals or massive crystals, and is relatively light and easy to handle. It is slightly soluble in water, and has good solubility in polar solvents such as absolute ethanol, methanol, dimethyl sulfoxide and chloroform, and is a mild and selective borohydride reagent. This allows the compound to be soluble in most commonly used solvents and to function in many chemical reactions. Stable to a certain extent, it can be stored for several months to several years at room temperature, and will not be easily decomposed. However, the compound is prone to decomposition under extreme conditions such as high temperature or high humidity, so it must be preserved properly to ensure its quality. The compound is stable and easy to store. These physical properties make it an important reducing agent and play an important role in organic synthesis. For the reductive amination of ketones and aldehydes, the reductive amination/lactoamylation of carbonyl complexes and amines, and the reductive amination of aryl aldehydes. The novel reductive amination catalyst has excellent universality and selectivity, mild reaction conditions, good catalytic reduction performance, easy separation and purification, the catalyst itself and by-products are non-toxic, and have no pollution to the environment. Has become the catalyst of choice for reductive amination reactions.
|
Chemical Formula |
C6H10BNaO6 |
|
Exact Mass |
212 |
|
Molecular Weight |
212 |
|
m/z |
212 (100.0%), 211 (24.8%), 213 (6.5%), 212 (1.6%), 214 (1.2%) |
|
Elemental Analysis |
C, 34.00; H, 4.76; B, 5.10; Na, 10.85; O, 45.29 |
|
|
|
Sodium triacetate borohydride is used as a selective and mild reducing reagent in modern organic chemistry. It is mainly used as a substitute for NaBH ∝ CN for the reductive amination of aldehydes and ketones. Due to the presence of only one hydrogen anion in the reagent, the dosage can be relatively strictly controlled. The advantage over NaBH ∝ CN is that it does not require adjustment of the acidity or alkalinity of the reaction system, and the absence of cyanide ions also increases safety. The current literature usage shows that the application of this reagent in reductive amination reactions is increasing.
This reagent can affect the reductive amination reaction of aldehydes and ketones with primary and secondary amines. However, when ketones are the substrate, a catalytic amount of acetic acid is required to increase the reaction rate or to react in acetic acid. ClCH ₂ CH ₂ Cl is the best solvent for this reaction and has the fastest reaction rate. This reaction can also be carried out using THF and MeCN as solvents, but the reaction rate is slightly reduced, especially for the latter. This reaction is generally carried out at room temperature, and the reaction between aldehydes and amines can be completed within a few minutes, while the reaction between ketones and amines takes several hours. In most cases, the yield of the generated product is at a moderate to high level.
Sodium triacetoxyborohydride is a novel catalyst specifically designed for reductive amination reactions and is highly favored due to its unique advantages. It has extremely high universality and selectivity, can catalyze reactions gently, and exhibits good reduction performance. In addition, its separation and purification process is simple, and the catalyst itself and by-products are non-toxic, making it an ideal catalyst for reductive amination reactions and environmentally friendly.
Although metal catalyzed hydrogenation such as platinum, palladium, or nickel is economical and effective in large-scale production, their products are usually mixtures with low yields. This method still has limitations as it cannot handle compounds containing carbon carbon bonds and reducible functional groups such as nitro and cyano groups, as their catalytic performance is inhibited by divalent sulfides.
The core of the reductive amination reaction is to convert carbonyl compounds into amines by first forming imines and then reducing them using sodium borohydride (including STB). Different types of sodium borohydride have similar reduction steps after forming imines, mainly reducing imines to amines. This process is carried out under weakly acidic conditions to enhance the electrophilicity of carbonyl groups while avoiding the decrease in nucleophilicity caused by excessive protonation of amines.
The use of sodium cyanoborohydride for reduction is superior to sodium borohydride because the electrostatic induction effect of the cyanide group reduces the activity of boron hydrogen bonds, ensuring selective reduction of only selegiline and avoiding non targeted reduction of aldehydes and ketone carbonyl groups, thereby reducing the occurrence of side reactions. By using NaBH (OAc) 3 as a reducing agent and ClCH2CH2Cl as a solvent, the reaction time can be effectively shortened and the yield of the product can be improved.
Sodium Triacetoxyborohydride is a kind of organic synthesis reagent, which is widely used in reactions such as reduction, condensation and synthesis of heterocyclic compounds. It is usually synthesized by several methods, all of which will be described in detail.
1. Cyclic tetraphenylphosphine salt method:
The cyclic tetraphenylphosphonium salt method is one of the main methods for preparing product. In the method, triphenylphosphine and triacetoxyborontriethyl ester are used as raw materials, and a reduction reaction occurs in the presence of tributylaluminum hydride and hydroxyethyltriphenylphosphine to generate it.
The reaction equation is as follows:
B(OAc)3 + 3Ph3P + 3EtOH → NaBH(OAc)3 + 3Ph3PO + 3EtOAc
The synthesis method has the advantages of high yield, mild reaction conditions and easy operation. However, due to the high price of raw materials, the production cost is relatively high.
2. Boric acid and ethyl iodide method:
The method of boric acid and ethyl iodide is a convenient synthesis method, and it is also one of the commonly used methods for preparing Sodium Triacetylborohydride. The method is based on the alkylophilicity of ethyl iodide, directly reacts boric acid and ethyl iodide to generate triiodoethyl borate, and then obtains Sodium Triacetylborohydride through the reduction reaction of sodium.
The reaction equation is as follows:
H3BO3 + 3I(C2H5) → B(I(C2H5))3 + 3H2O
B(I(C2H5))3 + 3NaH → NaBH(OAc)3 + 3C2H5I
The synthesis method has the advantages of simple operation and no need for special reaction conditions, but the product has low purity and needs to be further purified through steps such as recrystallization or column chromatography.
In conclusion, it is an important organic synthesis reagent with broad application prospects. It can be synthesized by various methods. Each method has its specific advantages and disadvantages, so in the actual production process, it is necessary to choose the appropriate method according to the specific situation.
Sodium Triacetoxyborohydride is a colorless, crystalline solid with the chemical formula NaBH(OAc)3, where BH(OAc)3 stands for triacetoxyborohydride. Its molecular weight is about 252.4 g/mol. At room temperature, it has high thermal and chemical stability, and can be stored and used under normal experimental conditions.
1. Molecular structure:
The molecular structure of it is composed of three acetoxy groups and a borohydride ion. The structure of the borohydride ion is similar to a regular tetrahedron, in which the B atom is located at the center, and three OAc groups are distributed equidistantly and equiangularly around it, and each H atom is connected to an OAc group to form a bond with the B atom. In addition to borohydride ions, sodium ions also play an important role in structure stabilization in the lattice.
2. Crystal structure:
The crystal structure of Sodium Triacetylborohydride was obtained in 1973 by G. W. Parshall et al. It is monoclinic with space group P21/c. The unit cell parameters are a = 13.236 Å, b = 16.145 Å, c = 9.048 Å, and β = 96.74°. The unit cell contains four molecules, each of which interacts with other molecules through hydrogen bonds, forming a three-dimensional network structure. In the lattice, the borohydride ion forms hydrogen bonds with three different OAc groups through H atoms, making the distance between them about 1.2 Å. The sodium ion forms an ionic bond with one of the three OAc groups.
The following is a brief introduction about the main chemical properties of the compound:
1. Reducibility:
Sodium Triacetylborohydride is a strong reducing agent that can reduce many organic compounds to lower oxidation states. For compounds containing oxygen functional groups, such as aldehydes, ketones, acids and esters, it will usually be selectively reduced to the corresponding alcohols or hydroxyl compounds. For compounds containing sulfur functional groups, such as mercaptans and disulfides, the reducing agent also has strong reducing properties.
3. Stability:
Although STB is a strong reducing agent, it is more stable than other commonly used reducing agents such as sodium borohydride. During storage and use, the compound is not easily affected by conditions such as air, moisture and temperature. At the same time, it should also be noted that it should avoid contact with oxidizing agents, such as hydrogen peroxide or potassium permanganate, otherwise dangerous reactions will occur.
Hot Tags: sodium triacetoxyborohydride cas 56553-60-7, suppliers, manufacturers, factory, wholesale, buy, price, bulk, for sale, DIMETHYLPHOSPHINE OXIDE, 3 Phenyltoluene, Additive, gs 441524 remdesivir, Synthetic Chemical, 2 Chloro 4 pyridinecarboxylic acid