Silane reagent

A silane reagent refers to a class of silicone monomers or small molecule compounds used in analysis or organic synthesis to modify or protect reactive groups in an organic compound. After the reaction, the silane group was removed and returned to its original state. There are more than 500 kinds, including: (1) Trimethylsilyl monofunctional SBA, such as trimethylchlorosilane, hexamethyldisilazane and the like. (2) sterically hindered single-energy SBA, such as tert-butyldimethylchlorosilane, triisopropylchlorosilane, and the like. (3) sterically hindered bifunctional SBA, such as dimethyldiacetoxysilane, di-tert-butyldichlorosilane, and the like. (4) Other protective agents such as trimethylhydroxyethylsilane, methyldiphenylhydroxyethylsilane, and the like. Silane reagents can be used in the field of analysis, organic synthesis (such as pharmaceutical synthesis). It can also be used as a modified drug, such as making it oily or losing bitterness. Silanization refers to the introduction of a silane group into a molecule, typically by replacement of an active hydrogen (eg, hydroxy-OH, carboxy-COOH, amino-NH2, fluorenyl-SH, phosphate). The substitution of the active hydrogen by the silane group reduces the polarity of the compound and reduces the hydrogen bond binding, so that the formed silylated derivative is more volatile; at the same time, the stability of the compound is also reduced due to the reduced number of reactive hydrogen-containing reactive sites. It has been strengthened. The silanized compound has weak polarity, enhanced ability to be measured, and improved thermal stability. The silylation reagents are very useful in GC analysis, and many of the hydroxyl or amino compounds which are considered to be non-volatile or thermally unstable at 200-300 ° C have been successfully chromatographed after silanization. Because silanization reagents are sensitive to active hydrogen and can react with them, silylation reagents are also very sensitive to moisture and decompose spontaneously in the presence of water. Generally, the silylation reagents are sealed in nitrogen. Nitrogen must be pre-dried and dried. After the silylation reagent is taken, it must be filled with nitrogen before sealing again. This will remove the air and avoid sealing into the air to bring the moisture in the air into contact with the silylating agent. The method of purging nitrogen can be carried out as follows: a nitrogen cylinder is connected to one end of a Teflon tube, and a Papillon is connected at one end. The head of the straw is inserted into the silanization reagent bottle to be filled with nitrogen, and the liquid surface of the silylation reagent is about 2 to 3 cm. Turn on the nitrogen switch and let the nitrogen slowly flow into the reagent bottle until the nitrogen has filled the blank space in the silanized reagent bottle. Remove the straw and immediately seal the bottle and turn off the nitrogen. Trimethylsilyl imidazole is the strongest silylating agent for silylated hydroxyl groups; it reacts rapidly and smoothly with hydroxyl and carboxyl groups. It does not react with amines or amides, so it can be used to prepare multiple derivatives of compounds containing both hydroxyl and amino groups. It can be used to silanize sugars in the presence of small amounts of water; it is ideal for silanized sugars when it is desired to analyze sugars as syrups. It is capable of deriving most of the terpenoid hydroxyl groups that are not hindered and severely hindered.