One-pot preparation of carbamoyl benzotriazoles and their applications in the preparation of ureas, hydrazinecarboxamides and carbamic esters
作者:Hui Mao、Huili Liu、Yawei Tu、Zhiyun Zhong、Xin Lv、Xiaoxia Wang
DOI:10.2298/jsc150126069m
日期:——
synthesized in one-pot from carboxylic acids, diphenylphosphorazidate (DPPA) and benzotriazole (BtH). The reactivity and applications of carbamoyl benzotriazoles were also explored. Carbamoyl benzotriazoles react smoothly with amino acids, hydrazines and alcohols respectively, thus providing facile access to the corresponding ureas, hydrazinecarboxamides and carbamicesters in good to excellent yields
ADDITION-CURABLE SILICONE RUBBER COMPOSITION AND CURED PRODUCT
申请人:SHIN-ETSU CHEMICAL CO., LTD.
公开号:US20180134871A1
公开(公告)日:2018-05-17
Provided is an addition-curable silicone rubber composition containing
(A) an alkenyl group-containing organopolysiloxane having alkenyl groups bonded to at least two silicon atoms per molecule,
(B) an organohydrogenpolysiloxane containing hydrogen atoms bonded to at least two silicon atoms per molecule,
(C) a platinum catalyst, and
(D) a benzotriazole derivative represented by general formula (I)
(in the formula, R
1
is a hydrogen atom or monovalent hydrocarbon group, R
2
is a monovalent organic group)
that makes it possible to provide silicone rubber that can lower the compression set without harming the curing rate and suppress discoloration after a heat resistance test.
Trapping of Isocyanates with Benzotriazole in situ - Preparation of Carbamoyl Benzotriazoles as an Isocyanate Alternative via Curtius Rearrangement
N-Aryl and N-alkenyl carbamoyl benzotriazoles were prepared in good to excellent yields from acyl azides and benzotri-azole via Curtiusrearrangement, while N-alkylcarbamoyl benzotriazoles were formed from N-alkanoyl benzotriazoles and sodium azide in one pot. The carbamoyl benzotriazoles can be used as a stable isocyanate alternative, as has been demonstrated by its reaction with amines to synthesize