Efficient Trimethylsilylation of Alcohols and Phenols with HMDS in the Presence of a Catalytic Amount of 1,3-Dibromo-5,5-Dimethylhydantoin (DBDMH) as a Safe and Cheap Industrial Chemical
1,3-Dibromo-5,5-dimethylhydantoin (DBDMH) is found to be an effective catalyst for trimethylsilylation various alcohols and phenols with hexamethyldisilazane (HMDS) in dichloromethane at room temperature.
Cu(OTf)2 was found to be an efficient catalyst in the acylation reaction of alcohols, phenols, amines and thiols with acetic anhydride in CH2Cl2 or acetic acid. A catalytic cycle has been proposed for the acylation reaction.
reducing agents suitable for prostaglandinsynthesis, diisobutylaluminum 2,6-di-t-butyl-4-methylphenoxide (1) is found to be among the best. Reduction of the C-15 ketone with 1 in toluene at −78 °C produced the desired 15S-alcohol in 95% yield with 92% stereoselectivity. The present procedure is suitable for the synthesis of prostaglandin derivatives and related polyfunctional natural products as shown in
OPTICAL RECORDING MEDIUM AND COMPOUND USED FOR THE SAME
申请人:SHIOZAKI Hiroyoshi
公开号:US20090306376A1
公开(公告)日:2009-12-10
A compound comprising a ring structure including a ring composed of four carbon atoms and two nitrogen atoms and a substituted or unsubstituted amino group bonded to the ring structure.
Oral care compositions with color changing indicator
申请人:Sabnis W. Ram
公开号:US20060222601A1
公开(公告)日:2006-10-05
The invention describes color changing toothpastes and mouthwashes which contains acid-base indicator(s) for interaction with the oral cavity to provide a color change indicative of treatment time.