The condensation reaction between 5-amino-4, 6-dichloro-2-methylpyrimidine and 1-acetyl-2-imidazolin-2-one using POCl3 as solvent gave 4, 6-dichloro-2-methyl-5-(1-acetyl-tetra- hydro-imidazo-2-ylidene)-aminopyrimidine...The condensation reaction between 5-amino-4, 6-dichloro-2-methylpyrimidine and 1-acetyl-2-imidazolin-2-one using POCl3 as solvent gave 4, 6-dichloro-2-methyl-5-(1-acetyl-tetra- hydro-imidazo-2-ylidene)-aminopyrimidine predominantly and 4, 6-dichloro-2-methyl-5-{1-[1-(2- oxo-tetrahydro-imidazolyl)]-acetyene}-aminopyrimidine as by-product. No 4, 6-dichloro-2- methyl-5-(1-acetyl-2-imidazolin-2-yl)-aminopyrimidine was found. The result indicated an esterifi- cation-addition-elimination mechanism.展开更多
In the presence of BF3.OEt2, 1-O-trimethylsilyi-2,3,4,6-tetra-O-benzyl-α-D-mannopyranose (1)reacted stereoselectively with a series of carboxylic acids to give the corresponding α-mannosyl carboxylates in good yield...In the presence of BF3.OEt2, 1-O-trimethylsilyi-2,3,4,6-tetra-O-benzyl-α-D-mannopyranose (1)reacted stereoselectively with a series of carboxylic acids to give the corresponding α-mannosyl carboxylates in good yields. The configuration of products was assigned mainly by 1H-NMR spectra (δH1 and 2J1.2).展开更多
文摘The condensation reaction between 5-amino-4, 6-dichloro-2-methylpyrimidine and 1-acetyl-2-imidazolin-2-one using POCl3 as solvent gave 4, 6-dichloro-2-methyl-5-(1-acetyl-tetra- hydro-imidazo-2-ylidene)-aminopyrimidine predominantly and 4, 6-dichloro-2-methyl-5-{1-[1-(2- oxo-tetrahydro-imidazolyl)]-acetyene}-aminopyrimidine as by-product. No 4, 6-dichloro-2- methyl-5-(1-acetyl-2-imidazolin-2-yl)-aminopyrimidine was found. The result indicated an esterifi- cation-addition-elimination mechanism.
文摘In the presence of BF3.OEt2, 1-O-trimethylsilyi-2,3,4,6-tetra-O-benzyl-α-D-mannopyranose (1)reacted stereoselectively with a series of carboxylic acids to give the corresponding α-mannosyl carboxylates in good yields. The configuration of products was assigned mainly by 1H-NMR spectra (δH1 and 2J1.2).
