intermediate yield
1.The yield and distribution of the pyrolysis products are almost unchanged under different kinds of atmosphere when the inert silica sand is used as media of the fluidized bed. When the catalyst CoMo-B is used and with hydrogen atmosphere,the intermediate BTXN yield reaches 2.52%(mass),daf,is 3.3 times of that when silica sand is used.
3.b) At 70℃ , under pH6.47 , Dione, the intermediate, can be converted into furanone with a yield of 67.94% after 33 hours.
4.During the synthesis ofβ-DDB, the key intermediate ofβ-DDB, methyl 2-bromo-3,4-dimethylenedioxy-5-methoxybenzoate, was synthesized in higher yield by three steps: cyclization with CH2I2 of methyl gallate, bromination with NBS, and then methylation.
5.During the synthesis ofα-DDB, the key intermediate ofα-DDB, methyl 2-bromo -3, 4- dimethylenedioxy-5-methoxybenzoate, was synthesized in higher yield by bromination of methyl 3,4-dihydroxy-5-methoxybenzoate with NBS before cyclizing with CH2I2 in DMF.
6.6,7-Dihydro-5H-cyclopenteno[b]pyridine, a key intermediate of cefpirome, was synthesized from diethyl adipate by condensation, amination, cyclization, hydrolysis/decarboxylation, chlorination and dechlorination with an overall yield of 31%.
7.The 3 β O tert butyldiphenylsilyl 26 acetoxy cholestan 5(6) ene 16,22 dione,a key intermediate of furostanol saponin,was synthesized from diosgenin in three steps by the literature method in 52% overall yield.
8.1-Chloro-2-methyl-4-acetoxy-2-butene was treated with hexamethylenetetramine, followed by hydrolysis to yield 4-acetoxy-2-methyl-2-butenal, a key intermediate for vitamin A. It was found that microwave radiation could accelerate the hydrolysis in Sommelet reaction with an improved yield of 77%.
9.The intermediate 4-[?N?-(pyridin-3-ylmethoxycarbonyl)aminomethyl] benzoic acid(Ⅰ) was prepared from 3-hydroxymethylpyridine by using CDI method at 0-10 ℃ in 83.9% yield.
10.Adenosine cyclophosphate(cAMP)was synthesized from adenosine by phosphorylation with phosphorylchloride in triethyl phosphate at lower temperature to give the key intermediate adenosine 5′- dichlorophosphate whichtreated with strong base to give the title compound of 99% purity in 58% yield.
