中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
6,7,8-三甲氧基-2-苯基-4,4a,6,7,8,8a-六氢吡喃并[3,2-d][1,3]二恶英 | methyl 4,6-O-benzylidene-2,3-di-O-methyl-α-D-glucopyranoside | 3051-89-6 | C16H22O6 | 310.347 |
—— | methyl 4,6-O-benzylidene-2,3-di-O-methyl-α,D-glucopyranoside | 3013-58-9 | C16H22O6 | 310.347 |
中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | (2R,3S,4S,5R,6S)-2-Benzyloxymethyl-4,5,6-trimethoxy-tetrahydro-pyran-3-ol | 120333-19-9 | C16H24O6 | 312.363 |
Hydrogenolysis (reductive cleavage) of the (R) isomers of the acetophenone 4,6-O-derivatives of glucopyranosides with LiAlH4/AlCl3 gives the 4-O-(1'-phenylethyl) ethers with (R) configuration; the corresponding (S) isomers produce the respective (R) 6-O-(1'-phenylethyl ) ethers are produced. The hydrogenolysis of other 4,6-O-ketals affords O 4 ether derivatives; the two diastereoisomeric 4,6-O-s-butylidene derivatives (cyclic ketals ) give O 4-ethers with the opposite absolute configuration. The stereoselectivity of these reactions is explained by the development of a four-centre transition state. The absolute configuration of the ethers has been determined by means of circular dichroism measurements.