Hi there,
If anyone out there can open their TBR orgo book 2 to page 131, I just have a clarification question dealing with 2 of the sugar questions.
In question 8, it asks which of the sugars in Figure 1 have an alpha-1,4- linkage and the answer was B. Maltose only which ruled out A. Lactose only.
I agreed with this answer because I thought the Lactose had beta 1,4- linkage.
Then in question 11, it asks for the full name of lactose of which C) 4-O-(beta-D-glucopyraosyl)-alpha-D-galactopyranose was the answer not D) 4-O-(Beta-D-glucopyranosyl)-beta-D-galactopyranosyl.
Why aren't both the linkages beta? To solve this question I always thought you just look how the bond of the oxygen involved in the linkage and the bond of the sixth carbon on the chair configuration is arranged. If both of the bonds are arranged in an equatorial fashion (as the picture suggests) shouldnt the answer be beta for both?
Thanks in advance!
If anyone out there can open their TBR orgo book 2 to page 131, I just have a clarification question dealing with 2 of the sugar questions.
In question 8, it asks which of the sugars in Figure 1 have an alpha-1,4- linkage and the answer was B. Maltose only which ruled out A. Lactose only.
I agreed with this answer because I thought the Lactose had beta 1,4- linkage.
Then in question 11, it asks for the full name of lactose of which C) 4-O-(beta-D-glucopyraosyl)-alpha-D-galactopyranose was the answer not D) 4-O-(Beta-D-glucopyranosyl)-beta-D-galactopyranosyl.
Why aren't both the linkages beta? To solve this question I always thought you just look how the bond of the oxygen involved in the linkage and the bond of the sixth carbon on the chair configuration is arranged. If both of the bonds are arranged in an equatorial fashion (as the picture suggests) shouldnt the answer be beta for both?
Thanks in advance!
