Question

How many aldose, ketose, furanose, pyranose and hemiactel units are present in the following structure :
(a) 2,0,0,2,1
(b) 1,1,1,1,2
(c)0,2,0,2,1
(d) 2,0,02,2
​

Answer 1

Explanation:

To Find -

• How many aldose, ketose, furanose, pyranose and hemiacteal units are present in MALTOSE ?

Solution -

Maltose is an aldose because it consists of two gluscoe molecules linked through an α(1→4) glycosidic bond. Glucose is an aldose and maltose consists of two glucose molecules. So, Maltose it is an aldose not ketose.

Maltose contain 2 aldose group & 0 ketose group.

Pyranose Ring -

• Ring formed due to 5 Carbon and 1 oxygen called pyranose ring.

Note -

Carbon number 6 placed outside the ring.

Furanose ring -

• Ring formed due to 4 Carbon and 1 oxygen called furanose ring.

Maltose consists of 2 pyranose ring & 0 furanose ring.

Hemiacteal linkage -

• When C=O of carbon no. 1 reacts with Carbon no. 5, this linkage is called Hemiacteal linkage. This results in formation of cyclic form.

Hence,

Maltose contains

2 Aldose group

0 Maltose group

0 Furanose ring

2 Pyranose Ring

1 Hemiacteal linkage

Therefore,

Option 1) is correct.

Answer 2

Explanation:

abundant six-carbon aldoses. Note that d- glucose and d-mannose differ in configuration only at C-2. ... 11.1.1. Pentoses and Hexoses Cyclize to Form Furanose and Pyranose Rings .