Chemistry of natural products: Carbohydrates, proteins and peptides, fatty acids, nucleic acids, terpenes, steroids and alkaloids. Biogenesis of terpenoids and alkaloids.
| YEAR |
JUN-2016 |
DEC-2015 |
JUN-2015 |
DEC-2014 |
JUN-2014 |
DEC-2013 |
JUN-2013 |
DEC-2012 |
JUN-2012 |
DEC-2011 |
JUN-2011 |
| No.of questions appeared |
4 |
3 |
3 |
3 |
5 |
7 |
6 |
7 |
4 |
2 |
3 |
1.Among the following, the compound(s) that can be classified as terpene derivative is (are)
(1) A and B
(2) A only
(3) B only
(4) B and C
Ans. (3)
Soln:
Only compound ‘B’ is terpene derivative and others are not terpene derivative
2.The major product formed in the following reaction is
Ans (1)
Soln:
The reagent H2, 10% Pd/C, EtOH, deprotect the ‘Bn’ and Cbz in amino acid.
3.The major product formed in the following reaction is….
Ans (1)
Soln:
Ring opening takes place from axial attack of H– at position (2)
4.At pH 10, tryptophan exists as
Ans (1)
Soln:
Tryptophan at pH = 10 exist in the following form
In case of Tryptophon (PI value is 5.9) the IP value is lower than pH value of solution So, Tryptophen exist in anionic form where pH > PI anionic form of amino acid.
5.D-Mannose upon fluxing in acetone with CuSO4 and H2SO4 gives
Ans (3)
Soln:
This is an example of protection of 1,2diol by acetone in the presence of acid. For the protection of 1,2diol the two hydroxyl group must be in cis-orientation. Hence only anomeric OH group remain unaffected rest all OH will form 5-membered cyclic acetal as thermodynamic product.
6.The correct match of the compound in column A with the description in column B is
(1.) P-Y, Q-Z, R-X
(2.) P-Z, Q-X, R-Y
(3.) P-Z, Q-Y, R-X
(4.) P-X, Q-Z, R-Y
Ans (2)
Soln:
Aspirin : acetyl salicylic acid
Ibuprofen : ISO butyl phenyl propanoic acid
Oil of winter green : methyl salicylate
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