ASSIGNMENT BOOKLET Bachelor s Degree Programme (B.Sc.) ORGANIC REACTION MECHANISM. Please Note

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1 ASSIGNMENT BOOKLET Bachelor s Degree Programme (B.Sc.) ORGANIC REACTION MECHANISM CHE-06 Valid from 1 st January to 31 st December 2014 It is compulsory to submit the Assignment before filling in the Term-End Examination Form. Please Note You can take electives (56 or 64 credits) from a minimum of TWO and a maximum of FOUR science disciplines, viz. Physics, Chemistry, Life Sciences and Mathematics. You can opt for elective courses worth a MINIMUM OF 8 CREDITS and a MAXIMUM OF 48 CREDITS from any of these four disciplines. At least 25% of the total credits that you register for in the elective courses from Life Sciences, Chemistry and Physics disciplines must be from the laboratory courses. For example, if you opt for a total of 64 credits of electives in these 3 disciplines, at least 16 credits out of those 64 credits should be from lab courses. You cannot appear in the Term-End Examination of any course without registering for the course. Otherwise, your result will not be declared and the responsibility will be yours. School of Sciences Indira Gandhi National Open University Madian Garhi, New Delhi (2014)

2 Dear Student, We hope, you are familiar with the system of evaluation to be followed for the Bachelor s Degree Programme. At this stage you may probably like to re-read the section on assignments in the Programme Guide that we sent you after your enrolment. A weightage of 30 per cent, as you are aware, has been earmarked for continuous evaluation, which would consist of one tutor-marked assignment. The assignment is based on Blocks 1, 2, 3 and 4. Instructions for Formatting Your Assignments Before attempting the assignments, please read the following instructions carefully. 1 On top of the first page of your answer sheet, please write the details exactly in the following format: ENROLMENT NO... NAME:.. COURSE CODE COURSE TITLE :... :... ADDRESS:.... ASSIGNMENT NO.:... STUDY CENTRE :... (NAME AND CODE) DATE:... PLEASE FOLLOW THE ABOVE FORMAT STRICTLY TO FACILITATE EVALUATION AND TO AVOID DELAY. 2 Use only foolscap size writing paper (but not of very thin variety) for writing your answers. 3 Leave 4 cm margin on the left, top and bottom of your answer sheet. 4 Your answers should be precise. 5 While writing answers, clearly indicate the Question No. and part of the question being solved. 6 Please note that: i) The Assignment is valid from 1 st January, 2014 to 31 st December, i The response to this assignment is to be submitted to the Study Centre Coordinator within eight weeks of the receipt of this booklet in order to get the feedback and comments on the evaluated assignment. In any case, you have to submit the assignment response before appearing in the term end examination. 7 We strongly suggest that you should retain a copy of your assignment responses. Wishing you all good luck.

3 Note: * Tutor Marked Assignment Organic Chemistry This assignment is based on all the four Blocks of the entire course. Course Code: CHE-06 Assignment Code: CHE-06/TMA/2014 Maximum Marks: 100 * All questions are compulsory. Marks for the questions are shown within brackets on the right hand side. * Please answer in your own words; do not copy from the course material. 1. a) Complete the following reactions making use of curved arrows. (5) b) The nitration of N,N-dimethylaniline, C 6 H 5 N(CH 3 ) 2, in 85% H 2 SO 4 gives 45% m- nitro product and 38% p-nitro product. Answer the following on the basis of this statement. (5) i) What is the species actually undergoing nitration to give the meta product? i iv) How is it formed? What is its relative reactivity to that of benzene? Why does this species under go meta substitution? 2. Write the product formed in the following reactions indicating the type of substitution mechanism. Also indicate the stereochemistry in case of chiral compounds. (10)

4 3. a) Explain the effect of nucleophilicity of the elements across a period, down the group and the nature of the species in terms of its charge. Arrange the following species in the order of their increasing nucleophilicity in dimethyl formamide (DMF) solvent. (5) CH 3 CO 2 ( ), I ( ), CH 3 O ( ),< Br ( ), CH 3 S ( ), N 3 ( ), CN ( ), Cl ( ) b) Explain the following: i) Addition reaction of alkene is an endothermic process. electrons of alkene are easily available to electron seeking reagent than that of electrons. i Alkynes are less reactive than alkenes. iv) Hydroboration follows Markovnikov s rule. v) Diels-Alder reaction is stereospecific. 4. a) Explain the following with suitable examples. (5) i) Aldehyde without - hydrogen does not undergo cannizzaro reaction. Aldehyde must contain - hydrogen for aldol condensation. i For Michael addition electron withdrawing group must be present with carbon carbon double bond. iv) Substitution of alkyl group on the carbonyl carbon decreases the reactivity of carbonyl compound. v) Tertiary alkyl halide does not give ylide. b) What do you understand by syn-elimination and anti-elimination? Explain with a suitable example. (3) c) The elimination of HCl from chlorofumaric acid is 50 times faster than from chloromalic acid. Explain. (2) 5. a) What is Oxidation State? Calculate the oxidation state of C-atoms in CH 3 COOH (2) b) Answer the following: (2) i) Who got the Nobel prize for Chemistry in 1973?

5 i iv) What do you understand by poisoned catalyst? What is radical ion? In which year Wolff Kishner reaction was discovered? c) Explain the following with suitable examples. (6) i) E2 elimination does not give rearranged product. Hofmann elimination gives less substituted alkene i For Michael addition electron withdrawing group must be present with carbon carbon double bond. 6. a) Explain the following: (5) i) Singlet carbene is less stable than triplet carbene. Only singlet carbene on reaction with cis-2- butene gives stereospecific product. b) Give the product(s) and mechanism of the following reactions: (5) OCH 3 i) Br NH 2 /NH 3 N 3 Aniline sol. 7. a) What is the difference between photolysis and the thermolysis? Explain with one suitable example in each case. (5) b) Write the products and mechanism for the bromination of cydohexene and ethyl benzene with N-Bromosuccinimide (NBS). (5) 8. a) Write the mechanism of the following rearrangement reactions: (5) i) Hofmann Beckmann b) Discus the products obtained from photo-induced and thermal-induced reactions of 2E, 4E-hexadiene. Give the mechanism of the reactions. (5) 9. a) Taking suitable examples discuss the mechanism of Norrish type II and Paterno-Buchi reactions. (5) b) How will you prepare of nitro aniline from aniline? Write all the steps involved in the preparation. (5) 10. How will you prepare? Write all the steps involved in the preparations. (10) i) Adipic acid from diethyl malonate Propanoic acid from ethylmagnesiumbromide i Barbituric acid from diethyl malonate iv) Cylopentyl methyl ketone from ethyl acetoacetate v) Propanol from methyl magnesium bromide.