UntukSoalan 1, sila jawab di kertas jawapan dan Lampiran I dan II. For Question 1, please answer in the answer script and Attachments I and II.

Transkripsi

1 UNIVERSITI MALAYA UNIVERSITY OF MALAYA PEPERIKSAAN IJAZAH SARJANA MUDA SAINS EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE SESI AKADEMIK 2014/2015 : SEMESTER 1 ACADEMIC SESSION 2014/2015 : SEMESTER 1 : KIMIA SEBATIAN SEMULAJADI NATURAL PRODUCT CHEMISTRY Disember 2014/Januari 2015 December 2014/January 2015 Masa : 2 jam Time : 2 hours ARAHAN KEPADA CALON : INSTRUCTIONS TO CANDIDATES : Jawab SEMUA soalan Answer ALL question UntukSoalan 1, sila jawab di kertas jawapan dan Lampiran I dan II. For Question 1, please answer in the answer script and Attachments I and II. Sila kepilkan Lampiran I VI bersama-sama dengan skrip jawapan anda. Please attach Attachments I VI together with your answer script. (Kertas ini mengandungi 5 soalan dalam 6 halaman yang dicetak) (This question paper consists of 5 questions on 6 printed pages)

2 1. Kamu dibekalkan dengan satu set data NMR ( 1 H, 13 C, COSY, HSQC, and HMBC) yang sepadan dengan salah satu sebatian di atas (Lampiran I VI). Berdasarkan spektrum yang dibekalkan (Lampiran I VI), tentukan sebatian (A atau B) yang sepadan dengan data spektrum yang disediakan. Jelaskan jawapan anda. Sebagai sebahagian daripada jawapan anda, anda dikehendaki menandakan setiap puncak dalam spektrum NMR 1 H dan 13 C (Lampiran I dan II). Sila kepilkan semua spektrum-spektrum ini (Lampiran I VI) bersama-sama dengan kertas jawapan anda. (Spektrum COSY, HSQC, dan HMBC di Lampiran III VI dibekalkan untuk membantu anda dalam proses penandaan puncak. Anda tidak akan digred dalam ketiga-tiga spektrum ini.) You are provided with a set of NMR data ( 1 H, 13 C, COSY, HSQC, and HMBC), which corresponds to one of the above compounds (Attachments I VI). Based on the spectra provided in Attachments I VI, determine which of the two compounds (A or B) corresponds to the spectral data provided. Explain your answer. As part of your answer, you are required to assign each peak in the 1 H and 13 C NMR spectra (Attachments I and II). Please attach all spectra (Attachments I VI), together with your answer script. (The COSY, HSQC, and HMBC spectrain Attachments III VI are provided to assist you in the assignment. You will not be graded in these three spectra.) (30 markah/marks) 2. (a) Tulis nota ringkas tentang peranan sebatian semulajadi dalam sebatian pewarna dan berwarna. Write short notes about the role of natural products in dyestuff and colored compounds. (5 markah/marks) (b) Apa itu minyak pati? Gariskan satu kaedah pengekstrakan minyak pati daripada satu sample tumbuhan. What are essential oils? Outline an extraction method of essential oils from a plant sample.

3 (5 markah/marks) (c) Kelaskan setiap sebatian-sebatian yang berikut (C G) mengikut kelas sebatian semulajadi (cth., terpena, alkaloida, dsb.). Classify the following compounds(c G) according to the class of natural product to which they belong (e.g., terpenes, alkaloids, etc.). (10 markah/marks) 3. (a) Berikan mekanisme terperinci bagi biosintesis asid lemak berikut dan kenalpastikan semua enzim utama yang terlibat. Cadangkan reagen bahan kimia yang setara dengan blok binaan biologi dan kofaktor bagi mekanisme yang terlibat. Provide a detailed mechanism for the biosynthesis of the fatty acid shown below, identifying all key enzymes. Suggest chemical reagents equivalent to the biological building blocks and co-factors you have used in your reaction mechanism. (10 markah/marks) (b) Berikan penerangan ringkas mengenai laluan metabolik sekunder yang menghasilkan molekul (1) dan (2). Bincangkan secara ringkas kepentingan biologi bagi molekul (1) dan (2). (Mekanisme tindak balas tidak diperlukan).

4 Provide a concise description of the secondary metabolic pathways leading to the molecules (1) and (2). Briefly discuss the biological importance of these molecules. (Reaction mechanisms are not required). (8 markah/marks) 4. Lukiskan mekanisme untuk oksidatif fenolik berganding untuk transformasi (3) kepada (4) dan (5). Draw out the oxidative phenolic coupling mechanism for the transformation of (3) to (4) and (5). (12 markah/marks) 5. (a) Langkah terakhir dalam sintesis biomimetik dehidroprogesteron W. S. Johnson ditunjukkan di bawah. Berikan semua reagen yang ketinggalan, A ke F, dan mekanisme bagi transformasi dari (8) ke (9). Apakah fungsi plumbum tetraasetat bagi penukaran dari (9) ke (10)? The final steps in W. S. Johnson s biomimetic dehydroprogesterone synthesis are shown below. Provide all missing reagents, A to F and the mechanism for the transformation of (8) to (9). What is the function of lead tetraacetate in the conversion of (9) to (10)?

5 (12 markah/marks) (b) Lukiskan mekanisme yang terperinci untuk transformasi (11) ke (14). Berikan sebatian perantara yang ketinggalan, G dan H. Draw out a detailed mechanism for the transformation of (11) to (14). Provide the missing intermediates, G and H.

6 (8 markah/marks) TAMAT END

7 Lampiran I - VI AttachmentsI - VI Lampiran I Attachment I Lampiran II Attachment II Lampiran III Attachment III Lampiran IV Attachment IV Lampiran V Attachment V Lampiran VI Attachment VI 1 H 1 H 13 C 13 C COSY COSY HSQC HSQC HMBC HMBC HMBC HMBC NO.PENDAFTARAN (DENGAN PERKATAAN) (Registration Number (in words) NO. PENDAFTARAN (DENGAN ANGKA) (Registration Number (in numbers) (Buku Jawapan ini mengandungi 7 halaman yang dicetak) (This Answer Booklet consists of 7 printed pages)

8 1 H NMR Lampiran/ Attachment I 8/7

9 Lampiran/Attachment II 13 C NMR 9/7

10 Lampiran/Attachment III COSY COSY Lampiran/Attachment IV 10/7

11 HSQC HSQC Lampiran/Attachment V 11/7

12 HMBC HMBC 12/7

13 Lampiran/Attachment VI HMBC HMBC 13/7

14 14/6