CÁC PHƯƠNG PHÁP PHÂN TÍCH CẤU TRÚC HỢP CHẤT HỮU CƠ – BÀI TẬP

CÁC PHƯƠNG PHÁP PHÂN TÍCH CẤU TRÚC HỢP CHẤT HỮU CƠ – BÀI TẬP Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Bài tập Cho H = 2.67519108 rads-1T-1 C = 6.726107 rads-1T-1 Máy đo phổ điều chỉnh để phân tích proton tần số 250 MHz a Tính giá trị cảm ứng từ B0 tương ứng b Với giá trị B0 trên, xác định tần số C đầu dò sử dụng để phân tích tín hiệu cộng hưởng 13C c Với giá trị B0 trên, nhân 27Al cộng hưởng 65.13 MHz Nếu muốn sử dụng đầu dò tần số C để phân tích 27Al cần điều chỉnh B0 giá trị nào? Bài tập Sau phản ứng quang clo hóa (photo-chlorination) toluen thu hỗn hợp sản phẩm có phổ NMR 1H bên Xác định sản phẩm thu tỉ lệ chúng? Bài tập Chọn kết luận đúng? Giải thích? A Jab > Jac C Jab < Jac B Jab = Jac D chưa đủ thông tin để kết luận Bài tập Vẽ dạng tín hiệu cộng hưởng thu proton Ha ghép spin với nhân b, c, d khác có spin I = 1/2, biết Jab = 10 Hz, Jac = Hz, Jad = Hz Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Bài tập Hợp chất X (C5H10O) có đồng phân X1 X2 với phổ NMR 1H 13C{1H} bên a Mẫu hòa tan dung mơi để xác định phổ 13C{1H}? Vì mũi dung mơi xuất dạng mũi 3? b Phân tích phổ NMR 1H 13C{1H}của X1 X2 c Xác định cấu trúc X1 X2 X1 X1 Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com X2 X2 Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Bài tập Phổ NMR 1H dimethyl-cyclopropanedicarboxylate bên Các số ghép spin (Hz) cung cấp đỉnh mũi đa a Cho biết phổ tương ứng với đồng phân cis hay trans hợp chất? cis trans b Xác định giá trị số ghép spin (Hz) cung cấp nhân nào, cách nối (xJXX)? CÁC PHƯƠNG PHÁP PHÂN TÍCH CẤU TRÚC HỢP CHẤT HỮU CƠ – BÀI TẬP (TT) Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Bài tập Một hợp chất X có cơng thức phân tử C10H10O2 (xác định từ phân tích MS phân tích nguyên tố) Dữ liệu phổ NMR 1H (1D 2D COSY) 13C (1D DEPT) X trình bày Hình 1-3 (giá trị số ghép spin, Hz, cho đỉnh mũi đa) a Xác định cấu trúc X Giải thích? b X có cấu hình E hay Z Giải thích? Hình Phổ NMR 1H X Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Hình Phổ NMR 2D COSY 1H-1H X Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Hình Phổ NMR 13C{1H} DEPT X Bài tập Hoạt chất curcumin từ nghệ vàng có tác dụng hủy diệt tế bào ung thư Curcumin dạng enol có cơng thức cấu tạo Hình Hình Cơng thức cấu tạo curcumin dạng enol Mẫu curcumin chuẩn bị dung mơi DMSO để phân tích đặc trưng cấu trúc phương pháp NMR 1H, 13C{1H}, 2D HSQC 1H-13C 2D HMBC 1H-13C a Phổ NMR 1H curcumin trình bày Hình Cho biết mẫu lẫn loại dung mơi nào, giải thích Điền thông tin vào cột 2, Bảng theo thứ tự  (m, số H, XJXX) Dựa vào phổ NMR 1H, so sánh pKa1 curcumin với pKa phenol Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Hình Phổ NMR 1H curcumin b Phổ NMR 13C{1H}, 2D HSQC 1H-13C 2D HMBC 1H-13C curcumin trình bày Hình 6, tương ứng Điền thông tin vào cột 3, 5, Bảng (cột điền  13 C, cột điền loại C mà proton vị trí ghi cột có tương tác spin) Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Hình Phổ NMR 13C{1H} curcumin Hình Phổ NMR 2D HSQC 1H-13C curcumin Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com 2a 300 MHz 1H NMR spectra are shown below for three of the following isomers of dinitrophenol Match each spectrum to the appropriate compound and assign the resonances of the spectrum to the appropriate protons in the compound (12 points) OH OH H6 NO2 H6 NO2 H5 NO2 H5 H3 H4 2,3-dinitrophenol Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com OH NO2 H6 NO2 O2N O2N H3 NO2 H5 H3 H4 2,4-dinitrophenol OH OH H6 O2N 2,6-dinitrophenol NO2 H4 H4 2,5-dinitrophenol H2 3,5-dinitrophenol SPECTRUM A Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) (ppm) SPECTRUM B Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) (ppm) SPECTRUM C Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) X (ppm) X This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use 2b 300 MHz 1H NMR spectra are shown below for 2-methylpyridine, 3-methylpyridine, and 4-methylpyridine Match each spectrum to the appropriate compound and assign the resonances of the spectrum to the appropriate protons in the compound (13 points) H4 H4 H5 H6 N H3 H5 CH3 H6 Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com 2-methylpyridine N CH3 CH3 H5 H2 H6 3-methylpyridine H3 N H2 4-methylpyridine SPECTRUM D Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) (ppm) SPECTRUM E Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) (ppm) SPECTRUM F Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) (ppm) This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use 300 MHz 1H NMR and 75 MHz 13C NMR spectra are shown below for the eight constitutional isomers of alcohols with the molecular formula C5H12O Spectra are collected in CDCl3 with tetramethylsilane (TMS) as an internal standard Write the structure and IUPAC name of each alcohol above its spectra (16 points) Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Hint: First work out the structures of the eight constitutional isomers of alcohols with the molecular formula C5H12O SPECTRUM A Structure: 80 60 40 4.0 3.0 2.0 SPECTRUM B Structure: 80 60 40 4.0 3.0 2.0 SPECTRUM C Structure: 80 60 40 4.0 3.0 2.0 IUPAC name: _ 20 ppm 1.0 ppm IUPAC name: _ 20 ppm 1.0 ppm IUPAC name: _ 20 ppm 1.0 ppm This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com SPECTRUM D Structure: IUPAC name: _ 80 60 40 20 ppm 4.0 3.0 2.0 1.0 ppm SPECTRUM E Structure: 80 60 40 4.0 3.0 2.0 SPECTRUM F Structure: 80 60 40 4.0 3.0 2.0 SPECTRUM G Structure: IUPAC name: _ 20 ppm 1.0 ppm IUPAC name: _ 20 ppm 1.0 ppm IUPAC name: _ 80 60 40 20 ppm 4.0 3.0 2.0 1.0 ppm This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use SPECTRUM H Structure: IUPAC name: _ 60 40 20 ppm 4.0 3.0 2.0 1.0 ppm Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com 80 This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use 300 MHz 1H NMR spectra in CDCl3 are shown below for five of the six isomers of dimethylphenol Match each spectrum to the appropriate compound and assign the resonances of the spectrum to the appropriate protons in the compound (15 points) OH H6 H5 OH CH3 H6 CH3 H5 H4 Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com 2,3-methylphenol OH CH3 H3 CH3 2,4-methylphenol CH3 H6 H3 CH3 OH OH CH3 CH3 H5 H4 2,5-dimethylphenol H3 H6 OH H2 H5 H6 CH3 H2 CH3 CH3 H4 CH3 H4 2,6-dimethylphenol 3,4-dimethylphenol 3,5-dimethylphenol SPECTRUM A Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) 5X expansion SPECTRUM B Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) 5X expansion This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use SPECTRUM C Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com 5X expansion SPECTRUM D Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) 5X expansion SPECTRUM E Identify the compound (here) _ and label the peaks (below) with the corresponding proton (with labels selected among H2, H3, H4, H5, and H6 as appropriate) 5X expansion This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use 1H NMR spectra are shown below for a single diastereomer of 2-phenyl-1-cyclohexanol (15 points) Ha OH Ph 2-phenyl-1-cyclohexanol Hb OH Ph Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com a Draw cis-2-phenyl-1-cyclohexanol in the most stable chair conformation and draw trans-2phenylcyclohexanol in the most stable chair conformation trans-2-phenyl-1-cyclohexanol cis-2-phenyl-1-cyclohexanol b Name the multiplets (multiplicity and J values) you would expect for Ha and Hb in the cis- and transdiastereomers cis-2-phenyl-1-cyclohexanol Ha _ cis-2-phenyl-1-cyclohexanol Hb _ trans-2-phenyl-1-cyclohexanol Ha _ trans-2-phenyl-1-cyclohexanol Hb _ c Shown below is a 300 MHz 1H NMR spectrum of a single diastereomer of 2-phenyl-1-cyclohexanol in CDCl3 Which stereoismer is it? How you know? 3.6 ppm 10 2.4 ppm 20 40 Hz 10 20 40 Hz This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use The 1H NMR spectrum of (S)-glycidyl benzyl ether (300 MHz in CDCl3, with TMS) is shown below, along with expansions of the resonances at 4.6, 3.7, 3.4, 3.2, 2.8, and 2.6 ppm (20 points) O O Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com (S)-glycidyl benzyl ether ppm 4.6 ppm 3.4 ppm 3.7 ppm 10 20 30 40 Hz 10 20 Hz 10 20 Hz 20 Hz 2.6 ppm 2.8 ppm 3.2 ppm 10 10 20 Hz 10 20 Hz a Assign the resonances at 4.6, 3.7, 3.4, 3.2, 2.8, and 2.6 ppm to the various protons in the molecule, by writing the chemical shift next to the prottons on the diagram below Appendix F from Silverstein is provided at the end of this problem to help you H H H H H H O H O b Describe the multiplets and measure the coupling constants for the resonances at 3.7, 3.4, 2.8, and 2.6 ppm: 3.7 ppm (description and coupling constants): 3.4 ppm (description and coupling constants): 2.8 ppm (description and coupling constants): 2.6 ppm (description and coupling constants): This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use c Explain the appearance of the resonances at 4.6 ppm: d Based on your analysis in sections a–c, write each geminal (2JHH) or vicinal (3JHH) coupling constant on the line by the corresponding arrow Hz Hz Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com Hz H H Hz Hz Hz H H H BnO O Explain the appearance of the resonances at 3.2 ppm Make a splitting diagram to aid in your explanation Use a scale of box is equal to Hz on the horizontal axis and accurately represent the relative heights of the lines on the vertical axis e What differences would you expect between the 1H NMR spectrum of (R)-glycidyl benzyl ether and the 1H NMR spectrum of (S)-glycidyl benzyl ether? f What differences would you expect between the 1H NMR spectrum of racemic glycidyl benzyl ether and the H NMR spectrum of (S)-glycidyl benzyl ether? This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use Collected by Nguyen Thanh Tu # Google.com/+DạyKèmQuyNhơn MailBox : tuhoahocqn@hotmail.com This work by Dr James S Nowick, Professor of Chemistry, University of California, Irvine, is licensed under a Creative Commons Attribution 4.0 International License Spectra are from Sigma-Aldrich (www.sigmaaldrich.com) under fair use