2. the (Document Not Provided on OCW) Provided Here As a PDF

Lecture 21 Assignments:

1. Silverstein 8.37, 8.40-8.41. (document not provided on OCW) Analyze the spectra and solve the structures. Identify any noteworthy heteroatoms present (S, Si, Cl, or Br). Determine the molecular formula, unsaturation number, and identify functional groups that are present. Identify key fragments from NMR. Mass spectra are EIMS, unless otherwise indicated. Letter the 1H resonances from the most downfield to the most upfield (a, b, c, d, etc.), number the 13C resonances from the most downfield to the most upfield (1, 2, 3, 4, etc.), and assign the resonances to the corresponding protons and carbon atoms in your structures. Please use this template (click here to download) for your answers.

2. The (document not provided on OCW) provided here as a PDF.

3.Part I Problem 1 from the 2006 final exam (24 page PDF).

4.Problem 10.1 (22 page PDF) Note that the compound is an amino acid. Small couplings often do not give visible crosspeaks in the COSY spectrum. Pay particular attention to assigning relative stereochemistry. (You cannot assign absolute stereochemistry, so choose a stereochemistry for one stereocenter and assign other stereochemistry relative to it.) Keep in mind that incomplete selectivity in irradiating a target peak in a 1D NOE spectrum may lead to spurious NOES associated with non-selective irradiation of a nearby peak.

5. I would like to have us start on one problem to demonstrate the utility of HMBC in "putting the pieces together". Let's do Silverstein 8.43 (document not provided on OCW). Analyze the spectra and solve the structures. Identify any noteworthy heteroatoms present (S, Si, Cl, or Br). Determine the molecular formula, unsaturation number, and identify functional groups that are present. Identify key fragments from NMR. Mass spectra are EIMS, unless otherwise indicated. Letter the 1H resonances from the most downfield to the most upfield (a, b, c, d, etc.), number the 13C resonances from the most downfield to the most upfield (1, 2, 3, 4, etc.), and assign the resonances to the corresponding protons and carbon atoms in your structures. Please use this template (click here to download) for your answers.

6.Use the NMR spectrometers in the Spec Lab to record the basic gradient-enhanced HMBC spectrum of strychnine (UCI NMR Manual pages 105-106). Remember to name your data sets with your initials. Plot your data with the 1H and 13C NMR spectra along the axes (UCI NMR Manual pages 28-36) and plotting expansions so as to be useful in working with the data.

7. Transcribe the numbers (1-21) to the 13C axis of the HMBC spectrum. Transcribe both the letters and numbers from last week's COSY spectrum to the 1H axis of the HMBC. Mark the letters and numbers of coupling partners of the carbonyl (#1) resonance on the HMBC spectrum.