Question

Need help correctly answering each of these questions. Please ignore the answers that are circled in some of the questions; as they were guesses mostly and I still need the correct answers.

Which of the following molecules best fits the following NMR spectrum? 2. OCH3 3. 5. 4. он он Which of the following molecules best fits the following NMR spectrum? 2 Cl 3 NH2 4. The spectrum shown could represent the molecule in the illustration. H3 H3C 1. True 2. False Which of the following molecules best fits the following NMR spectrum? 2 1. OCH3 OCH3 3. 5. 4. Order the following protons from lowest to highest chemical shift value. H NMR will allow one to distinguish between the following two molecules: Br Br. H 1. True 2 False The painkiller Demerol has the structure shown below. How many peaks would you expect to see in the 13C NMR spectrum of this substance? CH3 1. 10 3. 12 4. 14 5. 15 many cinnt Which of the following molecules best fits the following NMR spectrum? 2. 5. 4. Which of the following molecules best fits the following NMR spectrum? 1. 2. он 3. он он он 5. H 4. H HO но Which of the following molecules best fits the following NMR spectrum? 2 Cl 3 NH2 4. Which of the following molecules best fits the following NMR spectrum? 2. OCH3 3. 5. 4. он он

Answer 1

2) Option 2 is not correct because methly group is connected with electronegative O atom so its proton chemical shift(indicated by red colour) should come between 3.5 to 4 ppm, but in the given spectrum no peak is available in that reason Option 1 is not correct because it has 4 different diffrent type of protons as shown in figure by different colour, and whatever proton spectrum is given it has only 2 types of proton with different intenisty For this structure we should get 5 set of proton signal with intensity ratio of 2:2:2:2.6 option 3 is correct because the methyl group s directly connected with the carbonyl functional group and methly group attached with carbonyl gives a very characteristic signals a 2.5 ppm which is present in spectrum, and also 9 protons signal will comes between 1.5 to 2 ppm(for tertiary butyl group) option 4 and 5 is not correct because proton connected to acidic group should come above 10 ppm and this type of signal is not present in the spectrum

он This option is also wrong becaus all proton are in same environment so we should get only 1 set of signal for that This option is wrong because we should get 3 set of signal with the splitting pattern of quartet for terminal ethly group and triplet for CH2 group connected with Br as well as doublet of triplet for proton indicated by red colour which is not present in spectrum This option is wrong because both methly group are in same environment so we soluld get only one set of signal for that NH This option s wrong because wll give 2 set of signal with splitting pattern of triplet and quartret which is not presnt in spectrum NH2 This option is correct it will give 3 set of signal, one set for NH2 proton, one for proton indicated with red colour and one for methyl group, and all these 3 signal are present in spectrum, further for proton indicated in red colour will give splititng pattern of septet because it will split by methly group, and both the methyl group will appears as doublet (Splitted by proton indicated in red colour), Where NH2 proton will appear as broad singlet because it is Deuterium exchangable proton. All these pattern are visible in spectrum so this i corret option

ChemNMR H Estimation 5.39 5.05 1.82 он 4.18 1.70 1.82 | 1.70 4.18 5.39 5.05 PPM Answer is true. Clearly we can see that five type of signal will appear for given structure which is given in spectrum

нь Hc Hd На option 3 is correct maximum chemical shift will come for Hb because it is aromatic proton which comes in the region of 7-8 ppm. Then Hd because it is connected with the Sp2 hybridise orbital and its value comes in the region of 5-6ppm. after that Ha will come because it is adjacent to the carbonyl group which will give signals at 2.5 ppm H Br Br H False, we cannot indentify these 2 compound by simple 1H NMR technique because they are enantiomers.

ChemNMR 13C Estimation 529 327611 52.9 3211288 46.9-N 44.1 175.1 61.9 1348 1281 14 128.1 128.8 126.0 Estimation quality is indicated by color: good, medium, rough PPM Total 11 signal will come