Question

Uute! I. Concept Areer the following questions (25 pts) Poe 1. 10 pts) In a Boeyervilleger reaction ketones (R.CO) are converted to esters (COR) by using DRONY acids. With an unanimetrical ketone, two possible esters can be formed for 3,3-dimethyl-2-butanone as storting material. What are those? How could you use spectroscopic techniques: IH NMR, IR and MS to determine which enter is formed 2) Page 1. 5 pts) Drow and compare the structures of ethylene, acetylene, and benzer. Each of these compounds produces only one signal in its IH NMR spectrum Arrange these signals in order of increasing chemical shift 3) (Page 2, 10 pts) Identify the number of signals expected in the "C NMR spectrum of each of the following compounds Redraw and label it

Answer 1

1) methyl 2,2-dimethylpropanoate: NMR of this material will show singlet of 3H corrosponding to CH3 will show around 4.5ppm as the methyl group is attached to oxygen. IR will show ester C=O stretching peak at 1750cm-1.
Whereas, in case of tert-butyk acetate gives 9H, singlet at around 4.0ppm and 3H singlet at 2.5ppm. IR wil show ester C=O stretching peak at 1738cm-1.

1 0 mCPBA H C CH3 CH3 CH3 300 CH. CH2 + H2CO CH3 HC © CH, CH3 tert-butyl acetate methyl 2,2-dimethylpropanoate 3,3-dimethylbutan-2-one methyl 2,2-dimethylpropanoate: NMR of this material will show singlet of 3H corrosponding to CH3 will show around 4.5ppm as the methyl group is attached to oxygen. IR will show ester CEO stretching peak at 1750cm-1. Whereas, in case of tert-butyk acetate gives 9H, singlet at around 4.Oppm and 3H singlet at 2.5ppm. IR wil show ester C=O stretching peak at 1738cm-1. Нас H₂CT : CH3 O-CH₂ +H3COCHE CH3 base peak =57 Н.С. OCH H.C. O CH? CH3 - CH₃ CH3 CH3 base peak =43

HCECH H2C=CH2 Acetylene nmr shows peak at 2.8 ppm. Ethylene peak shows singlet at 5.5ppm. Benzene peak shows singlet at 7.2 ppm. Acetylene protons come in shielded reagion and hence shows most upfield.

Hæc hf HC Ce 9 H, CH3 CH3 a CH3 There are 7 13C NMR signals. There are 8 13C NMR signals. bod osao bb ca d Ob There are 4 13C NMR signals. 5 13C NMR There are signals. a de H₃C b c La C bab 16 There are 4 13C NMR signals. de There are 6 13C NMR signals.