NMR Spectroscopy - Solve the structure of unknown A

Hi, I have some data to help me solve a structure via High Resolution NMR, however being new to this, I am having extreme difficulty, and was wondering if someone could help please - or even point me in the right direction as how to go about solving for structure A? A has a molecular formula: C12H15O4N. The 13CNMR data showed signals the following 13C chemical shifts: 15.5, 25.6, 27.5, 42.2, 50.5, 60.4, 87.9, 123.0, 142,1, 172.5, and 203.5 ppm. I have attached data to this description, however, in an NOE experiment, radiation of the proton signal at 6.40 ppm resulted in a +ve enhancement of the signal at 2.46 ppm. Irradiation of the signal at 1.05 resulted in an enhancement at 1.2... click for more