Question

You are employed at Phenomenal Phenols, Inc., and have been asked by your Supervisor, O. H. Gruppa, to identify a compound A that was isolated from natural sources. Compound A, mp 129�130 �C, is soluble in NaOH solution and in hot water. The IR spectrum of A shows prominent absorptions at 3300�3600 cm�1 (broad) and 1680 cm�1; the EI mass spectrum of A has prominent peaks at m/z = 166 and 107, and the CI mass spectrum has an M 1 peak at m/z =167. The NMR spectrum of A is given below. Titration determined that A has two acidic groups with pKa values of 4.7 and 10.4. The UV spectrum of A is virtually unchanged as the pH of a solution of A is raised from 2 to 7, but the ?max shifts to much higher wavelength when A is dissolved in 0.1 M NaOH solution.

You are employed at Phenomenal Phenols, Inc., and have been asked by your Supervisor, O. H. Gruppa, to identify a compound A that was isolated from natural sources. Compound A, mp 129�½130 �½C, is soluble in NaOH solution and in hot water. The IR spectrum of A shows prominent absorptions at 3300�½3600 cm�½1 (broad) and 1680 cm�½1; the EI mass spectrum of A has prominent peaks at m/z = 166 and 107, and the CI mass spectrum has an M 1 peak at m/z =167. The NMR spectrum of A is given below. Titration determined that A has two acidic groups with pKa values of 4.7 and 10.4. The UV spectrum of A is virtually unchanged as the pH of a solution of A is raised from 2 to 7, but the ?max shifts to much higher wavelength when A is dissolved in 0.1 M NaOH solution.

Answer 1

You are employed at Phenomenal Phenols, Inc., and have been asked by your Supervisor, O. H. Gruppa, to identify a compound A that was isolated from natural sources. Compound A, mp 129-130 °C, is soluble in NaOH solution and in hot water. The IR spectrum of A shows prominent absorptions at 3300-3600 cm (broad) and 1680 cm; the El mass spectrum of A has prominent peaks at m/z 166 and 107, and the Cl mass spectrum has an M+ 1 peak at m/z167. The NMR spectrum of A is given below. Titration determined that A has two acidic groups with pKa values of 4.7 and 10.4. The UV spectrum of A is virtually unchanged as the pH of a solution of A is raised from 2 to 7, but the Amax shifts to much higher wavelength when A is dissolved in 0.1 M NaOH solution Propose a structure for A 1. COOH chemical shift, Hz 2400 2100 1800 1500 1200 900 600 300 OH 2H low-field region: 7.7 Hz 2H 1H 7.7 Hz 2H 13 12 1110 9 ppm (5) 2H 4 2 0

Compound is soluble in NaOH, indicates presence of acidic functional groups. pKa of 4.7 and 10.4 indicates presence of carboxylic acid and phenol respectively. 1H-NMR shows two triplets around 2.5ppm indicates presence of CH2-CH2 and two doublets around 7 ppm indicates para disubstitution. Thus, structure of given compound is as shown in above figure. It is confirmed by M+1 peak at 167