9,9-Dimethyl-2-nitrofluorene synthesis

Yield:605644-46-0 75%

Reaction Conditions:

with nitric acid;acetic acid at 50 - 80;

Steps:

2.5.2. Synthesis of 9,9-dimethyl-2-nitrofluorene (3)

In a 250 mL round-bottomed flask, 9,9-dimethylfluorene 2 (2.0 g,1.3 mmol) was dissolved in glacial acetic acid (16.7 mL) and the solutionwas warmed in an oil bath. The temperature was brought to 50 C andconc. HNO3 (2.66 mL) was slowly added with stirring. During theaddition, the solution turned slightly yellow and a small amount ofprecipitate formed. The oil bath was slowly brought to 60-65 Cwhereupon precipitate dissolved. Stirring with heating was continueduntil the temperature reached 80 C. TLC analysis indicated completeconsumption of starting material 2 and the oil bath was removed. Uponcooling the reaction to room temperature for 2 h, a solid mass includingsome fine needles was formed. Product 3 was collected on the Buchnerfunnel and washed with cold glacial acetic acid (12 mL), followed byseveral washings with water and finally drying to obtain 3 as yellowsolid (1.5 g, 75% yield). Mp 94-98 C (lit. 98-100 C) [40]. IR (νmax,cm 1): 434.6, 827.5, 887.1, 1103.3, 1334.4, 1513.3, 1587.8, 1811.5,1900.9, 2102.2, 2363.1, 3063.9, 3175.7. 1H NMR (400 MHz, CDCl3,25 C): δ (ppm) 1.54 (s, 6H, 2 × CH3), 7.43-7.53 (m, 3H, ArH), 7.81 (m,2H, ArH), 8.26 (dd, 1H, ArH), 8.29 (d, J = 16 Hz, 1H, ArH). 13C NMR(125 MHz, CDCl3, 25 C): δ (ppm) 26.1, 47.5, 118.5, 120.3, 121.6,123.1, 123.5, 127.7, 129.6, 136.9, 145.9, 154.7, 154.2. HRMS: m/zcalculated for C15H14NO2 (M++H): 240.1046. Found: 240.1025.

References:

Kaur, Paramjit;Kumar, Virendra;Mishra, Akriti;Shivani;Singh, Kamaljit [Dyes and Pigments,2022,vol. 200,art. no. 110160]