5,6-CARBOXYFLUORESCEIN DIPIVALATE synthesis

5synthesis methods

Product Name:5,6-CARBOXYFLUORESCEIN DIPIVALATE
CAS Number:144676-12-0
Molecular formula:C31H28O9
Molecular Weight:544.55

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108-46-3 Synthesis

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Yield:-

Reaction Conditions:

Stage #1: recorcinol;trimellitic Anhydridewith methanesulfonic acid at 80; for 24 h;
Stage #2: 2,2-dimethylpropanoic anhydride in tetrahydrofuran at 110; for 3 h;

Steps:

4 4. SYNTHESIS OF 5-CARBOXYFLUORESCEIN DIPIVALATE (16)

Trimellitic anhydride (436 mg, 1 equiv) and resorcinol (500 mg, 2 equiv) were stirred in methanes ulfonic acid (12 mL) at 80 °C for 24 h. The resulted mixture was poured into ice water (thO). The precipitate was collected and washed with water to yield the crude 5 (6) -carboxy fluorescein (15) (820 mg).5(6)-carboxyfluorescein (15): yellow powder; 'H NMR (500 MHz, methanol -d 8.59 (d, J = 1.5 Hz, 1H), 8.37 (dd, J = 8.0, 1.5 Hz, 1H), 8.31 (dd, J = 8.0, 1.5 Hz, 1H), 8.09 (d, J = 8.0 Hz, lH), 7.74 (s, 1H), 7.30 (d, J = 8.0 Hz, 1H), 6.70-6.72 (d, J = 9.7 Hz, 4H), 6.60- 6.42 (br s, 4H), 6.53-6.57 (m, 4H).5(6)-carboxyfluorescein (15) (490 mg) was stirred in trimethyl acetic anhydride (8 mL, 30 equiv) at 110°C for 3 h. The resulted mixture was then stirred in the mixed solution of water (15 mL) and THF (30 mL) at room temperature for 2 days. The solvents were removed in vacuo and the residue was purified by preparative HPLC using a Luna 5 mih C18 column (isocratic, 80% MeCN in 0.1% TFA) to yield 5 -carboxy fluorescein dipivalate (16) (221 mg) and 6-carboxyfluorescein dipivalate (198 mg).5-carboxyfluorescein dipivalate (16): yellow powder; 'H NMR (400 MHz, methanol-i/₄): d 8.56 (s, 1H), 8.23 (d, J = 8.0 Hz, 1H), 7.12 (dd, J = 8.0, 1.6 Hz, 1H), 7.05 (br s, 2H), 6.75-6.80 (m, 4H), 1.28 (s, 18H);¹³C NMR (100 MHz, methanol-iL): d 177.7, 169.6, 167.6, 157.6, 154.1 , 152.6, 137.6, 134.4, 130.0, 127.6, 127.5, 125.3, 1 19.1 , 1 16.8, 1 1 1.4,83.1 , 40.0, 27.4.

References:

WO2020/185610,2020,A1 Location in patent:Paragraph 0484; 0485

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76823-03-5 Synthesis