Formaldehyde → 5-Bromo-2-benzothiazoleethanol

Temperature

-78 °C

To a dry 100 mL flask, 2,2,6′,6′-tetra-methyl piperidine (0.56 g, 4 mmol) and 6 mL of THF was added and cooled to −78° C. Then n-BuLi (1.5 mL, 2.5M) was added rapidly, and the mixture of LiTMP was stirred for 3 hr. 5-Bromo-2-methyl-benzothiazole (0.75 g, 3.3 mmol) was added in solid form in to the reaction at −78° C., and after stirring for 4 hours at −78° C., 6 equivalents of para-formaldehyde was added to the reaction while stirring rapidly. The reaction was worked up by addition of sat. NH4Cl solution, and the reaction was extracted with CH2Cl2 dried, and concentrated in vacuo to give crude product, 1.02 g. The crude product was purified by flash chromatography, eluting with CH2Cl2, then with 20% MeOH/CH2Cl2 to elute the product. 1H NMR (400 MHz, CDCl3) d ppm 3.32 (t, J=5.76 Hz, 2 H) 4.11 (q, J=5.95 Hz, 2 H) 7.48 (dd, J=8.51, 1.92 Hz, 1 H) 7.70 (d, J=8.51 Hz, 1 H) 8.11 (d, J=1.92 Hz, 1 H)

1. stirringafter stirring for 4 hours at −78° C.
2. stirringwhile stirring rapidly
3. extractionthe reaction was extracted with CH2Cl2
4. customdried
5. concentrationconcentrated in vacuo
6. customto give crude product, 1.02 g
7. customThe crude product was purified by flash chromatography
8. washeluting with CH2Cl2
9. washwith 20% MeOH/CH2Cl2 to elute the product

ORD record

ord-4d84273d88514ce3b3e3af36fc9a68c8

Source dataset

uspto-grants-2008_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07358263B2