Formaldehyde → Benzaldehyde, 2-hydroxy-5-methyl-

p-Cresol (100 g) in dry THF(100 ml) was added over 30 minutes dropwise to a mechanically stirred, freshly prepared solution of ethyl magnesium bromide [magnesium (25.0 g) and bromoethane (75 ml)] in THF (500 ml) under nitrogen at a rate which maintained a slow reflux. After a further 30 mins toluene (1.21) was added, followed by 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidone (125 ml), and paraformaldehyde (70 g). The mixture was then heated at reflux for 16 h. The mixture was concentrated by distillation and aqueous hydrochloric acid (2M, 600 ml) then added. Water (600 ml) was added and the mixture filtered through "hyflo", dried and concentrated in vacuo to give a brown oil. The oil was steam distilled and the product extracted from the distillate with ether (1 liter). The organic extract was dried and concentrated in vacuo to give a pale yellow slurry which was triturated with ether at -10° C. to give the title compound as colourless needles, (131.4 g).

1. temperatureThe mixture was then heated
2. temperatureat reflux for 16 h
3. concentrationThe mixture was concentrated by distillation and aqueous hydrochloric acid (2M, 600 ml)
4. additionthen added
5. additionWater (600 ml) was added
6. filtrationthe mixture filtered through "hyflo"
7. customdried
8. concentrationconcentrated in vacuo
9. customto give a brown oil
10. distillationdistilled
11. extractionthe product extracted from the distillate with ether (1 liter)
12. extractionThe organic extract
13. customwas dried
14. concentrationconcentrated in vacuo
15. customto give a pale yellow slurry which
16. customwas triturated with ether at -10° C.

ORD record

ord-432fe2845c054f608c4ed806e3dd0225

Source dataset

uspto-grants-1994_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05332831