Rhodium (Chief Bee) 06-04-03 15:43 No 437833				Henry reaction with orthoformate water scavenger (Rated as: excellent)	Bookmark
						Nitroalkene synthesis (Henry reaction) using trimethyl orthoformate to remove the water formed in the reaction: (MeO)3CH + H2O -> 2 MeOH + HCOOMe 1-(2,6-dimethoxyphenyl)-2-nitropropene A mixture of nitroethane (3.4 g, 45 mmol), 2,6-dimethoxybenzaldehyde (7.0 g, 42 mmol), CH3COOK (2.4 g, 35 mmol), methylamine hydrochloride (3.4 g, 35 mmol), trimethyl orthoformate (10 ml), and methanol (30 ml) was stirred at reflux for 7 h. The reaction mixture was poured into water and extracted with ethyl ether. After the usual work up, the crude product was recrystallized from MeOH-Et2O to give 1-(2,6-dimethoxyphenyl)-2-nitropropene, 7.5 g (80%), mp 102-103°C. Reference: Tetrahedron 46, 7483 (1990)