2-methylbut-2-enoic acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Benzothiazol-6-ylamine (1 g, 6.667 mmol) was reacted with 2-methyl-but-2-enoic acid (1 g, 9.99 mmol), benzene-1,4-diol (51.38 mg, 0.467 mmol) and toluene (6 mL) to afford the crude product. Purification by column chromatography on silica gel (50% ethyl acetate in hexane) afforded 100 mg of the product (6.02% yield). to afford the crude product Purification by column chromatography on silica gel (50% ethyl acetate in hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Benzothiazol-6-ylamine (1 g, 6.667 mmol) was reacted with 2-methyl-but-2-enoic acid (1 g, 9.99 mmol), benzene-1,4-diol (51.38 mg, 0.467 mmol) and toluene (6 mL) to afford the crude product. Purification by column chromatography on silica gel (50% ethyl acetate in hexane) afforded 100 mg of the product (6.02% yield). to afford the crude product Purification by column chromatography on silica gel (50% ethyl acetate in hexane)

Conditions: temp:120.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A reaction flask was charged with ethylmagnesium chloride (CH3CH2MgCl) (2 M, 2.17 L) and cooled to −10° C. Isobutyraldehyde ((CH3)2CHCHO) (295 g) was fed over about 1 hour while the temperature was kept under 15° C. The reaction mixture was aged to room temperature over about 6 hours and then poured into a mixture of ice and acetic acid (293 g). Hexanes (350 mL) were added and aqueous and organic layers were split. The organic layer was separated, washed sequentially with sodium bicarbonate (NaHCO3), brine, and water, and further distilled to provide 2-methyl-pentan-3-ol (336 g). 2-Methyl-pentan-3-ol (153 g), 2-methyl-but-2-enoic acid (100 g), toluene (200 mL), and PTSA (8 g) were charged into to 2-L reaction flask fitted with a Dean-Stark trap. The reaction mixture was heated to reflux at about 120° C. Water was removed. The reaction mixture was aged at reflux for about 13-14 hours till GC analysis showed completion of the reaction. The resulting reaction mixture was washed sequentially with sodium bicarbonate and brine, and further purified by fractional distillation to provide 2-methyl-but-2-enoic acid 1-ethyl-2-methyl-propyl ester (81 g) with a boiling point of 91° C. at 1.1 mmHg. fitted with a Dean-Stark trap The reaction mixture was heated Water was removed at reflux for about 13-14 hours till GC analysis completion of the reaction The resulting reaction mixture was washed sequentially with sodium bicarbonate and brine further purified by fractional distillation

Conditions: temp:120.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Methyl-pentan-3-ol (prepared as above in EXAMPLE I) (153 g), 2-methyl-but-2-enoic acid (100 g), toluene (200 mL), and PTSA (8 g) were charged into to 2-L reaction flask fitted with a Dean-Stark trap. The reaction mixture was heated to reflux at about 120° C. Water was removed. The reaction mixture was aged at reflux for about 13-14 hours till GC analysis showed completion of the reaction. The resulting reaction mixture was washed sequentially with sodium bicarbonate and brine, and further purified by fractional distillation to provide 2-methyl-but-2-enoic acid 1-ethyl-2-methyl-propyl ester (81 g) with a boiling point of 91° C. at 1.1 mmHg. fitted with a Dean-Stark trap The reaction mixture was heated Water was removed at reflux for about 13-14 hours till GC analysis completion of the reaction The resulting reaction mixture was washed sequentially with sodium bicarbonate and brine further purified by fractional distillation