methyl 2,4-dibromobutanoate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: Ethyl 2-cyano-3-phenylbutyrate and ethyl 2,4-dichlorbutyrate can be used in place of methyl 2-cyano-3-phenylbutyrate and methyl 2,4-dibromobutyrate, respectively, in the alkylation reaction of Example 3 to produce the corresponding diethyl 2-phenyl-3-cyano-6-chlorohexane-3,4-dicarboxylate. The latter product can then be reacted with the tricarboxylate of Example 4 and the dicarboxylate of Example 7 to give the corresponding pentaester and tetraester products. respectively, in the alkylation reaction of Example 3

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

Procedure: A mixture of methyl 2-cyano-3-phenylbutyrate (78 g, 0.37 mole), methyl 2,4-dibromobutyrate (122 g, 0.47 mole), potassium carbonate (65 g, 0.47 mole) and DMSO (50 ml) was stirred on a ball mill apparatus. The reaction was completed in four hours. Ice water was added and the mixture was neutralized by adding cold hydrochloric acid. The aqueous solution was extracted several times with ether. The combined organic solution was washed sequentially with cold aqueous sodium bicarbonate and brine, then dried over magnesium sulfate. After removal of the solvent, the residue was purified by Kugelrohr distillation (100° C., 30 microns) to remove low boiling materials. The remaining oily residue (118 g., 84%) was found to be mainly the title bromide condensation product (μ<95% GC purity). MS m/e (% relative intensity) 383(M.+, 3) 381 (3), 202 (33), 182 (7), 180 (7), 105 (100). The aqueous solution was extracted several times with ether The combined organic solution was washed sequentially with cold aqueous sodium bicarbonate and brine dried over magnesium sulfate After removal of the solvent the residue was purified by Kugelrohr distillation (100° C., 30 microns) to remove low boiling materials the title bromide condensation product (μ<95% GC purity)

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: A solution of 3.10 g of 2-amino-5-methoxythiophenol and 5.20 g of methyl 2,4-dibromobutyrate in 30 ml of dimethylformamide was stirred at room temperature for 2 hours. The mixture was poured into ice-water and the resulting crystals were collected by filtration and washed with water. Recrystallization from methanol gave 3.94 g (65.2%) of 2-(2-bromoethyl)-7-methoxy-2H-1,4-benzothiazin-3(4H)-one as prisms, m.p. 142°-143° C. the resulting crystals were collected by filtration washed with water Recrystallization from methanol

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

Procedure: To a solution of 4.6 g of 2-aminothiophenol in 50 ml of dimethylformamide was added dropwise 9.55 g of methyl 2,4-dibromobutyrate with stirring at room temperature. After stirring one hour, the reaction mixture was poured into water to give crystals of 2-(2-bromoethyl)-2H-1,4-benzothiazin-3(4H)-one. The crystals were collected by filtration and washed with water, n-hexane and cold methanol. The yield was 6.32 g (63.3%). Recrystallization from ethyl acetate gave prisms, m.p. 151°-152° C. After stirring one hour

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

Procedure: In a second step of the reaction, the methyl-2,4-dibromobutyrate is reacted with methylamine in an aqueous solution at a temperature of below ambient in order to form N-methyl-2,4-dibromobutyramide. Then butyramide is then recovered and purified to obtain the solid intermediate product. In a second step of the reaction

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

Procedure: There is also provided by this invention a method for preparation of 3-hydroxy-N-methylpyrrolidone which comprises conversion of delta-butyrolactone to methyl-2,4-dibromobutyrate, conversion of the methyl-2,4-dibromobutyrate to N-methyl-2,4-dibromobutyramide, ring closure of the N-methyl-2,4-dibromobutyramide to form 3-bromo-N-methyl-2-pyrrolidone, and conversion of the 3-bromo-N-methyl-2-pyrrolidone to 3-hydroxy-N-methyl-2-pyrrolidone by reaction with alkali metal carbonate. There is also provided by this invention a method

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

Procedure: There is also provided by this invention a method for preparation of 3-hydroxy-N-methylpyrrolidone which comprises conversion of delta-butyrolactone to methyl-2,4-dibromobutyrate, conversion of the methyl-2,4-dibromobutyrate to N-methyl-2,4-dibromobutyramide, ring closure of the N-methyl-2,4-dibromobutyramide to form 3-bromo-N-methyl-2-pyrrolidone, and conversion of the 3-bromo-N-methyl-2-pyrrolidone to 3-hydroxy-N-methyl-2-pyrrolidone by reaction with alkali metal carbonate. There is also provided by this invention a method

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

Procedure: reacting the methyl-2,4-dibromobutyrate with methylamine in an aqueous medium to form N-methyl-2,4-dibromobutyramide;