2-chloro-3-oxobutanamide

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

Procedure: The prior art preparation of 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamides (Ia) has been effected by two methods. The first method has included (1) converting acetoacetamide to alphachloroacetoacetamide, (2) reacting this with 2-mercaptoethanol in a mutual solvent in the presence of a base, (3) subjecting the resulting product to acidic conditions whereby it cyclizes with loss of water to form 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamide (Ia) and (4) isolating said product from the reaction mixture. The second method of preparing same has used alkyl acetoacetate in place of acetoacetamide as a starting material. Thus, from the procedure analogous to the first method described above, the resulting 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboalkoxide (Ib) was converted to 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamide (Ia).

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

Procedure: The prior art preparation of 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamides (Ia) has been effected by two methods. The first method has included (1) converting acetoacetamide to alphachloroacetoacetamide, (2) reacting this with 2-mercaptoethanol in a mutual solvent in the presence of a base, (3) subjecting the resulting product to acidic conditions whereby it cyclizes with loss of water to form 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamide (Ia) and (4) isolating said product from the reaction mixture. The second method of preparing same has used alkyl acetoacetate in place of acetoacetamide as a starting material. Thus, from the procedure analogous to the first method described above, the resulting 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboalkoxide (Ib) was converted to 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamide (Ia).

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

Procedure: The prior art preparation of 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamides (Ia) has been effected by two methods. The first method has included (1) converting acetoacetamide to alphachloroacetoacetamide, (2) reacting this with 2-mercaptoethanol in a mutual solvent in the presence of a base, (3) subjecting the resulting product to acidic conditions whereby it cyclizes with loss of water to form 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamide (Ia) and (4) isolating said product from the reaction mixture. The second method of preparing same has used alkyl acetoacetate in place of acetoacetamide as a starting material. Thus, from the procedure analogous to the first method described above, the resulting 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboalkoxide (Ib) was converted to 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamide (Ia).

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

Procedure: A solution of 2-chloro-3-oxobutyramide (1 g) in acetic anhydride (5 ml) containing acetyl chloride (1 ml) was heated in a 100° oil bath for 2 hours. Excess reagent was evaporated under reduced pressure and the residue was vacuum distilled in a kugelrohr apparatus. The distilled product crystallized to give a colorless solid with mp 54°-8°; ir (Nujol) 3200 and 1700 cm-1 (broad); nmr (CDCl2) 2.28 (CH3), 2.47 (CH3), 5.53 (CH), and 9.7 ppm (NH), (a weaker set of singlets corresponding to the enol appears at 2.23, 2.52, and 8.7 ppm); mass spectrum m/e 43 (100%), 93, 135, and 177 (M+). was heated in a 100° oil bath for 2 hours Excess reagent was evaporated under reduced pressure distilled in a kugelrohr apparatus The distilled product crystallized to give a colorless solid with mp 54°-8°

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

Procedure: A solution of 2-chloro-3-oxobutyramide (1 g) in acetic anhydride (5 ml) containing acetyl chloride (1 ml) was heated in a 100° oil bath for 2 hours. Excess reagent was evaporated under reduced pressure and the residue was vacuum distilled in a kugelrohr apparatus. The distilled product crystallized to give a colorless solid with mp 54°-8°; ir (Nujol) 3200 and 1700 cm-1 (broad); nmr (CDCl2) 2.28 (CH3), 2.47 (CH3), 5.53 (CH), and 9.7 ppm (NH), (a weaker set of singlets corresponding to the enol appears at 2.23, 2.52, and 8.7 ppm); mass spectrum m/e 43 (100%), 93, 135, and 177 (M+). was heated in a 100° oil bath for 2 hours Excess reagent was evaporated under reduced pressure distilled in a kugelrohr apparatus The distilled product crystallized to give a colorless solid with mp 54°-8°

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

Procedure: The prior art preparation of 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamides (Ia) has been effected by two methods. The first method has included (1) converting acetoacetamide to alphachloroacetoacetamide, (2) reacting this with 2-mercaptoethanol in a mutual solvent in the presence of a base, (3) subjecting the resulting product to acidic conditions whereby it cyclizes with loss of water to form 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamide (Ia) and (4) isolating said product from the reaction mixture. The second method of preparing same has used alkyl acetoacetate in place of acetoacetamide as a starting material. Thus, from the procedure analogous to the first method described above, the resulting 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboalkoxide (Ib) was converted to 5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxamide (Ia).