(2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate

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 22 (50.6 g, 250 mmol), and Dowex 50W X8-100 H+ resin (76.5 g) in MeOH (500 ml), was heated at 50° C. for 2 hours, cooled to room temperature, filtered, and the resin washed with MeOH (1×200 ml). The methanol fractions were combined and concentrated in vacuo. The crude product was passed through a plug of silica gel using ethyl acetate:hexanes (1:1) as the eluent. Fractions containing the product were combined and concentrated in vacuo to afford 23 (32.8 g, 200 mmol, 81%) as an oil. The material was used in the next step without any further purification. filtered the resin washed with MeOH (1×200 ml) concentrated in vacuo Fractions containing the product concentrated in vacuo

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a well-stirred solution of solketal (21, 62.6 ml, 500 mmol), Et3N (83.6 ml, 600 mmol) and DMAP (5 g, 40.9 mmol) in tert-butyl methyl ether (11) at 0° C., n-butyryl chloride (52.4 mL, 500 mmol) was added dropwise over a 75 minute period. The mixture was stirred for an additional hour at 0° C. and then at room temperature for an additional 5 hours. The mixture was diluted with AcOEt (11), washed with water (11), dried (MgSO4), filtered and evaporated to afford 22 (104.6 g, 500 mmol, 100%) as an oil. The material was used in the next step without any further purification. washed with water (11) dried (MgSO4) filtered evaporated

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

Procedure: FIG. 2 illustrates four additional embodiments (methods A-D) for preparing the 1,3-oxathiolane ring. As a nonlimiting illustrative example of method A in FIG. 2, (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be prepared by a four-step process which does not require purification of the intermediate products. In a first step, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is prepared from solketal and n-butyryl chloride in t-butyl methyl ether, DMAP and triethylamine. The (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is then placed in solution with Dowex 50W X8-100 H+ resin in methanol, to yield 2,3-dihydroxypropyl butanoate. The resulting diol is then reacted with a solution of sodium periodate in distilled water to produce 2-oxoethyl butanoate. Using 2-oxoethyl butanoate, the (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be prepared by reaction with mercaptoacetic acid as p-TsOH.H2O in acetonitrile. The (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be converted into its 5-acetyloxy derivative by reacting with lithium tri-t-butoxy aluminum hydride in THF. for preparing the 1,3-oxathiolane ring purification of the intermediate products In a first step, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is prepared from solketal and n-butyryl chloride in t-butyl methyl ether, DMAP and triethylamine

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

Procedure: A solution of 22 (50.6 g, 250 mmol), and Dowex 50W X8-100 H+ resin (76.5 g) in MeOH (500 ml), was heated at 50° C. for 2 hours, cooled to room temperature, filtered, and the resin washed with MeOH (1×200 ml). The methanol fractions were combined and concentrated in vacuo. The crude product was passed through a plug of silica gel using ethyl acetate:hexanes (1:1) as the eluent. Fractions containing the product were combined and concentrated in vacuo to afford 23 (32.8 g, 200 mmol, 81%) as an oil. The material was used in the next step without any further purification. filtered the resin washed with MeOH (1×200 ml) concentrated in vacuo Fractions containing the product concentrated in vacuo

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a well-stirred solution of solketal (21, 62.6 ml, 500 mmol), Et3N (83.6 ml, 600 mmol) and DMAP (5 g, 40.9 mmol) in tert-butyl methyl ether (11) at 0° C., n-butyryl chloride (52.4 mL, 500 mmol) was added dropwise over a 75 minute period. The mixture was stirred for an additional hour at 0° C. and then at room temperature for an additional 5 hours. The mixture was diluted with AcOEt (11), washed with water (11), dried (MgSO4), filtered and evaporated to afford 22 (104.6 g, 500 mmol, 100%) as an oil. The material was used in the next step without any further purification. washed with water (11) dried (MgSO4) filtered evaporated

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a well-stirred solution of solketal (21, 62.6 ml, 500 mmol), Et3N (83.6 ml, 600 mmol) and DMAP (5 g, 40.9 mmol) in tert-butyl methyl ether (11) at 0° C., n-butyryl chloride (52.4 mL, 500 mmol) was added dropwise over a 75 minute period. The mixture was stirred for an additional hour at 0° C. and then at room temperature for an additional 5 hours. The mixture was diluted with AcOEt (11), washed with water (11), dried (MgSO4), filtered and evaporated to afford 22 (104.6 g, 500 mmol, 100%) as an oil. The material was used in the next step without any further purification. washed with water (11) dried (MgSO4) filtered evaporated

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

Procedure: FIG. 2 illustrates four additional embodiments (methods A-D) for preparing the 1,3-oxathiolane ring. As a nonlimiting illustrative example of method A in FIG. 2, (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be prepared by a four-step process which does not require purification of the intermediate products. In a first step, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is prepared from solketal and n-butyryl chloride in t-butyl methyl ether, DMAP and triethylamine. The (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is then placed in solution with Dowex 50W X8-100 H+ resin in methanol, to yield 2,3-dihydroxypropyl butanoate. The resulting diol is then reacted with a solution of sodium periodate in distilled water to produce 2-oxoethyl butanoate. Using 2-oxoethyl butanoate, the (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be prepared by reaction with mercaptoacetic acid as p-TsOH.H2O in acetonitrile. The (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be converted into its 5-acetyloxy derivative by reacting with lithium tri-t-butoxy aluminum hydride in THF. for preparing the 1,3-oxathiolane ring purification of the intermediate products In a first step, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is prepared from solketal and n-butyryl chloride in t-butyl methyl ether, DMAP and triethylamine

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

Procedure: FIG. 2 illustrates four additional embodiments (methods A-D) for preparing the 1,3-oxathiolane ring. As a nonlimiting illustrative example of method A in FIG. 2, (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be prepared by a four-step process which does not require purification of the intermediate products. In a first step, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is prepared from solketal and n-butyryl chloride in t-butyl methyl ether, DMAP and triethylamine. The (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is then placed in solution with Dowex 50W X8-100 H+ resin in methanol, to yield 2,3-dihydroxypropyl butanoate. The resulting diol is then reacted with a solution of sodium periodate in distilled water to produce 2-oxoethyl butanoate. Using 2-oxoethyl butanoate, the (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be prepared by reaction with mercaptoacetic acid as p-TsOH.H2O in acetonitrile. The (5-oxo-1,3-oxathiolan-2-yl)methyl butanoate can be converted into its 5-acetyloxy derivative by reacting with lithium tri-t-butoxy aluminum hydride in THF. for preparing the 1,3-oxathiolane ring purification of the intermediate products In a first step, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl butanoate is prepared from solketal and n-butyryl chloride in t-butyl methyl ether, DMAP and triethylamine

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

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