5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione

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

Procedure: A solution of tetrahydro-4H-pyran-4-ol (1.6 ml, 16.8 mmoles) and 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione (3.0 g, 16.1 mmoles) in dry benzene (50 ml) was heated under reflux for 4 hours. The solvent was removed in vacuo and the residue distilled at 146°-151°/14 mm Hg to afford the title product as a colourless oil, 2.84 g. Nmr (CDCl3)δ5.1 (m,H), 3.5 (s,3H). under reflux for 4 hours The solvent was removed in vacuo the residue distilled at 146°-151°/14 mm Hg

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

Procedure: 18.6 Grams of 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione and 50 ml tetrahydrofuran solution containing 22.2 g of 4-(1-ethoxyethoxy)cinnamyl alcohol were refluxed for 6 hours. After the reaction was completed, the solvent was removed by evaporation, and the residue thus obtained was purified by means of a silica gel column chromatography (eluent: ethyl acetate:n-hexane=1:4) to yield 5.8 g of 4-[(1-ethoxy)ethoxy]cinnamyl acetoacetate as in the form of an oily substance. were refluxed for 6 hours the solvent was removed by evaporation the residue thus obtained was purified by means of a silica gel column chromatography (eluent: ethyl acetate:n-hexane=1:4)

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

Procedure: 18.6 Grams of 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione and 50 ml tetrahydrofuran solution containing 22.2 g of 4-(1-ethoxyethoxy)cinnamyl alcohol were refluxed for 6 hours. After the reaction was completed, the solvent was removed by evaporation, and the residue thus obtained was purified by means of a silica gel column chromatography (eluent: ethyl acetate:n-hexane=1:4) to yield 5.8 g of 4-[(1-ethoxy)ethoxy]cinnamyl acetoacetate as in the form of an oily substance. were refluxed for 6 hours the solvent was removed by evaporation the residue thus obtained was purified by means of a silica gel column chromatography (eluent: ethyl acetate:n-hexane=1:4)

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

Procedure: A solution of tetrahydro-4H-pyran-4-ol (1.6 ml, 16.8 mmoles) and 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione (3.0 g, 16.1 mmoles) in dry benzene (50 ml) was heated under reflux for 4 hours. The solvent was removed in vacuo and the residue distilled at 146°-151°/14 mm Hg to afford the title product as a colourless oil, 2.84 g. Nmr (CDCl3)δ5.1 (m,H), 3.5 (s,3H). under reflux for 4 hours The solvent was removed in vacuo the residue distilled at 146°-151°/14 mm Hg

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

Procedure: The derivatives have not heretofore been known at all, but for the first time the present inventors have found a process for producing 2,2-dimethyl-1,3-dioxin-4-one as a compound belonging thereto. Namely, according to the process reported by the present inventors in Chem. Pharm. Bull. 31, (6) 1896 (1983), 2,2-dimethyl-1,3-dioxin-4-one was obtained from formyl Meldrum's acid in the presence of acetone and using a small amount of toluene or xylene as solvent, with a yield of 31%. This formyl Meldrum's acid seems to have a higher reactivity than that of similar acetyl Meldrum's acid. That is, in the case of the latter acid, its thermal decomposition yielded 2,2,6-trimethyl-1,3-dioxin-4-one, whereas in the case of the former acid, its mere heating in the absence of solvent formed only a resinous substance without yielding 2,2-dimethyl-1,3-dioxin-4-one, but when the former acid was heated in a xylene solvent containing acetone, the compound was obtained for the first time. However, its yield was not only low (yield: 31% as described above), but the loss of the raw material acid due to the resin formation was so great that the recovery of the raw material was impossible.

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

Procedure: The derivatives have not heretofore been known at all, but for the first time the present inventors have found a process for producing 2,2-dimethyl-1,3-dioxin-4-one as a compound belonging thereto. Namely, according to the process reported by the present inventors in Chem. Pharm. Bull. 31, (6) 1896 (1983), 2,2-dimethyl-1,3-dioxin-4-one was obtained from formyl Meldrum's acid in the presence of acetone and using a small amount of toluene or xylene as solvent, with a yield of 31%. This formyl Meldrum's acid seems to have a higher reactivity than that of similar acetyl Meldrum's acid. That is, in the case of the latter acid, its thermal decomposition yielded 2,2,6-trimethyl-1,3-dioxin-4-one, whereas in the case of the former acid, its mere heating in the absence of solvent formed only a resinous substance without yielding 2,2-dimethyl-1,3-dioxin-4-one, but when the former acid was heated in a xylene solvent containing acetone, the compound was obtained for the first time. However, its yield was not only low (yield: 31% as described above), but the loss of the raw material acid due to the resin formation was so great that the recovery of the raw material was impossible.

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

Procedure: A solution of tetrahydro-4H-pyran-4-ol (1.6 ml, 16.8 mmoles) and 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione (3.0 g, 16.1 mmoles) in dry benzene (50 ml) was heated under reflux for 4 hours. The solvent was removed in vacuo and the residue distilled at 146°-151°/14 mm Hg to afford the title product as a colourless oil, 2.84 g. Nmr (CDCl3)δ5.1 (m,H), 3.5 (s,3H). under reflux for 4 hours The solvent was removed in vacuo the residue distilled at 146°-151°/14 mm Hg

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

Procedure: 18.6 Grams of 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione and 50 ml tetrahydrofuran solution containing 22.2 g of 4-(1-ethoxyethoxy)cinnamyl alcohol were refluxed for 6 hours. After the reaction was completed, the solvent was removed by evaporation, and the residue thus obtained was purified by means of a silica gel column chromatography (eluent: ethyl acetate:n-hexane=1:4) to yield 5.8 g of 4-[(1-ethoxy)ethoxy]cinnamyl acetoacetate as in the form of an oily substance. were refluxed for 6 hours the solvent was removed by evaporation the residue thus obtained was purified by means of a silica gel column chromatography (eluent: ethyl acetate:n-hexane=1:4)

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

Procedure: 18.6 Grams of 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione and 50 ml tetrahydrofuran solution containing 22.2 g of 4-(1-ethoxyethoxy)cinnamyl alcohol were refluxed for 6 hours. After the reaction was completed, the solvent was removed by evaporation, and the residue thus obtained was purified by means of a silica gel column chromatography (eluent: ethyl acetate:n-hexane=1:4) to yield 5.8 g of 4-[(1-ethoxy)ethoxy]cinnamyl acetoacetate as in the form of an oily substance. were refluxed for 6 hours the solvent was removed by evaporation the residue thus obtained was purified by means of a silica gel column chromatography (eluent: ethyl acetate:n-hexane=1:4)

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

Procedure: A solution of tetrahydro-4H-pyran-4-ol (1.6 ml, 16.8 mmoles) and 5-acetyl-2,2-dimethyl-1,3-dioxane-4,6-dione (3.0 g, 16.1 mmoles) in dry benzene (50 ml) was heated under reflux for 4 hours. The solvent was removed in vacuo and the residue distilled at 146°-151°/14 mm Hg to afford the title product as a colourless oil, 2.84 g. Nmr (CDCl3)δ5.1 (m,H), 3.5 (s,3H). under reflux for 4 hours The solvent was removed in vacuo the residue distilled at 146°-151°/14 mm Hg

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

Procedure: The derivatives have not heretofore been known at all, but for the first time the present inventors have found a process for producing 2,2-dimethyl-1,3-dioxin-4-one as a compound belonging thereto. Namely, according to the process reported by the present inventors in Chem. Pharm. Bull. 31, (6) 1896 (1983), 2,2-dimethyl-1,3-dioxin-4-one was obtained from formyl Meldrum's acid in the presence of acetone and using a small amount of toluene or xylene as solvent, with a yield of 31%. This formyl Meldrum's acid seems to have a higher reactivity than that of similar acetyl Meldrum's acid. That is, in the case of the latter acid, its thermal decomposition yielded 2,2,6-trimethyl-1,3-dioxin-4-one, whereas in the case of the former acid, its mere heating in the absence of solvent formed only a resinous substance without yielding 2,2-dimethyl-1,3-dioxin-4-one, but when the former acid was heated in a xylene solvent containing acetone, the compound was obtained for the first time. However, its yield was not only low (yield: 31% as described above), but the loss of the raw material acid due to the resin formation was so great that the recovery of the raw material was impossible.