ethyl 4-hydroxybut-2-ynoate

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

Procedure: The title compound was prepared from (S)-5-(4-cyclohexyl-phenoxymethyl)-4,5-dihydro-oxazol-2-ylamine and 4-hydroxy-but-2-ynoic acid ethyl ester (G. Cai et al., Tetrahedron, 2006, 5697-5708) employing the procedure described in Example 99. [α]D25 +5.80 (c 0.5, DMSO)

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

Procedure: To 40 ml of a benzene solution of phosgene (containing 6.2 g (62.5 millimoles) of phosgene), 6.4 g (50 millimoles) of ethyl 4-hydroxy-2-butynoate was rapidly added under cooling with ice, and the mixture was stirred for 30 minutes under cooling with ice. The reaction mixture was returned to room temperature and left to stand for one night. Then, the reaction mixture was concentrated under reduced pressure to distil off benzene, whereby 8.1 g (yield: 85%) of oily ethyl 4-(chlorocarbonyloxy)-2-butynoate was obtained as the residue. under cooling with ice under cooling with ice was returned to room temperature left to stand for one night Then, the reaction mixture was concentrated under reduced pressure to distil off benzene

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

Procedure: To 40 ml of a benzene solution of phosgene (containing 6.2 g (62.5 millimoles) of phosgene), 6.4 g (50 millimoles) of ethyl 4-hydroxy-2-butynoate was rapidly added under cooling with ice, and the mixture was stirred for 30 minutes under cooling with ice. The reaction mixture was returned to room temperature and left to stand for one night. Then, the reaction mixture was concentrated under reduced pressure to distil off benzene, whereby 8.1 g (yield: 85%) of oily ethyl 4-(chlorocarbonyloxy)-2-butynoate was obtained as the residue. under cooling with ice under cooling with ice was returned to room temperature left to stand for one night Then, the reaction mixture was concentrated under reduced pressure to distil off benzene

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

Procedure: The title compound was prepared from (S)-5-(4-cyclohexyl-phenoxymethyl)-4,5-dihydro-oxazol-2-ylamine and 4-hydroxy-but-2-ynoic acid ethyl ester (G. Cai et al., Tetrahedron, 2006, 5697-5708) employing the procedure described in Example 99. [α]D25 +5.80 (c 0.5, DMSO)

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

Procedure: A solution of the compound of formula II, 3-amino-2H-1,4-benzoxazine (10.7 g, 72.1 mmol, described in Example 3) and hydroxymethylacetylenecarboxylate ethyl ester (9.7 g, 75.7 mmol) in ethanol (100 ml) was allowed to stand at room temperature (20° to 24° C.) for 6 days. The resulting precipitate was collected giving 12.03 g of the title compound as tan crystals with mp 235°-237° L C., the mp remaining unchanged or recrystallization from ethanol. The title compound had IR(nujol)3130, 1640 cm-1 ; NMR(Trifluoroacetic acid)δ5.2 (s,2H); 5.3(s,2H); 7.6(m,5H); Anal. Calc'd: C, 62.60%; H, 4.38%; N, 12.17%; Found: C, 62.32%; H, 4.24%; N, 12.17%. to stand at room temperature (20° to 24° C.) for 6 days The resulting precipitate was collected

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

Procedure: A solution of the compound of formula II, 3-amino-2H-1,4-benzoxazine (10.7 g, 72.1 mmol, described in Example 3) and hydroxymethylacetylenecarboxylate ethyl ester (9.7 g, 75.7 mmol) in ethanol (100 ml) was allowed to stand at room temperature (20° to 24° C.) for 6 days. The resulting precipitate was collected giving 12.03 g of the title compound as tan crystals with mp 235°-237° L C., the mp remaining unchanged or recrystallization from ethanol. The title compound had IR(nujol)3130, 1640 cm-1 ; NMR(Trifluoroacetic acid)δ5.2 (s,2H); 5.3(s,2H); 7.6(m,5H); Anal. Calc'd: C, 62.60%; H, 4.38%; N, 12.17%; Found: C, 62.32%; H, 4.24%; N, 12.17%. to stand at room temperature (20° to 24° C.) for 6 days The resulting precipitate was collected

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

Procedure: To 40 ml of a benzene solution of phosgene (containing 6.2 g (62.5 millimoles) of phosgene), 6.4 g (50 millimoles) of ethyl 4-hydroxy-2-butynoate was rapidly added under cooling with ice, and the mixture was stirred for 30 minutes under cooling with ice. The reaction mixture was returned to room temperature and left to stand for one night. Then, the reaction mixture was concentrated under reduced pressure to distil off benzene, whereby 8.1 g (yield: 85%) of oily ethyl 4-(chlorocarbonyloxy)-2-butynoate was obtained as the residue. under cooling with ice under cooling with ice was returned to room temperature left to stand for one night Then, the reaction mixture was concentrated under reduced pressure to distil off benzene

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

Procedure: To 40 ml of a benzene solution of phosgene (containing 6.2 g (62.5 millimoles) of phosgene), 6.4 g (50 millimoles) of ethyl 4-hydroxy-2-butynoate was rapidly added under cooling with ice, and the mixture was stirred for 30 minutes under cooling with ice. The reaction mixture was returned to room temperature and left to stand for one night. Then, the reaction mixture was concentrated under reduced pressure to distil off benzene, whereby 8.1 g (yield: 85%) of oily ethyl 4-(chlorocarbonyloxy)-2-butynoate was obtained as the residue. under cooling with ice under cooling with ice was returned to room temperature left to stand for one night Then, the reaction mixture was concentrated under reduced pressure to distil off benzene

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

Procedure: To 40 ml of a benzene solution of phosgene (containing 6.2 g (62.5 millimoles) of phosgene), 6.4 g (50 millimoles) of ethyl 4-hydroxy-2-butynoate was rapidly added under cooling with ice, and the mixture was stirred for 30 minutes under cooling with ice. The reaction mixture was returned to room temperature and left to stand for one night. Then, the reaction mixture was concentrated under reduced pressure to distil off benzene, whereby 8.1 g (yield: 85%) of oily ethyl 4-(chlorocarbonyloxy)-2-butynoate was obtained as the residue. under cooling with ice under cooling with ice was returned to room temperature left to stand for one night Then, the reaction mixture was concentrated under reduced pressure to distil off benzene

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

Procedure: The title compound was prepared from (S)-5-(4-cyclohexyl-phenoxymethyl)-4,5-dihydro-oxazol-2-ylamine and 4-hydroxy-but-2-ynoic acid ethyl ester (G. Cai et al., Tetrahedron, 2006, 5697-5708) employing the procedure described in Example 99. [α]D25 +5.80 (c 0.5, DMSO)

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

Procedure: A solution of the compound of formula II, 3-amino-2H-1,4-benzoxazine (10.7 g, 72.1 mmol, described in Example 3) and hydroxymethylacetylenecarboxylate ethyl ester (9.7 g, 75.7 mmol) in ethanol (100 ml) was allowed to stand at room temperature (20° to 24° C.) for 6 days. The resulting precipitate was collected giving 12.03 g of the title compound as tan crystals with mp 235°-237° L C., the mp remaining unchanged or recrystallization from ethanol. The title compound had IR(nujol)3130, 1640 cm-1 ; NMR(Trifluoroacetic acid)δ5.2 (s,2H); 5.3(s,2H); 7.6(m,5H); Anal. Calc'd: C, 62.60%; H, 4.38%; N, 12.17%; Found: C, 62.32%; H, 4.24%; N, 12.17%. to stand at room temperature (20° to 24° C.) for 6 days The resulting precipitate was collected