Triethylamine → 8-Benzyloxycarbonyl-1,4-dioxa-8-aza-spiro[4.5]decane-6-carboxylic acid methyl ester

HRID 1839206Notes

Reaction equation

C(N(CC)CC)C.[CH3:8][O:9][C:10]([CH:12]1[CH2:21][NH:20][CH2:19][CH2:18][C:13]21[O:17][CH2:16][CH2:15][O:14]2)=[O:11].[C:22]([O:30][C:31](Cl)=[O:32])(=O)[C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1>C(Cl)Cl>[CH3:8][O:9][C:10]([CH:12]1[CH2:21][N:20]([C:31]([O:30][CH2:22][C:23]2[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=2)=[O:32])[CH2:19][CH2:18][C:13]21[O:17][CH2:16][CH2:15][O:14]2)=[O:11]

Participants

Conditions

Temperature: 0 °C

Procedure

Triethylamine (29.0 mL, 208 mmol) was added to a solution of 1,4-dioxa-8-aza-spiro[4.5]-decane-6-carboxylic acid methyl ester (91) (16.6, 82.5 mmol) in CH2Cl2 (159 mL, 0.5 M). The solution was cooled to 0° C. in an ice bath, then benzoylchloroformate (12.8 mL, 89.9 mmol) was added dropwise, with stirring, over 40 minutes. When the reaction was judged complete by TLC (0.75 h), the solution was concentrated in vacuo and purified by silica gel chromatography (10:3 Hexanes:EtOAc) to provide pure 8-benzyloxycarbonyl-1,4-dioxa-8-aza-spiro[4.5]-decane-6-carboxylic acid methyl ester (92) (23.43 g, 85%). 1H NMR (CDCl3): 7.41-7.25 (5H, m), 5.10 (2H, broad s), 4.02-3.50 (11H, m), 2.80-2.62 (1H, broad s), 2.20-2.00 (1H, broad s), 1.70-1.50 (1H, broad s) ppm. 13C NMR (CDCl3): 170.26, 154.88, 136.47, 128.32, 127.86, 127.74, 106.78, 67.09, 64.90, 64.59, 51.71, 48.63, 43.94, 41.76, 33.15 ppm.

Workup

customwas judged complete by TLC (0.75 h)
concentrationthe solution was concentrated in vacuo
custompurified by silica gel chromatography (10:3 Hexanes:EtOAc)

Sources & evidence

ORD record: ord-3eabfb35ddee4419b30af876969eeffb
Source dataset: uspto-grants-2004_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06677332B1

Reaction notes

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