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

HRID 988787Notes

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-6c4c2c63761b47cdad7e7dbdc9d78ed5
Source dataset: uspto-grants-2003_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06635661B2

Reaction notes

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