ChemicalBook CAS DataBase List tert-butyl 4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)piperazine-1-carboxylate

tert-butyl 4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)piperazine-1-carboxylate synthesis

3synthesis methods

Product Name:tert-butyl 4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)piperazine-1-carboxylate
CAS Number:883738-19-0
Molecular formula:C22H35BN2O4
Molecular Weight:402.34

57260-71-6 Synthesis

57260-71-6
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$5.00/5g

3-(4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)-BENZALDEHYDE

380151-86-0
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$14.00/1g

tert-butyl 4-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)piperazine-1-carboxylate

883738-19-0
34 suppliers
$37.00/1g

Yield:883738-19-0 100%

Reaction Conditions:

Stage #1: 1-t-Butoxycarbonylpiperazine;3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenylcarboxaldehydewith acetic acid in DCM at 20;
Stage #2: with sodium tris(acetoxy)borohydride in dichloromethane at 10 - 15; for 0.166667 h;

Steps:

123 1,1-Dimethylethyl 4-{[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]methyl}-1-piperazinecarboxylate

Example 123 1,1-Dimethylethyl 4-{[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]methyl}-1-piperazinecarboxylate Benzaldehye-3-pinacolboronate (Fluorochem) (32 g, 138 mmol) was stirred in 300 mL of dry DCM in a 2000 mL 3-necked flask under nitrogen. A solution of Boc-piperidine (38.5 g, 207 mmol) in 350 mL of dry DCM was added dropwise over 6 min (negligible exotherm). Acetic acid (8.82 mL, 154 mmol) was then added dropwise over 6 min and washed in with a little more dry DCM. The mixture was stirred at ambient temperature for about 2.5 h. Then sodium triacetoxyborohydride (58.7 g, 277 mmol) was added portionwise over 10 min with cooling in an ice water bath to keep reaction temp at 10-15° C. After all had been added, the mixture was stirred at ambient temperature under nitrogen overnight. After a total of 21 h the reaction mixture was poured slowly onto 800 mL water with stirring. Gas evolution was observed. The mixture was stirred at room temperature until gas evolution had subsided. The mixture was partitioned between dichloromethane and water and the aqueous layer extracted well with dichloromethane. The combined organics were washed with water, brine, dried (MgSO₄), filtered and evaporated then put under high vacuum to give 57.8 g (104%) of a sticky white foam. Lab HPLC showed two major peaks: retention time 1.63 min (55%) and retention time 2.15 min (39%). LC-MS m/z 403 (M+H)⁺, 0.94-1.04 min (ret time-broad peak) [84% above named product] and m/z 320 (M+H)⁺, 0.65 min (ret time) [12% boronic acid product].

References:

US2009/203657,2009,A1 Location in patent:Page/Page column 81

865314-27-8 Synthesis