Potassium Carbonate → (S)-2-(2-Amino-7-(4-chlorophenyl)-5-methylbenzo[d]thiazol-6-yl)-2-tert-butoxyethyl pivalate

HRID 879281Notes

Reaction equation

HRID 879281 reaction equation
[C:1]([O:7][CH2:8][C@H:9]([C:15]1[C:24]([CH3:25])=[CH:23][C:18]2[N:19]=[C:20]([NH2:22])[S:21][C:17]=2[C:16]=1Br)[O:10][C:11]([CH3:14])([CH3:13])[CH3:12])(=[O:6])[C:2]([CH3:5])([CH3:4])[CH3:3].C([O-])([O-])=O.[K+].[K+].[Cl:33][C:34]1[CH:39]=[CH:38][C:37](B(O)O)=[CH:36][CH:35]=1.O1CCOCC1>C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.O>[C:1]([O:7][CH2:8][C@H:9]([C:15]1[C:24]([CH3:25])=[CH:23][C:18]2[N:19]=[C:20]([NH2:22])[S:21][C:17]=2[C:16]=1[C:37]1[CH:38]=[CH:39][C:34]([Cl:33])=[CH:35][CH:36]=1)[O:10][C:11]([CH3:14])([CH3:13])[CH3:12])(=[O:6])[C:2]([CH3:5])([CH3:4])[CH3:3]

Participants

7

Reactant 4

HCID 11430Potassium CarbonateHCID 312751,4-DioxaneHCID 742994-Chlorophenylboronic acidHCID 86699789(S)-2-(2-amino-7-bromo-5-methylbenzo[d]thiazol-6-yl)-2-tert-butoxyethyl pivalate

Product 1

HCID 86699790(S)-2-(2-Amino-7-(4-chlorophenyl)-5-methylbenzo[d]thiazol-6-yl)-2-tert-butoxyethyl pivalateYield 187.5%

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 962WaterSolvent2×

Conditions

Temperature
110 °C

Procedure

2 separate microwave tubes were each charged with (S)-2-(2-Amino-7-bromo-5-methylbenzo[d]thiazol-6-yl)-2-tert-butoxyethyl pivalate (768 mg, 1.74 mmol), K2CO3 (960 mg, 6.96 mmol), 4-chlorophenylboronic acid (325 mg, 2.09 mmol), Pd(PPh3)4 (200 mg, 0.174 mmol), dioxane (8.0 mL), and H2O (2.0 mL). The two sealed vessels were separately heated at 110° C. for 3 h. The reactions were cooled to 23° C. and combined. H2O (50 mL) was added, and the system was extracted with EtOAc (3×50 mL). The combined extracts were dried (Na2SO4), filtered, and concentrated. The residue was treated with benzene and purified via chromatography on silica gel (80 g “gold” ISCO column; Hex/EtOAc) giving (S)-2-(2-Amino-7-(4-chlorophenyl)-5-methylbenzo[d]thiazol-6-yl)-2-tert-butoxyethyl pivalate (1.55 g, 90% yield). LCMS-ESI+: calc'd for C25H31ClN2O3S: 475.2 and 477.2 (M+H+); found: 475.3 and 477.3 (M+H+). 1H-NMR: 400 MHz, (CDCl3) S: 7.49-7.41 (m, 2H), 7.36-7.32 (m, 2H), 7.22 (d, J=7.3 Hz, 1H), 5.19 (s, broad, 2H), 4.67 (dd, J=9.0, 2.7 Hz, 1H), 4.36 (dd, J=11.7, 9.0 Hz, 1H), 4.23 (dd, J=11.7, 2.7 Hz, 1H), 2.68 (s, 3H), 1.14 (s, 9H), 0.94 (s, 9H).

Workup

  1. custom2 separate microwave tubes
  2. temperatureThe reactions were cooled to 23° C.
  3. extractionthe system was extracted with EtOAc (3×50 mL)
  4. dry with materialThe combined extracts were dried (Na2SO4)
  5. filtrationfiltered
  6. concentrationconcentrated
  7. additionThe residue was treated with benzene
  8. custompurified via chromatography on silica gel (80 g “gold” ISCO column; Hex/EtOAc)

Sources & evidence

ORD record
ord-94ba846fbeff4f0897103461611c7ad0
Source dataset
uspto-grants-2015_03
Patent number
US08987250B2

Reaction notes

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