2,6,10,14,18,22,26,30,34,38-Tetracontadecaene, 1-bromo-3,7,11,15,19,23,27,31,35,39-decamethyl-, (2E,6E,10E,14E,18E,22E,26E,30E,34E)- synthesis

6synthesis methods

Product Name:2,6,10,14,18,22,26,30,34,38-Tetracontadecaene, 1-bromo-3,7,11,15,19,23,27,31,35,39-decamethyl-, (2E,6E,10E,14E,18E,22E,26E,30E,34E)-
CAS Number:68799-83-7
Molecular formula:C50H81Br
Molecular Weight:762.08

15575-04-9 Synthesis

15575-04-9
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2,6,10,14,18,22,26,30,34,38-Tetracontadecaene, 1-bromo-3,7,11,15,19,23,27,31,35,39-decamethyl-, (2E,6E,10E,14E,18E,22E,26E,30E,34E)-

68799-83-7
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Yield:68799-83-7 39.5 g (90.4%)

Reaction Conditions:

with pyridine;phosphorus tribromide in hexane;

Steps:

4.a a

a 1-Bromo-3,7,11,15,19,23,27,31,35,39-decamethyl-2,6,10,14,18,22,26,30,34,38-tetracontadecaene Under an atmosphere of argon, a solution of phosphorus tribromide (8.32 g, 30.7 mmol) in 27 ml of n-hexane was added in dropwise to a mixture of 3,7,11,15,19,23,27,31,35,39-decamethyl-2,6,10,14,18,22,26,30,34,38-tetracontadecaen-1-ol (40 g, 57.3 mmol) and pyridine (1.92 ml, 23.8 mmol) in 587 ml of n-hexane at the temperature below 10° C. The solution was stirred at 10° C. for an hour, allowed to warm slowly from 10° to 20° C., stirred at 20°-25° C. for an hour and poured into cracked ice with stirring. The resulting precipitate was filtered off and the filtrate was extracted with n-hexane. The organic layer was washed with 5% sodium bicarbonate aqueous solution, dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to dryness to afford 39.5 g (90.4%) of the desired compound, as a yellow oil. TLC: Rf=0.34 (silica gel, n-hexane:AcOEt=5:1). IR spectrum (v_max^neat) cm^-1: 2980, 2940, 1670. ¹ H-NMR spectrum (CDCl₃) δ ppm: 1.60-2.15 (69H, m, --CH₃ *11, --CH₂ --*18), 4.03 (2H, d, J=8.3 Hz, --CH₂ Br), 5.09-5.14 (9H, m, =CHCH₂ CH₂ --*9), 5.53 (1H, t, J=8.3 Hz, =CHCH₂ Br).