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20th September 2012 @ 03:14
Sc: 1-10
Synthesis of SC4-1 and SC4-2 from SC2-1.

HIRAC


SC4 HIRAC.jpeg


Procedure followed:

The procedure was identical to that used for SC3-1 and SC3-1. Reactions were also performed on a 0.1 g scale.

SC1-1 (0.1023 g, 0.41 mmol) was reacted with acetyl chloride (0.05 mL, 0.61 mmol) in the presence of 2,6-lutidine (0.05 mL, 0.48 mmol) in acetonitrile (0.03 M, 13 mL), under argon gas and with stirring, to give SC4-1.
SC1-1 (0.0997 g, 0.40 mmol) was again reacted under the same conditions, with the addition of Yb(OTf)3 (0.0085 g/mL, 1.3 mL, 0.017 mmol) to give SC4-2.

SC4%20reaction%20image.png

reaction%20values.PNG

SC4 reaction.JPG


13th September 2012

TLC analysis showed that SC4-1 and SC4-2 reactions had progressed considerably after 40 minutes of reaction time. (See TLC below.)

14th September 2012

Stirring was ceased after 21 hr.
SC4 reaction progress.JPG


SC4-2 had partially crystallised overnight as there were visible particulates in the reaction mixture. SC4-1 remained in solution. Samples refrigerated over the weekend.

18th September 2012

Products were extracted in ethyl acetate (3 x 10mL) using sodium hydrogen carbonate, as done for SC3-1 and SC3-2. The products were obtained as white/light-brown solids. Crude yields are listed below. Residual lutidine is suspected; both solids exuded an aroma characteristic of lutidine.

Crude yield for SC4-1: 0.1199 g, 0.41 mmol, 100.2%
Crude yield for SC4-2: 0.1393 g, 0.48 mmol, 119.5%

19th September 2012

SC4-1 was purified using silica column chromatography using ethyl acetate/hexane eluent. TLC analysis showed a clean reaction mixture. No co-spotting was observed, unlike during the purification of both SC3-1 and SC3-2 reaction mixtures. Fractions 15-33 were collected.

TLC analysis of SC4-1 crude sample:
column purification fractions 1-20.JPG
column purification fractions 21-40.JPG


20th September 2012

SC4-2 was column purified. A single spot was observed, indicative of one product. Fractions 15-40 were collected.

TLC analysis of SC4-2 crude sample:
SC4-2 fractions 1-20.JPG
SC4-2 fractions 21-40.JPG


21st September 2012

Final yields for purified products were obtained.
SC4-1: 0.0581g, 0.20 mmol, 48.6%, m.p.
SC4-2: 0.0539g, 0.19 mmol, 46.2%, m.p.

27th September 2012
NMR analyses of SC4-1 and SC4-2 show that cyclisation has occurred.
Starting material (SC1-1):
SC1-1 1H-NMR.pdf.pdf

SC4-1:
SC4-1 column frac 15-33 1H-NMR.pdf.pdf

SC4-2:
SC4-2 column frac 15-40 1H-NMR.pdf.pdf


Attached Files
SC4 reaction image.png
column purification fractions 1-20.JPG
column purification fractions 21-40.JPG
SC4 reaction progress.JPG
SC4 reaction.JPG
reaction values.PNG
SC4-2 fractions 1-20.JPG
SC4-2 fractions 21-40.JPG
SC4 HIRAC.jpeg
SC1-1 1H-NMR.pdf.pdf
SC4-1 column frac 15-33 1H-NMR.pdf.pdf
SC4-2 column frac 15-40 1H-NMR.pdf.pdf