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18th November 2011 @ 01:13
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Conversion of carboxylic acid PMY 8-3 to the acid chloride using thionyl chloride and its subsequent coupling with side chain PMY 9-1 to give TCMDC-123794.

Reaction Scheme

Reaction start time: 11.00 EST 18/11/11
PMY 8-3 (200 mg, 0.86 mmol, 1 equiv.) was dissolved in dry PhMe (10 mL). 1 drop DMF added followed by thionyl chloride (0.25 mL, 3.4 mmol, 4 equiv.). After 4 hours, 0.2 mL removed, concentrated and analysed by 1H NMR. Integrals of pyrrole-H indicate 65% conversion. not meticulously dry handling of mini work-up sample After 5 hours, reaction concentrated under reduced pressure. Then redissolved in DCM (10 mL) and freshly dried PMY 9-1 (224 mg, 0.86 mmol, 1 equiv.) added. 21/11/11 09.30 TLC shows formation of product along with side products. Concentrated under reduced pressure to a black solid. Purified by chromatography (0-1.5% MeOH/DCM). Column did not yield desired product, similar RF material appears to be SM by 1H NMR. Note different stain colour by vanillin after several hours. TLC does appear to show product (in comparison with PMY 11-3), but column TLC does not match.

TLC (10% MeOH/DCM) visualised with UV and vanillin:
TLC 0930 21/11/11

Left plate: SM, M, RM, RM + PMY 9-1, PMY 9-1.
Right plate: SM, M, RM, RM + PMY 11-3, PMY 11-3.

Column TLC

Column TLC: Right plate is a repeat on overlap region.

NMR:
NMR at acid chloride stage
NMR of fractions 16-30
NMR of fractions 31-48


Risk and Hazard Assessment:
See: Synthesis of TCMDC-123812 via acid chloride (PMY 10-1)

See also:
Synthesis of TCMDC-123794 using DIC/DMAP (PMY 11-3)
Synthesis of TCMDC-123794 via acid chloride (PMY 11-2)
Synthesis of TCMDC-123794 via acid chloride (PMY 11-1)
Synthesis of TCMDC-123812 via acid chloride (PMY 10-2)
Linked Posts
Attached Files
TLC 0930 21/11/11
Column TLC
NMR at acid chloride stage
NMR of fractions 16-30
NMR of fractions 31-48
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