Amino-thienopyrimidine Series

 

This experiment is a scale up of previous reactions in the JRC 15-x series. The product of this experiment is a crucial intermediate toward analogues within the thienopyrimidine series.

Conclusion: Title compound synthesised in 40% purified yield.



Methyl 3-aminothiophene-2-carboxylate (9.91 g, 63.0 mmol, 1 eq.), formic acid (2.51 mL, 66.5 mmol, 1.1 eq.) and ammonium formate (4.33 g, 68.7 mmol, 1.1 eq.) were dissolved in formamide (14.0 mL, 352 mmol, 5.6 eq). The mixture was heated at 140 °C for 72 h. The solution was allowed to cool to rt. A brown precipitate was formed, and collected by filtration. This brown substance was washed with chilled H2O to yield the title compound (by TLC) as brown crystals (8.7495 g, 57.49 mmol, 91%).

These crystals were then washed with chilled EtOH/H2O to yield the title compound (by TLC) as brown crystals (3.916 g, 25.73 mmol, 40%).

The filtrate was retained.

Urea SM = 102.5 mg, 0.415 mmol
Diboron = 253.7
AcOK = 216.3 mg
PdCl2dppf = 18 mg
dioxane = 8 mL

crude yield = 276 mg.
multiple product present by TLC (EtoAc: rf = 0, 0.4, 0.6, 0.8, 0.9). Column chromatography necessary.

This experiment is a Suzuki coupling to form a derivative within the thienopyrimidine series.

Conclusion: Desired product not synthesised. Homocoupled product looks to have been isolated by HNMR and low res. mass spec.

Experiment start time: 9:45 am, 13/12/20126-bromothieno[3,2-d]pyrimidin-4-amine (49 mg, 0.21 mmol, 1 eq), phenylboronic acid (36 mg, 0.30 mmol, 1.4 eq), dried potassium acetate (108.5 mg, 1.105 mmol, 5.3 eq) and PdCl2(dppf) (7.1 mg, 4.2 mol %) were dissolved in 1,4-dioxane/water (5:1, 5 mL). The solution was stirred whilst heated to reflux for 72 h.

Crude yield = 38 mg. Multiple products present by TLC (EtOAc: rf = 0.4, 0.5, 0.7, 0.8, 0.9). Difficult column will be necessary.

Column performed using 10% EtOAc/hex -> 100% EtOAc. One product eluted (8 mg). This product has an 1H-NMR spectrum consistent with the desired product, though the fairly complex aromatic region means that multiplicity could not be determined.

SPECTRUM NEEDS TO BE UPLOADED.

low res mass spec shows weight consistent with homocoupled thieno[3,2-d]pyrimidine.

This experiment is designed to test the following conditions for substitution at the 4-amine, on the thienopyrimidine core. Tosyl chloride will be used as a substituent. Thienopyrimidines with tosyl groups on the 4-amine have been tested previously, but none bearing the m-sulfamoylbenzene group at the 4-position. Thus, this experiment is not only a proof of methodology to acheive substitution at the 4-position, but it shall also generate a useful analogue.

Conclusion: Desired product looks to probably have been made (trace yield)

Experiment start time: 10:50 am, 11/12/2012JRC 40-1 (114 mg, 0.5 mmol, 1 eq), tosyl chloride (120.3 mg, 0.63 mmol, 1.3 eq) and DMAP (8.6 mg, 14 mol %) were dissolved in chloroform (5 mL) and stirred at rt. To the stirring solution was added DIPEA (0.35 mL, 2 mmol, 4 eq). The flask containing the resultant solution did not feel warmer to touch. The solution was stirred at rt for 2 hr. TLC analysis showed no significant change. Reaction therefore heated to reflux for 48 hr. No TLC comparison to SM's possible since none remains. Four spots by TLC (10% MeOH/DCM): rf 0.1, rf 0.5, rf 0.55m rf 1.

Reaction allowed to cool to rt. EtOAc (100 mL) added to the solution. Organic layer extracted with H2O (2 x 50 mL) and brine (50 mL) before being dried over MgSO4, and concentrated in vacuoto yield 148 mg product as a maroon solid.

This solid was purified via flash chromatorgaphy (10% EtOAc/hexane -> 100% EtOAc) to yield two aromatic products:

f1: 4 mg\

f2: 42 mg

NOTE: NMR files mistakenly named as JRC 54-1, JRC 54-1F1, and JRC 54-1F2

the first fraction looks to be the desired product by NMR (0.013 mmol, trace). this fraction was mistakenly thrown away.

This reaction is a repeat of JRC 32-2, and JRC 32-1, albeit using a microwave reactor and a bromine at the 6-position instead of an iodine.



4-(6-Bromothieno[3,2-d]pyrimidin-4-yl)morpholine (112.3 mg, 0.374 mmol, 1 eq.), 3-sulfamoylbenzene boronic acid, pinacol ester (37.7 mg, 0.13 mmol, 0.34 eq.) and AcOK (44 mg, 0.448 mmol, 1.1 eq.) were dissolved in 3 mL dioxane/H2O (degassed with argon). To this solution was added PdCl2(dtbpf) (6.3 mg, 0.11 mmol, 2.4 mol %). The solution was heated and stirred in a microwave reactor for 15 min at 150 °C at 150W. The solution was allowed to cool to rt.

NOTE: INCORRECT QUANTITIES USED.

TLC shows some starting material remaining, and several new products formed - all within a narrow rf band (0.3-0.4 in 10% MeOH/DCM). Crude reaction mixture purified via flash chromatography using DCM -> 10% MeOH/DCM as the eluent. Four pure fractions collected, though most mass remains in unisolated, non-pure fractions.

F1: 1% MeOH/DCM

F2: 2% MeOH/DCM

F3: 5% MeOH/DCM

F4: 10% MeOH/DCM


None of these fractions containes the desired product by NMR. This is confusing because F3, by mass spec, showed a minor peak corresponding to the desired product: