MJE3-2 (Step 3 Hantzsch Reaction)

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HIRAC- https://au-mynotebook.labarchives.com/share/Emmanuel_Marita_memm0740_Hons/MjMuNDAwMDAwMDAwMDAwMDAyfDE2MjQ3MC8xOC03L1RyZWVOb2RlLzY4MDM3NjE5NXw1OS40

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Reaction Scheme

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Method 27/02/23

• Combined ethanol (10mL), thiourea (0.0980g, 0.589mmol) and bromoketone (0.1298g, 0.648mmol). Reflux started at 10:02am to 10:30 am (28 mins, 80C). TLC (20% EtOAc/hexane) at 28 minutes to check completion.

Appearance- clear yellow after reflux

• Cooled reaction and poured over ice (30mL).
• Added sodium carbonate (10mL) to adjust to pH 8, to precipitate product.

Appearance- cloudy, luminescent yellow in ice water

• To collect product had disregarded vacuum filtration as product quite dissolved in water/ Na2CO3 mixture. Therefore did liquid-liquid extraction with DCM. Extracted 3 times.

• Rotor evaporated to remove DCM 11:45am to 12:05pm.

• Transfer to vial with DCM. Rotor evaporated DCM at 3:03pm.

  

Appearance- brown/black solid

• vial= 15.8542g vial +product= 17.7583g

-check via NMR if need to purify. MJE-3-2 crude product.pdf

Details- messy, need to column

28/02/23

• check if product present via mass spectrometry MJE3-2 crude ms.pdf

Details- product present (268 plus H, 290 plus Na, 557 (2) plus Na)

• To conduct a column multiple TLCs done to determine the correct solvent.

_Details-

1. 11:20am- 20% EtOAc/ Hexane dissolved in DCM Rf value= 0.5/4= 0.125

2. 11:30am- 40% EtOAc/ Hexane dissolved Rf= 2/4.1= 0.48 Note- streaking in both due to amine forming temporary salt with silicon hydroxides. Therefore added triethylamine to counteract acidic amine.

3. 11:42am- 30% EtOAc/ Hexane and triethylamine. (Technique- run without spot, then spot to reduce streaking) Rf= 2.4/4.5= 0.53 (too high)

4. 12:05pm - 30% EtOAc/ Hexane and triethylamine.

5. 12:45pm- 20% EtOAc/ Hexane and triethylamine. Rf= 1/3.9= 0.25 (close enough to 0.3)_

03/03/23

• after TLC vial (no lid)= 15.9418

• 11:00am silica column purification using 20% EtOAc/ Hexane and triethylamine Therefore 500mL EtOAc with 0.5mL (0.1%) triethylamine and 500mL Hexane with 0.5mL triethylamine. Details- product UV active; eluted between fraction 4 and 10 but two different peaks.

  Therefore TLC of fractions 6,7,8 and 10 to check Rf.

  

Details- fractions 6,7,8 Rf= 0.7/3.6= 0.194, fraction 10= 0.194 (same)

08/3/23

• 9:50am NMR fractions 4 and 10 and mass spec to check if same product- confirmed MJE3-2 frac 4 ms.pdf MJE3-2 frac 10 ms.pdf

• 2:00pm-2:33pm combine all fractions and rotor vap to remove EtOAc

• Final product

  

Details- vial= 15.9694g vial + product= 16.0114g

n= 0.0416/267.35= 0.000155moles %yield= 0.0001556/0.0005 x 100= 31%

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Characterisation 13/03/23

NMR NMR after fractions.pdf

Mass spectrometry MJE3-2 final product ms.pdf

IR MJE3-2 final IR.pdf