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30th January 2012 @ 10:39
Condensation of PMY 13-1 and propionaldehyde (ZYH 24-1)

reactionscheme24-1.jpg

Experiment start time: 10:50 EST 30/01/2012
PMY 13-1 was dissolved in ethanol (15 mL) and propionaldehyde was added dropwise. The mixture was heated to 60 °C and turned a darker orange-brown colour but no precipitate was observed. After four hours the reaction was complete by TLC and was cooled to room temperature but the products remained in solution. After evaporating the ethanol off under reduced pressure, the orange-brown oil was dissolved in ethyl acetate and washed with water (3 x 10 mL) and brine (15 mL). The organic layer was then dried over magnesium sulfate and evaporated under reduced pressure to give a brownish-orange solid powder. After an hour or so of exposure to air the solid became tacky, suggesting ready absorption of moisture from the air. The solid was dried again under high vacuum and placed in a sealed container in the fridge. TLC and H NMR suggested a mixture of products and the experiment was put aside for the present.

High resolution mass spectrometry:
HRMS (ESI (+)) Calcd. for [C12H12N2OSH+]: 233.0743, found: 233.0736.

TLC (10% methanol in dichloromethane) visualised using UV and vanillin:
TLC at 4 hrs


Hazard and risk assessment:
Refer to: Synthesis of phenyliminothiazolidinone-substituted arylpyrrole (ZYH 3-1)
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23rd January 2012 @ 00:55
Synthesis of cyclopentane substituted near neighbour analogue from ZYH 6-2.

reactionscheme22-1.jpg

Experiment start time: 12:45 EST 23/01.2012
ZYH 6-1 (202.0 mg, 0.4 mmol, 1 equiv.) was combined with DMF (10 mL) and stirred under a nitrogen atmosphere. Triethylamine (0.1 mL, 0.6 mmol, 1.5 equiv.) was added under a nitrogen atmosphere, followed by cyclopentylbromide (0.06 mL, 0.45 mmol, 1.1 equiv.). The mixture was allowed to stir at room temperature for 20 minutes and no change was observed, with the solid ZYH 6-2 remaining largely undissolved. The mixture was then heated to 60 °C and the solution turned clear yellow within a few minutes. After four hours there was some formation of product by TLC but the reaction was incomplete and the mixture was left at 85 °C under nitrogen overnight. In the morning the solution was brown but there was still no product evident by TLC. Product was precipitated out by addition of water, and filtered off. H NMR showed extra broad peaks in the alkyl region consistent with cyclopentane but not the additional peak downfield of the alkyl region expected for a CH attached to the nitrogen. The solid was washed with hexane to eliminate the possibility of contamination by unreacted bromocyclopentane. H NMR still showed the broad alkyl peaks and the experiment was set aside as it did not appear to correspond with the desired product.

Data summary table:
Yield % Melting point °C 1H NMR 13C NMR19F NMR IR Mass spec
ZYH 22-1 84 decomposes ~307Yes (pdf Not collectedNot collectedYes (pdf, .dx) ESI 532 M+Na (pdf,.raw)


Hazard and risk assessment:
Hazard and risk assessment
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17th January 2012 @ 04:19
Synthesis of acetyl thiazolidinone

reactionscheme21-1.jpg

Experiment start time: 15:10 EST 17/01/2012
ZYH 20-1 (1.5 g, 7.7 mmol, 1 equiv.) was mixed with sodium acetate trihydrate (1.05 g, 7.7 mmol, 1 equiv.) in ethanol (15 mL). The solids mostly did not dissolve. Ethyl bromoacetate (0.85 mL, 7.7 mmol, 1 equiv.) was added by portions and the mixture was heated to 60 °C. Solids remained undissolved but the solution turned a brownish-orange. After 2 hours one new spot was observed by TLC but the reaction was incomplete and the mixture was left stirring at 60 °C under nitrogen overnight. In the morning starting material was still present by TLC as well as two additional spots (total four spots). More ethanol was added and bath temperature was increased to 85 °C, and the mixture dissolved completely. TLC at the end of the day indicated the reaction was still incomplete and the mixture was left at 90 °C under nitrogen overnight. In the morning, the reaction was still incomplete by TLC and the mixture was poured over ice (~30 mL) and the yellow-white precipitate was filtered off (1.0 g, 55% yield). The solid still showed 3 spots including starting material by TLC, and was recrystallized. Clear glossy plates formed which TLC showed to be starting material. The original filtrate was extracted, and this and the mother liquor from recrystallization were both found by TLC and H NMR to be mixtures of different products. The two samples were stored in separate vials in the fridge.

TLC (5% methanol in dichloromethane) visualised using UV and Potassium Permanganate
TLC at 2 hr
TLC at 15 hr

Left spot: starting materials; middle spot: starting materials plus reaction mixture; right spot: reaction mixture.

Hazard and risk assessment:
Refer to: Synthesis of diphenyl thiazolidinone (ZYH 14-1)
Attached Files