2- Synthesis of thiolated triethyl chitosan (TEC-Cys) 2-1 synthesis of quaternized ammonium of chitosan (TEC) Triethyl chitosan (TEC) was synthesized as previously described byAvadi et al. [8, 15]with minor modification. Briefly,2 g of chitosan was dispersed in 50 ml of NMP at room temperature while being stirred magnetically. Then in a reflux condition 15 mL ethyl iodide was added stepwise every 1 h. Sodium hydroxide and sodium iodide were not applied in this process in order to decrease O- methylation of chitosan. After 24 hours by adding acetone,TEC precipitant was produced. Finally, for purification of TEC and ion exchange of I toCl,dialysis against 10 % NaCl solution was carried out for 24 hours. Then, purified quaternized ammonium of chitosan was precipitated by acetone and characterized by 1H-NMR using D2O as solvent. 2-2 Synthesis of thiolated quaternized ammonium of chitosan(TEC-Cys) The chemical structure of TEC-Cys is illustrated in figure 1.The covalent attachment of …show more content…
Briefly, 0.5 mg of TEC was dissolved in 500 μL of 0.5 M phosphate buffer pH 8.0. Then 500 μL of 0.03 % (m/v) of DTNB dissolved in 0.5 M phosphate buffer pH 8.0 was added. After incubation at room temperature for 2 hours, the thiol group was determined by using spectrophotometer (Optizen 2120UV Plus) at 405 nm wavelengths. 3- Formation of disulfide bond A 3% (m/v) solution of TEC-Cys was hydrated in 50 mM phosphate buffer pH 6.8 and incubated at 37±5˚C under shaking. At predetermined time intervals, 200 µL of hydrated conjugates were withdrawn and 50 µL of 1M HCl was added to stop further reactions. The amount of remaining thiol groups was determined using Ellman’s reagent [15]. 4- Preparation of nanoparticles In this work, insulin nanoparticles were prepared by PEC method[4, 16,
Science A CH1HP H Unit Chemistry C1 Chemistry Unit Chemistry C1 Monday 10 June 2013 1.30 pm to 2.30 pm Mark 1 2 3 4 5 6 7 TOTAL For this paper you must have: a ruler the Chemistry Data Sheet (enclosed).
This is confirmed 164 by extensive research with other familiar high-surface agents. 2. From Hydrocyanic Acid159: Diels 153 develop a practical laboratory synthesis of cyanuric chloride from a method originated by Kalson166. It improved by Fries 167 and Lemoult 155. The trace of alcohol is necessary.
Nevertheless, our initial attempts with the reported procedure to isolate the intermediate were proven futile and low yielding due to high reactivity and instability of the intermediate. To circumvent this problem, I revised the synthesis under one-pot reaction condition without the need for the isolation of the intermediate. Activation of the protected guanosine with 1.2 equivalent of the chloroformate and subsequent addition of an excess amount of the tryptamine (4 eqvi) resulted in the coupled product. Isolation and deprotection of the coupled product resulted in the final product with more than 70% yield. Next, we investigated the effect of TrpGc on the activity of hHint1 using a fluorescence assay described previously.3 At a fixed saturating substrate concentration, TrpGc exhibited a dose dependent decrease in the activity of hHint1 with maximum half inhibitory concentration (IC50) values of 25.5 ± 6.0 μM (Fig 1). We next employed isothermal titration calorimetry (ITC) to investigate the nature of non-covalent interactions on the inhibitory activity of Bio-AMS on hHint1. The ITC studies provided an experimental dissociation
M.p. 200-201 oC. 1H NMR (300 MHz, DMSO, ppm): δ 1.20 (t, 3H, J ¬= 7.1 Hz, COOCH¬2¬CH¬3), 1.31 (t, 3H, J¬ = 7.1 Hz, COOCH¬2¬CH¬3), 2.77 (t, 2H, J ¬= 5.6 Hz, H-4), 3.59 ( t, 2H, J = 5.1 Hz, H-5), 4.08 (q, 2H, J¬ = 7.0 Hz, COOCH¬2-CH¬3), 4.29 (q, 2H, J¬ = 7.0 Hz, COOCH¬2¬CH¬3), 4.45 (s, 2H, H-7). 8.55 (s, 2H, NH2), 11.42 (s, 1H, NH). 13C NMR (75 MHz, DMSO, ppm): δ 13.8 (CH3), 14.3 (CH3), 25.7 (C-4), ¬40.6 (C-5), 41.9 (C-7), 60.2 (CH2, ester), 60.7 (CH2, carbamate), 110.5 (C-3), 121.8 (C-3a), 128.4 (C-7a), 151.0 (C-2), 154.5 (C=O), 165.0 (C=O, carbamate), 178.7 (C=S). Anal. Calcd for C14H19N3O4S2 (357.45): C, 47.04; H, 5.36; N, 11.76; Found C, 46.91; H, 5.19; N,
Synthesis of Pentiptycene Hydroquinone: (100mg, 0.218 mmol) Pentiptycene quinone was suspended in 10mL THF. Sodium dithionite (321mg, 1.849mmol) was dissolved in 2mL in water. Aqueous solution was added to suspended starting material and the mixture was heated to 40°C while stirring vigorously for 1.5 hours until paled or no more starting material is present through TLC analysis. Reaction was cooled to room temperature and transferred to a separator funnel. Organic layer was washed with brine (3 ml) and dried over MgSO4. Solvent was removed under reduced pressure to yield white solid.
Chitin is a nitrogen-containing structural polysaccharide present in the cell wall of fungi and exoskeleton of crustaceans, insects and other arthropods. The exoskeleton serves are protection and structural support for the arthropods (Pechenik, 2009). Furthermore, in crustaceans, the chitinous substances is added with calcium carbonate for added protection (Berg, Martin, & Solomon, 2006). Chitin has several derivatives and one of them is chitosan. Chitosan is obtained through deacetylation of chitin under alkaline conditions the acetyl group present in chitin is removed and thus the substance is converted into chitosan (Rinaudo & Younes, 2015). Chitosan is a copolymer composed of N- acetyl glucosamine and glucosamine and possesses various properties such as antimicrobial activity, biocompatibility and biodegradability (Teli
An air-dried glass reaction vessel equipped with a magnetic stir bar was charged with, in order: 1,4-dioxane (15 mL), t-amyl alcohol (3 mL),2-bromo-3-chloro-5-methyl-6-(thiophen-2-yl)-5H-pyrrolo [2,3-b]pyrazine (0.84 g, 2.5 mmol), Pd(OAc)2 (0.057 g, 0.25 mmol), xantphos (0.25 g, 0.43 mmol), Cs2CO3 (1.66 g, 5 mmol) and tert-butyl carbamate (0.3 g, 2.5 mmol). The suspension was refluxed at 90 oC for 3 h. Once the reaction was complete by TLC, it was diluted with EA and filtered through a bed of celite. The filtrate was concentrated in vacuum. The residue was purified by silica chromatography (25% EA:hexane) to afford desired product as a crystalline solid.
The flask was placed in an ice bath with a magnetic stirrer. P-toluene sulfonyl chloride (5.13g/27 mmol) was added, using a powder funnel. The solution was mixed for 40mins and allowed to cool to room temperature. NaOH (20 mL, 6M) was added and stirred for 5mins. Distilled water (30 mL) was used to transfer product to a separatory funnel. Diethyl ether (3x25ML) was used to extract the organic layer from the inorganic layer. The combined ether layer were washed with HCL (6M, 3x25mL), NaHCO3 (10% 1 x 15 mL) and brine (1 x 15 mL). The ether layer was dried using anhydrous MgSO4. The solvent was evaporated from the product on a steam cone to yield tosylate (3.12g/11.63mmol).
6- The four component condensation of acetophenone, arylaldehydes, arylthiol, and malononitrile in the presence of non-ionic surfactants (Triton X-100, 5 mol%) afforded new derivatives of 4,6-diaryl-2-(arylthio)nicotinonitriles (48) in (80-95%) yield113, scheme 48.
6.3 Experimental - schematic representation and procedure for the synthesis of compounds V1-17 6.3.1 Synthesis of 6-nitro-1H-benzo[d]imidazole-2-thiol II (step 1) Ethanol (40 ml) and potassium hydroxide (0.01 mol, 56.11 gm/mol, 0.56 gm in 2 ml H2O) were taken in a dry round bottom flask. 4-nitrobenzene-1,2- diamine I (0.01 mol, 153.14 gm/mol, 1.53 gm) was added to it and stirred well to get a clear solution. Carbon disulfide (0.02 mol, 76.14 gm/mol, 1.2 mL) was added to the clear solution obtained above and refluxed for 12 -15 h. The ethanol was distilled off and then cooled to room temperature. The content was poured into water and acidified with diluted HCl till the precipitates were separated.
To a suspension of an a-N Boc protected 2,4-diaminobutanoic acid (1.0mmol, 1.0eq.) in MeOH (5mL), Ethyl 2 – azido – 2,2 – difluoroacetate (1.5mmol, 1.5eq.) and TEA (2.0mmol, 2.0eq.) were added. The reaction mixture was stirred for 3 hours at rt. After evaporation the mixture was dissolved in ethylacetate (10mL) and washed with 0.1M NaHSO4 aqueous solution, water, and brine, dried over anhydrous Na2SO4, filtered, and evaporated to dryness to give essentially pure (S)-2-amino-Boc-4-(2-azido-2,2-difluoroacetamido)butanoic acid. To this solution of acylated α–N–Boc protected diaminoacid in dry DCM (3mL) 4M HCl in dioxane solution (1.25mL, 5.0mmol, 5.0eq.) was added dropwise at 00C. The reaction mixture was stirred for 3 hours at rt. The precipitate
4-nitro-o-phenylenediamine (5 mmol, 0.77 g) in 25 ml ethanol was slowly added to ethanolic solution (25 ml) containing isatin (5 mmol, 0.74 g), followed by the slow addition of 5- bromosalicylaldehyde (5 mmol, 1.00 g) dissolved in 25 ml ethanol. A colored precipitate was obtained on refluxing the solution for 3 h, (cf. Scheme 1) [24]. The precipitate was filtered by suction and washed thoroughly with ethanol. The pure compound was dried in desiccator over anhydrous calcium chloride.
Benzoic acid (0.05g) was taken in a round bottom flask and the reaction vessel was placed in an ice bath. The Grignard reagent (), HCl (0.5mL, 3M) and MTBE (0.5mL) was added to the reaction vessel dropwise and mixed well. After removing all the aqueous layer and drying the MTBE, the product was analyzed using GC-MS. Results: The major component of the Grignard reaction was prepared by reacting 4-Bromo-N, N-dimethylaniline with magnesium turnings using THF as a solvent in an anhydrous condition as shown in equation 1. Methyl benzoate was reacted with the Grignard reagent in an anhydrous condition in the presence of THF, followed by hydrolysis in order to obtain green colored dye known as Malachite green, as shown in equation 2.
D’Souza along with other researchers were investigated the use of an artificial chymotrypsin with the binding site of cyclodextrin with the catalytic site of an imidazolyl group, a carboxylic acid and a hydroxyl acid. The synthetic chymotrypsin has a reduced molecular weight and they believed that the real and artificial enzyme had the same catalytic activity.
For this work, all the chemicals were used an analytical grade, and as received without additional purification. All aqueous solutions were made by using high purity deionized water with a resistivity (ρ) 18 MΩcm-1. Silver Nitrate (AgNO3, 99.0%), Copper (II) Sulfate Pentahydrate (CuSO4.5H2O, 99.0%), Povidone (PVP- (C6H9NO)n, 99.0%), Sodium borohydride (NaBH4, 99.0%), and Absolute Ethanol (C2H5OH,