Methods of Phyto-Constituent Detection
Ravindra Kumar Pandey, Shiv Shankar Shukla, Amber Vyas, Vishal Jain, Parag Jain, Shailendra Saraf in Fingerprinting Analysis and Quality Control Methods of Herbal Medicines, 2018
Salkowski test: When shaken with concentrated sulfuric acid, the lower layer of a chloroform solution of the test drug will turn yellow on standing.Lieberman–Burchard test: A chloroform solution of the test drug with a few drops of acetic acid and one mL of concentrated sulfuric acid produces a deep red at the junction of the 2 layers.Tschugajen test: A chloroform solution of the test drug with an excess of acetyl chloride and a pinch of zinc chloride, when warmed in a water bath, produces an Eosin red color.
Innovative industrial technology starts with iodine
Tatsuo Kaiho in Iodine Made Simple, 2017
Later, BP Chemicals Ltd. developed a Cativa catalyst (see the diagram) combining iodine and iridium. Under the Cativa method, acetic acid is produced by combining methanol and carbon monoxide. Methyl iodide (CH3I), acetyl chloride (CH3COCl), hydrogen iodide (HI), and iridium complex are formed as intermediates and have high reactivity, and efficiently produce acetic acid. The Cativa method, in comparison to the Monsanto method, requires less water in the reaction mixture, produces less acid, and uses simplified production facilities. Presently, most industrial acetic acid is produced using this method [33a,b].
Manual Methods for Protein/Peptide Sequence Analysis
Ajit S. Bhown in Protein/Peptide Sequence Analysis: Current Methodologies, 1988
HPLC grade solvent is fine for most purposes: triethylamine (TEA) and dimethylformam-ide (DMF) from Aldrich, HFo from Baker, heptane and acetonitrile (MeCN) from Burdick and Jackson. Sequencing grade ethyl acetate (EA), TFA, and PITC are necessary for sequencing (Pierce and B & J, or repurify these reagents yourself). Good DMF and tert-amines can be made from yellowed stocks by redistillation (in vacuo if the bp is high) from a little succinic anhydride. Distill 100% ethanol (EtOH, Aaper Chemical) from NaOH. Good water can be purchased, but slow redistillation of house-distilled water from NaOH/KMnO4 (2 g each per 4.5 ϵ water, collect between 300 and 3500 mℓ) makes a product at least as free of interfering materials as commercial water. The buffer used in the partition method (see below) is made from 15 μℓ hexafluoroacetone trihydrate (HFA) and 22 μℓ 25% aqueous trimethylamine (TMA, both from Aldrich) per 5 mℓ of solvent, but the latter is rather variable in actual concentration, so the ratio required for dilute aqueous pH 7.2 should be empirically determined. Polybrene (Aldrich), used as a carrier in the film method, is purified by Edman cycling 10 to 20 mg in a 13 × 100 mm tube and precipitation from methanol with acetone, or by dialysis against dilute aqueous TFA using Spectrapor 3500 MW cutoff. About half the polymer is lost by either process, and the oligomer-free product, now the TFA salt, should be completely soluble in methanol. Anhydrous HCl/MeOH is made by dropwise addition sans stirring of redistilled acetyl chloride to MeOH at 0°C in a vertical 13 × 100 mm tube. Use a ratio of 0.3:3.9 for 1 N and 0.6:3.6 for 2 N; store at 0°C. The conversion reagent, concentrated HCl, and EA should be protected from development of oxidizing agents by addition of about 0.02% ethanethiol. Working stocks of all reagents and solvents should be small and replenished periodically from main reserves. TEA and PITC should be kept cold and removed under N2 barrier, and all reserves should be stored at 0°C.
Design and synthesis of naphthalimide group-bearing thioglycosides as novel β-N-acetylhexosaminidases inhibitors
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Shengqiang Shen, Wei Chen, Lili Dong, Qing Yang, Huizhe Lu, Jianjun Zhang
As shown in Scheme 1, the key intermediate thiol 10 was obtained from N-acetyl-d-glucosamine as the starting material. In the procedure, acetyl chloride was first used for acetylation and chlorination. Thiourea was then used in substitution prior to removing carbamimidoyl by Na2S2O5 in DCM and H2O. These three steps can conveniently be carried out without chromatographic purification and has made large-scale preparation of compound 10 possible. Then, compound 10 was reacted with α,ω-dibromoalkane in the presence of potassium carbonate in acetone and H2O to obtain mono-bromide precursors 11a–11d. Meanwhile, 1,8-naphthalic anhydride 12 was refluxed with α,ω-diaminoalkane in ethanol to yield 13a–13c. Subsequently, the preparations of acetyl-protected compounds 14a–14l were completed by the reactions of bromides 11a–11d with excess naphthalimide derivatives 13a–13c under the condition of potassium carbonate and acetonitrile with 65–72% yield. Finally, deacetylation of hydroxyl groups by methanol-ammonia catalysis resulted in the target compounds 15a–15l.
Synthesis and pharmacological evaluation of novel isoquinoline N-sulphonylhydrazones designed as ROCK inhibitors
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Ramon Guerra de Oliveira, Fabiana Sélos Guerra, Cláudia dos Santos Mermelstein, Patrícia Dias Fernandes, Isadora Tairinne de Sena Bastos, Fanny Nascimento Costa, Regina Cely Rodrigues Barroso, Fabio Furlan Ferreira, Carlos Alberto Manssour Fraga
In a 50 ml round bottom flask, 300 mg of 6 (0.7 mmol) was dissolved in 15 ml of dry ethanol. Then, 1.570 mg of acetyl chloride (14 mmol) was added drop wise to a stirred solution of the N-(tert-butoxycarbonyl)-protected sulphonylhydrazone (6) at room temperature. The mixture was stirred overnight and evaporated in vacuum to give the title compound as a pale yellow solid, which was recrystallized in methanol (156 mg, 63% yield); mp: 186 °C.1 H NMR (400 MHz, DMSO-d6) δ (ppm): 12.07 (s, 1H); 9.92 (s, 1H); 8.95 (d, J = 6 Hz, 1H); 8.88 (d, J = 6 Hz, 1H); 8.75 (d, J = 8 Hz, 1H); 8.65 (d, J = 8 Hz, 1H); 8.10 (t, J = 8 Hz, 1H); 7.30 (d, J = 4 Hz, 1H); 3.05–3.07 (m, 2H); 2.74–2.81 (m, 2H); 2.34–2.40 (m, 1H); 1.69–1.72 (m, 2H); 1.39–1.47 (m, 2H). 13C NMR (50 MHz, DMSO-d6) δ (ppm): 153.2; 152.6; 149.9; 136.8; 136.0; 134.5; 132.9; 128.9; 128.2; 121.0; 42.2; 35.5; 25.0. IR (ATR, cm−1): 2949; 2695; 1327; 1179. HRMS (ESI, m/z): calculated for [M + H]+ C15H18N4O2SH+, 319.1223, found 319.1223.
Steroid-depleted polycystic ovarian syndrome serum promotes in vitro oocyte maturation and embryo development
Published in Gynecological Endocrinology, 2018
Elham Eyvaznejad, Mohammad Nouri, Aliyeh Ghasemzadeh, Amir Mehdizadeh, Vahideh Shahnazi, Samira Asghari, Alireza Mardomi, Masoud Darabi
Total fatty acid extraction from cultured cumulus cells was performed following a direct transesterification reaction after 48 h treatment [20]. Briefly, cells were harvested and washed by 1× phosphate buffered saline. After centrifugation, the supernatant was discarded and the achieved cellular pellet was transferred to glass tubes and 2 ml of methanol/hexane (4:1) (Merck, 1060091000/1043741000, Darmstadt, Germany) containing 50 µg/ml of tridecanoate (13:0) (Sigma, 1731-88-0, Schnelldorf, Germany), as the internal standard, was added to the tubes. Afterwards, 0.2 ml of acetyl chloride (Merck, 8222520100) was added slowly, and tubes were transferred to a 100 °C water bath for 1 h in a tightly closed cap tube condition. Tubes were then cool downed and 5 ml of 6% K2CO3 was added to each tube. The upper hexane phase was recovered after 1000 rpm centrifugation for 1 min. A volume of 0.5 µl concentrated fatty acid extract was injected to a Buck Scientific gas–liquid chromatograph (GLC, SRI instruments, Torrance, CA) equipped with a flame ionization detector (FID) and a TR-CN100 capillary column (60 m × 0.25 m × 0.2 μM) (Teknokroma, Barcelona, Spain). Helium was used as the carrier gas. The oven temperature was programed from 190 to 210 °C at the rate of 1 °C/min and then maintained stable for 20 min. Peak retention times and area under curve of standard chromatograms were generated by injecting known standards (Sigma chemicals, Schnelldorf, Germany). Peak Simple 3.59 software (SRI instrument, Torrance, CA) was used for calculation of the area under curve for each fatty acid, and data were presented as percentage ± standard division (SD).
Related Knowledge Centers
- Acetic Acid
- Acetonitrile
- Acyl Chloride
- Carbonylation
- Hydrogen Chloride
- Organic Compound
- Potassium Acetate
- Thionyl Chloride
- Acyl Halide
- Chloromethane