Synthesis of N-methoxy-N-methylaminocarbonyl-l, 4-benzoquinone: the First Quinone Carrying an N-methoxy-N-methylamino Group

We report herein a four-step preparation of the title compound. Gentisic acid (1) was firstly converted into its diacetate (2) by treatment with acetic anhydride in the presence of concentrated sulfuric acid. Treatment of the diacetate with oxalyl chloride in dichloromethane in the presence of dimethylformamide followed by N-D-dimethyl-hydroxyamine hydrochloride and pyridine gave 2, 5-diacetoxy-Nmethoxy- N-methylbenzamide (3). Reaction of this with sodium hydrogen carbonate to generate the hydroquinone (4) followed by oxidation with silver oxide gave the desired quinone (5)

Synthesis of 2-acetyl-5,8-dihydro-1,4-dihydroxy-3-methyl naphthalene: a product from the isomerisation of Diels-Alder adducts of both 5-methyl- and 6-methyl-2-acetyl-1,4-benzoquinone with 1,3-butadiene

2-Acetyl-5,8-dihydro-1,4-dihydroxy-3-methyl-naphthalene was synthesised via Diels-Alder addition of 2-acetyl-3-methyl-1,4-benzoquinone to buta-1,3-diene followed by enolisation. It was identical with material obtained by pyridine-induced acetyl migration from the 1,3-butadiene adducts of both 3- and 6-methyl-2-acetyl-1,4-benzoquinone

A Simple and Clean Method for Methoxymethylation of Phenols

A simple and clean procedure for the preparation of methoxymethyl ethers (MOM = CH2 OMe) of phenols having internally hydrogen bonded hydroxy groups is described. Thus treatment of 2,5-dihydroxybenzaldehyde (1) with a 1:1 mixture of methoxymethyl chloride-methyl acetate in ether at room temperature gives 2.5-bis( methoxymethoxy)benzaldehyde (2) in 57% yield; under similar conditions, the methoxymethyl ether (6) of salicylaldehyde was isolated in 75% yield. Yields of61-81 %, not optimised, of methoxymethyl ethers of several phenols lacking internal hydrogen bonding were also obtained

Bromination of 2,S-dimethoxybenzaldehyde

Bromination of 2,5-dimethoxybenzaldehyde (1) gives 4-bromo-2,5-dimethoxy-benzaldehyde (2) and not 6-bromo-2,5-dimethoxybenzaldehyde (3) as previously reported by Rubenstein (1925). It appears that the conjugation of the carbonyl group with the ortho methoxy group (as structure 4) does not control the orientation of this bromination reaction. A series of reactions which confirm the structure of the bromination product will be discussed

Lipase catalyzed betulinic acid derivatives and its cytotoxic activity / Yamin Yasin and Faujan Ahmad

Betulinic acid, a triterpenoid found in many plant species, has attracted attention due to its important pharmacological properties, such as anti-cancer and anti-HIV activities. In order to obtain derivatives potentially useful for detailed pharmacological studies, derivatives were synthesized through the reaction of betulinic acid with benzoyl chloride and acetic anhydride using a lipase catalyst. Enzyme-catalyzed reaction of betulinic acid with benzoyl chloride yielded 3B-benzoil-lup-20(29)-ene-28-oic acid ester (BCL), whereas the acetic anhydride reaction yielded 3B-acetoxy-lup-20(29)-ene-28-oic acid ester (BAA). The BAA underwent further reaction with l-decanol to produce 3B-acetoxy-lup-20(29)-ene-28 decanoate (BAAD). The prepared betulinic acid derivatives were tested for cytotoxic activity on three callcer cell lines in vitro: all tested compunds showed greater activity than betulinic acid

EVALUASI SISTEM PELAKSANAAN HASIL PEMBELAJARAN PRODUKTIF PADA PROGRAM KEAHLIAN ELEKTRONIKA INDUSTRI SMK NEGERI 3 WONOSARI

Penelitian ini bertujuan untuk mengevaluasi sistem penilaian hasil pembelajaran produktif. Evaluasi ini terdiri dari tiga tahapan yaitu Input, Process, dan Outcomes: (1) evaluasi (Input) masukan meliputi perencanaan penilaian hasil pembelajaran oleh guru; (2) evaluasi (Process) proses meliputi pelaksanaan penilaian hasil pembelajaran oleh guru; (3) evaluasi (Outcomes) keluaran meliputit indaklanjut dari hasil pembelajaran oleh guru. Penelitian ini termasuk jenis penelitian evaluasi program dengan model Provus. Penelitian ini dilakukan di SMK Negeri 3 Wonosari dengan subyek penelitian sebanyak 30 siswa kelas X dan 5 guru pengajar pada program keahlian Elektronika Industri. Metode pengumpulan data yang digunakan adalah angket, wawancara dan dokumentasi. Uji validitas instrumen dilakukan dengan menggunakan rumus korelasi product moment. Reliabilitas instrumen dianalisis dengan menggunakan metode belah dua (split-half method) atau formula Spearman Brown. Data yang diperoleh dianalisis dengan metode deskriptif kuantitatif kualitatif. Hasil penelitian menunjukkan bahwa pelaksanaan penilaian hasil pembelajaran produktif program keahlian Elektronika Industri SMK N 3 Wonosari secara umum dikategorikan baik. Hasil penelitian tersebut yaitu : (1) kesiapan pelaksanaan perencanaan penilaian hasil pembelajaran dalam kategori baik (74,76%), (2) proses pelaksanaan penilaian hasil pembelajaran dalam kategori sangat baik (80,43%), (3) aspek tindak lanjut penilaian hasil pembelajaran dalam kategori baik (72,23%)

Identification of aroma, earthy flavour and aftertaste in tilapia using sensory evaluation technique

Trained panelists were used to identify the flavour profile which consists of aroma, flavour and aftertaste of wild black tilapia (Oreochromis mossambica). For the purpose of comparison, 2 marine fish namely Indian mackerel(Rastrelinger kanagurta) and bonito (Euthynnus affins) and catfish (Clarias batrachus), a freshwater fish, were also evaluated. Ten and eight aroma, flavour and aftertaste attributes respectively were recognized in tilapia. However, the presence of kerosine-like attribute could be due to petrochemical contaminants. The presence of strong to moderate earthy attribute is dominantly recognized in its aroma and flavour which are consistently scored higher than that in catfish except for the aftertaste. The presence of geosmin in the tilapia muscle could most probably be in the range of 1. 0 to 10.0 mg-1. The earthy aroma may be reduced upon cooking

A Natural Flavour in an Amphiphilic Association Structure

The miscibility ofa banana flavour, amyl acetate, in a water-in-oil microemulsion of water/sodium dodecyl sulphate (SDS): hexan-1-01 (35:65) in n-decane and fJ-xylene system was carried out at 30°e. The systems were tested by a phasestudy and refractometry method. The solubility of the flavour was observed to be connected to the ratio of SDS: hexan-1-D1 and hydrocarbon; a higher solubility of the flavour was observed in a larger ratio. The solubility was, however, inversely proportional to the water content

Adsorption of methylene blue onto treated activated carbon

The potential feasibility of treated and untreated activated carbon for removal of methylene blue from aqueous solution was investigated. The effects of various experimental parameters such as contact time, solution pH and adsorbent dosage were investigated. The extent of methylene blue removal increased with the increased in contact time, solution pH and amount of adsorbent used. Adsorption data was better fitted to the Langmuir isotherm. The results in this study indicated that the treated activated carbon was an attractive candidate for removing organic dye of methylene blue which shows great reduction of colour while reducing the time contact to achieve equilibrium