.1.1 CYTOSINE ANALOGUE PREPARATION WITH AROMATIC ALDEHYDE when aromatic aldehyde is used, magnesium is added to anhydrous methanol or ethanol (4 eq relative to cytosine) and heated until complete dissolution of magnesium filings and add 2 mmol of cytosine, followed by the aromatic aldehyde in the amount of 4-6 eq, minimum of 4 eq relative to cytosine, the reaction mixture is heated up to 45-65°C for at least 3 hours, and later, a reducing agent, preferably NaBH(1 eq relative aldehyde) ,is added to the cooled mixture, then it is kept at room temperature for at least 15 minutes, followed by addition of inorganic acid solution; next, the mixture is evaporated, water is added and the mixture is extracted with ethyl acetate to isolate the product; …show more content…
Hardee and his group developed a process of activation of aliphatic carboxylic acids taking 3, 3-dichlorocyclopropenes in presence of tertiary amine base , DIPEA (diisopropylethylamine)[22] FIGURE 3.3 ACTIVATION OF ALIPHATIC ACID Racemization is frequent in the course of coupling reaction at the C-terminal amino acid residue due to the ionization of the α-hydrogen atom and formation of an oxazolone intermediate in peptide synthesis, so of course this will not reagent of choice in peptide synthesis, where suitable peptide coupling reagent can be selected, which is out of scope of this review.[22] 3.2 SELECTED PROCESS Out of all the processes mentioned in the survey, these processes were selected on the behalf of having most appropriate reaction conditions and environment of the research lab, i.e modification with …show more content…
in the first step benzoic acid was reacted with excess of thionyl chloride using acetonitrile as a solvent and keeping the mixture on an ice bath for 3-4 hours (labeled as reaction mixture a) In the second step gemcitabine hydrochloride along with 3eq tri-ethyl amine and using ethanol again as a solvent was stirred for 15-20 minutes without ice-bath. next with a poisterizing tube the reaction mixture a was drop wise added to reaction mixture b yielding a third and final, reaction mixture c giving off white fumes of socl2. it is stirred for 19 hours and 15minutes at 80c and colour changes to light yellow The preparation of benzoyl chloride from benzoic acid using thionyl chloride at 0’c is an in-situ preparation procedure: FILTERATION: Evaporate reaction mixture and dissolved in hexane and then filter it. The best TLC system for filterate is ethyl acetate : hexane , 4.5:0.5 3.3.2 PROCESS 2 FIGURE 3.5ACETYL DERIVATIVE PROCEDURE In 75mg of gemzar, 2ml ethanol is added and then solubility is checked. After 5 minutes add 0.1 ml (5 drops) DMF, then add 0.104ml Et3N and add 0.036 ml acetyl chloride and stirr it for 17 hours r at 47C