A kinetic study of candida rugosa lipase-catalyzed synthesis of 4,6-dimethyl-3-cyano-2-pyridone

Abstract

A síntese da 4,6-dimetil-3-ciano-2-piridona foi estudada na reação catalisada pela lipase de Candida rugosa. A metodologia de superfície de resposta (MSR) foi aplicada para a otimização das condições experimentais. O estudo mostrou que a temperatura e a razão molar cianoacetamida/ acetilacetona têm grande influência sobre o rendimento da reação. O rendimento máximo foi obtido a 44o C e razão molar cianoacetamida/acetilacetona igual a 36. A cinética da síntese enzimática da 4,6-dimetil-3-ciano-2-piridona foi investigada, e foi determinado que o mecanismo ping-pong bi-ter com inibição da cianoacetamida é coerente com os resultados obtidos. O mecanismo da reação catalisada pela Lipase foi proposto.The synthesis of 4,6-dimethyl-3-cyano-2-pyridone was studied in a reaction catalyzed with Candida rugosa lipase. A response surface methodology (RSM) was applied for the optimization of the experimental conditions. The study showed that temperature and molar ratio cyanoacetamide/ acetylacetone have a great influence on the yield of the reaction; the maximum yield was achieved at 44 °C with a molar ratio cyanoacetamide/acetylacetone of 36. The kinetics of the enzymatic synthesis of 4,6-dimethyl-3-cyano-2-pyridone was investigated, and it was determined that a pingpong bi-ter mechanism with cyanoacetamide inhibition fits the obtained results. The mechanism of lipase-catalyzed reaction was proposed.

Enzymatic synthesis of vitamin B6 precursor

“…29 The assumed reaction mechanism is schematically presented in Fig. The high value of K s,A /K s,B (109.6) indicates that the lipase from C. rugosa has a higher affinity towards the 1,3-diketone compared to 2-cyanoacetamide, which was also observed in a previous study.…”

“…29 3-Cyano-4-(ethoxymethyl)-6-methyl-2-pyridone was isolated by filtration and purified using Akta Purifier HPLC equipped with a fraction collector. The enzyme (1.2 % w/v) was added to the freshly prepared reaction mixture and incubated on a shaker at 150 rpm at 50 °C.…”

“…29 A graphical illustration of the proposed mechanism is given in Fig. The value of local maximum rate increased as the fixed concentration of 2-cyanoacetamide increased up to 2.4 mol dm -3 .…”

“…Due to their ability to utilize a variety of substrates, lipases are very important and increasingly employed enzymes in a large number of fields, such as in the food, textile, dairy, cosmetics, and pharmaceutical industries. In a previous work, 29 the condensation of 2-cyanoacetamide and 2,4-pentanedione was optimized using the response surface methodology (RSM). [21][22][23] Moreover, their high enantio-and regio-selectivity are extremely important in the production of key intermediates for organic and medicinal chemistry.…”

Synthesis of 4,6-dimethyl-3-cyano-2-pyridone catalysed by amino acids

“…Pored hemijske sinteze u literaturi je opisana i enzimska sinteza 3-cijano-2-piridona čime su prevaziđeni nedostaci poput produženog zagrevanja na povišenim temperaturama, upotrebe jakih baza, neselektivnosti u slučaju asimetričnih dikarbonilnih jedinjenja i nastajanja sporednih proizvoda. Kao enzim korišćena je lipaza iz Candida rugosa, a dialkil-i aril-metil-supstituisani 3-cijano-2-piridoni sintetisani su u vodenoj sredini na temperaturi od 40 o C. Dobijeni su prinosi piridona od 60 do 99,8 %, a ispitivanjem je potvrđeno da se u slučaju nesimetričnih 1,3-diketona dobija isključivo jedan izomer kod kojeg je voluminoznija alkil-grupa u položaju 4 piridonovog prstena [21][22][23][24][25]. Od značaja je istaći enzimsku sintezu 4-etoksimetil-6-metil-3-cijano-2-piridona iz etoksiacetilacetona i cijanoacetamida.…”