This article presents the results of obtaining an alkene derivative of chitin from a chitin biopolymer. Chitin from a crab shell was used for the reaction in the work. The reaction was carried out in the presence of EDC, NHS, and DMAP. Acrylic acid was first used to introduce a double bond into the chitin molecule. It was found that at 20-40°C the reaction does not occur, and at 50°C the reaction follows the Michael reaction path. Then, using the same method, a reaction was carried out with but-3-enoic acid. Using a less electrophilic acid, the expected compound was obtained The article concludes that to obtain an alkene derivative of chitin, it is necessary to use a less electrophilically activated acid to ensure the reaction proceeds in the desired direction. The structure of the compound was identified using nuclear magnetic resonance.