Degradation Products Formed from Glucosamine in Water

Abstract

An aqueous solution of glucosamine hydrochloride was heated to 150 °C for 5 min under different pH conditions. The reaction product mixture obtained was analyzed by GC/MS. It was found that the major products formed were furfurals, especially at pH = 4 and 7. At pH = 8.5, additional flavor components were generated, including pyrazines, 3-hydroxypyridines, pyrrole-2-carboxaldehyde, furans, acetol, and several other compounds. Of the components identified, it is worthwhile to note the formation of pyrazine and methylpyrazine as major components at pH = 8.5. It is proposed that a retro-aldol condensation plays an important role in the formation of the intermediates, α-aminoacetaldehyde (I) and α-amino propanal (II). As a result, self-condensation of I generates pyrazine and combination of I and II generates methylpyrazine. In addition, it is also interesting to note the formation of 3-hydroxypyridines and pyrrole-2-carboxaldehyde. It is suggested that both groups of compounds are derived from furfurals. As the ammonia is liberated from glucosamine, it initiates the ring-opening of furfurals to form 5-amino-2-keto-3-pentenals. Intramolecular condensations of these intermediates between the amino group and the carbonyl groups lead to the formation of 3-hydroxypyridines and pyrrole-2-carboxaldehyde. Keywords: Glucosamine; retro-aldol condensation; α-amino acetaldehyde; α-amino propanal; GC/MS

A Model Study to Unravel the Complexity of Bio‐Oil from Organic Wastes

“…[36][37][38] In this way, several interaction products are formed that are mainly related to substituted pyridines andp yrroles. [42][43][44][45] These compounds may also be generated through the condensation of aldehydes, ketones or a,bunsaturated carbonylic compounds with ammonia. [39][40][41] Pyridines are likely formed through aM aillard-type reaction that involves acarbonyl group of afurfural derivatives and ammonia (derived from carbohydratesa nd from protein degradation, respectively) according to the proposed mechanisms shown in Scheme 2.…”

“…[39][40][41] Pyridines are likely formed through aM aillard-type reaction that involves acarbonyl group of afurfural derivatives and ammonia (derived from carbohydratesa nd from protein degradation, respectively) according to the proposed mechanisms shown in Scheme 2. [42][43][44][45] These compounds may also be generated through the condensation of aldehydes, ketones or a,bunsaturated carbonylic compounds with ammonia. [46] Pyrroles can be formed through three major pathways: (i)Strecker degradation between an amino acid and 3-deoxyhexosone followed by dehydration and ring closure; [47] (ii)conjugation of furan derivatives( with ac arbonyl function in the 2position) with amines or amino acids (Scheme 2); [48] (iii)Knorr condensation of a-aminocarbonyls with ketoneso ra ldehydes.…”

General Protocol to Obtain D‐Glucosamine from Biomass Residues: Shrimp Shells, Cicada Sloughs and Cockroaches

“…Therefore, D‐glucosamine and its salts are employed in dietary supplement products, which have demonstrated positive effects on the treatment of osteoarthritis, knee, and back pain . In the context of sustainable chemistry, D‐glucosamine was recently proposed as a renewable precursor for the preparation of valuable specialty chemicals, such as 5‐(hydroxymethyl)furfural and other furfural derivatives …”

“…[41][42][43] In the context of sustainable chemistry, D-glucosamine was recently proposed as a renewable precursor for the preparation of valuable specialty chemicals, such as 5-(hydroxymethyl)furfural and other furfural derivatives. [17,44,45] The use of co-solvents during the acidic hydrolysis has been proposed as a strategy to decrease the concentration of corrosive acids used during chitin hydrolysis. Recently, Zhang and Yan demonstrated that using diethylene glycol diethyl ether as co-solvent provided glucosamine in 80% yield of from pure chitin using low concentration of sulfuric acid at 175 °C, for 1 h. [46] Having in mind the importance of obtaining D-glucosamine from renewable sources, this work describes the isolation of pure D-glucosamine from three biomass residues: shrimp shells, cicada sloughs, and cockroaches, using a general protocol that works for all chitin sources tested.…”

The effect of solvents on the thermal degradation products of two Amadori derivatives

“…Davidek et al 15 studied the effects of phosphate ions on the degradation products of 1-L-glycine-1-deoxy-Dfructose, and the results showed that the addition of phosphate ions could accelerate the degradation processes. Shu et al 16 reported that at a pH of 8.5, the major products formed from the degradation of glucosamine were pyrazine and methylpyrazine. Hofmann et al 17 reported that the formation of phenylacetaldehyde was favored during the degradation of 1-Lphenylalanine-1-deoxy-D-fructose catalyzed by ambient oxygen.…”