Studies on Vitamin B₁ and Its Related Compounds. XIV

Volatile products formed from the thermal degradation of thiamin at high and low moisture levels

“…Furans were found in greater quantity and number in the water system. This is in agreement with previous work (Hartman et al, 1984) and is supported by other works (Matsukawa et al, 1951; van der Linde et al, 1979) that suggest water is required for production of 3-mercapto-5hydroxy-2-pentanone and its subsequent formation of furans.…”

“…In agreement with previous work with thiamin as a reaction component, acetic acid, ethyl acetate, acetol acetate, 2-pentanone, and 2,3-pentanedione were either produced in a higher quantity or only formed in the water system (Hartman et al, 1984). The presence of pentanones only in the water system supports the view that water is required for production of 3-mercapto-5-hydroxy-2-pentanone, the likely precursor of the pentanones identified (Matsukawa et al, 1951). The chlorinated pentanones are most likely unreacted synthetic intermediates of thiamin.…”

Reaction mechanisms of thiamine with thermostable factors.

“…On the other hand, about 70% was thiamine disulfide in the reaction mixture of thiamine and Factor 2; Pm-CH2-NH2 was difficult to detect from the mixture on the paper partition chromatogram. and caffeic acid or catechol, strongly supports the presumption that the mechanism in this case is the same as that described by MATSUKAWA et al (11) . On the other hand, there are also many factors in nature, such as flavonoids, which ac celerate mainly or partly the oxidation of thiamine into thiamine disulfide, as indicated in the case with 6, 7, 4'-trihydroxyisoflavone, quercetin and rutin.…”

Identification and synthesis of new odor compounds from photolysis of thiamin

“…However, this scheme does not account for the formation of the compounds we isolated from thiamin photolysis; therefore, we propose the mechanism shown in Scheme V. The first step in thiamin degradation is proposed to be the disruption of the C-Nand C-Sbonds resulting in compound 18, which can be considered as the key intermediate in the formation of all degradation products. Formation of this compound in heated thiamin solutions is demonstrated by Matsukawa et al (1951). The same intermediate was proposed in the thermal degradation of thiamin (van der Linde et al, 1978); thus, the first degradation step may be the result of a photochemical or a hydrolysis reaction.…”