Application of acylation agent, such as benzoyl chloride, acetic anhydride, and
p-nitrobenzoyl chloride, to the thiol-type vitamin B
1 respectively yielded crystals of m. p. 173-174° (decomp.) (VII), m. p. 122-123° (decomp.) (VIII), and m. p. 135° (decomp.) (IX). These compounds gave negative thiochrome reaction but the reaction became positive after treatment with acid or alkali. From such facts and from their elemental analytical values, they were respectively assumed as 2-methyl-4-amino-5-[N-(3′-benzoylmer-capto-5′- benzoy-Δ
2′-pentenyl-2′)]-formaminomethylpyrimidine (VII), (O, S-dibenzoyl B
1) 2-methyl-4-amino-5-[N-(3′-acetylmercapto-5′-acetoxy-Δ
2′-pentenyl-2′)]-formaminomethyl-pyrimidine (VIII) (O, S-diacetyl B
1), and 2-methyl-4-amino-5-[N-(3′-
p-nitrobenzoylmercapto-5′-hydroxy-Δ
2′-pentenyl-2′)]-formaminomethylpyrimidine (IX) (S-
p-nitrobenzoyl B
1). These compounds were tested for the prevention of B
1-deficiency in
Uroloncha domestica and were found to have almost equal efficacy as vitamin B
1. It was also found that the absorption of (VII) and (VIII) through the alimentary canal was better compared to vitamin B
1. Since (VIII) is easily formed from vitamin B
1 and
vice versa, it may be assumed that, as a part of biochemical actions of vitamin B
1, the pyrophosphate of S-acetyl B
1 undergoes transacetylation and acetylates coenzyme A to form acetylcoenzyme A.
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