541508-62-7Relevant academic research and scientific papers
(3aS, 6aR)-1, 3-dibenzyl-tetrahydro -4H-thieno [3, 4-d] imidazole -2, 4-(1H)-dione simple method for preparing
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, (2016/12/01)
The invention relates to a simple preparation method for (3aS,6aR)-1,3-dibenzyl-tetrahydro-4H-thieno[3,4-d]imidazole-2,4-(1H)-dione. The method comprises the following steps: with L-cysteine methyl/ethyl ester hydrochloride as a starting raw material, carrying out N-benzyl protection, ester group reduction and mercapto protection so as to obtain (R)-2-benzylamino-3-acetylmercapto-propanol; then carrying out oxidation with sulfur trioxide-pyridine so as to prepare aldehyde; reacting aldehyde with benzylamine and sodium cyanide so as to prepare (2R,2S),(3R)-dibenzylamino-4-acetylmercapto-n-butyronitrile; carrying out amidation and deprotection cyclization so as to obtain (3aS,6aR),(3aR,6aR)-1,3-dibenzyl-tetrahydro-4H-thieno[3,4-d]imidazole-2,4-(1H)-dione; and carrying out thermal arrangement so as to obtain (3aS,6aR)-1,3-dibenzyl-tetrahydro-4H-thieno[3,4-d]imidazole-2,4-(1H)-dione. The method has the advantages of cheap and easily available raw materials, easily operable reaction conditions, high reaction selectivity, low cost and applicability for industrial production.
A practical synthesis of (+)-biotin from L-cysteine
Seki, Masahiko,Hatsuda, Masanori,Mori, Yoshikazu,Yoshida, Shin-Ichi,Yamada, Shin-Ichi,Shimizu, Toshiaki
, p. 6102 - 6110 (2007/10/03)
α-Amino aldehyde 4, which is readily derived from L-cysteine through cyclization and elaboration of the carboxy group, was subjected to the Strecker reaction, which, via sodium bisulfite adduct 16, afforded α-amino nitrile 5 with high diastereose-lectivity (syn/anti = 11:1) and in high yield. Amide 6, derived from 5, was converted to thiolactone 8, a key intermediate in the synthesis of (+)-biotin (1), by a novel S,N-carbonyl migration and cyclization reaction. The Fukuyama coupling reaction of 8 with the zinc reagent 21, which has an ester group, in the presence of a heterogeneous Pd/ C catalyst allowed the efficient installation of the 4-carboxybutyl chain to provide 9. Compound 9 was hydrogenated and the protecting groups removed to furnish 1 in 10 steps and in 34 % overall yield from L-cysteine.
INTERMEDIATE FOR BIOTIN AND PROCESS FOR PRODUCING THE SAME
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Page 21, (2008/06/13)
The present invention is to provide a process for preparing a synthetic intermediate of biotin which is industrially advantageous, and discloses a process for preparing a compound represented by the formula (I) : ???wherein R1 and R2 may be the same or different from each other, and each represents hydrogen atom, a benzyl group which may have a substituent(s) on the benzene ring, a benzhydryl group which may have a substituent(s) on the benzen ring, or a trityl group which may have a substituent(s) on the benzene ring, R3 represents cyano group, carboxyl group, an alkoxycarbonyl group, an alkylthiocarbonyl group, or a carbamoyl group which may have a substituent, or a salt thereof which comprises subjecting a compound represented by the formula (II-a) : ???wherein the symbols have the same meanings as defined above, or a salt thereof to ring transformation.
2-Thiazolidinone: A novel thiol protective surrogate of complete atom efficiency, a practical synthesis of (+)-biotin
Seki, Masahiko,Kimura, Mayumi,Hatsuda, Masanori,Yoshida, Shin-Ichi,Shimizu, Toshiaki
, p. 8905 - 8907 (2007/10/03)
2-Thiazolidinone derivatives were shown to be novel protective surrogates of a thiol group in L-cysteine derivatives. After elaboration at the C-4 substituent, the thiol group was completely liberated by simple heating in DMF whose atom efficiency is 100%. A practical synthesis of (+)-biotin was accomplished by the use of the strategy employing 4-functionalized 2-thiazolidinone derivatives as the intermediates, allowing a synthesis of (+)-biotin in 10 steps and in 31% overall yield. Short steps, high yield, and ease of operation of the present approach would permit the hitherto most efficient access to (+)-biotin.
