57378-70-8

The invention provides a preparation method for preparing d-biotin by removing N-benzyl by Lewis acid, which comprises the following steps: removing dibenzyl from a dibenzyl biotin solution and Lewisacid in an anhydrous organic solvent under the protection of inert gas by one-step reaction to obtain d-biotin with the total yield of 90% or above and the content of 99% or above, wherein the productmeets the European Pharmacopoeia EP10.0 standard.

Mycobacterium tuberculosis (Mtb) depends on biotin synthesis for survival during infection. In the absence of biotin, disruption of the biotin biosynthesis pathway results in cell death rather than growth arrest, an unusual phenotype for an Mtb auxotroph. Humans lack the enzymes for biotin production, making the proteins of this essential Mtb pathway promising drug targets. To this end, we have determined the crystal structures of the second and third enzymes of the Mtb biotin biosynthetic pathway, 7,8-diaminopelargonic acid synthase (DAPAS) and dethiobiotin synthetase (DTBS), at respective resolutions of 2.2 and 1.85 A. Superimposition of the DAPAS structures bound either to the SAM analogue sinefungin or to 7-keto-8-aminopelargonic acid (KAPA) allowed us to map the putative binding site for the substrates and to propose a mechanism by which the enzyme accommodates their disparate structures. Comparison of the DTBS structures bound to the substrate 7,8-diaminopelargonic acid (DAPA) or to ADP and the product dethiobiotin (DTB) permitted derivation of an enzyme mechanism. There are significant differences between the Mtb enzymes and those of other organisms; the Bacillus subtilis DAPAS, presented here at a high resolution of 2.2 A, has active site variations and the Escherichia coli and Helicobacter pylori DTBS have alterations in their overall folds. We have begun to exploit the unique characteristics of the Mtb structures to design specific inhibitors against the biotin biosynthesis pathway in Mtb.

A concise and efficient TEA-mediated desymmetrization of meso-thioanhydride 6 with 5-ethoxy-5-oxopentylzinc bromine has been developed, which affords a convenient strategy for the stereospecific total synthesis of (±)-biotin 1.

There is disclosed a process for producing hexahydro-2-oxo-1H-thieno[3,4-d]imidazole-4-pentanoic acid of the formula (2): which is characterized by contacting a compound of the formula (1): wherein R1and R2represent a hydrogen atom or a benzyl group, but R1and R2do not simultaneously represent a hydrogen atom, and R3represents a hydrogen atom or a carboxyl group, with sulfuric acid in the presence of an aromatic hydrocarbon.

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A total synthesis of (+/-)-biotin 1 based on the photochemical cycloaddition raection of 1,3-diacetylimidazolin-2-one 2 with 3,4-dihydro-2-methoxy-2H-pyran 3 is described.The photoadduct 4 was converted into the lactone 6, which bears the complete carbon framework and all the requisite stereochemical features, via hydrolysis, Wittig olefination, and catalytic hydrogenation to the cyclobutanol 5 followed by oxidative rearrangement.Subsequent conversion of the lactone to (+/-)-biotin followed from literature precedent (5).

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Biotin is prepared by (a) ozonizing methylcyclohexene; (b) reacting nitromethane with the methyl-6-oxohexanoate from a to form 7-nitro-6 hydroxyheptanoic acid methyl ester; (c) acylating to form the corresponding 6 acyloxy compound; (d) forming a double bond at the 6 position; (e) reacting the product of d with nitroethanethiol to form dl-7-thia-6-nitromethyl-9-nitro-nonanoic acid methyl ester; (f) forming a furoxan by cyclization; (g) reducing the furoxan and acylating to form dl-2(4-carbomethoxybutyl)-3,4-bis(acylamido)-2,5-dihydro thiophene; (h) selectively hydrogenating to form the 3,4-cis-bis(acylamido)-2,5-dihydro thiophene; and (i) hydrolyzing and cyclizing to form dl-biotin. The products formed at steps (e)-(h) are novel, as are the individual steps (e), (f), (g), and (h).

A novel procedure for the preparation of biotin, using cysteine as the starting material is disclosed. This process results in the obtention of pure d-biotin thus obviating the need for a chemical resolution. Novel intermediates are also disclosed.

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A method of preparing racemic biotin comprises reacting 2,3,8,9-tetradehydrobiotin with triethylsilane and trifluoroacetic acid.

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