Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
  • C07C45/29—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation of hydroxy groups
  • C07C45/296—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation of hydroxy groups with lead derivatives
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C35/00—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a ring other than a six-membered aromatic ring
  • C07C35/22—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a ring other than a six-membered aromatic ring polycyclic, at least one hydroxy group bound to a condensed ring system
  • C07C35/23—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a ring other than a six-membered aromatic ring polycyclic, at least one hydroxy group bound to a condensed ring system with hydroxy on a condensed ring system having two rings
  • C07C35/32—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a ring other than a six-membered aromatic ring polycyclic, at least one hydroxy group bound to a condensed ring system with hydroxy on a condensed ring system having two rings the condensed ring system being a (4.3.0) system, e.g. indenols
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C401/00—Irradiation products of cholesterol or its derivatives; Vitamin D derivatives, 9,10-seco cyclopenta[a]phenanthrene or analogues obtained by chemical preparation without irradiation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
  • C07C45/30—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with halogen containing compounds, e.g. hypohalogenation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C47/00—Compounds having —CHO groups
  • C07C47/20—Unsaturated compounds having —CHO groups bound to acyclic carbon atoms
  • C07C47/26—Unsaturated compounds having —CHO groups bound to acyclic carbon atoms containing hydroxy groups
  • C07C47/267—Unsaturated compounds having —CHO groups bound to acyclic carbon atoms containing hydroxy groups containing rings other than six-membered aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C47/00—Compounds having —CHO groups
  • C07C47/20—Unsaturated compounds having —CHO groups bound to acyclic carbon atoms
  • C07C47/277—Unsaturated compounds having —CHO groups bound to acyclic carbon atoms containing ether groups, groups, groups, or groups
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/55—Design of synthesis routes, e.g. reducing the use of auxiliary or protecting groups

Definitions

• This invention relates to the synthesis of 1 ⁇ -hydroxyvitamin D compounds. More specifically, this invention relates to a process for generating key intermediates for the preparation of 1 ⁇ -hydroxyvitamin D compounds.
• 1 ⁇ -hydroxylated vitamin D metabolites are well-known regulatory agents. Particularly important in this regard is 1 ⁇ ,25-dihydroxyvitamin D 3 (1,25-(OH) 2 D 3 ), the natural hormonal form for the maintenance of calcium homeostasis in vivo, but a variety of other 1 ⁇ -hydroxyvitamin D derivatives (e.g. 1 ⁇ -hydroxyvitamin D 3 , 1 ⁇ -hydroxyvitamin D 2 , 1 ⁇ ,25-dihydroxy- vitamin D 2 ) , and certain fluorinated analogs, also exhibit potent calcemic activity. All of these compounds are of great practical importance as therapeutic agents for the treatment of a variety of calcium balance disorders, e.g.
• the known methods of synthesis of 1 ⁇ -hydroxyvitamin D compounds are of three types, namely a) synthesis from a suitable steroid precursor, b) synthesis from a vitamin D precursor, i.e. by direct hydroxylation at carbon 1, and c) total synthesis of the desired vitamin D compound from simple precursors, generally involving the coupling of a unit representing ring-A of the desired vitamin to a suitable partner representing the C/D-ring portion so as to generate the complete vitamin D structure and characteristic triene chromophore.
• a) synthesis from a suitable steroid precursor i.e. by direct hydroxylation at carbon 1
• c) total synthesis of the desired vitamin D compound from simple precursors generally involving the coupling of a unit representing ring-A of the desired vitamin to a suitable partner representing the C/D-ring portion so as to generate the complete vitamin D structure and characteristic triene chromophore.
• the protected alcohol of structure A below (representing ring-A of the vitamin molecule) is initially prepared and is then, after conversion to the Wittig reagent B, condensed with the separately synthesized ketone C (where in this case, R represents the side-chain of 25-hydroxycholesterol) to obtain the 1 ⁇ ,25-(OH) 2 D 3 -derivative.
• the crucial ring A-1,3-diol unit (structure A, below) is synthesized from the monoterpene d-carvone in a procedure involving twelve synthetic steps.
• a new method for preparing of ring A-diol units suitable for the synthesis of 1 ⁇ -hydroxyvitamin D compounds has been developed.
• the method specifically provides the ring A-1,3-diol unit having the general structure shown below:
• each of R 1 and R 2 represent hydrogen or a hydroxy- protecting group
• X is a hydroxymethyl (-CH 2 OH) or a carboxaldehyde (-CHO) group.
• 1 ⁇ -Hydroxy-ring-A units, where X is a hydroxyethyl group can be used for the synthesis of any desired 1 ⁇ -hydroxyvitamin D compounds, by condensation with the appropriate C/D-ring fragment as demonstrated by Baggiolini et al. (supra).
• a suitable partner i.e. by Wittig, Grignard or aldol-type reactions
• hydroxy-protecting group signifies any group commonly used for the temporary protection of hydroxy functions.
• groups are, for example, acyl groups of 1-5 carbons, in all isomeric forms, or aroyl groups, such as benzoyl or halo, nitro- or alkyl-substituted benzoyl groups, or alkylsilyl groups (such as trimethylsilyl, triethylsilyl, t-butyl- dimethylsilyl, etc.) or ether-protecting groups such as tetrahydropyranyl, tetrahydrofuranyl, methoxymethyl, methoxyethyl, methoxyethoxymethyl and related groups.
• a "protected hydroxy” group therefore, is a hydroxy function derivatized with one of these protecting groups.
• An “alkyl” group is a hydrocarbon radical of 1 to 5 carbons in all isomeric forms.
• the preparation of the above-shown ring A-synthons comprises the steps shown in Process Scheme I.
• the starting material is a 1 ⁇ -hydroxyvitamin D compound, represented by the general structure in Process Scheme I, where each of R 1 and R 2 represent hydrogen or a hydroxy-protecting group and where
• R can be any compatible side-chain group, which may, for example, have the general structure shown below:
• R 3 and R 4 independently represent hydrogen, hydroxy or a protected hydroxy group, where R 5 represents hydrogen, hydroxy, protected hydroxy or an alkyl group, and where R 6 and R 7 represent hydrogen, hydroxy, protected hydroxy or, taken together, form a carbon-carbon bond.
• Preferred starting materials are 1 ⁇ -hydroxyvitamin D 3 or 1 ⁇ -hydroxyvitamin D 2 or their hydroxy-protected derivatives. These starting material are readily available by known processes.
• the starting material of structure is dihydroxylated at carbons 7 and 8 to obtain the 7,8-diol derivative (see Process Scheme I), where R, R 1 and R 2 have the meaning as defined above.
• a suitable oxidant for the introduction of the hydroxy groups is osmium tetroxide. This reaction is conducted in an organic solvent, and at a temperature of from ca. 0°C to about 50°C. Under such conditions the 7,8-vicinal diol 2 is formed as the major product and it is noteworthy that there is little or no attack by the oxidant on the other available double bonds of the triene system, e.g. the 5,6- or 10,19-double bonds.
• the 1 ⁇ -hydroxyvitamin D 7,8-diols of general structure are new compounds.
• Three vitamin D 7,8-diols, but lacking the crucial 1 ⁇ -hydroxy-function, namely the 7,8-diols of vitamin D 2 and D 3 and the 7,8-diol of 25-hydroxyvitamin D 3 have been prepared previously (Lythgoe, Chem. Soc. Rev. 9, 449 (1980); Toh and Okamura, J. Org. Chem.43, 1414 (1983); and DeLuca et al. U.S. Patent 4,448,726).
• the next step of the process comprises the cleavage of the 7,8-diol function in compound so as to obtain the aldehyde of general structure where R 1 and R 2 have the meaning as defined above (see Process Scheme I).
• the cleavage of the 7,8-diol can be accomplished with diol cleavage reagents.
• Effective reagents are, for example, periodate salts, or lead tetracetate.
• the reaction is conducted in an organic solvent (e.g. an alcoholic solvent or a hydrocarbon or ether solvent) at a temperature from about 0°C to about 50°C.
• the desired aldehyde of structure 3 can be isolated from the reaction mixture by chromatography. Products of structure , containing the synthetically very useful, but also chemically sensitive and reactive conjugated aldehyde group, are new compounds.
• the other product resulting from 7,8-vicinal diol cleavage is the fragment corresponding to rings C and D plus side-chain of the original vitamin D-starting material.
• This CD-ketone if desired, can also be isolated and purified by chromatography, but for the purposes of the present invention, the material is simply removed as a side product.
• the alcohol of structure where R 1 and R 2 represent hydrogen or a hydroxy-protecting group can then be used (as illustrated by the report of Baggiolini et al., supra) for the synthesis of any desired 1 ⁇ -hydroxyvitamin D compound by coupling this unit (e.g. via Wittig-type reactions) with a suitable partner representing rings C and D of the desired vitamin product.
• the aldehyde of structure in addition to being an intermediate to alcohol , can serve directly as a building block for the ring
• A-unit of 1 ⁇ -hydroxyvitamin D compounds by condensing it with a suitable C/D-ring fragment, via standard and conventional coupling reactions, such as the Wittig reaction, the Grignard reaction, or by aldol condensation.
• the above-described process provides a convenient method for generating a 1 ⁇ -hydroxy ring A unit in the form of aldehyde or of alcohol 4, and this unit can then be used as a synthetic building block for the preparation of a broad range of desirable 1 ⁇ -hydroxyvitamin D metabolites and analogs according to known methods.
• a notable feature of the present process is that it provides either aldehyde 3 or alcohol 4 .
• a further advantage is that the stereochemistry of all substituents in the 1 ⁇ -hydroxy-ring A units of type 3 or 4 is exactly known and defined by the starting material used, and that these starting materials required for the above process are readily available, e.g. in the form of 1 ⁇ -hydroxyvitamin
• D 3 or 1 ⁇ -hydroxyvitamin D 2 or their hydroxy-protecting derivatives i.e. the compounds represented by structure 1 in the process scheme, where R is the side-chain of cholesterol and ergosterol, respectively.
• R is the side-chain of cholesterol and ergosterol, respectively.

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• Chemical & Material Sciences (AREA)
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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (4)

• 1985
  • 1985-06-10 US US06/743,129 patent/US4755329A/en not_active Expired - Lifetime
• 1986
  • 1986-05-20 AU AU59511/86A patent/AU598469B2/en not_active Expired
  • 1986-05-20 EP EP19860903850 patent/EP0225915A4/en not_active Withdrawn
  • 1986-05-20 JP JP61503063A patent/JPS63500033A/ja active Granted
  • 1986-05-20 WO PCT/US1986/001088 patent/WO1986007364A1/en not_active Ceased
  • 1986-05-23 CA CA000509865A patent/CA1304389C/en not_active Expired - Lifetime
  • 1986-06-09 IE IE152686A patent/IE58441B1/en not_active IP Right Cessation
  • 1986-06-09 GB GB8613945A patent/GB2178424B/en not_active Expired
• 1987
  • 1987-02-03 DK DK054787A patent/DK54787D0/da not_active Application Discontinuation
• 1992
  • 1992-09-30 JP JP4283646A patent/JPH0662558B2/ja not_active Expired - Lifetime
• 1996
  • 1996-01-23 JP JP8028614A patent/JP2741497B2/ja not_active Expired - Lifetime

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