Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
  • C07D263/52—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems
  • C07D263/62—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems having two or more ring systems containing condensed 1,3-oxazole rings

Definitions

• the present invention relates to cyclic compounds, processes for their preparation, their use as complex ligands and complexes containing them.
• crown ethers can be used as multidental complexing agents. It is a class of planar macrocyclic polyethers. The oxygen atoms are often linked by ethylene bridges, with one or more benzene or cyclohexane rings being often fused on. The oxygen atoms of the crown ethers can also be partially or completely replaced by other heteroatoms such as nitrogen, phosphorus or sulfur. This gives, for example, aza, phosphate or thia crown ethers. There may also be polar groups which can assume the donor position.
• crown ethers known to date do not have a consistently suitable property profile for all complexation tasks. There is therefore still a demand for cyclic complex ligands which show new property profiles.
• the object of the present invention is to provide cyclic compounds which can preferably be used as complex ligands.
• XYZ N CO 1 , R 2 , R 3 H, C 1-6 alkyl.
• the radicals R, R 2 and R 3 can be chosen so that they do not hinder the cyclization reaction for the preparation of the compounds of the general formula (I).
• the radicals are each independently hydrogen atoms or C 1-3 alkyl radicals, particularly preferably hydrogen atoms or methyl radicals, in particular hydrogen atoms.
• cyclic compounds of the general formula (I) can be prepared by cyclization of compounds of the general formula (II)
• R 4 -COOH or a derivative thereof, n are each 1 or 2, to obtain the stoichiometry, R 1, R 2, R 3 H, Ci- ö alkyl.
• the radical R is a carboxylic acid radical or a derivative thereof.
• the derivative is preferably an acid chloride, an ester, an amide or another corresponding carboxylic acid derivative.
• Esters are preferably esters of lower alkanols such as C 1-4 alkanols.
• Amides are preferably derived from ammonia or primary alkylamines.
• the cyclization is preferably carried out by heating in polyphosphoric acid. As a rule, the process is carried out under a protective gas atmosphere (nitrogen).
• the compounds of the general formula (III) are preferably prepared by photochemical reaction of smaller precursor compounds. This is explained in more detail below using a preferred connection.
• the cyclic compounds of the general formulas (I) and (III) can be used for a large number of applications. They are preferably used as complex ligands.
• the invention also relates to corresponding complexes containing a complexed metal ion and at least one cyclic compound of the general formulas (I) and (III) as complex ligands.
• Preferred metal ions to be complexed are derived from alkali metals.
• cyclic compounds according to the invention there may also be other ligands which are customary in the field of complex chemistry.
• Compound (5) is in the form of a rigid and flat ring and is similar to a 16-crown-4 ether.
• compound (8) resembles a porphyrin system.
• the imidazoles are tautomeric, so that the hydrogen atom on nitrogen can change from position 1 to position 3 and back.
• a metal atom in the center of the compound (8) can be bonded by 4, 3, 2 or a covalent bond or without covalent bond.
• the most general process for the preparation of 2-R-benzoxazoles involves the condensation of a 2-aminophenol with a suitable carboxylic acid, acid chloride, ester, amide or other derivative of the carboxylic acid.
• a suitable carboxylic acid acid chloride, ester, amide or other derivative of the carboxylic acid.
• the amide (4) can be prepared from the precursor 2-hydroxy-3-nitrobenzamide (3).
• the desired compound (5) can be obtained in acceptable yields.
• the yield was 32%, the compound forming colorless crystals with an unexpectedly high melting point of 520 ° C.
• the substance is very slightly soluble in all organic solvents.
• the compound has the expected UV spectrum, with a maximum for the long wavelengths at 364 n in CHC1 3 .
• cyclo-2,4 ': 2, 7 "2"4'":2"', 7-quaterbenzimidazol (8) can be carried out in a manner similar to the preparation of (5).
• 2-amino-3-nitrobenzoic acid (6) in dilute ammonia can be catalytically reduced with H 2 / Pd, an ammonium salt of 2,3-diaminobenzoic acid (7) being obtained.
• This acid (7) can then be heated in polyphosphoric acid to obtain the cyclic compound (8).
• An unoptimized yield of 14.5% was found for the special compound (8).
• the compound (8) forms a yellow microcrystalline powder, the one still has lower solubility in organic solvents than the compound (5).
• the compound (8) can be sublimed at 630 ° C. and 6 ⁇ 10 "3 hPa. At normal pressure under nitrogen, the compound changes color from yellow to brown at a temperature between 700 ° C. and 750 ° C. This results in partial sublimation, however no melting was observed.
• the 1 H-NMR spectrum permits the unambiguous assignment of the aromatic protons which correspond to structure (8).
• the maximum for long wavelengths in the UV-vis spectrum is 393 nm (in DMSO) for the compound (8).
• Benzoxazole can be symmetrically photodehydrodimerized to form 2,2 'dibenzoxacolyl. This reaction takes place during irradiation in aerated polar solvents.
• 7,7 ': T, 2 ": 7", 7 "' - quaterbenzoxazole (13) can be prepared by irradiating a solution of (12) in methanol with light of a wavelength of 245 nm Solution in the form of colorless crystals with analytical purity.
• the solubility of compound (13) in methanol, ethanol and acetonitrile is ⁇ 10 " mol / 1.
• An improved solubility is given in chloroform and dimethylformamide.
• the synthesis of the compound (5) described above allows the individual benzoxazole units to be connected between positions 2 and 7.
• Isomeric molecules in the form of the compound (5) can also be prepared by appropriate synthetic methods using different starting materials or more units are connected between positions 2 and 4. As a result, the nitrogen atoms are directed towards the center of the molecule.
• the compounds (5) and (13) can also be replaced by corresponding compounds in which the benzoxazole units have been replaced by other benzo-x-azoles (8).
• UV Perkin-Elmer model 320
• the compound (2) used can be prepared from the free acid, as described in J. Het. Chem. 1971, 8, pages 989 to 91. At this point, both the preparation of esters and amides are described. It also describes how the nitro compound can be converted into the amino compound. Thus, other possible analogs of compounds (2), (3) and (4) are also described in this reference.
• the product was sublimed by sublimation at 630 ° C and 6 x 10 "3 hPa to obtain a yellow-green product.
• the substance slowly darkened at a temperature between 700 and 750 ° C without melting (when heated under nitrogen and at normal pressure), the process was accompanied by partial sublimation.
• UV (DMSO): ⁇ max (lg ⁇ ) 393 nm (3.99), 372s (4.24), 356s (4.78), 349 (4.82), 340 (4.87),
• 2-Amino-3-nitrobenzoic acid can be prepared as described in J. Med. Chem. 1990, 33, pages 814 to 819. This document also describes the further conversion to substituted benzimidazoles, see the reaction schemes on page 815. Substituted 2,3-diaminobenzoic acids are described on page 816 in Scheme II. Possible substituents are also mentioned in Table II, so that this document also describes the preparation of similar, substituted compounds.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)
• Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)

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• 2002
  • 2002-02-15 DE DE10206366A patent/DE10206366A1/de not_active Withdrawn
• 2003
  • 2003-02-14 US US10/503,587 patent/US20050159596A1/en not_active Abandoned
  • 2003-02-14 WO PCT/EP2003/001490 patent/WO2003068779A1/de not_active Ceased
  • 2003-02-14 JP JP2003567906A patent/JP2005525343A/ja not_active Withdrawn
  • 2003-02-14 EP EP03702641A patent/EP1476447A1/de not_active Withdrawn
  • 2003-02-14 AU AU2003205767A patent/AU2003205767A1/en not_active Abandoned

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