Vladimir Rapić

Ferrocene compounds ☆: Part XXXIII. Synthesis and characterization of amino acids containing skeletal 1,1′-ferrocenylene unit

Abstract The syntheses of 1′-(3-aminopropyl)ferrocene-1-carboxylic acid (7), 1′-amino-1-ferrocenebutyric acid (14) and their derivatives are reported. Reactions of 1′-methoxycarbonyl-1-ferrocenebutyric acid (3) or methyl 1′-carboxy-1-ferrocenebutyrate (10) with ethyl chloroformate/triethylamine/sodium azide gave methyl 1′-(3-azidocarbonylpropyl)ferrocene-1-carboxylate (4) and methyl 1′-azidocarbonyl-1-ferrocenebutyrate (11). These azides were rearranged by heating in acetic anhydride and hydrolyzed into N-acetyl derivatives of 7 and 14. The crucial intermediates 4 and 11 were transformed by the action of t-BuOH into Boc-7 and Boc-14. The crystal and molecular structures of the intermediates methyl 1′-(3-acetamidopropyl)ferrocene-1-carboxylate (5) and tert-butyl 1′-(3-methoxycarbonylpropyl)-1-ferrocenecarbamate (15) have been determined by the single crystal X-ray analysis. Compound 5 crystallizes in two polymorphic forms (5a and 5b); one of them (5b) contains two crystallographically independent molecules. The molecules 5a and 5b differentiate only in the conformation of (CH2)3NHAc part of the molecules exhibiting conformational polymorphism. The crystal structure is dominated by the intermolecular hydrogens bonds of NH⋯O type (2.820(1)–2.840(2) A) linking molecules into endless chains in all three structures. The chains are further interconnected by the CH⋯O hydrogen bonds (3.483(1)–3.267(2) A) in 5a and 15, but not in 5b.The structural features of 5 and 15 determined by the single crystal X-ray analysis, reveal existence of intermolecular hydrogens bonds of NH⋯O type (2.820(1)–2.840(2) A).

Stereochemie von Metallocenen, 40. Mitt.@@@Stereochemistry of metallocenes, 40; Ferrocenederivatives, 61: Preparation and chiroptical properties of optically active, α- and β-disubstituted ferrocenes of known chirality and enantiomeric purity for applying the theory of chirality functions: Darstellung und chiroptische Eigenschaften optisch aktiver, α- und β-disubstituierter Ferrocene bekannter Chiralität und enantiomerer Reinheit zur Anwendung der Theorie der Chiralitätsfunktionen

Starting from optically active methylferrocene-α- and-β-carboxylic acids (1 a and1 b) of known absolute configuration and enantiomeric purity about 15 chiral ferrocenes (of each isomeric series—α and β) were obtained by suitable ligand transformations. Thereby (almost) all possible chiral combinations of the ligands CH3, COOH (COO−), COOCH3, C≡N and NH2 (NH3+) were accessible which are necessary for a potential test of approximations of chirality functions for compounds with basic symmetry C5v. The chiroptical properties of these disubstituted ferrocenes are recorded.Preliminary tests using a shortened Ansatz revealed large discrepancies between calculated (χ) and found [M]D-values. Possible reasons for this failure are discussed.

Synthesis and Structure of Some 3, 4-Annelated Coumarin Systems

Refluxing of 4-chlorocoumarin-3-carbonitrile, heteroarylamines (3-aminopyrazole, 3-aminopyrazole-4-carbonitrile, 3-amino-1, 2, 4-triazole-5-thiol, 2-amino-6-fluorobenzothiazole, 2-amino-pyridin-3-ol, 1-aminoisoquinoline) and the catalytic amount of trimethylamine in acetonitrile gave the corresponding 3, 4-annelated coumarins 1-6 in high yields. The spectral analysis showed that 7-amino-5-oxa-7a, 8, 11-triazacyclopenta[b]phenantren-6-one (1) existed as enamine, 2 as a mixture of enamine 7-amino-6-oxo-5-oxa-7a, 8, 11-triazacyclopenta[b]phenantren-10-carbonitrile (2a) and imine 7-imino-6-oxo-7H, 8H-5-oxa-7a, 8, 11-triazacyclopenta[b]phenantren-10-carbonitrile (2b), whereas 10-fluoro-7-imino-7H-5-oxo-12-thia-7a, 13-diazaindeno[1, 2-b]phenantren-6-one (4), 11-hydroxy-7-imino-7H-7a, 12-diazabenzo[a]anthracen-6-one (5) and 7-imino-7H-5-oxa-7a, 14-diazadibenzo[a, h]anthracen-6-on (6) took imino forms.

Ferrocene compounds. XXV.* Synthesis and characterization of ferrocene-containing oligoamides, their precursors, and analogues

A general method for preparation of ferrocene-containing monoamines (5–7) and diamines (10, 11) starting from the corresponding quaternary ammonium iodide 3 and ferrocene mono- (4) and dithiaaliphatic acids (8, 9) was developed. Amines obtained have been characterized as acet- and benzamides (12–15). The oligoamide precursors (16, 17, 22, 23) were synthesized by reactions of succinic or glutaric anhydride with amines (6, 7, 10, 11). Their conversion into oligoamide analogs (20, 21, 25) failed. The desired diamides (20, 21) were prepared by condensation of amines (6, 7) with alkanedioyl chlorides, (CH2)n(COCl)2 (n = 0, 1, 2, 3). Reactions of diamine 10 with succinic or glutaric anhydride gave amino acids 28—formal monomers for the planned oligomerization. Oligomers 29 were synthesized by condensation of equimolar amounts of diamines 10 and the above mentioned alkanedioyl chlorides in dichloromethane at 0°C. The structure of oligomers 29 was indicated from their IR and 1H-NMR spectra in comparison with the model substances 12–28. The degree of polymerization of compounds 29 was determined by 1H-NMR end-group analysis (DPn = 4–6).

Ferrocenderivate LX. Rationelle synthesen der ferrocen-1,1′-dicarbonsäure sowie von isomeren methyl-, phenyl-ferrocen- und [3]ferrocenophan-mono- und -1,1′-di-carbonsäuren

Abstract Mono- or 1,1′-bis-acylation of ferrocene, its mono and 1,1′-dimethyl and phenyl derivatives and of [3]ferrocenophane with o -chlorobenzoyl chloride/AlCl 3 affords the corresponding (isomeric) chlorobenzoyl ferrocenes in high yields which can be separated by column, layer or high pressure liquid chromatography and in the case of the monomethylferrocene monoketones also by crystallization. The cleavage of the ( o -chlorobenzoyl)ferrocenes by potassium-t-butoxide (and traces of water) yields the corresponding ferrocene carboxylic acids except for the α-phenyl derivatives in almost quantitative yields, thus offering a very convenient access to these acids. In all cases the isomer distribution and thereby the relative site reactivities were determined.

A One-Pot Synthesis and Structure Determination of 3-(1-Phenyl-5-p-tolylpyrazol-3-yl)-2-p-tolylindole Ethanol Solvate

The Fischer indolization afforded the title compound C31H25N3·C2H5OH as the major product in the reaction of 1,5-di(p-tolyl)pentane-1,3,5-trione with phenylhydrazine hydrochloride in ethanol. The structure assignment of this novel pyrazolylindole derivative is based on the data of elemental analysis, IR, 1H NMR, and 13C NMR spectroscopy. The structure is also confirmed by means of X-ray crystallography. The molecule crystallizes in the orthorhombic space group P 212121, with a = 10.298(2), b = 14.984(5), c = 18.133(3) A, Z = 8, V = 2798.0(12) A3. The absolute structure has been determined. The ethanol molecule forms intermolecular hydrogen bonds with the pyrazole and indole nitrogen atoms.

FERROCENE COMPOUNDS XXIII. SYNTHESIS AND REACTIONS OF THE NEW TYPE OF METHYL FERROCYLOXYALKANOATES

The new types of ferrocenyloxaaliphatic acid ester, FcCHROCHR′COOMe (R = H, Me, Ph; R′ = H, Me) (7) have been prepared by the action of alkoxides derived from methyl glycolate or methyl lactate on the corresponding ferrocenylcarbinyl acetates (2) or N,N,N-trimethylferrocylammonium iodides (4). The esters obtained were accompanied by a small quantity of oligomeric esters, FcCHR(OCHR′CO)n OMe (9), and with more or less ferrocyl methyl ethers (8). As opposed to the alkaline hydrolysis of the analogous methyl benzoxyacetate (6) into benzoxyacetic acid (5) the acidification of sodium alkanoates 10 obtained by saponification of esters 7 gave unexpectedly the corresponding ferrocenylcarbinols 1. In a similar way the esters 7 were converted into mixtures of the mentioned carbinols and diferrocyl ethers 11 under action of aqueous hydrochloric acid. The mechanisms of the reactions 10 → 1 and 7 → 1, 11 are discussed.

Ferrocene compounds. XVII: Synthesis of some ferrocenyl carbinols, ethers, and ureas

Abstract Reduction of several aroylferrocenes ( 1 ) with sodium borohydride in methanol has given 20–64% yields of α-arylferrocenemethanols ( 2 ). Reaction of ferrocene with benzaldehyde in sulphuric acid at −10°C gave α-phenylferrocenemethanol ( 2b ) (29%) and bis[phenyl(ferrocenyl)methyl] ether ( 3a ) (35%), and similar reaction with tolualdehyde gave the corresponding carbinol 2e (21%) and the sym -ether 3b (42%). Condensations of the carbinols with methyl isocyanate gave N -[aryl(ferrocenyl)methyl]- N,N′ -dimethylureas ( 4 ) in 22–61% yields.

Ferrocene compounds XXII. Synthesis and reactions of some ferrocenylthiaaliphatic acids

Condensation of several ferrocenylcarbinols (1) with thioglycolic acid, β-mercaptopropionic acid or β-mercaptoisobutyric acid in the presence of trifluoroacetic acid have given the corresponding ferrocenylthiaaliphatic acids (2–4) with 65–99% yields. Instead of the expected intramolecularly cyclized products, reactions of the acids 2–4 with trifluoroacetic anhydride give 23–30% ofthe 1,2-disubstituted 1,2-diferrocenylethanes (8), 15–26% of trimeric species (9), and about 30% of oligomeric species (10). The mechanism of the reactions is discussed.

Ferrocene compounds: XI. Synthesis and cyclization of some ferrocenecarboxylic acids☆

Abstract The ferrocenecarboxylic acids FcCHC(CO 2 H)(CH 2 ) 1–2 CO 2 H (Fc = ferrocenyl) were converted in good yields, under the conditions of the Clemmensen reduction, to the saturated products FcCH 2 CH(CO 2 H)(CH 2 ) 1–2 CO 2 H. The possible course of these reactions, via the corresponding δ- or γ-lactones, is discussed. By the action of trifluoroacetic anhydride (or acetic anhydride) these ferrocenecarboxylic acids were converted into the corresponding cyclic anhydrides. The intramolecular Friedel-Crafts reaction of α-ferrocenylmethylglutaric anhydride gave the heteroannularly cyclized product 1,1′-[β-(2-carboxyethyl)-α-oxotrimethylene]ferrocene, and under the same conditions α-ferrocenylmethylsuccinic anhydride was converted into the homoannularly cyclized cyclopentadienyl(4,5,6,7-tetrahydro-5-carboxy-7-oxoindenyl)iron.