Reactions of organotin chlorides R2SnCl2 (R = Et, But, or Ph) with lithium 4,6-di( tert -butyl)- N -(2,6-diisopropylphenyl)- o -amidophenolate. Synthesis and structures of tin( IV ) o -iminoquinone complexes

The exchange reactions of tin diorganohalides R₂SnCl₂ (R = Et, Bu^t, or Ph) with lithium amidophenolate APLi₂ (AP is the 4,6-di(tert-butyl)-N-(2,6-diisopropylphenyl)-o-iminobenzo-quinone dianion) in tetrahydrofuran produced the new five-coordinate (Et₂SnAP(THF) (3)) and four-coordinate (R₂SnAP (R = Bu^t, Ph)) tin(IV) complexes. The reaction of Ph₂SnCl₂ with APLi₂ in a nonpolar solvent (hexane or toluene) is accompanied by the additional redox process giving rise to the paramagnetic complex Ph₂Sn(ImSQ)Cl (6) (ImSQ is the 4,6-di(tert-butyl)-N-(2,6-diisopropylphenyl)-o-iminobenzoquinone radical anion). The molecular structures of complexes 3 and 6 were established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 253–258, February, 2007.     

Synthesis,Characterization and Stability Constants of Polynuclear Metal Complexes

Unsymmetric tridentate ligands, 4-methyl-2,6-di(4-methyliminomethyl)phenol (HL¹), 4-(t-butyl)-2,6-di(4-methylphenyliminomethyl)phenol (HL²), 2,6-di(4-bromophenyliminomethyl)-4-methylphenol (HL³), 2,6-di(4-bromophenyliminomethyl)-4-(t-butyl)phenol (HL⁴), 2,6-di(4-hydroxyphenyliminomethyl)-4-methylphenol (HL⁵) and 4-(t-butyl)-2,6-di(4-hydroxyphenyliminomethyl)phenol (HL⁶), and their binuclear Cu^II, Co^II and Ni^II complexes were synthesized and characterized by elemental analysis, FT-IR, u.v.-vis spectrometry magnetic moments, ¹H(¹³C)-n.m.r. and mass spectral data. Also, the electrical conductivities of the complexes have been measured using 10-³ M solutions in MeCN. The complexes are weak electrolytes. In the electronic spectra of the complexes of the HL¹-HL⁶ ligands, the 480-410 nm band has been determined as the charge-transfer band. While the HL⁵ and HL⁶ ligands have five potential donor atoms, other ligands have only three. Protonation constants of the ligands have been studied in dioxan-water mixtures. In addition, the antimicrobial properties of the ligands and their metal complexes have been studied:Bacillus megaterium, Micrococcus luteus, Corynebavterium xenosis, Enterococcus faecalis, bacteria and Saccoramyces cerevisia, yeast. The keto-enol tautomeric equilibria of the ligands have been investigated in polar and non-polar solvents.     

Anionic polymerization of N-substituted maleimide. II. Polymerization of N-ethylmaleimide

Anionic polymerization of N-ethylmaleimide (N-EMI) was carried out with potassium t-butoxide, lithium t-butoxide, n-butyllithium, and ethylmagnesium bromide as initiators in THF and in toluene. An almost quantitative yield of poly(N-EMI) was obtained with potassium t-butoxide as initiator in THF in a wide range of polymerization temperatures. Initiators possessing lithium as counter cation produced poly(N-EMI) in slightly lower yields and ethylmagnesium bromide gave the polymer only in less than 35% yield in THF. As a polymerization reaction solvent, THF was preferable for the polymerization of N-EMI compared with toluene with respect to polymer yields. Poly(N-EMI) obtained with anionic initiators exerted unimodal molecular weight distribution. From ¹H- and ¹³C-NMR spectra of poly(N-EMI) anionic polymerization of N-EMI with potassium t-butoxide was revealed to proceed at carbon–carbon double bond. t-Butoxide system was found to have a “living” polymerization character, i.e., the observed average degree of polymerization was in good agreement with the one calculated from the initial molar ratio of N-EMI/initiator and the yield of polymer.     

On pyrrolidine derivatives I. An efficient synthesis of 3-substituted (2S,5S)-pyrrolidine-2, 5-dicarboxylic acids

(2S,5S)-3-Alkylpyrrolidine-2, 5-dicarboxylic acid derivatives I were stereoselectively synthesized by means of an efficient method starting from L-aspartic acid ( 1 ). Dieckmann reaction of 4-benzyl 1-t-butyl N-t-butyl-oxycarbonyl-N-ethoxycarbonylmethyl-L-aspartate ( 4 ) provided product 5 which consisted of a mixture of (2S,5S)- and (2R,5S)-1-t-butyloxycarbonyl-3-oxopyrrolidine-2, 5-dicarboxylates in a ratio of 95:5. Treating 1-t-butyl 6-ethyl 2-L-(t-butyloxycarbonyl)anuno-5-diazo-4-oxoadipate ( 8 ), prepared from 1 , with rhodium(II) acetate dimer also afforded a good yield of 5 . The Wittig reaction of 5 , followed by catalytic hydrogenation and then deprotection provided compound I .     

Potassium and sodium 2,6-di-tert-butylphenoxides and their properties

The crucial factor of the reaction of 2,6-di-tert-butylphenol with alkali hydroxides is temperature, depending on which two types of potassium or sodium 2,6-di-tert-butylphenoxides are formed. These types exhibit different catalytic activity in the alkylation of 2,6-di-tert-butylphenol with methyl acrylate. More active forms of 2,6-Bu^t ₂C₆H₃OK or 2,6-Bu^t ₂C₆H₃ONa are synthesized at temperatures higher than 160 °C and are predominantly the monomers, which dimerize on cooling. The data of ¹H NMR, electronic, and IR spectra for the corresponding forms of 2,6-Bu^t ₂C₆H₃OK and 2,6-Bu^t ₂C₆H₃ONa isolated in the individual state are in agreement with cyclohexadienone structure. In DMSO or DMF, the dimeric forms of 2,6-di-tert-butylphenoxides react with methyl acrylate to form methyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate in 64–92% yield. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2138–2143, December, 2006.     

Generation and Reactions of Lithiated tert-Butyl and 2,6-Di(tert-butyl)-4-methylphenyl Cyclopropanecarboxylates

tert-Butyl and 2,6-di(tert-butyl)-4-methylphenyl (BHT) cyclopropanecarboxylates ( 4 , 6 , 24 , 25 ) are lithiated with LiN(i-Pr)₂ and t-BuLi, respectively. Reactions with alkyl halides, aldehydes, acyl chlorides, and heteroelectrophiles give α-substituted BHT esters which can be cleaved (t-BuOK/H₂O/THF) to the corresponding carboxylic acids or reduced (LiAlH₄/THF) to the cyclopropanemethanols.     

On the chichibabin amination of pyrimidine and N-alkylpyrimidinium salts using liquid ammonia/potassium permanganate

Treatment of the 2-R-pyrimidines ( 1 , R = methyl, ethyl, i-propyl and t-butyl) with potassium amide/liquid ammonia/potassium permanganate leads to amination at C-4(6). The yields of the 4(6)-amino compounds 3 in-crease in the order 2-methyl (10%), 2-ethyl (30%), 2-i-propyl (45%) and 2-t-butyl (60%). Treatment of the 2-R-N-methylpyrimidinium salts ( 4 , R = hydrogen, methyl) with liquid ammonia/potassium permanganate leads to a regiospecific imination at C-6, the corresponding 2-R-1,6-dihydro-6-imino-1-methylpyrimidines 6 being obtained in 80-85% yield. It is proved by ¹⁵N-labelling that no ring opening is involved in these imination reactions. Treatment of the imino compounds with base leads to the corresponding 2.R-6-methylamino-pyrimidines 8 , involving, as proved by ¹⁵N-labelling, an ANRORC-mechanism. 2-t-Butyl-1-ethylpyrimidinium tetrafluoroborate ( 9b ) when treated with liquid ammonia/potassium permanganate undergoes N-deethylation, 2-t-butylpyrimidine being exclusively formed.     

Tetrahydropyridines and furans from the reaction of 4-t-butylpyridine 1-oxide with t-butyl and 1-adamantyl mercaptan

The reaction of 4-t-butylpyridine 1-oxide (1) with t-butyl or 1-adamantyl mercaptan in acetic anhydride yielded the expected 2- and 3-alkylthio-4-t-butylpyridines and 1-acetyl-2,6-bis-(alkylthio)-3-acetoxy-4-t-butyl- and the unexpected 1-acetyl-2-acetoxy-3,6-bis(alkylthio-4-t-butyl-1,2,3,6-tetrahydropyridines. The addition of t-butyl mercaptan to a solution of 1 in acetic anhydride containing triethylamine produced the expected 1-acetyl-2-t-dmtylthio-3-acetoxy-4-t-butyl-6-hydroxy-1,2,3,4-tetrahydropyridine ( 6a ) and the unexpected 1-acetyl-2,6-bis(hydroxy)-3-t-butylthio-4-t-butyl-1,2,3,6-tetrahydropyridine. Mild alkaline hydrolysis of 6a yielded predominantly 2-[(acetamido) (t-butylthio)methyl]-3-t-butyl-5-hydroxy-2,5-dihydrofuran. The latter was converted by very mild acidic reagents to the corresponding furan and with 2,4-dinitrophenylhydrazine and sulfuric acid furnished 3-t-butylfurfural 2,4-dinitrophenyl-hydrazone.     

Zwitterionic Base‐Stabilized Digermadistannacyclobutadiene and Tetragermacyclobutadiene

The syntheses of a zwitterionic base‐stabilized digermadistannacyclobutadiene and tetragermacyclobutadiene supported by amidinates and low‐valent germanium amidinate substituents are described. The reaction of the amidinate Ge^I dimer, [LGe:]₂ ( 1 , L=PhC(NtBu)₂), with two equivalents of the amidinate tin(II) chloride, [LSnCl] ( 2 ), and KC₈ in tetrahydrofuran (THF) at room temperature afforded a mixture of the zwitterionic base‐stabilized digermadistannacyclobutadiene, [L₂Ge₂Sn₂L′₂] ( 3 ; L′=LGe:), and the bis(amidinate) tin(II) compound, [L₂Sn:] ( 4 ). Compound 3 can also be prepared by the reaction of 1 with [L^ArSnCl] ( 5 , L^Ar=tBuC(NAr)₂, Ar=2,6‐iPr₂C₆H₃) in THF at room temperature. Moreover, the reaction of 1 with the “onio‐substituent transfer” reagent [4‐NMe₂‐C₅H₄NSiMe₃]OTf ( 8 ) in THF and 4‐(N,N‐dimethylamino)pyridine (DMAP) at room temperature afforded a mixture of the zwitterionic base‐stabilized tetragermacyclobutadiene, [L₄Ge₆] ( 9 ), the amidinium triflate, [PhC(NHtBu)₂]OTf ( 10 ), and Me₃SiSiMe₃ ( 11 ). X‐ray structural data and theoretical studies show conclusively that compounds 3 and 9 have a planar and rhombic charge‐separated structure. They are also nonaromatic.     

Ring and Cluster Structures of {Li[C(NtBu)2(HNtBu)]}2·(THF) and {Li2[C(NtBu)3]}2, Containing the Novel Anions [C(NtBu)2(HNtBu)]−- and [C(NtBu)3]2−

The reaction of tert.-butyl carbodiimide with one equivalent of LiNH^tBu in tetrahydrofuran at-78 °C produces {Li[C(N^tBu)₂(HN^tBu)]}₂-(THF) (1), which is an eight-membered Li₂C₂N₄ ring; the deprotonation of (1) with two equivalents of n-BuLi in tetrahydrofuran at -78 °C and recrystallisation of the product from n-pentane yielded the unsolvated dimer {Li₂[C(N^tBu)₃]}₂ (2), which adopts the structure of a distorted hexagonal prism.     

Scandium,yttrium, and ytterbium bisalkyl complexes stabilized by monoanionic amidopyridinate ligands

A reaction of Sc, Y, and Yb amidopyridinate dichlorides with the corresponding amount of LiCH₂SiMe₃ was used to synthesize bis(trimethylsilylmethyl) complexes (Ap)Ln(CH₂SiMe₃)₂-(THF) (Ap is N-mesityl-6-(2,4,6-triisopropylphenyl)pyridine-2-amide (Ap^9Me), Ln = Y (2); Ap is N-(2,6-diisopropylphenyl)-6-(2,4,6-triisopropylphenyl)pyridine-2-amide (Ap*), Ln = Sc (3), Yb (4)). An exchange reaction of yttrium amidopyridinate dichloride derivative 1 with 4 equiv. of Bu^tLi in hexane gave the corresponding di-tert-butyl derivative Ap^9MeY(Bu^t)₂(THF) (5). Molecular structures of complexes 3 and 4 were established by X-ray diffraction. A method of the ligand solid angles was used to calculate the completion degree of the metal atom coordination sphere for the series of isomorphic derivatives (Ap*)Ln(CH₂SiMe₃)₂(THF) containing the central metal ions with different ionic radii (Sc, Y, Yb, Lu). According to this method, the amidopyridinate ligand solid angle in these complexes virtually does not vary, while the solid angles of coordinated THF molecule and alkyl ligands vary within a wide range.     

Synthesis of 3-alkoxycarbonylaminomethylcarbonylamino-4-benzoyl-1,2-dihydropyridines and their cyclization to 5-phenyl-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-ones

The regiospecific reaction of 3-benzyloxycarbonylaminomethylcarbonylamino-4-benzoylpyridine (6a) , or 3-t-butoxycarbonylaminomethylcarbonylamino-4-benzoylpyridine (6b) , with either acetyl chloride or ethyl chloroformate, and either n-butylmagnesium chloride or phenylmagnesium bromide afforded the respective 1-acetyl (or ethoxycarbonyl)-2-n-butyl (or phenyl)-3-benzyloxy (or t-butoxy) carbonylaminomethylcarbonylami-no-4-benzoyl-1,2-dihydropyridines 7 in 60-75% yield. Reaction of 1-acetyl (or ethoxycarbonyl)-2-n-butyl (or phenyl)-3-t-butoxycarbonylaminomethylcarbonyl-4-benzoyl-1,2-dihydropyridines 7b, 7f, 7d, 7h with trifluoroacetic acid gave the corresponding 5-phenyl-8-acetyl (or ethoxycarbonyl)-9-n-butyl (or phenyl)-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-ones 8a, 8b, 8c, 8d respectively in 45–63% yield. N¹-Methylation of 5-phenyl-8-acetyl-9-n-butyl (or phenyl)-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-ones 8a, 8b using sodium hydride and iodomethane yielded the corresponding N¹-methyl derivatives 9a (48%) and 9b (54%). Oxidation of 5,9-diphenyl-8-ethoxycarbonyl-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-one (8d) using p-chloranil afforded 1,3-dihydro-5,9-diphenyl-2H-pyrido[3,4-e]-1,4-diazepin-2-one (10) . 5-Phenyl-8-acetyl-9-n-butyl-1,3,8,9-tetrahydro-2H-pyrido[3,4-e]-1,4-diazepin-2-one (8a) and the corresponding 8-ethoxycarbonyl analog 8c exhibited weak anticonvulsant activity indicating that 8a and 8c may be acting at the same site as the 7-halo-1,4-benzodiazepin-2-one class of compounds.     

Chromogenic amides of pyridine-2,6-dicarboxylic acid as anion receptors

The synthesis of simple, chromogenic pyridine-2,6-dicarboxylic acid amides, derivatives of isomeric nitroanilines and aminonitrophenols, and their ion binding properties are described. The ligands' response to ionic species was examined by naked eye and was studied with the use of UV–vis spectroscopy in DMSO and its mixture with water. The effect of the localisation and the type of the substituents in aromatic rings were discussed. ¹H NMR experiments were carried out to probe the mechanism of anion recognition, i.e. complexation via hydrogen bond formation versus ligand deprotonation. A selective response of N,N′-bis(2-hydroxy-4-nitrophenyl)pyridine-2,6-dicarboxamide (L5) towards dihydrogen phosphate was found in both DMSO and DMSO–water (95:5) solvent mixture. The structure of N,N′-bis(2-hydroxy-5-nitrophenyl)pyridine-2,6-dicarboxamide (L4) was confirmed by X-ray crystallography.     

Alkali Blues: Blue-Emissive Alkali Metal Pyrrolates

2-Iminopyrroles [H^tBuL, 4-tert-butyl phenyl(pyrrol-2-ylmethylene)amine] are non-fluorescent π systems. However, they display blue fluorescence after deprotonation with alkali metal bases in the solid state and in solution at room temperature. In the solid state, the alkali metal 2-imino pyrrolates, M(^tBuL), aggregate to dimers, [M(^tBuL)(NCR)]₂ (M=Li, R=CH₃, CH(CH₃)CNH₂), or polymers, [M(^tBuL)]_n (M=Na, K). In solution (solv=CH₃CN, DMSO, THF, and toluene), solvated, uncharged monomeric species M(^tBuL)(solv)_m with N,N′-chelated alkali metal ions are present. Due to the electron-rich pyrrolate and the electron-poor arylimino moiety, the M(^tBuL) chromophore possesses a low-energy intraligand charge-transfer (ILCT) excited state. The chelated alkali cations rigidify the chromophore, restricting intramolecular motions (RIM) by the chelation-enhanced fluorescence (CHEF) effect in solution and, consequently, switch-on a blue fluorescence emission.     

Stoffwechselprodukte von Mikroorganismen. 139. Mitteilung. Synthesen in der Sideramin-Reihe: Rhodotorulasäure und Dimerumsäure

t-Butyl (E)-O-acetyl-Δ²-anhydromevalonate could be prepared. by a Reformatsky reaction of 4-acetoxybutan-2-one and t-butyl bromoacetate. Condensation of its activated derivatives with the diketopiperazine of N⁵-hydroxy-L -ornithine led to di-O-acetyl dimerumic acid, which could be transformed, by ammonolysis, to dimerumic acid, identical with the natural compound. The corresponding acetohydroxamic acid, prepared by acetylation of the diketopiperazine, was identical with natural rhodotorulic acid.     

“Instant Methylide” Modification of the Corey–Chaykovsky Epoxide Synthesis

Abstract

We report that Me₃S(O)⁺I^? (1) and Me₃S⁺I^? (2) form stable, dry mixtures with KOt-Bu and NaH, respectively, which remain stable upon prolonged storage (>1 year). The corresponding methylides (Me₂SO=CH₂ and Me₂S=CH₂) are generated upon addition of DMSO or DMSO/THF solutions of carbonyl compounds, cleanly affording epoxides via the Corey–Chaykovsky reaction in good yields and short reaction times (as short as 20 min when 1–2 mmol of various ketones and aldehydes were treated with a mixture of 1 and KOt-Bu at 50–60°C).     

Monoaryloxo ytterbium(III) chlorides supported by β‐diketiminato ligands as novel initiators for the living ring‐opening polymerization of ε‐caprolactone

Ring‐opening polymerization of ε‐caprolactone (ε‐CL) was carried out using β‐diketiminato‐supported monoaryloxo ytterbium chlorides L¹Yb(OAr)Cl(THF) (1) [L¹ = N,N′‐bis(2,6‐dimethylphenyl)‐2,4‐pentanediiminato, OAr = 2,6‐di‐tert‐butylphenoxo‐], and L²Yb(OAr′)Cl(THF) (2) [L² = N,N′‐bis(2,6‐diisopropylphenyl)‐2,4‐pentanediiminato, OAr′ = 2,6‐di‐tert‐butyl‐4‐methylphenoxo‐], respectively, as single‐component initiator. The influence of reaction conditions, such as polymerization temperature, polymerization time, initiator, and initiator concentration, on the monomer conversion, molecular weight, and molecular weight distribution of the resulting polymers was investigated. Complex 1 was well characterized and its crystal structure was determined. Some features and kinetic behaviors of the CL polymerization initiated by these two complexes were studied. The polymerization rate is first order with respect to monomer. The M_n of the polymer increases linearly with the increase of the polymer yield, while polydispersity remained narrow and unchanged throughout the polymerization in a broad range of temperatures from 0 to 50 °C. The results indicated that the present system has a “living character”. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1147–1152, 2006     

Synthesis and biological properties of 3-methyl-10-propargyl-5,8-dideazafolic acid

The synthesis of N³-methyl-10-propargyl-5,8-dideazafolic acid ( 1b ) is described. Ring closure of methyl-5-methylanthranilate with chloroformamidine hydrochloride gave a high yield of pure 2-amino-4-hydroxy-6-methylquinazoline treatment of which with iodomethane/sodium hydroxide provided the corresponding 3-methylquinazoline (6) which was converted to its 2-pivaloylamino derivative. This synthetic approach, next involving functionalisation of the 6-methyl group, was not further pursued because of difficulty encountered in removing the pivaloyl group. Methyl 5-methylanthranilate was treated with p-toluenesulfonyl chloride and the product then N-methylated. The tosyl group was cleaved with hydrogen bromide/phenol and the resulting methylamine ring-closed with chloroformamidine hydrochloride to provide 2-amino-1,4-dihydro-1,6-dimethyl-4-oxoquinazoline ( 11 ). The 2-pivaloylamino derivative of 11 was prone to hydrolytic deamination when attempts were made to remove the pivaloyl group and further elaboration of this heterocycle, with the intention of obtaining N¹-methyl-10-propargyl-5,8-dideazafolic acid was, too, not attempted. Di-t-butyl N-(4-propargylamino)benzoyl)-L-glutamate was therefore prepared and coupled with 2-amino-6-bromomethyl-4-hydroxyquinazoline hydrobromide. The resulting antifolate diester was N-monomethylated. Removal of the t-butyl groups with trifluoracetic acid afforded the target compound 1b and its structure was proved by degradation to the quinazoline 6 . Its IC₅₀ for L1210 thymidylate synthase (TS) was 26 μM; the control value for 10-propargyl-5,8-dideazafolic acid ( 1a ) was 0.02 μM. Thus the substitution of the lactam hydrogen in 1a by a methyl group reduced the TS inhibition by 1300-fold. Compound 1b was poorly cytotoxic to L1210 cells in culture (ID₅₀ > 100 μM). An unperturbed lactam group in this class of antifolate is important for binding to TS.     

Synthesis of the penta-glutamyl derivative of N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)-propyl]amino]benzoyl]-L-glutamic acid (5-DACTHF). An acyclic analogue of tetrahydrofolic acid

The penta-glutamyl derivative of N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]amino]-benzoyl)-L-glutamic acid (1, 5-DACTHF, 543U76) was synthesized by a convergent route. L-γ-Glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-glutamic acid heptakis t-butyl ester ( 20 ) was prepared in ten steps from L-glutamic acid di-t-butyl ester and N-(benzyloxycarbonyl)-L-glutamic acid α-t-butyl ester. 4-[N-[3-(2,4-Diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]trifluoroacetamido]benzoic acid ( 6 ), which was synthesized from pyrimidinylpropionaldehyde 3 in three steps, was condensed with 20 , followed by deprotection to provide N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]amino]benzoyl]-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-glutamic acid ( 2 ). Hexaglutamate 2 is a potent inhibitor of glycinamide ribonucleotide transformylase.     

Phenylene‐bridged β‐Ketoiminate Dilanthanide Aryloxides: Synthesis,Structure, and Catalytic Activity for Addition of Amines to Carbodiimides

The synthesis and reactivity of a series of bimetallic lanthanide aryloxides stabilized by a p‐phenylene‐bridged bis(β‐ketoiminate) ligand is presented. The reaction of 1,4‐diaminobenzene with acetylacetone in a 1:2.5 molar ratio in absolute ethanol gave the compound 1,4‐bis(4‐imino‐2‐pentanone)benzene ( 1 ) (LH₂) in high yield. Compound 1 reacted with (ArO)₃Ln(THF)₂ (ArO = 2,6‐tBu₂‐4‐MeC₆H₂O, THF = tetrahydrofuran) in a 1:2 molar ratio in THF, after workup, to give the corresponding dilanthanide aryloxides L[Ln(OAr)₂(THF)]₂ [Ln = Yb ( 2 ), Y ( 3 ), Sm ( 4 ), Nd ( 5 ), La ( 6 )] in high isolated yields. Compound 1 and complexes 2 – 6 were fully characterized, including X‐ray crystal structure analyses for complexes 2 , 3 , 5 , and 6 . Complexes 2 – 6 can be used as efficient pre‐catalysts for catalytic addition of amines to carbodiimides, and the ionic radii of the central metal atoms have a significant effect on the catalytic activity with the increasing sequence of La ( 6 ) < Nd ( 5 ) ≈ Sm ( 4 ) < Y ( 3 ) ≈ Yb ( 2 ). The catalytic addition reaction with 2 showed a good scope of substrates including primary and secondary amines.