Preparation of 4-trifluoroethylidene-1,3-dioxolane derivatives via new stable (trifluoromethyl)ethynylation reagent

Perfluoroalkylated 4-trifluoroethylidene-1,3-dioxolane derivatives 2a-q were prepared in excellent yields from the reaction of new stable (trifluoromethyl)ethynylation reagent 1a with 1.3 equiv. of TBAF at −15°C for 10 min, followed by treatment with 2 equiv. of phenyl perfluoroalkylated ketone derivatives at room temperature. The reaction of 1a with 1.3 equiv. of TBAF, followed by treatment with 1 equiv. of aldehyde or ketone at −15°C for 10 min and then with trifluoroacetophenone (1 equiv.) at room temperature afforded perfluoroalkylated 4-trifluoroethylidene-1,3-dioxolane derivatives 2t-u in moderate yields.     

Reactions of novel trifluoromethyl propargylic carbocation with carbon nucleophiles

Trifluoromethyl propargylic carbocation [I] generated from the reaction of 1-amino substituted 3-trifluoromethyl-2-propynyl trimethylsilyl ether 1 with TMSOTf in CH₂Cl₂ at −15 °C, followed by warming to room temperature reacted with 1.2 equiv of substituted benzenes, RMgBr and allylsilane to give the enones 3a-l and 5, respectively. The reaction of [I] with anisole, followed by treatment with Grignard reagents afforded the corresponding allyl amine derivatives 7, which underwent cyclization reaction to give indene derivatives 8 by using 2 equiv of TMSOTf.     

Formation and skeletal transformations of perfluoroindan-1-one and perfluoroindan-1,3-dione in the reaction of perfluoroindan with SiO2/SbF5

Perfluoroindan-1-one (2) is obtained in the reaction of perfluoroindan (1) with SiO₂/SbF₅ at 70 °C. Compound 1 heated with SiO₂/SbF₅ at 130 °C and then treated with water, gives 3-hydroxy-perfluoro-3-methylphthalide (4). Ketone 2 is converted, under the action of SbF₅ at 130 °C, to perfluoro-2-ethylbenzoic acid (9) and disproportionates to compound 1 and perfluoroindan-1,3-dione (3); the latter is transformed to phthalide 4 under the reaction conditions.     

New binucleating ligand with two [P,S] chelation pockets on a single phenyl ring: Syntheses and X-ray structures of 1,4-bis(diphenylphosphino)-2,5-difluoro-3,6-bis(methylthio)benzene and of bimetallic complex (CO)3Fe(μ-[(PPh2)(SMe)C6F2(SMe)(PPh2)])Fe(CO)3

Double deprotonations of 1,4-dibromo-2,5-difluorobenzene with LDA (2 equiv., T < −90 °C) generate a reasonably stable organodilithium intermediate. Quenching this reaction mixture with chlorophosphines ClPR₂ produce p-bis(phosphino)benzenes R₂P-C₆Br₂F₂-PR₂ (R = Ph, 4a; R = ⁱPr, 4b). Facile lithium-bromine exchange occurs upon exposure of 4a to BuLi (2 equiv., −80 °C), leading to the generation of another organodilithium intermediate. Addition of MeS-SMe (2 equiv.) to such reaction mixtures gives 1,4-bis(diphenylphosphino)-2,5-difluoro-3,6-bis(methylthio)benzene (2). Compound 2 is the first example of a neutral binucleating ligand featuring the [P,S] chelating sites on the opposite sides of a single phenyl ring. Compound 4b does not undergo the analogous transformation when subjected to the same conditions (2BuLi/2MeS-SMe). Addition of 2 to Fe(CO)₅/2(Me₃NO · 2H₂O) reaction mixtures led to the isolation of the bimetallic complex {(CO)₃Fe[P,S]-C₆F₂-[P,S]Fe(CO)₃} (3), ([P,S] represents the chelating pockets formed by adjacent -PPh₂ and -SMe groups). All of the new compounds were characterized by spectroscopic and analytical techniques (multinuclear NMR, mass-spectrometry, and/or elemental analysis). In addition, compounds 2 and 3 were characterized via single crystal X-ray diffraction methods.     

Enantioselective synthesis of planar chiral azaferrocenes via chiral ligand-mediated ring- and lateral-lithiations

Lithiation of 1′,2′,3′,4′,5′-pentamethylazaferrocene (1) with sec-BuLi/(−)-sparteine (3) in Et₂O at −78°C followed by quenching with electrophiles gave the ring-substituted products 2 in 74-81% ee. On the other hand, lithiation of 1′,2,2′,3′,4′,5,5′-heptamethylazaferrocene (6) with sec-BuLi in the presence of S-valine-derived bis(oxazoline) 5 in Et₂O at −55°C and subsequent reaction with electrophiles afforded the laterally functionalized products 7 in excellent enantioselectivity (96-99% ee).     

An efficient preparation of novel 5-fluoropyrazolin-3-one derivatives from α-trifluoromethylated α-arylacetates

The reactions of α-trifluoromethylated α-arylacetates 1 with 3 equiv of hydrazine, methylhydrazine or benzylhydrazine in 1,4-dioxane at reflux for 24 h afforded the corresponding 5-fluoropyrazolin-3-one derivatives 3a-m in high yields. Similarly, treatment of 1 with 3 equiv of PhNLiNH₂ in THF at −78 °C, followed by warming to room temperature, resulted in the formation of 3n-s in high yields.     

Intramolecular carbolithiation promoted by a DTBB-catalysed chlorine-lithium exchange

The reaction of 6-chlorohex-1-ene 1 with lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 5% molar) in THF at −78°C gives the corresponding organolithium intermediate 2, which by reaction with different electrophiles affords, after hydrolysis with diluted hydrochloric acid, the expected products 3. The same reaction performed at −30°C gives cyclopentyl derivatives 5, probably by cyclisation of the open-chain intermediate 2 to give the cyclic organolithium compound 4. When the double bond in the starting material contains an alkyl substituent, for instance compounds 6 and 9, the corresponding cyclisation is inhibited, so the corresponding acyclic products 8 and 11 are respectively, obtained. However, when the substituent at the same positions is a phenyl group, like in starting materials 12 and 15, the cyclised products 14 and 17 were respectively, isolated. In the case of the secondary starting chlorinated material 18, the reaction can be directed to both, the acyclic products 20 or the cyclic ones 22, working at −78 or −30°C, respectively, as it happens in the case of the unsubstituted chlorinated material 1. For the tertiary chloro derivative 23, only the cyclic compound 27 could be isolated at −30°C due to the great instability of the corresponding tertiary organolithium intermediate 24, which undergoes a proton abstraction even at −78°C. From allyl 2-chlorophenyl ether 28 or N,N-diallyl-2-chloroaniline 32, only the corresponding cyclic compounds 31 and 33, respectively, are isolated either at −78 or at −30°C. In all cases a carbanionic cyclisation, better than a radical one, is postulated to occur as mechanistic pathway.     

Synthesis and X-ray structures of new chiral Ag(I) complexes with biaryl-based N4-donor ligands

Condensation of (R)-2,2′-diamino-1,1′-binaphthyl or (R)-6,6′-dimethylbiphenyl-2,2′-diamine with 2 equiv of 2-pyridine carboxaldehyde in toluene in the presence of molecular sieves at 70 °C gives (R)-N,N′-bis(pyridin-2-ylmethylene)-1,1′-binaphthyl-2,2′-diimine (1), and (R)-N,N′-bis(pyridin-2-ylmethylene)-6,6′-dimethylbiphenyl-2,2′-diimine (3), respectively, in good yields. Reduction of 1 with an excess of NaBH₄ in a solvent mixture of MeOH and toluene (1:1) at 50 °C gives (R)-N,N′-bis(pyridin-2-ylmethyl)-1,1′-binaphthyl-2,2′-diamine (2) in 95% yield. Rigidity plays an important role in the formation of helicate silver(I) complexes. Treatment of 1, or 3 with 1 equiv of AgNO₃ in mixed solvents of MeOH and CH₂Cl₂ (1:4) gives the chiral, dinuclear double helicate Ag(I) complexes [Ag₂(1)₂][NO₃]₂ (4) and [Ag₂(3)₂][NO₃]₂ · 2H₂O (6), respectively, in good yields. While under the similar reaction conditions, reaction of 2 with 1 equiv of AgNO₃ affords the chiral, mononuclear single helicate Ag(I) complex [Ag(2)][NO₃] (5) in 90% yield. [Ag₂(1)₂][NO₃]₂ (4) can further react with excess AgNO₃ to give [Ag₂(1)₂]₃[NO₃]₂[Ag(CH₃OH)(NO₃)₃]₂ · 2CH₃OH (7) in 75% yield. All compounds have been fully characterized by various spectroscopic techniques and elemental analyses. Compounds 1 and 5-7 have been further subjected to single-crystal X-ray diffraction analyses.     

Efficient approach to allylated quinolines via palladium-catalyzed cyclization–allylation of 1-azido-2-(2-propynyl) benzenes with allyl methyl carbonate

The palladium-catalyzed cyclization–allylation reaction of ortho-azido propynylbenzenes 1 and allyl methyl carbonate 2d gives the corresponding allylated quinolines in moderate to good yields. The reaction of 1-azido-2-(2-propynyl)benzene 1a proceeds smoothly with 10 mol % Pd(PPh₃)₄ and 5 equiv K₃PO₄ or NaOAc in DMF at 100 °C to afford 3,4-diallylquinoline 3a in 69% yield in the case of R² = H and 3-allylquinoline 4 in 67% yield in the case of R² ≠ H.     

Cationoid rearrangements in reactions of perfluoro-1-arylbenzocyclobutenes with antimony pentafluoride

In the presence of antimony pentafluoride at 130 °C, the four-membered ring of perfluoro-1-(2-ethylphenyl)benzocyclobutene (2) undergoes cleavage, forming perfluoro-2-ethyl-2′-methyldiphenylmethane (5). Compound 5 is converted, under the action of SbF₅ at 170 °C, to perfluoro-8,9-dimethyl-1,2,3,4-tetrahydrofluorene (8). Perfluoro-1-(4-ethylphenyl)benzocyclobutene (3) remains unchanged at 130 °C, whereas at 170 °C it gives a mixture of perfluorinated 4′-ethyl-2-methyldiphenylmethane (9), 6-ethyl-1,2,3,4-tetrahydroanthracene (11) and 2-ethyl-9,10-dihydroanthracene (12). When heated with SbF₅ at 170 °C, perfluoro-1-phenylbenzocyclobutene (1) remains unchanged. Solution of compounds 2, 3, 5 and 9 in SbF₅-SO₂ClF generated the perfluorinated 1-(2-ethylphenyl)-1-benzocyclobutenyl (29), 1-(4-ethylphenyl)-1-benzocyclobutenyl (30), 2-ethyl-2′-methyldiphenylmethyl (31) and 4′-ethyl-2-methyldiphenylmethyl (32) cations, respectively.     

Convenient synthesis of 3,3,3-trifluoropropanoic acid by hydrolytic oxidation of 3,3,3-trifluoropropanal dimethyl acetal

A convenient and efficient method for preparing 3,3,3-trifluoropropanoic acid (1) is reported. The starting material is 1-chloro-3,3,3-trifluoropropene (2) that can be easily transformed into 3,3,3-trifluoropropanal dimethyl acetal (4) on treatment with methanol and KOH followed by acid-catalyzed addition of methanol. Direct transformation of 4 into 1 was efficiently achieved with 30% aqueous hydrogen peroxide (4.0 equiv.) in the presence of FeCl₃ (0.025 equiv.) and hydrochloric acid (0.5 equiv.).     

One pot synthesis of novel α,β-dichloro-β-trifluoromethylated enones and their application to the synthesis of trifluoromethylated heterocycles

Trifluoropropynyllithium was reacted with 1 equiv of Weinreb benzamides in THF at −78 to 0 °C, followed by treatment with 4 equiv of trifluoromethanesulfonyl chloride to give α,β-dichloro-β-trifluoromethylated enones 1 in 61-68% yield. The reactions of 1a with substituted amidines or hydrazines in refluxing 1,4-dioxane-CH₃CN afforded trifluoromethylated chloropyrimidines 3 and chloropyrazoles 6 in 58-98% yields. The microwave-assisted coupling reactions of 3 with substituted phenylstannane and allylstannane in refluxing CH₃CN in the presence of Pd(PPh₃)₄ provided the corresponding phenyl and allyl substituted pyrimidines 4 in 89-98% yields.     

Reductive opening of 1H,3H-benzo[de]isochromene: synthesis of 1,8-difunctionalised naphthalenes

The lithiation of 1H,3H-benzo[de]isochromene (6) with lithium and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 5% molar) in THF at −50 °C gives dianionic intermediate 7, which by reaction with different electrophiles {H₂O, D₂O, ^tBuCHO, PhCHO, Me₂CO, (CH₃CH₂)₂CO, [CH₃(CH₂)₄]₂CO, (CH₂)₅CO, (CH₂)₇CO, (−)-menthone} at the same temperature followed by hydrolysis leads to functionalised alcohols 8. If after addition of a carbonyl compound as the first electrophile [^tBuCHO, (CH₂)₅CO, (−)-menthone], the resulting dialcoholate 9 is allowed to react at 0 °C, a second lithiation takes place to give intermediate 10 which by reaction with a second electrophile [H₂O, ^tBuCHO, (CH₂)₅CO, CO₂], yields, after hydrolysis, 1,8-difunctionalised naphthalenes 11. Cyclization under acidic conditions of diols 8e-i gives oxygen-containing eight-membered heterocycles, which are homologous to the starting material 6.     

Preparation, crystal structure, and spectroscopic, chemical, and electrochemical properties of (2E,4E)-4-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)-1,3-butadiene compared with those of (E)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)ethylene

Wittig reaction of 3-[4-(dimethylamino)phenyl]propanal (5) with (3-guaiazulenylmethyl)triphenylphosphonium bromide (4) in ethanol containing NaOEt at 25 °C for 24 h under argon gives the title (2E,4E)-1,3-butadiene derivative 6E in 19% isolated yield. Spectroscopic properties, crystal structure, and electrochemical behavior of the obtained new extended π-electron system 6E, compared with those of the previously reported (E)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)ethylene (12), are documented. Furthermore, reaction of 6E with 1,1,2,2-tetracyanoethylene (TCNE) in benzene at 25 °C for 24 h under argon affords a new Diels-Alder adduct 8 in 59% isolated yield. Along with spectroscopic properties of the [π4+π2] cycloaddition product 8, the crystal structure, possessing a cis-3,6-substituted 1,1,2,2-tetracyano-4-cyclohexene unit, is shown. Moreover, reaction of 6E with (E)-1,2-dicyanoethylene (DCNE) under the same reaction conditions as the above gives no product; however, this reaction in p-xylene at reflux temperature (138 °C) for four days under argon affords a new Diels-Alder adduct 9 in 54% isolated yield. Although reaction of 6E with DCNE in toluene at reflux temperature (110 °C) for four days under argon provides 9 very slightly, reaction of 6E with dimethyl acetylenedicarboxylate (DMAD) in toluene at reflux temperature for two days under argon yields a new Diels-Alder adduct 10, in 58% isolated yield, which upon oxidation with MnO₂ in CH₂Cl₂ at 25 °C for 1 h gives 11, converting a (CH₃)₂N-4″ into CH₃NH-4″ group, in 37% isolated yield. The crystal structure of 11 supports the molecular structure 10 possessing a partial structure cis-3,6-substituted 1,2-dimethoxycarbonyl-1,4-cyclohexadiene. The title basic studies on the above are reported in detail.     

Four- and five-coordinate magnesium compounds containing ketiminate ligands. Synthesis and characterization of L2Mg, L2Mg(LH), and L2Mg(Py), where L = MeC(O)CHC(NAr)Me

Magnesium complexes containing ketiminate ligands were synthesized and characterized. MgBu₂ reacted readily in toluene with two equiv. of [MeC(O)CHC(NHAr)Me], where Ar = 2,6-diisopropylphenyl, to generate [MeC(O)CHC(NAr)Me]₂Mg (1) in 43% yield. The four-coordinate magnesium compound 1 is very moisture sensitive and acts as a Lewis acid, accepting one equiv. of Lewis base to form five-coordinate magnesium compounds. Compound [MeC(O)CHC(NAr)Me]₂Mg[MeC(O)CHC(NHAr)Me] (2) was obtained in 57% yield from the reaction in toluene of MgBu₂ with three equiv. of [MeC(O)CHC(NHAr)Me]. Treatment of 1 with one equiv. of free ketimine ligands [MeC(O)CHC(NHAr)Me] also led to the formation of 2. The bulky η¹-ketimine of 2 can be replaced with a less bulky Lewis base such as pyridine. Treatment of 1 with excess pyridine in toluene at ambient temperature led to the formation of compound [MeC(O)CHC(NAr)Me]₂Mg[NC₅H₅] (3) as colorless crystalline solids in 51% yield. Compounds 1, 2, and 3 were characterized by NMR and X-ray crystallography. Compounds 2 and 3 showed no activity toward the polymerization of ε-caprolactone at 25 °C after 3 h. However, when the temperature was increased to 70 °C, compounds 2 and 3 efficiently catalyzed polymerization of ε-caprolactone to generate high molecular weight poly-ε-caprolactones. The polydispersity index (PDI) of these poly-ε-caprolactones is in the range 1.57-3.18.     

Reductive ring opening of dihydrodibenzothiepine and dihydrodinaphtho-oxepine and -thiepine

The 4,4′di-tert-butylbiphenyl (DTBB)-catalysed lithiation of dihydrodibenzothiepine (1) at −78 °C for 30 min followed by reaction with a carbonyl compound [^tBuCHO, Ph(CH₂)₂CHO, PhCHO, (n-C₅H₁₁)₂CO, (CH₂)₅CO, (CH₂)₇CO, (−)-menthone] at the same temperature leads, after hydrolysis with 3 M hydrochloric acid, to sulphanyl alcohols 2. If after addition of a carbonyl compound as the first electrophile [Me₂CO, (CH₂)₅CO, (−)-menthone], the resulting dianion of type II is allowed to react at room temperature for 30 min, a second lithiation takes place to give an intermediate of type III, which by reaction with a second electrophile [Me₂CO, Et₂CO, (CH₂)₅CO, ClCO₂Et], yields, after hydrolysis, difunctionalised byphenyls 4. The cyclisation of the sulphanyl alcohol 2c under acidic conditions yields the eight-membered sulphur containing heterocycle 3. The lithiation of dihydrodinaphthoheteroepines 7 and 10 with 2.2 equiv of lithium naphthalenide in THF at −78 °C followed by reaction with different electrophiles [H₂O, D₂O, ^tBuCHO, Me₂CO, Et₂CO, (CH₂)₄CO, (CH₂)₅CO] at the same temperature leads, after hydrolysis, to unsymmetrically 2,2′-disubstituted binaphthyls 9 and 12, respectively. When the lithiation is performed with an excess of lithium in the presence of a catalytic amount of DTBB (10% molar), a double reductive cleavage takes place to give the dianionic intermediate VII, which by reaction with different electrophiles [H₂O, Me₂CO, Et₂CO, (CH₂)₄CO, (CH₂)₅CO], followed by hydrolysis with water, yields symmetrically 2,2′-disubstituted binaphthyls 8 and 11. In the case of starting from (R)- or (S)-dihydrodinaphthoheteroepines 7 and 10, these methodologies allow us to prepare enantiomerically pure compounds 8, 11 and 12.     

Oxygen replacement by fluorine in carbonyl derivatives of perfluoroaromatic compounds and isomerization of perfluoroindan-1,3-dione to perfluoro-3-methylenephthalide under the action of HF/SbF5

When acted upon by HF/SbF₅ at 95 °C, carbonyl groups of perfluorinated acetophenone (10), 3,4-dihydronaphthalen-1(2H)-one (8), 2,3-dihydronaphthalene-1,4-dione (9), benzocyclobutenone (6), benzocyclobutenedione (7) and indan-1-one (1) are converted into difluoromethylene groups to give the corresponding perfluoroaromatic products. Perfluoroindan-2-one (5), under the same conditions, is transformed to bis(perfluoroindan-2-yl) ether (21). On heating with HF/SbF₅, perfluoroindan-1,3-dione (2) isomerizes into perfluoro-3-methylenephthalide (4) at 95 °C, and gives 4,5,6,7-tetrafluoro-3-trifluoromethyl-phthalide (14) at 130 °C. Compound 4 in the absence of a solvent dimerizes giving perfluorodispiro[phthalide-3,1′-cyclobutane-2′,3″-phthalide] (18), and when heated with SbF₅ at 130 °C, it is converted into perfluoro-3-methylphthalide (3). When acted upon by HF/SbF₅ at 95 °C, perfluorinated benzoic acid (12) and phthalic anhydride (13) give the corresponding products with trifluoromethyl groups.     

Reductive opening of 2,7-dihydrodinaphthoxepine and thiepine: easy regioselective preparation of 2,2′-difunctionalised binaphthyls

The lithiation of 2,7-dihydrodinaphthoheteroepines (5) with 2.2 equiv of lithium naphthalenide in THF at −78 °C gives dianionic intermediates 8, which by reaction with different electrophiles [H₂O, D₂O, ^tBuCHO, Me₂CO, Et₂CO, (CH₂)₄CO, (CH₂)₅CO] at the same temperature, followed by hydrolysis, leads to unsymmetrically 2,2′-disubstituted binaphthyls 6. When the lithiation is performed with an excess of lithium in the presence of a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 10 mol %), a double reductive cleavage takes place to give dianionic intermediate 9, which by reaction with different electrophiles [H₂O, Me₂CO, Et₂CO, (CH₂)₄CO, (CH₂)₅CO], followed by hydrolysis with water, yields symmetrically 2,2′-disubstituted binaphthyls 7. In the case of starting from (R)-5a, the reductive opening by treatment with 2.2 equiv of lithium naphthalenide followed by reaction with H₂O or (CH₂)₅CO as electrophiles and final hydrolysis, leads to enantiomerically pure compounds (R)-6aa and (R)-6af, respectively.     

Rhodium(I) carbonyl complexes of quinoline carboxaldehyde ligands and their catalytic carbonylation reaction

The dimeric rhodium precursor [Rh(CO)₂Cl]₂ reacts with quinoline (a) and its three isomeric carboxaldehyde ligands [quinoline-2-carboxaldehyde (b), quinoline-3-carboxaldehyde (c), and quinoline-4-carboxaldehyde (d)] in 1:2 mole ratio to afford complexes of the type cis-[Rh(CO)₂Cl(L)] (1a-1d), where L = a-d. The complexes 1a-1d have been characterised by elemental analyses, mass spectrometry, IR and NMR (¹H, ¹³C) spectroscopy together with a single crystal X-ray structure determination of 1c. The X-ray crystal structure of 1c reveals square planar geometry with a weak intermolecular pseudo dimeric structure (Rh?Rh = 3.573 Å). 1a-1d undergo oxidative addition (OA) with different electrophiles such as CH₃I, C₂H₅I and I₂ to give Rh(III) complexes of the type [Rh(CO)(COR)Cl(L)I] {R = -CH₃ (2a-2d), R = -C₂H₅ (3a-3d)} and [Rh(CO)Cl(L)I₂] (4a-4d) respectively. 1b exhibits facile reactivity with different electrophiles at room temperature (25 °C), while 1a, 1c and 1d show very slow reactivity under similar condition, however, significant reactivity was observed at a temperature ∼40 °C. The complexes 1a-1d show higher catalytic activity for carbonylation of methanol to acetic acid and methyl acetate [Turn Over Frequency (TOF) = 1551-1735 h⁻¹] compared to that of the well known Monsanto’s species [Rh(CO)₂I₂]⁻ (TOF = 1000 h⁻¹) under the reaction conditions: temperature 130 ± 2 °C, pressure 33 ± 2 bar, 450 rpm and time 1 h. The organometallic residue of 1a-1d was also isolated after the catalytic reaction and found to be active for further run without significant loss of activity.     

Synthesis and characterisation of titanium pyridine- and pyrimidine-thiolates and their application as precursors to titanium disulfide

The reaction of TiCl₄ with pyridine- and pyrimidine-thiol has been investigated. Reaction of TiCl₄ with 3 equiv. of 2-mercaptopyridine and 3 equiv. of tert-butylpyridine in toluene at room temperature resulted in the formation of the tris(pyridine-2-thiolate) complex [TiCl(SC₅H₄N)₃] (1). The related reaction between TiCl₄ with 3 equiv. of 2-mercaptopyrimidine and 3 equiv. of tert-butylpyridine in toluene at room temperature resulted in the isolation of the complex [TiCl(SC₄H₃N₂)₃] (2). Compound 2 has been characterised by X-ray crystallography. Low pressure CVD of 1 and 2 produced brown/gold films of TiS₂/TiO₂ on glass substrates at 550 and 600 °C.