Fluorinated Derivatives of 4-Phosphino- and 4-Iminophosphorano-2,5-Dimethyl-2H-1,2,3-Diazaphospholes and Their Metal Complexes

Abstract

Although there has been considerable interest in the chemistry and metal complexation of low coordinate phosphines, there are very few examples of bisphosphine systems where both phosphorus atoms are trivalent and only one of the centers is two-coordinate^1,2. An example of such a system is the 4-phosphino-2,5-dimethyl-1,2,3-diazaphosphole obtained from acetone methylhydrazone and phosphorus trichloride³. This bisphosphine contains a two-coordinate endocyclic phosphorus and a three-coordinate exo phosphorus center. The exo phosphorus preferentially coordinates to metals but under certain conditions the two-coordinate phosphorus will also coordinate⁴.     

Unusual behavior of 3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one towards some phosphorus reagents: Synthesis of novel diethyl 2-phosphonochromone,diethyl 3-phosphonopyrone and 1,3,2-oxathiaphosphinines

The chemical reactivity of 3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one (1) towards some phosphorus reagents was studied. The enaminone 1 was cyclized into diethyl 2-phosphonochromone 2 via its treatment with diethyl phosphite in basic medium. However, its reaction with triethoxy phosphonoacetate gave the substituted pyrone phosphonate 3. In addition, two novel examples of 4-(dimethylamino)-6-(2-hydroxyphenyl)-2-sulfido-4H-1,3,2-oxathia-phosphinines 6 and 7 were obtained from treatment of enaminone 1 with O,O-diethyl dithiophosphoric acid and Lawesson’s reagent. When enaminone 1 was also treated with phosphorus decasulfide, it was turned into 4H-thiochromene-4-thione while its treatment with phosphorus tribromide, phosphorus oxychloride, or phenylphosphonic dichloride, 4H-4-oxo-chromene was isolated in all cases. The possible reaction mechanisms of the formation of these products were discussed. The structures of newly isolated products were established by elemental analysis and spectral tools.     

Mechanism of the reaction of 3,3-dimethyl-2-trimethylsiloxy-1-trimethylsilyl-1-phosphabut-1-ene with diethyl phosphite

The reaction of a stable two-coordinate phosphorus compound, 3,3-dimethyl-2-trimethylsiloxy-1-trimethylsilyl-1-phosphabut-1-ene, with diethyl phosphite was studied in terms of the density functional theory [DFT B3PW91/6-31G(d)]. A two-step mechanism of the reaction was established.     

The synthesis of novel polycyclic heterocyclic ring systems. 3. Synthesis and NMR spectroscopy of 15-chloro[1]benzo-thieno[2″,3″:3′,4′]naphtho[1′,2′:4,5]thieno[2,3-c]quinoline

The polycyclic heterocyclic compound with a novel ring system, 15-chloro[1]benzothieno[2″,3″:3′,4′]-naphtho[1′,2′:4,5]thieno[2,3-c]quinoline was synthesized via photocyclization of 3-chloro-N-phenyl[1]-benzothieno[2′,3′:3,4]naphtho[2,1-b]fhiophene-2-carboxamide followed by chlorination with phosphorus oxychloride. The assignment of its ¹H and ¹³C nmr spectra was accomplished by utilizing two-dimensional nmr methods.     

Action of Nucleophilic Phosphorus Reagents on Heterocyclic cis-Disulfides

As a contribution to previous studies of the reaction of phosphorus nucleophiles with heterocyclic cis-disulfides,^1,2 the reactivity of trialkyl phosphites 2 toward 5-p-chlorophenyl-4-cyano-1,2-dithiol-3-thione 1a, 5-phenyl-1,2,4-dithiazol-3-thione 1b and its 3-carbonyl derivative 1c has now been investigated.     

The Synthesis and Molecular Structure of the First Two-Coordinate,Dinuclear σ-Bonded Mercury(I) RHgHgR Compound

A linear Si-Hg-Hg-Si arrangement and a Hg–Hg distance of 265.69 pm are exhibited by the first two-coordinate, dinuclear σ-bonded organomercury(I ) compound 1. It was formed unexpectedly in the reaction of two equivalents of the silane (Me₃SiMe₂Si)₃SiH with tBu₂Hg. In contrast if the reagents are allowed to react in a 1:1 ratio the expected mercury(II ) compound (Me₃SiMe₂Si)₃SiHgtBu is obtained.     

Synthesis of 2-(p-Toluenesulfonamido)-4-phenyl-4, 5-dihydro-1H-1, 3, 4-diazaphosphole 4-oxides

Some novel unsaturated five-membered organophosphorus heterocyclic compounds, 2-(p-toluenesulfonamido)-4-phenyl-4, 5-dihydro-1H-1, 3, 4-diazaphosphole 4-oxides 8 have been synthesized by Mannich-type reaction of p-toluenesulfonylguanidine with phenyldichlorophosphine and ketones.     

Synthesis,Reactions, and Spectral Characterization of New Fused Pyrazolothienopyridine and Pyrazolopyrrolopyridine Systems

4‐Oxo‐1‐phenyl‐4,7‐dihydropyrazolo[3,4‐b ]pyridine‐5‐carbonitrile compound ( 4 ) was prepared by the reaction of 5‐amino‐3‐methyl‐1‐phenyl pyrazole ( 1 ) with ethyl 2‐cyano‐3‐ethoxyacrylate followed by cyclization using diphenyl ether. The pyrazolopyridinone compound 4 was converted to the chloropyrazolopyridine 5 by the reaction with phosphorus oxychloride. Compound 5 was used as a starting material to synthesize 3‐amino‐4‐substituted pyrazolothienopyridine derivatives 10a–f and ethyl‐3‐aminopyrazolopyrrolopyridine‐2‐carboxylate 21 , which were used as a versatile precursors for synthesis of poly‐fused heterocyclic compounds.     

AN UNUSUAL ADDITION AND RING-CLOSURE REACTION OF 1-(2-BROMOETHYL)-2,3-DIHYDRO- 3-PROPYL-1,3,2-BENZO-DIAZAPHOSPHORIN-4(1H)-ONE 2-OXIDE WITH CARBON DISULFIDE FOR A NEW AND CONVENIENT SYNTHESIS OF THE FUSED PHOSPHORUS HETEROCYCLIC COMPOUND

ABSTRACT

The reaction of 1-(2-bromoethyl)-2,3-dihydro-3-propyl-1,3,2-benzodiazaphosphorin-4(1H)-one 2-oxide with carbon disulfide takes an alternative pathway in the use of different bases. The sodium hydride mediated reaction leads to the formation of the tricyclic fused 1,2,3,4,4a,4b,5,6-octahydro-6-oxo-5-propyl-4-thia-3,4b,4a-thiazphosphaphenanthridine 4a-oxide via addition of H-P bond across the double bond of carbon disulfide followed by intramolecular cyclization. In the presence of triethylamine, refluxing a mixture of 1-(2-bromoethyl)-2,3-dihydro-3-propyl-1,3,2-benzodiazaphosphorin-4(1H)-one 2-oxide with carbon disulfide in benzene takes an unusual course with formation in excellent yield of the first example of fused phosphorus heterocyclic 4-[1′-(β-bromoethyl)-4′-oxo- 3′-propyl-1′,2′,3′,4′-tetrahydro-1,3,2-benzodiazaphosphorin-2′- sulfide]-1,2,3,4,4a,4b,5,6-octahydro-6-oxo-5-propyl-3,4b, 4a-thiazphosphaphenanthridine 4a,2′-dioxide, which was confirmed by spectroscopic methods, microanalyses and single crystal X-ray structure determination.     

1,2-Fused pyrimidines. III. Derivatives of 12H-pyrido[1′,2′:1,2]pyrimido[4,5-b]quinoline,a novel heterocyclic system

Reactivities of 2-amino-4H-pyrido[1,2-a]pyrimidin-4-ones and 4-amino-2H-pyrido[1,2-a]pyrimidin-2-ones, both N,N-dialkyl and (N-alkyl, N-phenyl)substituted, when treated with the N,N-dimethylformamide/phosphorus oxychloride Vilsmeier-Haack reagent XII were compared. Starting from 2-[(N-alkyl, N-phenyl)amino] compounds IXa,b , the expected XVIa,b and XVIIa,b were obtained, which are derivatives of 12H-pyrido[1′,2′:1,2]pyrimido[4,5-b]quinoline, a novel heterocyclic system. When 2-(phenylamino) compound IXc was used a mixture of 3-formylderivative XVIII and 12H-pyrido-[1′,2′:1,2]pyrimido[4,5-b]quinolin-12-one ( XIX ) resulted from the reaction. On the other hand, 2-(dialkylamino)-4H-pyrido[1,2-a]pyrimidin-4-ones IIIa-c plainly afforded high yields of 3-formylderivatives XIVa-c. In contrast, no significant reaction occurred when 4-(dialkylamino) and 4-[(N-alkyl,N-phenyl)amino] compounds IIa-c and VIIIa,b were treated with the reagent XII , under the same as well as more severe conditions. A clear difference in the nucleophilic reactivity of C-3 position between these two classes of isomers is pointed out by the above summarized results.     

Aminoacids in the synthesis of heterocyclic systems. The synthesis of methyl 2-acetylamino-3-dimethylaminopropenoate and 2-(N-methyl-N-trifluoroacetyl)amino-3-dimethylaminopropenoate and their application in the synthesis of heterocyclic compounds

Methyl (Z)-2-acetylamino-3-dimethylaminopropenoate (3) was prepared from N-acetylglycine (1), which was converted with N,N-dimethylformamide and phosphorus oxychloride into 4-dimethylaminomethylene-2-methyl-5(4H)-oxazolone (2), followed by treatment with methanol in the presence of potassium carbonate, into 3. The compound 3 was shown to be a versatile reagent in the synthesis of various heterocyclic systems. With N-nucleophiles, such as heterocyclic amines 4, either methyl 2-acetylamino-3-heteroarylaminopropenoates 5 or fused pyrimidinoncs 6 were formed, dependent on the reaction conditions and/or heterocyclic substituents: C-nuclcophiles with an active or potentially active methylene group, such as 1,3-dicarbonyl compounds 7, 8 and 9, substituted phenols 10a,b, naphthols 11, 12a-c, and substituted coumarin 13a, afforded substituted pyranones 20 and 22, and fused pyranones 21, 23–26. The nitrogen containing heterocycles 14–19 produced pyranoazines 27–31 and pyranoazole 32. In all of these systems the acetylamino group is attached at position 3 of the newly formed pyranone ring. The orientation around the double bond for methyl (Z)-2-(N-methyl-N-trifluo-roacetyl)-3-dimethylaminopropenoate (36) was established by X-ray analysis.     

Mono‐ and Binuclear Rhodium and Platinum Complexes of 1, 3, 5‐Trimethyl‐1, 3, 5‐triaza‐2σ3λ3‐phosphorin‐4, 6‐dionyloxy‐substituted Calix[4]arenes

The reaction behaviour of 1, 3, 5‐triaza‐2σ³λ³‐phosphorin‐4, 6‐dionyloxy‐substituted calix[4]arenes towards mono‐ and binuclear rhodium and platinum complexes was investigated. Special attention was directed to structure and dynamic behaviour of the products in solution and in the solid state. Depending on the molar ratio of the reactands, the reaction of the tetrakis(triazaphosphorindionyloxy)‐substituted calix[4]arene ( 4 ) and its tert‐butyl‐derivative ( 1 ) with [(cod)RhCl]₂ yielded the mono‐ and disubstituted binuclear rhodium complexes 2 , 3 , and 5 . In all cases, a C₂‐symmetrical structure was proved in solution, apparently caused by a fast intramolecular exchange process between cone conformation and 1, 3‐alternating conformation. The X‐ray crystal structure determination of 5 confirmed [(calixarene)RhCl]₂‐coordination through two opposite phosphorus atoms with a P ⃜P separation of 345 pm. The complex displays crystallographic inversion symmetry, and the Rh₂Cl₂ core is thus exactly planar. Reaction of 1 and of the bis(triazaphosphorindionyloxy)‐bis(methoxy)‐substituted tert‐butyl‐calix‐[4]arene ( 7 ) with (cod)Rh(acac) in equimolar ratio and subsequent reaction with HBF₄ led to the expected cationic monorhodium complexes 5 and 8 , involving 1, 3‐alternating P‐Rh‐P‐coordination. The cone conformation in solution was proved by NMR spectroscopy and characteristic values of the ¹J(PRh) coupling constants in the ³¹P‐NMR‐spectra. Reaction of equimolar amounts of 4 with (cod)Rh(acac) or (nbd)Rh(acac) led, by substitution of the labile coordinated acetylacetonato and after addition of HBF₄, to the corresponding mononuclear cationic complexes 9 and 10 . Only two of the four phosphorus atoms in 9 and 10 are coordinated to the central metal atom. Displacement of either cycloocta‐1, 5‐diene or norbornadiene was not observed. For both compounds, the cone conformation was proved by NMR spectroscopy. Reaction of 4 with (cod)PtCl₂ led to the PtCl₂‐complex ( 11 ). As for all compounds mentioned above, only two phosphorus atoms of the ligand coordinate to platinum, while two phosphorus atoms remain uncoordinated (proved by δ³¹P and characteristic values of ¹J(PPt)). NMR‐spectroscopic evidence was found for the existence of the cone conformation in the cis‐configuration of 11 .     

Metalated 1, 3‐Azaphospholes: η1‐(1H‐1, 3‐Benzazaphosphole‐P)M(CO)5 and μ2‐[(1, 3‐Benzazaphospholide‐P)(cyclopentadienide)nickel] Complexes

1H‐1, 3‐Benzazaphospholes react with M(CO)₅(THF) (M = Cr, Mo, W) to give thermally and relatively air stable η¹‐(1H‐1, 3‐Benzazaphosphole‐P)M(CO)₅ complexes. The ¹H‐ and ¹³C‐NMR‐data are in accordance with the preservation of the phosphaaromatic π‐system of the ligand. The strong upfield ³¹P coordination shift, particularly of the Mo and W complexes, forms a contrast to the downfield‐shifts of phosphine‐M(CO)₅ complexes and classifies benzazaphospholes as weak donor but efficient acceptor ligands. Nickelocene reacts as organometallic species with metalation of the NH‐function. The resulting ambident 1, 3‐benzazaphospholide anions prefer a μ₂‐coordination of the η⁵‐CpNi‐fragment at phosphorus to coordination at nitrogen or a η³‐heteroallyl‐η⁵‐CpNi‐semisandwich structure. This is shown by characteristic NMR data and the crystal structure analysis of a η⁵‐CpNi‐benzazaphospholide. The latter is a P‐bridging dimer with a planar Ni₂P₂ ring and trans‐configuration of the two planar heterocyclic phosphido ligands arranged perpendicular to the four‐membered ring.     

New synthesis of chalcogenolactones. 1H,3H-benzo[c]selenophen-1-one, 1H,3H-benzo[c]tellurophen-1-one and the related 3,4-dihydro-1H-2-benzoselenin-1-one and 3,4-dihydro-1H-2-benzotellurin-1-one

The synthesis of three new basic heterocyclic systems namely, 1H,3H-benzo[c]tellurophen-1-one (2-tellurophthalide), 3,4-dihydro-1H-2-benzoselenin-1-one (3,4-dihydro-2-isoselenocoumarin) and 3,4-dihydro-1H-2-benzotellurin-1-one (3,4-dihydro-2-isotellurocoumarin), is reported through the cyclisation of o-(bromoalkyl)benzoyl chlorides.     

5-Methyl-2-phenyl-2H-1,2,3-diazaarsole in reaction with ethyl diazoacetate

5-Methyl-2-phenyl-2H- 1,2,3-diazaarsole 1 reacts with ethyl diazoacetate to form a 1:1 bicyclic product 3a , 8-ethoxycarbonyl-4-methyl-2-phenyl-1-arsa-2,3,6,7-tetraazabicyclo[3.3.0]octa-3.7-diene. The latter isomerizes to a two-coordinate arsenic compound 5 , 3-ethoxycarbonyl-5-[α-(phenylhydrazono)ethyl] 1-1,2,4-diazaarsole. The X-ray crystal structure analyses of both products 3a and 5 have been carried out.     

Water-mediated,green, and efficient synthesis of bisquinolones under catalyst-free conditions

Water-mediated, green, and efficient synthesis involving condensation of 4-hydroxy-1-methylquinoline-2(1H)-one (3) with different aromatic and heterocyclic aldehydes (4a–n) leading to 3,3′-(arylmethylene)-bis-(4-hydroxy-1-methylquinolin-2(1H)-one) 5(a–n) under catalyst-free conditions is described. This reaction has an easy workup without using column chromatography and provides excellent yields of the products in shorter reaction times. It does not require any catalyst and uses water as the medium which is the greenest solvent. 3 required in this work was itself obtained by condensation of N-methylaniline (1) with malonic acid (2) in the presence of POCl₃ using a previously reported procedure.     

Synthesis of 2-[3-(trifluoromethyl)phenyl]furo[3,2-<Emphasis Type="Italic">c</Emphasis>]pyridine derivatives

2-[3-(Trifluoromethyl)phenyl]-4,5-dihydrofuro[3,2-c]pyridin-4-one (I) was prepared by a three-step synthesis. Its reaction with phosphorus sulfide rendered thione II which was methylated to 2-[3-(Trifluoromethyl)phenyl]-4-methylsulfanylfuro[3,2-c]pyridine (III). 5-Methyl-2-[3-(trifluoromethyl)phenyl]-4,5-dihydrofuro[3,2-c]pyridin-4-one (IV) was obtained by the reaction of I with methyl iodide in PTC conditions. The chlorine atom in derivate V was replaced with heterocyclic secondary amines via nucleophilic substitution and 4-substituted furopyridines VIa and VIb were thus prepared. 2-[3-(Trifluoromethyl)phenyl]furo[3,2-c]pyridine-4-carboxylic acid (VII) was obtained by hydrolysis of the corresponding carbonitrile Va.     

Synthesis and reactions of 2,3-dimethylfuro[3,2-c]pyridines

Summary A number of substituted 2,3-dimethylfuro[3,2-c]pyridines was synthesized. 3-(4,5-Dimethyl-2-furyl)propenoic acid (1) was converted to the acid azide2, which in turn was cyclized to give 2,3-dimethyl-5H-furo[3,2-c]pyridine-4-one (3) by heating at 240°C in Dowtherm. The pyridone3 was chlorinated with phosphorus oxychloride to give4, which was reduced with zinc and acetic acid to 2,3-dimethylfuro[3,2-c]pyridine (5). Treatment of4 with several secondary heterocyclic amines led to compounds6a–6c. Reaction of pyridone3 with phosphorus pentasulfide rendered the thione7, which was methylated to8a. The 4-methoxy derivative8b was obtained from4 with sodium methoxide. 2,3,5-Trimethylfuro[3,2-c]pyridine-4-one (9) was obtained by reaction of3 with methyl iodide.Dedicated to Professor Dr.Fritz Sauter on the occasion of his 65th birthday     

2-Alkyliden-1, 3-dithia-Heterocyclen aus 5-Sulfonyl-1, 2-dithiol-3-onen und Alkoholaten

Asymmetrically substituted 5-sulfonyl-1, 3-dithiafulvenes (9a–g), all of which have the same configuration (called α), are obtained by reaction of 4-chloro-5-sulfonyl-1, 2-dithiol-3-ones (3a–e) with sodium alkoxides. Side-products formed are 4-chloro-5-alkoxy-1, 2-dithiol-3-ones (5a and 5b), 3, 5-bis-alkylidene-1, 2, 4-trithiacyclopentanes (21 and 22), and (in some instances) minor amounts of compounds 33, 34, or 35. Reaction of 4-phenyl-5-methylsulfonyl-1, 2-dithiol-3-one with sodium methoxide results in the formation of 4-phenyl-5-methoxy-1, 2-dithiol-3-one (5c), the two cis-trans-isomers of 2, 4-bis-alkylidene-1, 3-dithiacyclobutane 24 and 25, and the 2, 5-bis-alkylidene-1, 2, 4, 5-tetrathiacyclohexane 26. Some conceivable reaction mechanisms are discussed, and proof is given for the structure of the major compounds. By treating 4-chloro-5-(2′-chloro-ethylthio)-1, 2-dithiol-3-one with sodium methoxide, the 2-alkylidene-1, 3-dithiolane 13 is obtained. The sulfonyl groups of the 1, 3-dithiafulvenes 9a–g described may be easily replaced by hydrogen or secondary amines, yielding compounds 14, 16 and 19, respectively. When dissolved in strong acids and reprecipitated, asymmetrically substituted 2-alkylidene-1, 3-dithia compounds may be converted into mixtures of all possible cis-trans-isomers thereof. Those isomers may be separated by fractional crystallization. Isomers 31 (called β) of 9 a--g, and 32 of 16a, b, are obtained accordingly.     

Ring closure reactions of methyl N-(haloacetyl)anthranilates with ammonia

In the presence of ammonia, methyl N-(bromoacetyl)anthranilate ( 4 ) is cyclized into 3H-1,4-benzodiaze-pine-2,5(1H,4H)-dione ( 1 ). However, when 4 is replaced with methyl N-(chloroacetyl)anthranilate ( 6 ), the only heterocyclic product formed in the reaction is 2-(chloromethyl)quinazoline-4(3H)-one ( 7 ). Under analogous conditions, 3-haloacetamidocrotonates (9, 10) do not yield any heterocyclic products and no 1,4-diazepines can be obtained.