Déplacements Chimiques induits en RMN par un Réactif Lanthanidique: II—Analyse Conformationnelle de Sulfinamates Cycliques: Oxo-2 Oxathiazannes-1,2,3 et Oxo-2 Benzo-5,6 Dihydro-3,4 Oxathiazines-1,2,3

Re-examination of recent results in the literature about 2-r-substituted 5-c-tert-butyl-1,3,2-dioxaphosphorinanes and 3,3-dimethyl-1-oxothiethan made us select, under the indicated conditions, the static model because it is easier to use than the dynamic one. Its application to 17 cyclic sulphinamates belonging to two series—the 2-oxo-1,2,3-oxathiazans (I) and the 5,6-benzo-3,4-dihydro-2-oxo-1,2,3-oxathiazins (II)—confirms, in the presence of Eu(fod)₃, the structures established without the shift reagent, from chemical shifts and coupling constants only, and shows their conformational diversity. For the series (I) the following conformations are found: (i) standard chairs with an axial S?O group (CA) when the molecule is not substituted in the 4 and 6 positions or when the substituents are equatorial (with the exception of 3-tert-butyl-4-t-methyl-2-r-oxo-1,2,3-oxathiazan); the substituents R?Me, iPr or tBu on the nitrogen atom are preferentially axial; (ii) strained chairs with axial Me-4 and S?0 groups (CA); in this conformation R?Ph may be partially conjugated and R?Me or tBu may prefer the more favourable axial orientation; (iii) twist conformations with a 1,4-axis and an axial S?O group (COA) for the two 4-c,6-c- and 4-t,6-c-di-tert-butyl-2-r-oxo-3-phenyl-1,2,3-oxathiazans; (iv) the twist conformation with a 3,6-axis and an axial S?O group (CNA) for trans-3-tert-butyl-4-methyl-2-oxo-1,2,3-oxathiazan because of the 4-methyl—3-tert-butyl 1,2-interaction. For the series (II) half-chair forms with an axial S?O group are proposed.     

Reactions of phenylenedioxytrihalophosphoranes with arylacetylenes: XIII. Reaction of 5-tert-butyl-2,2,2-trihalo-1,3,2λ5-benzodioxaphospholes with acetylenes

Reactions of 5-tert-butyl-2,2,2-trichloro-, 2,2,2-tribromo-5-tert-butyl-, and 2,2-dibromo-5-tert-butyl-2-fluoro-1,3,2λ⁵-benzodioxaphospholes with aryl- and alkylacetylenes lead to quantitative formation of 2-halo-1,2λ⁵-benzoxaphosphinine 2-oxides which may be regarded as phosphorus analogs of natural heterocyclic compounds, coumarin and chromene. The major products (>70%) are 4-aryl-7-tert-butyl-2,6-dichloro-, 4-aryl-2-bromo-7-tert-butyl-, and 4-aryl-7-tert-butyl-2-fluoro-1,2λ⁵-benzoxaphosphinine 2-oxides. Hydrolysis of these compounds and their treatment with amines gives the corresponding 2-hydroxy and 2-amino derivatives, as well as ammonium salts. The structure of some compounds was proved by X-ray analysis.     

Conformational analysis of cyclic phosphates derived from 5-C′ substituted 1,2-O-isopropylidene-α-d-xylofuranose derivatives

Twelve 2-phenoxy-2-oxo-1,3,2-dioxaphosphorinanes fused with a 1,2-O-isopropylidene-α-d-xylofuranose moiety in cis orientation and substituted at the C′5 position were prepared in two steps from commercially available diacetone-α-d-glucose. Their conformations, and configurations were determined by ¹H and ³¹P NMR and X-ray crystallographic techniques. Both, chair-twisted-chair and chair-boat equilibria were observed in solution. We observed that the strong anisotropic shielding effect of the benzene ring in the phenoxy group generates an upfield shift of the H¹ hydrogen atom, when the cyclic phosphates adopt a boat conformation. This is due to a relative cis-orientation of the P-phenoxy group and the H¹ proton of the 1,2-O-isopropylidene-α-d-xylofuranose moiety. Therefore, the configuration of the phosphorus center (S_P or R_P) can be determined by ¹H NMR spectroscopy. Interestingly, the crystal structure of one of the cyclic phosphates exhibits two independent molecules in the asymmetric unit, one with a chair and the other one with a boat conformation.     

Oxydative Derivatisierung von 1,3,2-Dioxaphosphorinanen unter Verwendung von Tetrachlormethan als Oxydans

Oxidative Derivatization of 1,3,2-Dioxaphosphorinanes Using Carbon Tetrachloride as Oxidant 2-Alkoxy- and 2-dialkylamido-1,3,2-dioxaphosphorinanes react with CCl₄ in presence or absence of protic nucleophiles under ring opening forming acyclic derivatives of phosphates. 2-Anilido-1,3,2-dioxaphosphorinane, however, forms 2-amido-2-phenylimido-1,3,2-dioxaphosphorinanes ( 6 ) retaining the heterocyclic ring system. The latter are also obtained in the reaction of 2-dialkylamido-1,3,2-dioxaphosphorinanes with CCl₄ and aniline. 2-Amino-2-oxo-1,3,2-dioxaphosphorinanes ( 8 ) are prepared from 2-hydrido-2-oxo-1,3,2-dioxaphosphorinane ( 7 ) by means of the Atherton-Todd reaction. In combination with the Staudinger reaction the latter yields N(2-oxo-1,3,2-dioxaphosphorinanyl)phosphazenes ( 10 ).     

Spectroscopic study of the conformation of 1,3,2-dioxaphosphorinanes with a P=S bond

5,5- Dimethyl-2-thio-2-phenoxy- and 5,5-dimethyl-2-thio-2-ethoxy-1,3,2-dioxaphosphorinanes exist in the liquid state and in solution in a three-component equilibrium featuring two chair forms with equatorial orientation of the P=S bond differing in the orientation of the OPh or OEt groups and a chair form with an axial P=S bond. The P=S bond in 4-methyl-2-thio-2-phenoxy-1,3,2-dioxaphosphorinane occupies the equatorial position.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 479–482, February, 1990.     

Conformational analysis of 4-methyl-2-trimethylsiloxy-1,3,2-dioxaphosphinane

Conformational analysis of 4-methyl-2-trimethylsiloxy-1,3,2-dioxaphosphinane was performed by the dipole moment method and quantum-chemical calculations. The 1,3,2-dioxaphosphinane heteroring was found to adopt a chair conformation with equatorial orientation of the 4-methyl group and axial orientation of the irregular trimethylsiloxy substituent. The conformational equilibrium involves non-eclipsed gauche and trans conformers (the latter prevailing) interconvertible through rotation about the exocyclic P-O bond.     

Stereochemistry of organophosphorus cyclic compounds—II : Stereospecific synthesis of cis- and trans 2-halogeno-2-oxo-4-methyl-1,3,2-dioxaphosphorinans and their chemical transformations

cis- and trans-2-Chloro-2-oxo-4-methyl-1,3,2-dioxaphosphorinans have been obtained by stereospecific reactions of diastereomerically pure 2-methoxy-4-methyl-1,3,2-dioxaphosphorinans or 2-hydrogen-2-oxo-4-methyl-1,3,2-dioxaphosphorinans with chlorine and sulphuryl chloride, respectively. Similarly, the action of the corresponding brominating agents on isomeric phosphites and phosphonates afforded pure cis- and trans-2-bromo-2-oxo-4-methyl-1,3,2-dioxaphosphorinans. It has been shown that halogenolysis proceeds with retention of configuration at the P atom. On the basis of the ¹H- and ³¹P-NMR spectra conformation of the halogenoanhydrides obtained has been discussed briefly.It has been also found that model nucleophilic substitution reactions occur with inversion of configuration at the P atom in the cyclic halogenoanhydrides.     

2-(5-O-nitro-1,4:3,6-dianhydro-D-glucit-2-yloxy)-5-R-5-nitro-2-oxo-1,3,2-λ5-dioxaphosphorinanes: synthesis and structure

5,5-Disubstituted 1,3,2-dioxaphosphorinanes were synthesized by the reaction of (5-O-nitro-1,4:3,6-dianhydro-D-glucit-2-yl) phosphochloridate with 2-nitro-2-R-propane-1,3-diols in the presence of organic bases. The structure of 5-bromo-5-nitro-2-(5-O-nitro-1,4:3,6-dianhydro-d-glucit-2-yloxy)-2-oxo-1,3,2-λ⁵-dioxaphosphorinane was established by X-ray diffraction.     

Reactivity of 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carbonitrile

By reaction of carbonyl compounds with 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c]-[1,2,4]triazine-8-carbonitrile 3-tert-butyl-8-R-4,6,9,10-tetrahydropyrimido[4′,5′:3,4]pyrazolo[5,1-c][1,2,4]-triazine-4,10-diones and (3-tert-butyl-4-oxo-8-cyano-4,6-dihydropyrazolo[5,1-c][1,2,4]triazin-7-yl)acetamide were obtained.     

Synthesis and reactivity of ethyl 7-amino-3-tert-butyl-4-thioxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carboxylate

Treatment of ethyl 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carboxylate with P₂S₅ in pyridine gave ethyl 7-amino-3-tert-butyl-4-thioxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carboxylate which was subjected to acylation, decarboxylation, and hydrazinolysis.     

Chlorinations of derivatives of 2,2,2-trichlorobenzo-1,3,2-dioxaphospholes

By ³¹P, ¹³C, ¹³C-{¹H}, and ¹H NMR spectroscopy the chlorination of 4-and 5-methyl-2,2,2-trichlorobenzo-1,3,2-dioxaphosphols was shown to provide in quantitative yield 4-methyl-2,2,2,5-tetrachloroand 6-methyl-2,2,2,5-tetrachlorobenzo-1,3,2-dioxaphosphols. Their hydrolysis led to the formation of difficultly available 4-methyl-5-chloro-and 3-methyl-4-chloro-1,2-dihydroxybenzenes. The structure of the latter compound was established by XRD analysis. The 5-methyl-2-chlorobenzo-1,3,2-dioxaphosphol treated with excess chlorine was converted in succession into 5-methyl-2,3,4,5,6,6-hexachlorocyclohex-1-en-3-yl dichlorophosphate and 5-methyl-1,2,4,4,5,6-hexachlorocyclohex-1-en-3-yl dichlorophosphate. The hydrolysis resulted in 5-methyl-2,3,4,5,6,6-hexachlorocyclohex-2-en-1-yl dihydrophosphate. The configuration of three chiral carbon atoms in the latter was established by XRD study. In the course of the chlorination the aromaticity of the ortho-phenylene fragment was distorted and 3,3-sigmatropic shift of the dichlorophosphoryl group occurred. The reaction with chlorine of 5-tert-butyl-2,2,2-trichlorobenzo-1,3,2-dioxaphosphol and 2,2,2-trichloro-benzo-1,3,2-dioxaphosphol was not selective: The reaction product obtained in excess chlorine transformed on hydrolysis into tetrachloropyrocatechol. Its solvates with water and dioxane were studies by XRD analysis.     

Synthetic and structural study of 4-phosphacyclohexanones and 3-aza-7-phosphabicyclo[3.3.1]nonan-9-ones

The synthesis of bicyclic phosphorus–nitrogen (PN) compounds containing the rigid bicyclo[3.3.1]nonan-9-one framework was attempted using the Mannich condensation reaction of four different phosphorinanone classes with amines and aldehydes. Three different isomers of 4-tert-butyl-2,6-di(methoxycarbonyl)-3,5-bis(p-dimethylaminophenyl)-4-phosphacyclohexanone were obtained from the Michael addition reaction of tert-butylphosphine with 2,4-di(methoxycarbonyl)-1,5-bis(p-dimethylaminophenyl)penta-1,4-dien-3-one. The reaction of the all-equatorial isomer with methylamine and formaldehyde produced the bicyclic PN compound 7-tert-butyl-1,5-di(methoxycarbonyl)-6,8-bis(p-dimethylaminophenyl)-3-methyl-3-aza-7-phosphabicyclo[3.3.1]nonan-9-one. The identical Mannich reaction of the enol tautomer also yielded the same product, as well as the PN compound 4-tert-butyl-6-methoxycarbonyl-5-(p-dimethylaminophenyl)-2-methyl-2-aza-4-phosphacyclohexanone and the E/Z isomers of 3-(p-dimethylaminophenyl)methyl-2-propenoate. The newly synthesised 3-aza-7-phosphabicyclo[3.3.1]nonan-9-one PN compound adopts a chair–chair conformation both in solution and the solid state.     

Chemistry of iminofurans: XIII. Recyclization of 4-arylamino-2-<Emphasis Type="Italic">tert</Emphasis>-butyl-5-oxo-2,5-dihydrofuran-2-yl acetates with ethyl cyanoacetate

Recyclization of 4-arylamino-2-tert-butyl-5-oxo-2,5-dihydrofuran-2-yl acetates with ethyl cyanoacetate in the presence of triethylamine afforded the corresponding ethyl 2-amino-1-aryl-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-1H-4,5-dihydropyrrole-3-carboxylates.     

Stereochemistry of organophosphorus cyclic compounds—III : The stereospecific synthesis of cis- and trans-2-N-phenylamino-2-oxo-4-methyl-1,3,2-dioxaphosphorinans

On the basis of chemical transformations and spectroscopic data the cis- and trans-geometry was assigned to the previously reported diastereoisomeric 2-N-phenylamino-2-oxo-4-methyl-1,3,2-dioxaphosphorinans (1). The addition of phenyl azide to cyclic phosphite (3) as well as the reaction of the resulting adduct (4) with carbon disulphide or benzoic acid takes place with overall retention of configuration at the P-atom. The conformation of the 1,3,2-dioxaphosphorinanyl ring system in both cis- and trans-1 is suggested.     

Reactions of [(3,5-Di-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-oxocyclohexa-2,5-dien- 1-ylidene)methyl]phosphonates with Phenols

Dialkyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonates reacted with phenol and benzenediols in the presence of trifluoromethanesulfonic acid to give products of electrophilic substitution in the benzene ring, the corresponding diarylmethylphosphonates or [phenylenebis(arylmethylene)]- diphosphonates. The reaction of diphenyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonate with 2-methylbenzene-1,3-diol at a ratio of 1: 1 afforded 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-6-hydroxy-7-methyl-2-phenoxy-2,3-dihydro-1,2λ⁵-benzoxaphosphol-6-one.     

Synthesis oftert-butyl substituted polymethine 1-benzothiopyrylium dyestuffs

A series of polymethine thiopyrylium dyestuffs of symmetrical and unsymmetrical structure, containing one to fourtert-butyl groups, has been synthesized from 6-tert-butyl-2-(p-tert-butylphenyl)-4-methyl-, 4,6-di(tert-butyl)-2-methyl-, and 6-tert-butyl-2,4-dimethyl-1-benzothiopyrylium perchlorates.     

Three-dimensional structures of phosphorus-containing heterocycles 50. 2-dimethylamino-2-oxo- and -2-thiono-1,3,2-oxathiaphosphorinanes

Conclusions A chair conformation with an axial orientation of the phosphoryl or thiophosphoryl group is preferable for 2-dimethylamino-2-oxo- and-2-thiono-1,3,2-oxathiaphosphorinanes. The cis isomer of 2-dimethylamino-2-oxo-4-methyl-1,3,2-oxathiaphosphorinane has a similar structure with an equatorial orientation of the 4-methyl group, while the corresponding sulfide is characterized by a trans configuration with a reoriented positioning of the substituents attached to the phosphorus atom.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1369–1374, June, 1989.The authors thank I. A. Litvinov and V. A. Naumov for carrying out the x-ray diffraction analysis.     

Thermochemistry of Heteroatomic Compounds XXI: Heat Capacities of Some Derivatives of Methylphosphonic and Dithiophosphorus Acids

The heat capacities of 2,4-dimethyl-2-oxo-(I)-, 2,5,5-trimethyl-2-oxo(II)-1,3,2-dioxaphosphorinanes, methylphosphonic acid (III), O,O-dimethyl(IV)-, O,O-diethyl(V)-, O,O-di-isopropyl(VI)esters of dithiophosphorus acid, 4,5-dimethyl-2-thiono-2-mercapto-1,3,2-dioxaphospholane(VII), and 4-methyl-2-thiono-2-mercapto-1,3,2-dioxaphosphorinane(VIII) were determined using the scanning calorimetry.     

Analyse Conformationnelle par RMN du Proton des Oxo-2 Oxathiazannes-1,2,3 (Sulfinamates Cycliques) Diversement Substitués en 3, 4 et 6

In this study, carried out with 16 compounds, the chair form with an axial S?O group (CA) is found, in the absence of C-4, C-5 and C-6 substituents, to be the most stable (ΔG>8,4 kJ mole^?1), as previously reported for analogous cyclic sulfites. When methyl or tert-butyl substituents are present on the 4 and 6 carbon atoms, the conformation of the ring depends on their respective orientation towards the S?O group, and on the nature of the substituent of the nitrogen atom. For the trans isomers, the conformation remains anancomeric chair (CA) except when important gauche interactions exist: thus the strong Me/tBu gauche interaction in the 3-tert-butyl-4-t-methyl-2-r-oxo-1,2,3-oxathiazan induces a twist form with a 3,6-axis and an axial S?O group (CNA). When the 4- or 6-substituent is cis, the conformation of the sulfinamate may be either a chair form with an axial S?O group (CA), if the 4-substituent is a methyl, (even with a tert-butyl group in the 3-position which would be in the axial orientation) or a twist form with a 1,4-axis and an axial S?O group (COA) if the 4-substituent is a tert-butyl. Unlike cyclic sulfites, the equatorial SO chair form (CE) and the twist forms with a 2,3-axis and an isoclinal S?O group (CS, CS′) are rarely involved.     

Reaction of 2,2,3,3-tetracyanocyclopropyl ketones with sodium and potassium hydroxides

Reaction of 2,2,3,3-tetracyanocyclopropyl ketones with water solution of sodium hydroxide after neutralization with sulfuric acid leads to the formation of 4-amino-1-hydroxy-3,6-dioxo-2,3,5,6-tetrahydro-1Hpyrrolo[3,4-c]pyridine-7-carbonitriles. Pivaloyltetracyanocyclopropane reacts in another way and is converted into sodium 6a-tert-butyl-3,4-dicyano-5-oxo-1,5,6,6a-tetrahydropyrrolo[2,3-b]pyrrol-2-olate. 1-Benzoyl-1-methylcyclopropane-2,2,3,3-tetracarbonitrile reacts with the sodium hydroxide with the retention of the threemembered ring and the formation of 11-methyl-4-phenyl-3,5,9-triazatetracyclo[5.3.1.01,7.0^4,11]undecane-2,6,8,10-tetraone.